A STUDENT'S TEXT-BOOK OF ZOOLOGY
CORRIGENDA
Page s). Line 7. For " chordate " read " non-chordate."
„ 16. Line 6. Omit " mesodermal."
„ 17. In the description of flg. 6, for " spina " read " spinal."
„ 117. Line 5. For " branchia " read " branchial."
„ 125. Line 8. For " Myliobates " read " Myliobatis."
„ 146. Line 8. For " somactido " read " somactids."
„ 152. Line 13. The genus Odontaspis is not extinct, see line 1 of "the same page.
„ 210. Line 15 from bottom. For " Oastrosteus " read " Gasterosteus."
„ 219. Line 4. For " vulggaris " read " vulgaris."
„ 219. Line 20. For " E. Ind. Oreinus ; McClell " read " E. Ind. ; Oreinus McClell,
„ 220. Line 12. For " RHODENIA " read " RHODEINA."
„ 229. Line 26. For " trumpetor " read " trumpet or."
„ 230. Line 13. Insert a comma after " JRaf."
„ 231. Line 6 from bottom. Omit " Seriolella."
„ 235. Line 18. For " specie " read " species."
„ 242. Line 27. Insert comma after Elanura, and another after Melletes.
„ 242. Line 11-12 from bottom. The 5th letter of the word Stellerina'js indistinct.
„ 244. Line 23. For " Thallasso- " read " Thalasso-".
„ 255. Line 14 from bottom. For " succus " read " saccus."
„ 273. In the second footnote for " Paratoids " read " Parotoids."
„ 276. Line 13 from bottom. Insert after the words " in other Amphibia." " In Rancr
the ductus endolymphaticus which passes off from the saccule enters the cranial
cavity through the foramen endolymphaticum and there dilates into the saccus
endolymphaticus. This extends back into the neural canal of the vertebral
column, where it lies in close apposition to its fellow along the dorsal side of
the spinal cord and gives off transverse diverticula which end in small dilata-
tions over the posterior root ganglia. The fluid contained in the saccus and
its extensions is milk-white, the milkiness being due to the presence of crystals
of carbonate of lime (otoliths). The CALCAREOUS GIAXDS are the terminal
dilatations of the transverse diverticula above referred to (see Gaup, o<p. cit.,
p. 261). The function of this peculiar extension of the membranous labyrinth
is unknown (for a somewhat similar condition in the Ascalabota, see p. 323),
„ 287. Line 12. The word " is " has dropped out.
„ 315. Line 10 from bottom. For "• Trimatosaurus " read " Trematosaurus."
„ 334. Line 21. For " phenodon " read " Sphenodon."
„ 393. Line 6. For " Ion ifrons " read " longifrons."
„ 400. In description of Fig. 221. For " (Pareiasaurus) " read ".(Pariasaurus)."
„ 412. Line 3 from bottom. For " Sectional " read " Section 1."
„ 459. The footnote is referred to on line 1 of p. 460.
,, 465. Line 25. For " M. gallopavo " read " Meleayris gallopavo."
„ 473. Line 8 from bottom. Delete " Picoides."
„ 475. Line 21. For " M. superba " read " Menura superba." '
„ 582. Line 21. After " birth ; " insert " Dicotyles Cuv,"
„ „ Line 7 from bottom. For " H ." read " Hippopotamus,"
„ 653. For " Order 21," read " Order 22 "
,, 655. Line 16, for " pectora " read " pectoral."
A STUDENT'S TEXT-BOOK
ZOOLOGY
BY
ADAM SEDGWICK M.A. F.R.S.
FELLOW AND TUTOR OP TRINITY COLLEGE, CAMBRIDGE
AND HEADER OF ANIMAL MORPHOLOGY IN THE UNIVERSITY
LONDON
SWAN SONNENSCHEIN AND CO. LTT>
NEW YORK: THE MACMILLAN CO.
1905
^ L-
PREFACE
IN presenting the second part of my work on Zoology to the
public I must apologise for the delay in its appearance and
for the fact that I am not keeping to the undertaking which
I gave in the preface to my first volume that the work would
be completed in two volumes The delay in publication
has been caused in part at least by the fact that the Verte-
brata compel a lengthier and more detailed treatment than
the other groups. Not only is more known about them,
but they excite greater interest, and their palaeontological
history has been more completely worked out than in the
case of any other phylum. The result has been the present
bulky volume which deals only with them and with Amphi-
oxus.
Embryology is of course excluded, except in the case of
Amphioxus, but I have endeavoured to deal fairly fully
with anatomy, habits, and classification. In the systematic
portions I have probably been too ambitious, but the
usefulness of a book of this kind depends largely upon ita
completeness in this respect, and in cases of doubt I have
generally included rather than excluded. In Aves alone
have I made a selection ; for there are many excellent
works devoted to them and it would be impossible to give
anything like a complete list of their genera.
In judging the anatomical portions I would ask the reader
to remember that this is not exclusively a work on Compara-
tive Anatomy, and limitations of space forbid an exhaustive
treatment. This branch of the subject has not, however,
been neglected, and questions of general interest have usually
been at least touched upon.
Considerable space has been given to extinct forms.
VI PREFACE
As in the first volume I have endeavoured in the index to
refer the reader to the page on which technical terms are
defined and most of the abbreviations are explained in the
same place.
To Mr. J. J. Lister, F.R.S., I am again under very great
obligations. He has looked through all the proof sheets
and has given me the full benefit of his wide knowledge and
great critical powers. I am also indebted to his pencil for
the excellent illustrations on p. 341 and p. 532.
My thanks are also due to Professor Newton, Professor
Kay Lankester, Mr. Boulenger, Professor MacBride, Pro-
fessor Graham Kerr, Dr. Chalmers Mitchell, Dr. Andrews,
Mr. Walter Heape, Mr. Assheton, Dr. Gaskell, Dr. Marett
Tims and others for the assistance they have given me in
different parts of the work.
My principal sources of information are acknowledged in
the footnotes, but I must not omit to mention here works
from which I have obtained special help ; these are Gadow's
Amphibia and Reptiles and Evans' Aves in the Cambridge,
Natural History, Flower and Lydekker's work on Mammalia
Living and Extinct, Smith Woodward's Outlines of Vertebrate
Palaeontology and Zittel's Grundriss der Palaeontologie, and
Gunther's Introduction to the Study of Fishes. The excel-
lent volume on fishes in the Cambridge Natural History and
Weber's great work on the Saugethiere appeared too late to
be utilised.
Of the illustrations about fifty are new ; of the remainder
a considerable number are from Claus' Lehrbuch, but some,
of which I have been permitted to make use by the
courtesy of the author and publisher, are from Smith
Woodward's Vertebrate Palaeontology, Reynold's Vertebrate
Skeleton, Flower and Lydekker's Mammalia Living and
Extinct, Flower's Osteology of Mammalia, Huxley's Anatomy
of Vertebrate Animals, Shipley and MacBride's Zoology,
Zittel's Grundzuge der Palaeontologie, Korschelt and Heider's
Text Book of Embryology, Gegenbaur's V ergleichende
Anatomie der Wirbelthiere Wiedersheim's Grundriss der
Anatomie der Wirbelth^ r , Terrier's Traite de Zoologie,
PREFACE VII
Balfour's Comparative Embryology, Gadow's Amphibia and
Reptiles.
The third volume, which is in the press, will deal with
the Tunicata, Enteropneusta, Echinodermata and Arthro-
poda.
It has been pointed out to me by friends who have read
the proofs that I have made statements which without a
fuller treatment may give rise to the view that I am unortho-
dox on the great question of organic evolution. This is not
the place to give that fuller treatment, but in order to pre-
vent misunderstandings'! may say that any such view would
be erroneous. I am and always have been a convinced
evolutionist. I hold, that is to say, that matter is constantly
undergoing change, and that natural selection, taking advan-
age of its endless diversity in form and properties, has played
and is playing an important part in determining what form
of it (whether living or non-living) shall exist and what shall
cease to exist. I hold further that the forms of living matter,
as well as those of non-living matter, owe their existence and
their properties to the operation of natural laws, though
here we are treading on more uncertain ground, for we
know nothing of the origin of living matter or of the sources
of its properties. The chemist has made many forms of
matter which have, at present at least, no existence in
nature apart from organisms, but he has not yet succeeded
in making living matter. Whether he will ever be able to
do so is a question which may fairly be asked, but is one
which cannot now be answered. The view that living
matter arose in response to the operations of natural laws
cannot be either proved or disproved. It must remain a
matter of belief for which there is much to be said. As to
the origin of the manifold properties of living matter we
know nothing. The Darwinian theory did not account for
properties ; it left their origin to an imperfectly understood
interaction between the organism and the environment,
and further than this we cannot at present go. It may,
however, be pointed out that there are two ways in which
Vlll PREFACE
this great question may be attacked. One of these is by
the method of experiment — a method which is being
pursued with increasing vigour by more than one school
of Biologists ; the other is the careful and thorough exam-
ination of living and extinct organisms, particularly in their
relations to one another. It is the second of these methods
which comes under our notice in the three volumes of the
first part of this work dealing with systematic zoology. It
is unquestionable that this study does shed light, if only a
dim light, on the course of organic evolution and indirectly
on the origin of the properties of living matter, and it is
most important that the light so obtained should be brought
to bear upon the problem. To discover this we must
approach the subject with unbiassed minds, for it is one
of immense complexity and it is extremely unlikely that
any particular solution which commends itself to us
will turn out to be final. I would therefore ask for
lenient judgment if in some pages of this work I have
seemed to take up an unduly critical position with regard
to views widely prevalent at the present time on some
aspects of organic evolution. That does not mean that I
am unsound on the great question itself, but only that
I am sceptical as to the value of some hypotheses widely
held as to the course of organic evolution. It is true that
working hypotheses are necessary in constructive work, but
in a subject of the complexity of the present one, they can only
be provisional and as such are legitimately open to criticism.
It may be urged that I have said too much or too little, that
I ought not to have touched upon the matter unless I was
prepared to state fully my own views. While allowing
that there would be some justice in such a criticism, I do
not admit its complete validity. In deference to it, how-
ever, I have materially altered in proof what I had written
in manuscript, but it was not possible to remove all refer-
ence to the subject. It was necessary to note the facts in
passing. In the final volume on the Principles of Zoology
which I yet hope to write, I shall return to it and endeavour
to justify, in the fuller treatment which will there be pos-
PREFACE IX
sible, the criticisms which are only hinted at here. At the
same time I cannot hope to build. That is the task of the
great band of workers in many departments of Biology, who,
undeterred by failure and urged on by the fire, enthusiasm,
and generous aspirations of youth, return time after time,
generation after generation, to the assault of the fortresses
of nature well knowing that their material reward will be
small, that defeat means the world's neglect and that success,
except the greatest, brings but a pittance of its esteem. To
them I inscribe this book in the hope that it may serve if
only to a small extent to smooth over the difficulties of part
of the road which at first they have to traverse.
A. SEDGWICK.
TRINITY COLLEGE, CAMBRIDGE,
February, 1905.
TABLE OF CONTENTS
An asterisk signifies that the group is extinct.
PAGE
THE CHORDATA . . . . 1
PHYLUM CEPHALOCHORDA . 10
PHYLUM VERTEBRA! A . . 45
Class I. PISCES .... 51
Sub-class 1. MARSIPOBRANCHII 95
., 2. ELASMOBKANCHII 118
. Order I. Pleuropterygii* . 145
„ 2. Aeanthodii* . . 146
„ 3. lehthyotomi* . . 147
„ 4. Selaehii (Plagio-
stomi) . . .148
Sub-order 1. Notidani . . 149
2. Squali . . 150
3. Raji . . .153
Order 5. Holoeephali . . 155
Sub-class 3. GANOIDEI . .159
Order 1. Chondrostei . .167
Order 2. Crossopterygii . .171
Sub-order 1. Osteolepida* . 175
2. Cladistia . .176
Order 3. Lepidostei . . .176
4. Amioidei . 180
Sub-class 4. TELEOSTEI
183
Sub-order 1. Malacopterygii
( Salmonidupei-
formes) . .213
„ 2. Ostariophysi
(Cyprinisiluri-
formes] . .216
Sub-class TEIEOSTEI — contd. PAGE
Sub-order 3. Symbranchii
(Symbranchi-
formes) . . 222
,, 4. Apodes (An-
guilllformes} 223
„ 5. Haplomi
(Esociformes) 225
„ 6. Heteromi(Der-
cetifwmes) . 227
„ 7. Cateostomi
(Gastrostei-
formes] . . 228
Tribe A. Selenichthyes . . 228
„ B. Hemibranchii . . 228
„ C. Lophobranchii . . 229
„ D. Hypostomides . . 230
Sub-order 8. Percesoces
(Mugiliformes] 230
„ 9. Anacantliini
(Gadiformes) 232
„ 10. Acanthoptery-
gii . . .233
Tribe A. Perciformes . . 233
B. Scombriformes . . 238
C. Zeorhombi . . 239
D. Kurtiformes . . 240
E. Gobiiformes . .241
F. Discocephali . . 241
G. Scleroparei . . 241
H. Jugulares . . 243
„ I. Taeniosomi . . 244
Sub-order 11. Opisthomi . 245
12. Pediculati
(Lopkii formes) 245
13. Plcctognathi
(Bqlistiformcs) 246
Tribe A. Sclerodermi . . 246
„ [B. Gymnodontes . . 247
Xll
TABLE OF CONTENTS
PAGE
Sub-class 5. DIPNOI . . .248
A. Ctenodipterini* . 259
B. Sirenoidei . . 259
ARTHRODIRA* . 260
A. Heterostraci* . . 261
B. Osteostraci* . : 261
C. Antiarcha* . . 261
Icthyodorulites*. 262
Conodonts* . . 262
Class II. AMPHIBIA . . .263
Order 1. Gymnophiona
(Apoda) 300
„ 2. Urodela (Caudata) . 304
„ 3. Anura (Batraehia) . 307
Sub- order 1. Aglossa . . 309
„ 2. Phaneroglossa 310
Order 4. Stegocephali* . .313
Sub- order 1. Branchiosauri* 315
„ 2. Aistopoda* .315
,, 3. Labyriniho-
dontia* 315
Microsauria* 315
Class III. REPTILIA ... 316
Sub-class 1. RHYNCOCEPHALIA 329
„ 2. LEPIDOSAURIA . 334
Order 1. Dolichosauria* . 334
„ 2. Mosasauria* . . 334
„ 3. Lacertilia . . .335
Sub- order 1. Lacerlilia vera 348
„ 2. Rhiptoglossa . 354
Order 4. Ophidia . . . 355
372
381
Sub-class 3. CROCODILIA . .
Order 1. Parasuchia* . .
„ 2. Pseudosuchia* . . 382
„ 3. Eusuchia . . .382
Sub-class 4. DINOSAURIA* . 383
Order 1. Theropoda* . . 384
„ 2. Sauropoda* . . 385
3. Predentata* . - . 386
Sub-class DINOSAURIA* — contd. PAGE
Tribe 1. Ornithopoda* . . 386
„ 2. Stegosauria* . . 387
3. Ceratopsia* . . 387
Sub-class 5. PTEROSAURIA* . 388
„ 6. ICHTHYOSAURIA* 391
7. PLESIOSAURIA* . 395
8. ANOMODONTIA* 398
Order 1. Pareiasauria* . . 399
„ 2. Theriodontia* . . 400
3. Dicynodontia* . .401
Sub-class 9. CHELONIA .
. 402
Sub-order 1. Athecae .
. 412
„ 2. Thecophora
. 412
A. Cryptodira .
. 412
B. Pleurodira .
. 414
C. Trionychoidea
. 415
Class IV AVES . . .
416-
Order 1. Archaeornithes*
. 454
„ 2. Neornithes . .
. 456
Sub-order 1. Ratitae. .
. 456
2. Odontolcae*
. 458
„ 3. Carinatae
. 460
Tribe 1. Ichthyornithes*
. 466
„ 2. Colymbiformes
. 466
3. Sphenisciformes
. 466
„ 4. Procellariiformes
. 461
„ 5. Ciconiiformes .
. 461
„ 6. Anseriformes .
. 462
„ 7. Falconiformes .
. 463
,, 8. Tinamiformes .
. 464
„ 9. Galliformes
. 464
„ 10. Gruiformes
. 466
„ 11. Charadriiformes
. 466
,, 12. Cuculiformes
. 469
„ 13. Coraciiformes .
. 471
„ 14. Passeriformes. .
. 474
Class V. MAMMALIA. . . 479
Order 1. Monotremata . . 524
„ 2. Marsupialia . . 529
Sub-order 1. Diprotodontia 534
„ 2. Polyprotodontia538
3. Allotheria* . 541
TABLE OF CONTEXTS
•Kill
PAGE
PAGE
Order 3.
Edentata . . .
542
Order 12.
Tillodontia* .
. 607
Xenarthra .
543
„ 13.
Ancylopoda* .
. 609
Nomarthra
548
„ 14.
Condylarthra* .
. 609
,. 4.
Sirenia . . . .
549
„ 15.
Creodonta*
. 611
„ 5.
Cetacea . . .
553
„ 16.
Carnivora . .
. 612
Sub-order 1. Mystacoccti .
560
Aeluroidea
. 618
„
2. Odontoceti
561
Cynoidea .
. 621
»
3. Zeuglodonta* .
564
Arctoidea .
. 622
Order 6.
Hyracoidea . .
565
„ 17.
Pinnipedia .
. 624
„ 7.
Proboseidea . .
567
„ 18.
Rodentia .
. 627
„ 8.
Ungulata . . .
573
Simplicidentata
. 632
Sub-order 1. Artiodactyla .
576
Duplicidentata
. 636
„
2. Perissodactyla
592
„ 19.
Insectivora . .
. 636
»
3. Lipoterna*
602
„ 20.
Chiroptera . .
. 641
Order 9.
Amblypoda* . .
603
„ 21.
Prosimiae . .
. 649
„ 10.
Toxodontia* . .
605
00
,, _-.
Primates . .
. 653
„ 11.
Typotheria* . .
606
TABLE OF GEOLOGICAL PERIODS
AND FORMATIONS
TERTIARY OR CAINOZOIC PERIOD.
Pleistocene
Pliocene . .
Miocene . .
Oligocene . .
Eocene
Recent Deposits.
1 Valley and Cave Deposits
I Glacial Deposits.
r Cromer Beds.
j Norwich Crag.
-[ Red Crag.
I Coralline Crag.
I In India, the Siwalik Formation.
Not known in Britain but wide-spread on the Continent
of Europe.
It Loup Fork.
Lacustrine deposits of North America] Deep River.
I John Day.
The Santa Cruz Beds of Patagonia are referred to the
Miocene.
I Hamstead and' Bembridge Beds.
-J Headon and Osborne Beds.
I In N. America the freshwater White River Beds belong
^ to the Oligocene.
Upper : Barton Beds ; In N. America, Uinta Group.
Middle: Bracklesham Beds. InN. America, BridgerGroup.
Lower : Bagshot Sands, London Clay, Woolwich and
Reading Beds.
('1. Wind River Group.
2. Wasatch Group.
a "j 3. Torrejon Group.
[4. Puerco Group.
xiv
TABLE OF GEOLOGICAL PERIODS AND FORMATIONS
XV
Cretaceous
Jurassic
Triassic
MMdle
SECONDARY OR MESOZOIC PERIOD.
Chalk (with flints),
le Chalk (with few flints),
•j Lower Chalk.
Upper Greensand.
VGault.
( Lower Greensand.
Upper
Lower
\Wealden.
( /Purbeck and Portland Beds.
Upper -I Kimmeridge Clay (Solenhofen Slates in Bavaria. )
vCorallian and Oxford Clay.
,,.-,, (Great Oolite.
le (Inferior OoliteJ(Stonesfield Slate belongs here).
( Upper Lias.
Lower j Middle Lias.
^ Lower Lias.
I
\Keuper Marls and Sandstone.
Middle: Muschelkalk, absent in Britain.
Lower : Bunter Sandstone, Pebble Beds,
Africa.
Karoo of S
Permian .
Carboniferous .
Devonian
Silurian
PRIMARY OR PALAEOZOIC PERIOD.
/ Upper : Magnesian Limestone.
^ Lower : Red Sandstones.
( TT ( Coal Measures.
Upper |M}llstone Grit>
( Lower : Carboniferous Limestone and Shales.
( Upper Old Red Sandstone.
' -c Limestones (marine).
Lower Old Red Sandstone.
f Ludlow.
J Wenlock.
I May Hill Sandstone (Llandovery).
( Bala.
Upper Cambrian* J Llandilo,
Lower Cambrian .
Tremadoc Series.
Lingula Flags.
Menevian Series.
Harlech Series.
Olenellus Beds.
Precambrian
L. Silurian of Murchison, Ordovician of Lapworth.
CHAPTER I.
CHORDATA.
Animals with a notochord, a hollow dorsally placed nervous
system, and a pharynx opening to the exterior by lateral passages.
The group Chordata is a division of the animal kingdom
superior to a phylum. It includes four phyla and is to be
compared in its rank to such groups as the Metazoa and Coelo-
mata, both of which are phylum -including divisions. The four
phyla into which the group Chordata is divided are, stating them
in the order in which they are dealt with in this work, the
Cephalochorda, which includes but a single genus, Amphioxu3 ; the
Vertebrata, which is by far the largest and most important
division of the group ; the Tunicata, which includes a con-
siderable number of marine forms of low organization ; and
lastly the Enteropneusta, which has but a small number of
genera mainly of vermiform appearance and is the most out-
lying phylum of the group. Indeed, by some highly competent
authorities the Enteropneusta are placed altogether outside the
Chordata, largely on account of their early development, which
differs in important particulars from that of other Chordata
and approaches that of Echinodermata ; and because it is not
certain that they possess that typically chordate organ, the
notochord. While not presuming to pronounce an opinion
on the latter point beyond saying that if the notochord is present
in Enteropneusta, its development, structure and relations to
other organs differ considerably from those of the notochord in
the other phyla, we desire to emphasise quite distinctly our
opinion that the Enteropneusta are Chordates. They present
most clearly the other characteristic features of that group, viz.,
the hollow central nervous system and the perforated pharyngeal
wall — features of organization found in no other group of the
CHORD ATA.
animal kingdom ; and in the arrangement of their coelom they
come close to the Cephalochorda and Vertebrata.
The notochord itself is a rod-like structure in all cases
developed from the dorsomedian endoderm of the embryonic
enteron.^ This streak of tissue undergoes a modification of
structure almost identical with that presented by the axial endo-
derm of the tentacles of many Coelenterata. The modification,
which may be described as being of a skeletal nature, consists
in both cases of a a vacuolisation of the protoplasm of the
endodermal tissue (Fig. 1) and of a
considerable development within this
tissue of cuticular structures (vide
Vol. i, p. 101). Indeed the function
of the notochord, like that of the ten-
tacular endoderm referred to, is a sup-
porting one : it supports the axis of
the body and particularly the central
nervous system beneath which it lies.
In the Cephalochorda this function is
discharged by the notochord during
the whole of life ; in the Vertebrata
and Tunicata however it is purely
embryonic or larval in its duration.
In the Vertebrata the notochord,
though it may in some forms, e.g.
Pisces, persist throughout the whole of
life, becomes surrounded by a stiff
sheath, which takes over its function of
axial support and becomes, especially in those forms in which
the endoskeleton acquires rigid texture, divided up into segments
corresponding with those of the embryonic muscular system.
The central nervous system develops from the ectoderm of
what is usually called the dorsal surface, and at first nearly
always has the form of a groove, which, excepting in the Enter o-
pneusta, extends along the whole of the dorsal surface and closes
completely to form a canal — the central canal of the nervous
system. It is characteristic of Cephalochorda, Vertebrata and
Tunicata that this canal opens in the embryo for a shorter or
longer pericd unto the enteron (neurenteric canal). This
neurenteric communication is however never maintained in
FlG.r>' 1. — Transverse section
through notochord and spinal
cord of the larva of Bombina-
tor igneus (after Gotte, jrom
Claus). ChS notochordal
sheath ; Ch notochord ; Sk
skeletogenous layer ; N spinal
cord.
MOUTH AND ANUS. 3
the adult, and its transitory existence is a highly remarkable
fact for which no satisfactory explanation has ever been offered.
In the Enteropneusta alone is the central nervous system
confined to a short portion only of the dorsal surface (so-called
collar region), and in them alone does the central canal remain
permanently open and never acquire a communication with
the enteron.
We have said that the central nervous system arises on the
dorsal surface. Now it is quite clear that this surface corresponds
to the ventral surface of other Coelomata, so that it would
be convenient to exchange the term dorsal for a term which would
include the same surface in all Coelomata. Such a term is
afforded by the term neural surface, which implies, and cor-
rectly implies, that the central nervous system is developed
upon it. Another term, blastoporal, having reference to the
position of the embryonic blastopore might also be used. In
all the Coelomata the blastopore is not only placed on the neural
surface of the body, but actually perforates the embryonic
rudiment of the central nervous system. This is seen most
clearly in the embryonic history of the Cephalochorda, the Verte-
brata, the Annelida, Arthropoda and Mollusca. In the Entero-
pneusta and Echinodermata this relation is masked, and by
many morphologists would be held not to occur at all. But that
it does exist we are convinced, and is a most important morpho-
logical fact appertaining to all Coelomata. Now in some Coelo-
mata it has been definitely proved that the mouth and anus
of the adult animal are directly derived from the embryonic
blastopore, and it becomes a question whether this derivation,
though not embryonically manifested in all forms, does not
also hold throughout the Coelomata. Believing as we do
in the homology of the mouth and anus, at least in the
phyla Annelida, Arthropoda and Mollusca, it follows that
this relation holds for them. In Peripatus the mouth
and anus are not only derived from the elongated blasto-
pore by its constriction into two openings, but remain
throughout life included within the nerve ring derived
from the neural rudiments of the embryo.* If in other
* Sedgwick, " Monograph of the Development of Peripatus capensis"
Studies from the Morphological Laboratory of the University of Cambridge,
4, 1889, p. 1.
4 CHORDATA.
Arthropoda, in Annelida and in Mollusca we find, as we do, that
the nerve ring referred to is, in the adult, incomplete behind the
anus, and that the mouth and anus, though obviously referable
to the blastopore, are not actually both derived from it, must we
on this account deny this most obvious relation and maintain
that the mouth or anus, as the case may be, in these forms is
not homologous with that of Peripatus ?
To maintain such a position appears to us impossible, and we
entirely accept the doctrine that the mouth and anus of
the Annelida, Arthropoda and Mollusca are both perfor-
ations of the embryonic neural surface and are specialisations
of parts of one original opening which is represented in most
embryos by the blastopore. When however we come to apply
this doctrine to the Chordata we stand upon more debatable
ground. Placing the Enteropneusta on one side as not ob-
viously conforming to our plan, we find that it is a fact of
observation that in the Chordata the blastopore perforates the
embryonic nerve rudiment, and that in some of them the anus
is directly derived from it (many Pisces, some Amphibia,
e.g. newt), whereas in others, not at all remote from these,
the blastopore closes entirely and the anus is a new formation
(some Pisces and Amphibia, e.g. frog, Amniota). Here also
we think it may fairly be maintained that notwithstanding
the diversity in the mode of development of the anus it is, in all
Vertebrata at least, a derivate of the blastopore. The non-
inclusion of the anus within the nerve rudiment in the adult,
and its shift on to the ventral surface, cannot be brought against
this view, because these facts apply both to animals in which
the anus is a persistent part of the blastopore, as weh1 as to
those in which it is a new formation. Here again, as in the
invertebrate phyla already dealt with in this connection, the
anus escapes in the adult from the embryonic nerve rudiment ;
or to put it in another way the part of the nerve rudiment behind
the anus never attains full development, but early undergoes
atrophy.* So far then all is plain sailing, in the Vertebrata at
least : the anus is a persistent portion — not the whole, as is clear
from a consideration of the development of Elasmobranchs and
some Amphibia — of the blastopore, as it is in the invertebrate
* See especially Lepidosiren, in which the medullary folds of the embryo
include the blastopore which becomes the anus.
MOUTH.
5
Coelomata ; and as in most of the latter the part of the nerve
rudiment behind it (in the primitive position, anterior in the
position which the anus secondarily acquires on the ventral
surface) undergoes atrophy.
We now come to the question of the chordate mouth, a much
vexed question, and one about which much of a highly specu-
lative character has been written. We may at once concede
3--
Fm. 2. — Heads of young Elasmobranch embryos (Scyllium canicida) (after Sedgwick).
A. Ventral view of head of embryo, 7 mm. in length, with two open pharyngeal clefts.
The mouth is present as a longitudinal groove in the ectoderm of the buccal depression.
B. Same view of a slightly older embryo ; the buccal groove has become a longitudinal
slit. C. Side view of head of embryo, 9 mm. in length, with three open slits. D. Side
view of head of embryo, 11 mm. in length ; rudiments of external gills have appeared on
the hyoid and on the first and second branchial arches. E. Side view of head of embryo
of 16 mm. ; external gills have appeared on mandibular arch and the angle of the jaw is
marked. 1 mandibular arch ; 2 angle of jaw ; 3 second pharyngeal cleft ; 4 nasal pit ;
5 eye ; 6, midbrain ; 7, auditory sac ; 8 hyoid arch ; 9 spiracle.
the point that the chordate mouth has never been brought
into developmental relation with the blastopore. Even if it be
allowed that the chordate blastopore really extends to the
front end of the nerve rudiment (medullary plate), which is in
itself a disputed point, no morphologist has ever brought to
light any embryological fact which is at all in favour of the
view that the mouth was originally within the nerve rudiment,
6 CHORDATA.
and that its present position outside it and on the ventral surface
is a secondary one, due to shifting and to atrophy of the part of
the nerve rudiment in front of it. There are a number of
features of vertebrate morphology of the highest interest in
connection with this point : such are the cranial flexure, the
close relation of the infundibulum, which there is good reason
to believe is the real front end of the nerve axis, to the anterior
end of the mouth, the slit-like form * (Fig. 2), which at first
characterizes the buccal opening, and its extension into the rudi-
ment of the pituitary body ; but there is no actually ascertained
fact which tends to show that the mouth is a derivate of the
blastopore, as it must be conceded to be in most other coelomate
phyla, t
The last chordate character to be considered is the posses-
sion of lateral pharyngeal apertures. These are often used
for respiration and are in consequence generally termed gill-
slits. They are not however always respiratory in function
— indeed in the majority of the Vertebrata in which they
form a very conspicuous feature they are not respiratory at
all, but are entirely functionless, being found only in the
embryo.
An attempt has been made in some quarters to refer the
chordate mouth to a modification of a pair of these structures.
We can see no fact in favour of such a view, and we are not
prepared to give up the homology of the chordate mouth with
that of other Coelomata. We have already stated the case with
regard to its relation to the blastopore, and we have seen that
there is no good embryological evidence in favour of its being
so related, but we do not consider that this absence of evidence
is sufficient to put out of court the view that it is the homologue
of the mouth of other Coelomata. In many of these, too, no
relation can be shown between the mouth and the blastopore in
development, but yet we well know that in them the mouth
is homologous with the mouth of forms in which it is directly
derived from a part of the blastopore.
Finally there is one point in the morphology of the Chordata,
* Sedgwick, "Notes on Elasmobranch Development," Q.J.M.S., 33,
1892, p. 559.
f For a fuller discussion of these questions, the reader is referred to the
article "Embryology" in the recently issued supplement of the Encyclo-
paedia Britannica.
COELOM.
which though not referred to in the definition, is of considerable
importance, and must be shortly dealt with here, and that is the
form and development of the Coelom. In the Cephalochorda
and Enteropneusta the coelom originates as outgrowths of the
primitive gut (archenteron). In Vertebrata, though there is
no actual outgrowth of the enteron, the walls of the coelom
originate from tissue which is derived from the wall of the
enteric space, and there can be but little doubt that the mode of
development is referable to the enterocoelic type, found in
the two other phyla, and is indeed a modification of it.
If then we leave out of consideration the Tunicata, which
in this respect cannot at present be brought into line with the
other chordate phyla,
we may assert that
an enterocoelic origin
of the coelom, or a
modification of it, is
characteristic of the
Chordata. Ou t s i d e
the Chordata a similar
mode of origin of the
coelom is found in the A
Chaetognatha (vol. i, B
p. 590), in the Bra-
chiopoda (vol. i, p.
580), probably in the
Phoronidea (vol. i, p.
546), and as will be shown further on in the Echinodermata.
But the coelomic resemblances between these animals go farther
than this. In the Enteropneusta the archenteric outgrowths
are five in number — two pairs and an anterior unpaired out-
growth (Fig. 3). These, following the nomenclature of Bateson,
have been named according to the position they occupy in the
adult : the anterior unpaired sac is called the proboscis cavity ;
the sacs of the anterior pair are the collar cavities ; and the
posterior sacs are the trunk cavities. In the Enteropneusta
they undergo no further division, but remaining in the parts
of the body indicated by their names, they give rise to the
coelomic spaces of the adult.
In Amphioxus the anterior unpaired sac is called the preoral
—4
FIG. 3. — Diagrams showing the origin and primitive
relations of the coelomic sacs A in Balanoglossus, B
in Amphioxus (after MacBride). 1 proboscis cavity
in A, preoral cavity in B ; 2 collar cavity ; 3 anterior
somite of trunk ; 4 trunk cavity.
CHORDATA.
or head cavity ; it obviously corresponds to the proboscis cavity
and remains in the head region of the animal. The sacs of the
second pair are called the collar cavities, because they correspond
to those cavities of the Enteropneusta. They are in reality the
anterior pair of somites, and give rise dorsally to the first pair
of myotomes. Their exact disposition in the adult is not quite
certain, but they appear to get some backward extension. The
posterior sacs which come off as one pair from the enteron and
correspond to the trunk cavities of Enteropneusta undergo in
subsequent growth a segmentation and give rise to the whole of
the mesoblastic somites of the trunk from the second pair back-
wards.* In the development and arrangement of its coelomic
sacs Amphloxus resembles in a remarkable manner the Entero-
pneusta, the difference between them consisting in the segment-
ation which the trunk cavities undergo in Amphioxus.
In the Vertebrata, though it is not possible to point to such
close resemblances as those which we have just described,
there is a remarkable similarity in the embryonic arrangement.
The first coelomic sac is preoral and unpaired ; the second is
paired and large, extending backwards in the mandibular arch,
so as to overlap the following somites. These mandibular
cavities are clearly homologous with the collar somites of the
other types. Following them we find on each side one large
cavity, the dorsal parts of which are divided up into segments and
become the myocoeles, and their walls the myotomes of the later
embryo. These posterior cavities clearly correspond to the trunk
cavities of the other types : as in them they are extensive, and
occupy the whole trunk region, and as in Amphioxus they are
metamerically segmented.
In Amphioxus it is said that the preoral somite does not give rise to
striated muscles ; in Vertebrata it gives rise to a considerable number of
the eye muscles.
With regard to the nonchordate phyla with enterocoelic
coelonij we have only space to say this, that in the Echinoderms
the Enteropneust plan of an unpaired anterior cavity and two
pairs of posterior cavities can, according, to MacBride's researches,
generally be made out ; that in the Chaetognatha there is an ap-
proximation to the Enteropneust arrangement, but the unpaired
* MacBride, Q.J.M.S., 40, 1898, p. 589.
CHORD AT A. 9
cavity is at the hind end ; in the Phoronidea there are indications
that the Enteropneust arrangement or a modification of it exists,
but the indications are not very clear ; while in the Brachiopoda
according to our present knowledge no resemblance to the
Enteropneust plan exists save in the enterocoelic origin of the
coelom.
The formation of the coelom in the other chordate phyla,
the Annelida, the Mollusca, and the Arthropoda, must be regarded
as a modification of the enterocoelic method, but it is never
possible in them to trace the arrangement into an unpaired
chamber and two pairs of chambers which is so characteristic
of the Chordata.
CHAPTER II.
PHYLUM CEPHALOCHORDA.*
With dorsal tubular nerve-cord, and persistent notochord extend-
ing forwards in front of the nerve-cord. The muscular system and
gonads are segmented, and the pharynx possesses a large number of
branchial slits which open into an atrial cavity and are provided
with tongue bars. Without paired fins, jaws, brain, vertebrae
and generative ducts. The larval life is prolonged and the larva
is remarkably asymmetrical.
The phylum Cephalochorda contains but the single genus,
Amphioxus Yarrell. It was discovered by Pallas in 1778, who
took it for a slug and named it Limax lanceolatus. Its true
position in the animal kingdom was first recognized in 1834 by
Costa, by whom it was named Branchiostoma. Two years later
it was described by Yarrell, who called it Amphioxus, by which
* J. Miiller, Ueber den Bau und die Lebenserscheinungen des Branchi-
ostoma lubricum (Amphioxus lanceolatus), Berlin, 1844. Quatrefages,
" Sur le systeme nerveux et sur 1'histologie du Branchiostome," Ann. des
Sci. Nat. (3), 2, 1845. Kowalevsky, " Entwick, v. Amphioxus lanceolatus,"
Mem. Acad. Imp Sc., St. Petersbourg (7), 2, 1867. Id. " Weitere Studien,
etc.," Arch. f. mic. Anat. 13, 1877. Stieda, " Ueb. d. Amphioxus lanceo-
latus," Mem. Acad. Imp. Sc., Petersbourg, (7), 19, 1873. Rolph, " Ueb.
d. Bau d. Amphioxus," Morph. Jahrb. 2, 1876. Langerhans, " Zur Anat.
d. Amphioxus," Arch. mic. Anat., 12, 1876. A. Schneider, Anat. u. Ent-
wick. der Wirbelthiere, Berlin, 1879. Hatschek, " Ueb. d. Entwick. Am-
phioxus," Arb. a. d. Zool. Inst. Wien, 4, 1881, also Zool. Anz., 7, 1884,
p. 517, and Anat. Anz., 3, 1888, p. 662. Rohon, " Ueb. Amphioxus lanceo-
latus," Denksch. k. Akad. d. Wissenschaft, Wien, 45, 1882. Lankester,
" Contributions to the knowledge of Amphioxus lanceolatus," Q.J.M.S., 29,
1889, p. 364. MacBride, " The Early Development of Amphioxus,"
Q.J.M.S., 40, 1898, p. 589. A. Willey, Amphioxus, etc., New York, 1894,
and Q.J.M.S., 31, 1890, p. 445, and 32, 1891, p. 183. v. Wijhe, " Beitr. z.
Anat. des Kopf region des Amphioxus," Petrus Camper, 1901, and Anat.
Anz., 8, 1893. C. F. Cooper, " Cephalochorda," in J. S. Gardiner's Fauna
etc. of Maldive and Laccadive Archipelago, 1, 1903, p. 347. R. C. Punnett,
" Meristic Variation in Cephalochorda," Ibid., p. 361.
HABITS. 11
name it has since been known. According to the strict rules of
zoological nomenclature this is incorrect, the generic nam:
Branchiostoma having two years' precedence over Amphioxus.
But, as so often happens in human affairs, the unwritten law has
triumphed over the written, and the almost universal custom
of zoologists has been to call the genus Amphioxus. From this
custom we shall not venture to depart in this work.
Having thus entered our protest against a breach of con-
ventional rule which is made knowingly, we had almost said
wantonly, by all zoologists, we may proceed to consider the
actual position in the system of this remarkable creature.
Here fortunately there is no conflict between preaching and
practice,, between a pedantic conformity to rule and a lawless
adhesion to custom. For law and custom alike agree that the
position of an animal in the system shall be determined by its
natural affinities as revealed by a study of its structure and
development. Judged by this test there can be no question
that Amphioxus is closely allied to the Vertebrata and must be
placed either within that group or in close juxtaposition to it.
As our readers know we have adopted the latter 'course and
have placed Amphioxus in a special phylum of its own, equal in
morphological importance but very inferior in the number of
its members to the great phylum Vertebrata, and have applied
to it, out of a number of claimants,* the name Cephalochorda,
in allusion to the extension of its notochord into the anterior
part of the cephalic region.
Amphioxus'f is a small, semi-transparent, colourless animal.
Its body is elongated, laterally compressed, and pointed at each
end ; and it may attain a length of two inches. . It is entirely
marine, and is found at moderate depths in many parts of the
world. It has a remarkable power of moving in sand, in which
it is usually partially buried, its mouth alone protruding. But
it is capable of swimming, and when removed from the sand
bends its body with great activity from side to side. The
mouth is an elongated oval aperture on the ventral surface
immediately behind the anterior end of the body. It is sur-
rounded by a number of delicate ciliated processes, the oral cirri.
* Pharyngobranchii, Acrania, Leptocardii, etc.
(• The anatomical description refers, unless otherwise stated, to A.
!atit8.
12 PHYLUM CEPHALOCHORDA.
The anus is also ventral and is placed slightly to the left of
the middle line at some little distance from the posterior end
of the body (Fig. 5). Extending from the mouth backwards
along the ventral surface for about two-thirds of the length of
the animal is a wide median groove, bounded by lateral folds
and perforated at its hind end by a pore (Fig. 5). The folds are
called the metapleural folds and the pore the atrial pore.
There are no paired fins, but there is a continuous median fin
consisting of a fold of skin extending along the whole length of the
dorsal surface (dorsal fin), and round the hind end of the body
on to the ventral surf ace 'as far forwards as the ventral groove
(Fig. 4). Anteriorly it is also continued on the ventral surface,
reaching as far as the mouth, with the right side of which it is
continuous (Fig. 5). The portion between the ventral groove
and the anus may be called the anal fin, and that between the
anus and the hind end of the body the ventral part of the caudal
fin.
Amphioxus is a segmented animal. The segmentation is
marked externally by a number of V-shaped grooves, placed
one behind the other on each side of the body, the apex of the
V being directed forwards (Fig. 4). These markings are caused
by the insertion into the skin of a number of transverse septa
of connective tissue, which divide the great lateral longitudinal
muscles of the body into a series of successive segments, placed
one behind the other and called myotomes. The grooves of the
two sides of the body alternate with one another. The seg-
mentation is also exhibited by the gonads which consist of a
series of saccular bodies extending throughout the greater part
of the pharyngeal region as far back as the atrial pore (Fig. 4).
They correspond in number with the myotomes of that part of
the body in which they occur and alternate with those of the
opposite side of the body.
The body of Amphioxus is traversed throughout almost
its entire length by a flexible skeletal rod — the notochord.
The notochord is pointed at either end and is placed in the
centre of the body, but nearer to the dorsal than the ventral
surface (Fig. 4). Lying immediately on the dorsal side of the
notochord is a cord of nervous matter which may be called the
cerebrospinal cord and constitutes the central nervous system.
Behind, this nervous cord tapers and ends in a point, or a small
PHYLUM CEPHALOCHORDA.
13
e<
14 PHYLUM CEPHALOCHORUA.
swelling, immediately over the hind end of the notochord ; in
front it tapers very slightly, and possesses a somewhat blunt
termination placed some little distance behind the front end of
the notochord. On the ventral side of the notochord is the
alimentary canal, which has the form of a straight tube extending
between the mouth and the anus. The central nervous system
therefore, lies entirely dorsal to and the alimentary canal
entirely ventral to the notochord.
The alimentary canal consists of three parts : —
1. The buccal cavity. This is a short chamber opening to
the exterior by the mouth and behind by a somewhat constricted
opening into the pharynx.
2. The pharynx is the widest and longest portion of the
alimentary canal, extending nearly half the length of the body.
Its walls are perforated on each side by a number of obliquely
directed slits (from above and in front ventralwards and back-
wards) which place its cavity in communication with a space
lying immediately outside it, and called the atrial or peripharyn-
geal chamber. The atrial chamber entirely surrounds the
pharynx except along the dorsal middle line (vide Fig. 10 and
explanation). It opens to the exterior by the atrial pore —
already mentioned — which is found at the hind end of the ventral
groove (Fig. 5). The pharynx is mainly a respiratory organ,
inasmuch as the blood which circulates in its walls and in the
walls of the atrial cavity is aerated by the water which is con-
tinually being taken in by the mouth and driven by the action
of cilia through the pharyngeal slits — or gill slits as they
may be called — into the atrial cavity.
3. The intestine which extends as a straight tube from the
hind end of the pharynx to the anus. The anterior part of the
intestine is slightly dilated and receives ventrally a simple
caecalsac, which, pushing the body wall before it, extends for-
wards in the atrial cavity on the right side of the pharynx and
is called the liver.
Detailed Description of the Organs.
The ectoderm consists of a single layer of columnar or in some
places cubical cells, which cover the whole external surface of
the animal, are prolonged for a short distance into the buccal
cavity and line the whole of the atrial cavity (Fig. 10). They
SKELETON. 15
are without cilia except on the cirri, in the mouth and in the
atrial cavity, and their outer surface is covered by a porous
cuticle. Immediately beneath the ectoderm is a layer of fibril-
lated tissue called the cutis. Beneath this comes the subcu-
taneous tissue which consists of a gelatinous matrix containing
sinuous fibres. The tissue within this has a similar form and
extends between the myotomes, as the inter- muscular septa,
to become continuous with the sheath of the notochord. In
fact all the connective tissues of the body may be said to form
a continuous framework which supports the organs and is on the
whole of very similar structure throughout. In some parts
it is firmer than in others and in some places it contains fibres,
but it never presents a modification of a cartilaginous or osseous
nature and never, except at the ventral ends of the primary
pharyngeal bars, contains cells other than the epithelial cells
which bound the spaces contained within it. These spaces are
in some cases vascular and in others coelomic, but it is not possible
in every case to be certain as to which of these two organs they
belong. This absence of what we may call mesenchymatous
elements from the connective and supporting tissues is one of
the most remarkable peculiarities of Amphioxus.
As skeletal tissue we may rank the notochord, the supporting
tissue of the buccal ring and the axial tissue of the buccal cirri,
possibly also the axial tissue of the pharyngeal bars. The
notochord is made up of a number of discs placed verti-
cally, and transversely to the long axis, and consisting of
gelatinous tissue. It is surrounded by a tough sheath of
connective tissue, which is continuous with the rest of the
connective tissue framework of the body. Nuclei are present
on the dorsal and ventral sides in the neighbourhood of two
spaces, the so-called dorsal and ventral lymph canals of the
notochord.
The edges of the mouth contain a ring of skeletal tissue the
buccal ring, resembling the notochord in structure. It consists
of about twelve pieces on each side, and each piece gives attach-
ment to a rod of the same substance, which occupies the axis
and forms the support of one of the oral cirri.
The tissue of this buccal skeleton consists of a number of gelatinous
discs surrounded by a fibrous sheath. By some observers it is claimed
as cartilage, each disc being a cell and the surrounding membrane the
16 PHYLUM CEPHALOCHORDA.
cartilaginous matrix. The tissue of the axial rods of the pharyngeal bars is
sometimes described as skeletal. It consists of a clear chitin-like substance
devoid of cellular structures except in the ventral bifurcated parts of the
primary bars, which contain branched cells. Excluding the nuclei of the
notochord, which is an endodermal structure, this is the only instance
of a mesodermal tissue containing mesenchymatous elements.
The nerve-cord is surrounded by a tough sheath, which is
continuous with the sheath of the notochord.
The fin-rays are found in the greater part of the dorsal
fin in a single series, and in the anal fin in a double series (Figs.
4 and 5). They are absent from the cephalic fin, and from the
anterior and posterior portions of the dorsal fin, and from the
ventral parfc of the caudal fin. They consist of small cubical
pieces of a tough fibrous connective tissue, which in the dorsal
fin are continuous with the fibrous investment of the nerve-
cord. They are more numerous than the metameres, there
being four or five to each muscle segment.
The fins contain a longitudinal canal lined by epithelium and divided
by septa into compartments. In the region of the fin-rays each of these
compartments contains a fin-ray which pushes in its ventral wall and
projects into it. The nature of these fin spaces is not known, but it is
stated by Hatschek and others that they are, in the dorsal fin at least,
coelomic in origin, being derived from the coelom of the muscle-plate (see
below).
The muscular system consists of striated and unstriated
muscular tissue. The striated muscles are composed of fibrillated
rhombic plates, and are devoid of sarcolemma. They con-
stitute the lateral muscles, the transverse muscles, the muscles
of the lips and cirri, and the sphincter muscle of the velum and
anus.
The great lateral muscle of the body is divided up into a
number of successive segments, the myotomes (myomeres)
by septa of connective tissue. These septa have a peculiar
V-shaped course, and their insertion into the skin causes the
V-shaped external markings already referred to (Fig. 4). The
myotomes of opposite sides alternate with one another, i.e.
the intermuscular septa of one side are opposite the middle
of the myotomes of the other side. The full number of
myotcmes is laid down in the embryo. In Amphioxus lanceolatus
there are about sixty-two on each side. The plate-like n, res
of which these muscles are composed extend the whole length
NERVE CORD.
17
of the myotome from septum to septum. The other striated
muscles are very similar to the lateral muscle in structure, but
the cross-striation is less marked, and they are not segmentally
arranged, nor derived from the myotomes of the embryo. The
transverse muscles extend from the ventral end of the lateral
muscles to the middle line of the floor of the ventral groove,
where they are inserted into a median connective tissue septum
(Fig. 10). The unstriped muscle confers contractility on the
walls of the intestine and larger blood-vessels. It is exceedingly
inconspicuous and thin. It is doubtful indeed if it really exists
as a distinct tissue.
The nervous system. The
nerve-cord (cerebro - spinal
cord) contains in its ventral
portion a small circular cen-
tral canal, which extends as a
narrow fissure to the dorsal
summit of the cord (Fig. 6).
This canal is lined by colum-
nar epithelial cells, some of
which are continued into the
substance of the cord as sup-
porting fibres, while others
may have the form of nerve
cells. The cells lining the
dorsal part of the canal are in
close contact, so that the
cavity here is virtual. The
nerve cells are for the most part placed in the central part of
the cord, and some of them are of giant size,* and extend
right across the fissure-like part of the central canal. On the
ventral side of the canal, at short (metameric) intervals along
the whole length of the cord behind the second myotome, are
small groups of black pigmented cells, f These structures are
probably sensitive to light. There is also a pigment spot,
commonly called the eye, and placed at the front end of the
cord in the anterior wall of the cerebral vesicle.
* For the arrangement of these giant nerve-cells and of the giant fibres
which issue from them, we refer the reader to Rohde, in Zool. Beitrage, 2,
1888, p. 169.
f Hesse, Z. f. w. Z., 63, 1898, p. 456.
Z. ii. C
FIG. 6. — Transverse section of the spina I
cord of Amphioxus (after Rohde). gz
nerve cells ; stf supporting fibres ; ck cen-
tral canal.
18 , PHYLUM CEPHALOCHORDA.
Anteriorly, though the cord itself tapers slightly, the central
canal widens out into a spacious vesicle, the cerebral vesicle.
This is the only representative of the brain of the Vertebrata.
It gives off from its front dorsal wall a small hollow diverticulum,
which ends blindly against the inner side of a small asymmetrical
pit of ectoderm called the olfactory pit. This pit is placed
on the left side of the body, is lined by ciliated cells, and is
supposed to be olfactory in function. In the larva the process
of the cerebral vesicle and the pit are in communication by a
pore, wln'ch appears to be the persistent neuropore of the
embryo. The cerebral vesicle is also said to possess a ventral
diverticulum in the hinder part of its floor, which has been com-
pared with the infundibulum of the vertebrate brain, but it is
doubtful if it is always present. Posteriorly the cord tapers
considerably and ends, usually in a small swelling, just short
of the hind end of the notochord. In some cases it is said to
extend as a filament round the hind end of the notochord on
to the ventral surface.
The nerves issuing from this cord, except in the case of
the first two, are dorsal and ventral in their origin and
correspond with the dorsal and ventral roots of the spinal
nerves of the Vertebrata. In Amphioxus they do not join
and there are no ganglia on the dorsal roots. The dorsal
nerves arise from the dorsal part of the cord. The nerves
of the first two pairs (so-called cranial nerves) arise opposite
one another, altogether in front of the myotomes. They are
entirely sensory, and supply the preoral part of the body. Their
finer branches possess nerve cells not far from their terminations.
The remainder of the dorsal nerves alternate in their origin
on the two sides, and contain motor as well as sensory fibres.
They pass out behind the myotome to which they belong, and
divide in the subcutaneous connective tissue into dorsal and
ventral branches. The ventral of these supplies nerves to the
transverse muscle of the sub-atrial floor. The dorsal nerves
also supply the muscles of the lips and velum. The sides of
the mouth (oral hood) and the cirri are supplied by the third
to seventh dorsal nerves, and the nerves to the inner side of
the lips of both sides are derived from the dorsal nerves which
arise on the left side of the cord (reminiscence of larval con-
dition, see below). The velar supply comes from dorsal nerves
four to seven.
ALIMENTARY CANAL.
19
The ventral nerves (Fig. 7) are not united
in bundles nor surrounded by a sheath, but
issue as linear groups of fine fibres, which pass
immediately to the adjacent myotome. They
arise slightly anterior to the dorsal nerve of
the segment to which they belong, and are
exclusively motor for the muscles of the myo-
tomes.
Sense organs, Scattered amongst the ecto-
derm cells are cells bearing short hairs. They
are specially numerous at the front end of the
body and round the mouth. They may be
supposed to be tactile organs. They are also
found in the mouth and on the velum.
Organs which are supposed to be visual and
olfactory have already been described.
The most striking peculiarities of the ner-
vous system of Amphioxus as compared with
that of the Vertebrata are the absence of an
anterior cerebral enlargement ; the peculiar form
of the central canal, the dorsal fissure-like por-
tion of which is probably represented by the FIG. ?.— Anterior en i
dorsal fissure of the vertebrate spinal cord ;
the absence of a junction between the dorsal
and ventral nerve roots and of a ganglion on
the dorsal roots ; and, lastly, the imperfect
condition of the organs of special sense.
IV
is a
ches of the second
nerve arises indepen-
dently from the cord
in the preparation
after
ys f 'anc2"
It leads into a spacious fJn(J secz°A/d/n ™
The alimentary canal. The mouth
large, somewhat circular opening, placed on
the ventral side of the body, a little distance ts0crhyne
from the front end.
cavity, the buccal cavity, which is bounded by
a fold of the integument called the oral hood
(Fig. 4). The free edge of the oral hood,
which may be called the lip, contains the skeletal framework
already described, and bears a number (from twenty to thirty,
increasing with age) of delicate ciliated processes, the oral
cirri. The right side of this oral hood is, as has already been
mentioned, continuous with the preoral ventral part of the
median fin, which is in accordance with what might be expected
20
PHYLUM CEPHALOCHORDA.
from the development of the parts (see below). The buccal
cavity is bounded behind, at the level of the anterior angle
of the seventh myotome, by a muscular membrane, the velum,
which separates it from the pharynx and is perforated by an
aperture, which has been sometimes called the true mouth
and is the actual opening which formed the mouth in the larva.
The edges of the velum around this opening bear twelve delicate
tentacles, the velar tentacles, which project backwards into
the pharynx. The buccal cavity is lined by a ciliated epithelium,
and bears on its roof slightly to the right of the median line
a pit called Hatschek's pit, or simply the preoral pit (Figs. 8, 9).
This organ is lined by a columnar epithelium, the cells of which
bear stiff sensory hairs. It opens in a groove of columnar
finely ciliated epithelium, which extends a short distance in
front of it in the roof of the mouth and behind bifurcates
into two ciliated grooves ; these pass obliquely backwards and
outwards to the velum, and then pass ventrally along the
junction of the velum and sides of the mouth. They terminate
either by simply coming to an end, or by running into one
another on the floor of the buccal cavity. These two diverging
ciliated furrows
give off access-
ory furrows,
which are
formed by folds
of the antero-
lateral walls of
the main fur-
rows. The ac-
cessory ciliated
furrows pass for-
wards for a
short distance
on the roof and
sides of the
ion12 mouth. The
FIG. 8.— View of the roof of the buccal cavity of Amphioxus m^^\^
lanceolatus from below (after v. Wijhe). 1 posterior wall WnO
of buccal cavity ; 2 ciliated groove of left side ; 3 left side «^n0f,'f«f«0 +^~
of preoral hood ; 5 notochord ; 6 second myotome ;
7 Hatschek's (preoral) pit ; 8 ciliated pit ; 9 right side of « ,T/uQ~i ~__ „ j»
preoral hood ; 10 third myotome ; 11 ciliated groove of Wile organ
right side; 12 accessory ciliated groove; 13 sphincter ^f r Tvn;il™ T*
muscle of velum ; 14 velar tentacles. ot J • Mllller.
-14
PHARYNX.
21
is an organ for creating currents in the mouth back to the
pharynx. The preoral pit which opens into its front part
has been variously interpreted as a sensory organ and a gland.
If the preoral (Hatschek's) pit be regarded as a gland, it has been sug-
gested by v. Wijhe that it is comparable to the neural gland of the Tunicata,
and that the ciliated groove is comparable to the opening of that gland,
the dorsal tubercle, the edges of which are frequently drawn out in a manner
--20
— 17
FIG. 9. — Transverse section through the middle of the buccal cavity of Amphioxus lanceolatus
to show the preoral (Hatschek's) pit and the ciliated furrow (after v. Wijhe). >1 Hatschek's
pit ; 2 right side of preoral hood ; 3 outer lip-cavity ; 4 inner lip cavity (3 and 4 arejparts
of the left collar somite of the embryo) ; 5 labial nerve ; 6 coelom (dorsal buccal, a portion
of the collar somite of the embryo) ; 7 contorted blood vessel (continuation of right aorta) ;
9 aorta ; 10 Hatschek's nephridium (a process from the pharynx) ; 11 buccal cavity ;| 12
internal labial muscle ; 13 skeleton of cirrus ; 14 cavity (lymph space) of cirrus ; 15 exter-
nal labial muscle ; 17 left side of preoral hood ; 18 second, 19 third, 20 fourth myotome.
very similar to the course of the ciliated groove of Amphioxus. Against
this interpretation we must set the fact that the preoral pit, whatever
its origin (see below), has no relation to the central nervous system.
Moreover the interpretation of it as a gland is a very doubtful one. Van
Wijhe describes a special part of the ciliated furrow just behind and in
close connection with Hatschek's pit as the ciliated pit (Fig, 8, 8).
The pharynx is a large chamber tapering slightly posteriorly
on account of the dorsal inclination of its ventral wall. Its side
22 PHYLUM CEPHALOCHORDA.
walls are perforated throughout their whole dorso- ventral
extent (except for a short distance behind the velum) by a
number of vertically directed slits, which have a slight inclination
ventralwards and backwards (more marked in the preserved
than in the living animal), and which open into the atrial cavity.
The dorsal and ventral parts of the pharyngeal wall are not
perforated and constitute the hyperpharyngeal groove and the
endostyle (hypopharyngeal groove) respectively. These termi-
nate independently of one another posteriorly, but anteriorly
they are connected by the peripharyngeal ciliated bands which
arch round the pharynx immediately in front of the gill -slits.
In front .of the peripharyngeal bands there is a small portion
of the pharnyx adjacent to the velum without gill-slits.
The pharynx is lined by a ciliated epithelium, which is con-
tinuous through the slits with the ectodermal epithelium lining
the atrial cavity. 'Along the endostyle there are four bands of
specially glandular cells, which, like the remaining pharyngeal
cells, bear cilia, and secrete the mucus, which passing forwards
along the endostyle is driven upwards by the peripharyngeal
bands into the front end of the hyperpharyngeal groove. Along
this it is carried by ciliary action into the stomach. The food,
consisting of smaU floating organic bodies brought into the
pharynx by the ciliary currents, is entangled in this mucus and
so separated from the water which passes through the gill-slits
into the atrial cavity and out by the atrial pore.
New gill-slits continue to be formed long after the development
has ceased, during the growth of the animal. They are conse-
quently more numerous in large than in small specimens. In
large specimens there may be as many as 180 secondary (see
below) or 90 primary gill-slits on each side.
The new slits are formed at the hind end of the pharynx close
to the junction with the stomach, as small circular perforations
(see Fig. 24 in the account of the development). These soon
become partly divided into two by the growth ventralwards of a
process from the dorsal wall of the aperture (Fig. 25). This
downward projection, from its resemblance to the tongue of a
Jew's harp, is called the tongue bar. It eventually fuses with the
ventral wall of the slit, so that the primary slit becomes completely
divided into two secondary slits separated by the tongue bar.
In correspondence with this we may call the parts of the pharyn-
GILL-SLITS. 23
geal wall intervening between two primary slits the primary
$.
li
ci
"\f /fltU
FIG. 10. — Diagram of a transverse section through Ampkioxus in the hinder part of the
pharyngeal region showing the brown canals (after Lankester, from Perrier) . The division
of the more ventral portion of the myotomes into two groups of fibres separated by a
connective fascia is shown ; a atrium ; ad root of dorsal aorta ; b primary bar ; ft1 secondary
bar ; c liver (caecum) ; ca lymph space ; cd notochord ; e^'tube of atriocoelomic
funnel ; en connective tissue framework of the body ; c p SQmatic wall covering
caecum ; ct t skeletal plate of endostyte ; e ectoderm ; / branchial slit ; g$ hyper-
pharyngeal groove ; gv endostyle •, li ventral canal of notocljorol ; Is dorsal canal of
the notochord ; m transverse muscle of atrial floor ; M myotomes ; mt metapleure ;
AT spinal cord ; na ventral, np dorsal root of a spinal nerve ; o go*n.ad ; p portion of a
t Id in dorsal wall of atrium ; ph pharynx ; r dorsal fin raj' ; s' so-called lymph-'spaces.
i the case of the hepatic caecum, s points to the blood-vessels.
24 PHYLUM CEPHALOCHORDA.
bar. The primary gill-slits of opposite sides alternate with one
another, as do the myotomes. In the adult they are more
numerous than the myotomes, though when they first make their
appearance, they correspond with them. The anterior primary
slit on each side is not divided by a tongue bar.
On account of the obliquity of their direction a great many,
both of primary and tongue bars, are cut in transverse section
(Fig. 10). The primary bars differ from the tongue bars in
structure (Fig. 11, A, B). In both there is an axial rod of a
clear chi tin-like substance (insoluble in potash), placed nearer
the atrial than the pharyngeal side of the bar. In the primary
bar this rod is double and without a cavity, while in the tongue
bar it is single and has a cavity. These rods are continued inwards
towards the pharynx as a thin membrane called the septal
membrane (Fig. 11). The character of epithelium covering
the bars may be gathered by an inspection of Fig. 11. On the
outer side the ectoderm of the atrium is found. It is said to be
non-ciliated and to be separated from the more extensive pharyn-
geal endoderm by some pigmented cells. The cilia of the endo-
derm vary in character on different portions of the bar, recalling
the condition found in the Lamellibranch gill. The primary
bar con tains between the ectoderm and the skeletal rod a chamber
which is a portion of the coelom, being continued dorsally into
the dorso-pharyngeal coelom, and ventrally into the endostylar
coelom. In addition three blood-vessels can be seen in the
primary bar in the positions and with the names indicated in the
figure. In the tongue-bar the visceral (10) and somatic (7)
vessels are present, and in addition there is a space in the
skeletal rod (3). This is interpreted by Lankester and Benham
as coelomic, by others as vascular. According to Benham this
space contains a blood-vessel (omitted in the figure) corresponding
to the external blood-vessel of the primary bar (4). Successive
primary bars are connected by transverse bars (synapticuld),
which thus pass across the primary slits, internally to the tongue
bars, with which, however, they are connected (Fig. 12,5). The
primary bars may thus be distinguished from the tongue bars
in transverse section ; and they may be distinguished by in-
spection of the pharynx as a whole for the skeletal rod of the
primary bars bifurcates ventrally on reaching the level of the en-
dostyle, whereas thai of the tongue bars does not bifurcate. Dor-
INTESTINE.
25
sally the skeletal rods of both bars bifurcate and arch over the
clefts to join the branches of the adjacent bars. Below the
endostyle are some flat plates of skeletal tissue, which partially
overlap one another. They correspond in number with the
primary slits at the lower end of which they are placed,
FIG. 11. — Transverse sections at right angles to the length of the pharyngeal bars of Amphioxus
lanceolatm, A of a tongue bar, B of a primary bar (after Benham slightly altered). The
relative sizes of the two bars is maintained. 1 endoderm epithelium on the pharyngeal end
of a bar ; 2 pigment cells ; 3 coelom of the primary bar in B, coelom or external blood-
vessel contained in the skeletal rod of the tongue bar in A (coelom according to Lankester
and Benham) ; 4 external blood-vessel of the primary bar f'5 atrial epithelium ; 6 skeletal
rod ; 7 somatic blood-vessel ; 8, 9 septal membrane ; 10 visceral blood-vessel.
The pharynx opens posteriorly into the intestine which' runs
straight back to open by the anus placed a little to the left
of the median line at the level of the septum between the 51st
and 52nd myotome. The anus is provided with a sphincter of
striated muscular fibres. The intestine is lined by a columnar
ciliated epithelium. The anterior part of the intestine is slightly
dilated and called the stomach. It gives off a forwardly directed
26 PHYLUM CEPHALOCHORDA.
diverticulum, the liver, which pushes before itself the ventral
body wall, the whole projection lying in the atrial cavity along-
side the pharynx on its right side (Fig. 10). This process is
attached to the dorsal wall of the atrium in front. The lining
cells of the hepatic caecum are coloured green in the living
animal, as are the cells of the stomach from which it is given off.
Outside the intestinal epithelium is a thin connective tissue
layer which may contain unstriated muscular fibres.
The atrial cavity is a space lined by ectoderm and surround-
ing the pharynx and anterior part of the intestine ventrally and
laterally. It opens to the exterior at the hind end of the ventral
groove at the level of the 36th myotome. It extends back on
the right side behind the atrial pore almost as far as the anus.
Its lining cells are in part ciliated and pigmented with a brown
pigment. The dorsal wall of the atrium is folded, in consequence
of the fact that it is reflected on to each of the primary
bars at a point considerably ventral to that at which
it joins the secondary bars (Fig. 12, Id). This gives rise
to somewhat puzzling features in transverse sections in
which the dorsal regions of the primary bars appear to
be connected to the side walls of the atrium by strands
of tissue traversing the atrium (Fig. 10). The ligarnentum
denticulatum of J. Miiller is this folded roof of the atrium
cut longitudinally. It follows from this arrangement that
the atrium is prolonged further dorsally in the region of the
tongue bars than it is over the primary bars.
The brown canals are two tubes lined by a pigmented epithe-
lium, and projecting into the dorso-pharyngeal coelom (Fig. 10).
They lie parallel to the long axis of the body and probably
end blindly in front at the 27th myotome. Posteriorly at the
level of the junction of the pharynx and intestine they open by
funnel-shaped apertures into the dorsal part of the atrial cavity,
one on each side. They are to be regarded as forwardly directed
diverticula of the atrium, of unknown function.
These structures are often called the atrio-coelomic funnels. They
were discovered by Lankester. It is doubtful whether they end blindly in
front or open into the dorso-pharyngeal coelom.
There is a well- developed coelom with which the gonads are
in relation. A complete comprehension of the coelom cannot
.
EXCRETORY ORGANS. 27
be obtained until the development is studied, but the main
features in its topographical arrangement seem fairly clear, and
may be described at this point. In the adult there are many
spaces in the tissues the exact nature and origin of which is not
understood. Such will be referred to by the general term lymph
spaces. It has been stated by some observers (Schneider,
Lankester and others) that the coelom and vascular system are
in certain parts of the body continuous. But having regard to
the doubtful character of many of the body-spaces above referred
to and to the difficulties to investigation presented by the
vascular system, this statement cannot be accepted without
further evidence.
In the region of the intestine there is a perivisceral cavity which
is coelomic. It entirely surrounds the intestine except dorsally,
where it is interrupted by the mesentery. In the region of the
pharynx the same cavity is found, but it is broken up by the
gill-slits into a number of parts all continuous with each other.
There are two dorsolateral chambers, one on each side of the
hyperpharyngeal groove. These extend a little way outward
in the lateral walls of the atrium, and dip down into the folds
of its roof along the primary bars. They constitute the dorso-
pharyngeal coelom, and are continuous through the above-
mentioned folds with the coelom present on the outer side of
each primary bar. Ventrally the coelom of the primary bars
opens into a median ventral chamber below the endostyle,
called the endostylar coelom.
The arrangement of the coelom about the mouth, which has been
described by v. Wijhe, is too complicated for description in this work :
it is, however, referred to in the section on development.
Excretory organs. In the dorsal wall of the atrium lying between the
atrial epithelium and the epithelium of the dorso-pharyngeal coelom are
a number of tubes with a ciliated lining, which have been supposed to be
renal in function (Figs. 12, 13). They correspond in number and position with
the primary gill-slits and do not extend behind the region of the pharynx.
They open into the atrium opposite the dorsal end 'of a tongue bar and at
the summit of one of the dorsal pouches of the atrium found at that point
(p. 26). They divide into two canals close to the opening ; one of these
passes forward and then turns round to travel for a short distance ventral-
wards ; the other passes backwards. They possess a variable number of
branches (from 1-5), the number being least at the two ends of the series
and greatest in the middle of it. Curious fibres ending in small knobs,
each of which contains a nucleus, pass off from the ends of these branches
and project into the coelom. These fibres are fine tubes ending blindly
internally and opening into the secretory tube. They contain a long
28 PHYLUM CEPHALOCHORDA.
vibratile flagellum, arising from the protoplasm around the nucleus at
the internal knobbed end and extending along their whole length so as to
project into the excretory tube (Fig. 13). They have been termed soleno-
cytes from their resemblance to the fibres found on the excretory tubes
of some invertebrates (e.g. polychaetous annelids). The tubes them-
selves are lined by a ciliated epithelium and a tuft of specially long
cilia projects through the renal opening into the atrium. They receive
a special vascular supply from the dorsal ends of the pharyngeal vessels,
the blood being returned into the adjacent aorta. That these organs are
excretory is inferred from their structure, which, as stated, closely resembles
that of the excretory organs of some polychaetous annelids, etc., among
the invertebrates, and on account of Weiss' experiments. He fed the
7ns
^ ----nc
Jr^ — nfc
^T |^
11 '
FIG. 12. — Dorsal portion of the left pharyngeal wall of Amphionus, showing three rena
canals, on one of which the solenocytes are shown ; seen from the side, diagrammatic (from
Korschelt and Heider after Boveri). Id optical section of the folded ventral wall of the
dorso-pharyngeal coelom (ligamentum denticulatum) ; m myotome ; ms intermuscular
septum ; nc termination of the branches of the renal tube with the solenocyte? removed ;
nk renal canal ; np opening of the renal canal into the atrium ; s synapticulum ; I primary
gill-bar ; II tongue bar.
animal with finely- divided carmine, and then found that the cells of the
main tubes contained carmine particles. But he also found carmine in
the lining cells of the atrium including those of Miiller's papillae. It is
possible, of course, that Weiss' interpretation of these facts is correcf,
and that the carmine found in these cells was in the act of being excreted
from the system into which it had been taken by the intestinal epithelium,
but on the other hand it may well be that the carmine entered the cells
concerned from the atrial cavity directly, in the same way that, according
to Weiss' view it must have entered the intestinal walls.*
* Vide Weiss, Q.J.M.S., 31, 1890, p. 497 ; and Boveri, Zool. Jahrb., 5,
1892, p. 429. Goodrich, Q.J.M.S., 45, 1902, p. 493.
VASCULAR SYSTEM.
29
The vascular system. There is no heart, but the larger
vessels are peristaltically contractile. Lying on the ventral
side of the endostyle in the pharyngeal wall there is a
longitudinal sub -pharyngeal vessel, which corresponds to
the heart and ventral aorta of the Vertebrata. Anteriorly it
terminates by branching to the lips. Laterally all along
its course it gives off branches,
which have on their bases small
contractile swellings called bul-
bils, to the primary bars. These
ascend dorsalwards and open
into the aortic root of their own
side. The secondary bars receive
their blood supply from the
primary through the transverse
bars. The roots of the aorta lie
on each side of the hyperpharyn-
geal groove (Fig. 10). In the
intestinal region they unite to
form the single dorsal aorta,
which gives off branches to the
intestine and lateral body walls.
Both the aortic roots are con-
tinued forward as the carotid
arteries. These are joined to-
gether by a transverse anasto-
mosis, and the right vessel gives
off a large much convoluted
branch which passes ventral-
wards at the level of the velum
and ends blindly (Fig. 9). The
anterior part o*f the right carotid
has the form of a plexus, and
gives off branches to the oral cirri of both sides.
The intestinal blood is collected into a sub-intestinal vein lying
in the ventral wall of the intestine. This vein is not a simple
vessel, but consists of a plexus of vessels, frequently communi-
cating and lying side by side. Anteriorly the sub -intestinal vein
appears to break up into a capillary system on the wall of the
hepatic caecum. The blood of the caecum is collected into the
FIG. 13. — Portion of the excretory canal
of a young Amphioxus with its soleno-
cytes, from the living animal (after
Goodrich). 1 solenocyte ; 2 tube of
solenocyte ; 3 excretory canal ; 4
flagellum of solenocyte.
30 PHYLUM CEPHALOCHORDA.
vein, the hepatic vein, which like the sub-intestinal vein consists
of a plexus of vessels (Fig. 10). These commence in front and
behind unite to form a single vein which is continued into the
hind end of the sub-pharyngeal vessel. The hepatic vessels are
said to communicate at the front end of the caecum with the
dorsopharyngeal coelom, but this statement must be accepted
with caution. There is undoubtedly a connection between the
anterior end of the caecum and the lateral wall of the atrium.
The blood is colourless ; it contains amoeboid cells, and accord-
ing to some observers a few red oval corpuscles.
In the larva the hind end of the subintestinal vein is continued directly
into the sub-pharyngeal vessel. The direction of the flow of blood is
forward in the subintestinal vein and subpharyngeal vessels, both of which
are, according to J. Miiller, contractile. It follows from this that
the flow must be dorsalwards in the pharyngeal bars, backwards in the
dorsal aorta and ventralwards in the peri-intestinal vessels. There is a
considerable vascular development in the lateral walls of the atrium and
a longitudinal vessel runs along the line of the gonads, but how these
and the body- wall vessels generally are related to the main trunks described
above is not known.
The other spaces of the body may be classed as lymph-spaces. They
are lined by an epithelium and contain a coagulable fluid. Their origin
and relations are not certainly known. Some of them, e.g. the lymph
canals in the fins and certain spaces within the myotomes are said to be
coelomic and derived from the mesoblastic somites of the embryo. Others
may possibly be purely vascular ; e.g. the large canal found in each meta-
pleure — the metapleural lymph canals.
Generative organs. The sexes are separate. There are no
external sexual differences. Generative ducts are absent,
and the generative organs, which are segmented in cor-
respondence with the myotomes and are placed in the
lateral wall of the atrium at the ventral ends of the myo-
tomes, dehisce their products into the atrial cavity by
rupture of their walls. From the atrium the generative
products pass to the exterior usually through the atrial
pore, but in some cases, according to the observations of
Kowalevsky and Hatschek on the living, and of Marshall on the
preserved animal, they occasionally pass from the atrium through
the gill-slits into the pharynx and are spawned by the mouth.
Spawning takes place at sundown only and fertilization is effected
either in the sea or in the atrium.
In a fully-developed Amphioxus lanceolatus the gonads are
somewhat cubical bodies, twenty-six in number on each side.
THE EGG. 31
The first of them appears to be placed at the ventral end of
myotome 10, and the last at the ventral end of myotome 35 just in
front of the atriopore. They are contained in coelomic sacs,
which in development are derived from the ventral ends of the
myotomes, and to the wall of which they are attached.
The phylum possesses only a single genus* Amphioxus Yarrell (Branch-
iostoma Costa). It is found in all seas. About ten species are known.
They differ in the number of myotomes, the presence or absence of a
caudal expansion of the median fin, the presence of gonadial sacs on one
or on both sides of the body, the continuity of the right metapleur with
the anal fin or the cessation of both right and left metapleur behind the
atrial pore ; the presence or absence of fin-rays and fin-ray spaces in the anal
fin. There appears to be a considerable range of meristic variation in some
of the species (Punnett). A. lanceolatus Pallas, Europe and most seas ;
A. bassanum Giinther, right metapleur continuous with anal fin, gonads
on right side only, anal fin with fin-rays and fin-ray spaces, Bass Straits ;
A. cultellum Peters, like the last, anal fin with chambers but without rays,
Torres Straits ; A. lucayanum Andrews, like the last, but without caudal
fin, hind end of body being a urostyle-like process without myotomes, and
fin-rays and chambers absent from anal fin, Bahamas.
It has been suggested that one or two species are pelagic, but this is
uncertain.
Development. The development of Amphioxus presents some
remarkable features, and contrary to our usual custom we have
decided to give a full account of it in this work. Though
strangely similar in many of its features to the type of develop-
ment found in the Vertebrata, it presents some very marked
features of difference. Of these we may at once mention the
small size of the ovum, the archenteric origin of the coelom, the
absence of any nephridial apparatus comparable to that of
the Vertebrata, the origin of the gonads from the myocoel, and
the extraordinary asymmetry of the larva.
Our account is based upon the important researches of
Hatschek and Willy, who, as is well known, worked at the
species found in the Pantano at Faro in Sicily.
The egg is small ('1 mm. in diameter), is surrounded by a vitel-
1'ne membrane and contains but a small quantity of yolk, which
is uniformly distributed. Only one polar body is attached to the
ovum after deposition ; it is probable that this is the second,
* By some zoologists the phylum has been broken up into genera and
rkaldy, Q.J.M.S., 37, 1895, p. 303), but this, considering
er of species and points of difference, seems hardly necessary
32
PHYLUM CEPHALOCHORDA.
the first having been formed in the ovary and rubbed off during
the dehiscence. The segmentation is complete and almost equal ,
the segments of the lower pole being slightly larger than those
of the upper. It leads to the formation of a hollow blast o-
FIG. 14. — Cleavage of Amphioxus (after Salensky from Korschelt and Heider). A egg before
cleavage, with polar body ; B two-cell stage ; C four-cell stage ; D the same seen from the
upper surface ; E eight-cell stage ; F sixteen-cell stage ; G stage showing more rapid division
at the animal pole ; H the same in section ; / surface view of blastosphere.
sphere (Fig. 14). This becomes invaginated to form a cup-
shaped gastrula (Fig. 15). The blastopore, at first wide, snrm
narrows to a small opening placed at the hind end of the future
dorsal surface. The embryo now elongates in the direction of
the antero-posterior axis (Fig. 16), and the ectoderm of the dorsal
MEDULLARY CANAL.
33
surface becomes more columnar to
form the medullary plate (Fig. 17).
As the medullary plate extends to the
hind end of the dorsal surface, the
blastopore is included in it. The
lateral part of the ectoderm now be-
comes detached from the medullary
plate, and grows over it (Fig. 17).
This overgrowth begins at the hind
end of the medullary plate, so that
the blastopore is covered over and
comes to open into the space between
the overgrown ectoderm and the
medullary plate (Fig. 18). I Later the
medullary plate curves over dorsally
(Fig. 17), and by the junction of its
two lateral edges forms the walls of the
medullary canal (Fig. 26). From what
has been said it is clear that the
medullary canal, which is gradually
developed from behind forwards, opens
posteriorly into the archenteron by
the
the
medullary canal becomes the central
canal of the nervous system, the
blastopore is henceforward known as
Hhe neur enteric canal. It closes soon
after the commencement of larval life.
The anterior neuropore persists
throughout
the blastopore and anteriorly to
exterior by the neuropore. As
0
FIG. 15.— Formation of the
gastrula of Amphioxus (from
Claus, after Hatschek). A blas-
tosphere ; B commencing in-
vagination of the lower surface
of the blastosphere to form
the endoderm ; C later gas-
trula ; all in optical section ;
0 anterior lip of blastopore.
The cilia of the ectoderm are
omitted.
larval life and only
closes on the attainment of the
adult state. It marks the site of
the olfactory pit.
Meanwhile two pairs of dorsb-
lateral outgrowths of the archen-
teron are formed (Figs. 17, 18).
The anterior of these retain their
communication with the archen-
•hdtrfanTHeidiear)SChek teron for some 'time and give rise
D
34
PHYLUM CEPHALOCHORDA.
to the somites of the first pair. They are the " collar " somites
of MacBride (Fig. 19, 6'). The posterior outgrowths constitute
the coelomic grooves of MacBride. They remain open to the
gut for a considerable time behind, but as growth progresses
they are continually constricting off sacs anteriorly (Fig. 19, 5).
Eventually when about fourteen pairs of somites have been
formed they become separate from the endoderm of the arch-
enteron and form a solid plate on each side from which the
remainder of the somites are successively developed. In addition
to these two pairs of archenteric outgrowths there is a median
anterior outgrowth (Fig. 19, /). This grows back on each side
FIG. 17. — Transverse section through two embryos of AmpMoxus to show the enclosure of
the medullary plate and the formation of the coelcmic pouches. A section through an em-
bryo with the rudiment of one pcuch and of the notcchord. £ section through a slightly
older embryo, showing the complete separation of a coelomic poueh from the archenteroii
(from Korschelt and Heider alter Batscfcek) ; ok ectodeim ; ch rudiment of r.otochord ;
hb lateral ectoderm growing over the medullary plate ; ik, U endoderm*; Ih entejon
Ik future coelcm ; ntk coelcmic rcuch (future scmite) ; np medullary plate.
and becomes separated from the gut as a single cavity with two
backwardly projecting horns. This unpaired anterior sac gives
rise to the head cavities ; it becomes divided into two, of which
the right shifts ventrally, becomes thin-walled, and forms the
cavity of the snout in the larva (Fig. 20). It becomes largely
obliterated in the adult. The left head-cavity, on the other
hand, becomes transversely placed beneath the notochord and
opens to the exterior on the left side in front of the mouth
(Fig. 20, w). It becomes the preoral (Hatschek's) pit, and gives
rise by the extension of its lips to the wheel organ (p. 20). The
collar-somites (so-called first pair) and the somites developed
from the coelomic groove give rise to the mesoderm, bo
HATCHING.
nip
and generative organs in a manner de-
scribed below. The collar-somites send
forward a process dorsal to the head
cavities on each side, the walls of
which give rise to the mesodermal
structures of the preoral region.
"While these changes have been tak-
ing place the notochord is developed.
It arises as a groove of the dorso-
median endoderm (Fig. 17 B], .which
is constricted off so as to form, a solid
rod of cells lying between the dorsal
endoderm and the medullary plate. It
develops from before backwards, ex-
cept the front portion, which separates
from the endoderm later than the
rest and extends to the anterior end
of the body.
The embryo becomes hatched and
begins to swim freely in the sea by
means of the cilia of the ectoderm cells at about the stage of
Fig. 18, about twelve hours after fertilization. But it remains
opaque and, being incapable of taking in food, is generally spoken
of as an embryo until about the thirty-sixth hour, when the yolk
is sufficiently absorbed to leave the tissues transparent, and the
mouth, anus, and first gill-slit are formed (Fig. 20).
The mouth is
formed on the
left side ; the
first gill -slit on
the ventral
FIG. 18. — Longitudinal- vertical
section through an embryo of
Amphioxus with the rudi-
ments of two somites (after
Hatschek). mp pole-cells, the
existence of which is now
denied ; mr uncovered part of
medullary plate ; mr1 space
between the medullary plate
plate and overgrown ectoderm
(future medullary canal );
us', us" mesoblastic somites.
moving on to
the right side,
and the anus at
the hind end of
FIG. 19. — Diagrammatic longitudinal section through an embryo «"® body Slightly
of Amphioxus, to show the formation of the coelomic sacs. f_ fr_ .. i-ff _f fu _
The figure combines features which in reality would only be u
shown by two sections. 1 neuropore ; 2 neural canal ; 3 neuren- ^ j^lp linp
teric canal ; 4 coelomic groove ; 5 somite constricted off from ""V**1 Line,
anterior end of coelomic gro<5ve ; 6 cavity of first mesoblastic T'Tio IQT»TTC»I
somite (so-called collar cavity) ;_"? head cavity ; 8 archenteron. L * L v ** L
36 PHYLUM CEPHALOCHORDA.
stage lasts for about three months, during which the larva
swims freely usually at a considerable depth by the contrac-
tion of its body, and acquires the adult form and habits. The
principal changes which take place relate to the formation of
the gill -slits, of the preoral hood, and symmetrical adult mouth,
and of the atrial cavity.
The mouth acquires a gigantic size and forms a most con-
spicuous object on the left side of the body (Figs. 21, 22). The
gill-slits are formed successively on the ventral middle line to the
number of fourteen.* All of these except the last few shift
soon after their formation on to the right side. They corre-
spond in number to the myotomes in the part of the body
FIG. 20. — Ampfiioxus larva of about thirty-six hours from the left side, when the preoral pit-
mouth, first gill-slit and anus are established (from Korschelt and Heider after Hatschek);
c larval caudal fin ; ch notochord ; en neurenteric canal ; d alimentary canal ; h right preoral
sac ; k club-shaped gland, which has acquired an opening to the exterior on the left side
ventral to the mouth ; ks first gill-slit ; m mouth ; mr nerve tube ; np neuropore ; sv sub-
intestinal vein ; w preoral pit (left head cavity).
in which they occur, but this relation is ultimately lost,
when they become more closely packed and the myotomes
increase in size. Of these fourteen first-formed gill-
slits the first and the last five close up, so that eight only are
left.
atrial folds arise as ridges of the skin. Posteriorly they
lie close together in the middle line enclosing between them a
small groove (Fig. 23). Anteriorly they pass on to the right
side, one on either side of the gill-clefts. By the union of these
ridges, which begins in their posterior region and gradually
extends forwards, the groove becomes converted into a canal,
* These first formed gill-slits are -often called the primary gill-slits, in
contradistinction to the later formed secondary slits which, when the
animal becomes symmetrical, are placed on the right side, the primary
slits having passed over to the left side. Forster Cooper (op, cit.) describes
a larva taken in the open ocean in the Maldive Archipelago containing as
many as thirty-one primary slits.
fs|
37
38 PHYLUM CEPHALOCHORDA.
the atrial cavity (Fig. 23). At their hind end they remain
separate, thus giving rise to the atriopore. At first the atrial
cavity is a small canal restricted to the ventral side of the
pharynx. Later it becomes larger and acquires the adult
relations.
Meanwhile a row of eight or nine gill -clefts appear on the right
side of the body dorsal to those first formed (Figs. 24, 25). Both
sets of gill-clefts acquire the U-shaped form, the tongue bar being
developed (except in the first cleft (Fig. 25) which remains
simple). The first-formed clef ts then shift on to the left side of
the body, and become the gill-clefts of the left side. At the
same time the mouth shifts to the middle line, and the preoral
ZT
FIG. 23. — Ventral view of three larval stages of Amphioxus (after Lankester and Willey*
from Korschelt and Heider) ; A, the atrium is still entirely open ; B, the atrium is partially
closed behind ; C, the atrium is almost completely closed ; ap atriopore ; k gill-slits ;
If left atrial fold ; m mouth ; rf right atrial fold ; w preoral pit.
hood which had made its first appearance while the mouth was
still on the left side becomes developed. The apertures of the
club-shaped gland (see below) and of the ciliated pit are both
enclosed by the preoral hood. The original mouth opening
shifts to the back of the oral cavity and persists as the aperture
in the velum.
The principal phases of the development are now accom-
plished and the larva, in the main symmetrical, assumes the
sand-burrowing habits characteristic of the adult.
The mesoblastic somites, after their separation from the
archenteron, which after that event is termed simply enteron,
extend ventralwards on each side (Fig. 26), till they meet on the
SOMITES.
39
ventral side of the alimentary canal. The septum between them
(ventral mesentery) breaks down and the somites of the two
sides become continuous.
FIG. 24. — Two larval stages of Amphioxus from the right side, showing the origin of the gill-
clefts of the right side of the adult (from Korschelt and Heider, after Willey). 1. 2,
9, 12, 14 first, etc., to fourteenth gill-cleft of future left side • /, VII first and seventh
of the later formed set which eventually belong to the right side ; au eye-spot ; ch noto-
chord ; dr club-shaped gland ; es rudiment of endostyle ; fh dorsal, /&' ventral fin spaces ;
k rudiments of the later formed gill-clefts ; m margin of mouth ; mf edge of right
metapleure ; n nerve cord ; p atrial cavity ; si sub-pharyngeal vessel ; ^v velum ; w
preoral pit.
FIG. 25. — Ventral view of Amphioxus larva, rather later than Fig. 24 (from Korschelt and
Heider, after Willey). 2 second, 12 vestige of twelfth cleft of the first-formed row, now
passed on to the left side ; I, VIII first and eighth of the later formed clefts of the right
side ; be buccal cirri ; ch notochord ; [es endostyle ; m mouth (larval) ; v velum. ;
At the same time a septum is formed, dividing off the dorsal
part of the somites from the ventral. The dorsal part becomes
40
PHYLUM CEPHALOCHORDA.
the myotome ; it retains its original segmentation and the septa
separating the successive somites here persist as the myosepta
(intermuscular septa). In the ventral portion (comparable to
the lateral mesoblastic plate of the Vertebrata) the transverse
septa, formed by the adjacent walls of the successive somites of
the same side, break down and the cavities of the somite become
continuous to form the splanchnocoele or body-cavity of the
adult. The cells of the inner wall of the myotome become con-
verted into muscles, and consti-
tute the lateral muscles of the
adult, while the outer wall
which is applied to the ectoderm
mk"
FIG. 26. — Transverse section through
the middle of the body of an Amphi-
oxus embryo with 11 somites. On the
right side the section has managed to
cut two somites (from Korschelt and
Heider) . ak ectoderm ; ch notochord ;
dh enteron ; ik endoderm ; Ih coelom ;
mk' somatic, mk" splanchnic layer
of mesoderm ; n nerve tube ; us meso-
blastic somite.
FlO. 27. — Transverse section of
the middle of the body of an
^ Amphioxus larva with five
^ gill-slits, diagrammatic (from
Korschelt and Heider). 1
j outer wall of myotome (cutis
i layer) ; 2 inner or muscular
wall of myotome ; 3 com-
mencement of the sclerotome ;
4 septum between myocoele
and splanchnocoele : 5 somatic
mesoderm ; 6 splanchnic
mesoderm ; I myocoele ; //
splanchnocoele. The sub-in-
testinal vein is shown in the
splanchnic mesoderm.
remains thin (Fig. 27). The sclerot'ome is an outgrowth
from the ventral and inner wall of the myocoele (Fig. 27). It
acquires a considerable development extending dorsalwards
between the muscles and the notochord and spinal chord (Fig. 28).
Its inner wall gives rise to the sheath of the notochord and of the
nerve cord, while its outer wall forms the so-called fascia-layer,
or internal sheath (Fig. 29).
The dorsal part of the myocoele is said to give rise to the
dorsal fin canal ; and a ventral extension of the same space to
the ventral fin canal. The myocoele appears to abort in the
adult, but the sclerocoele probably in part persists as the lymph
spaces on the internal sides of the lateral muscles.
GOXADS.
41
In the region of the pharynx, the atrial cavity extends dorsal-
wards between the splanchnocoele and the ventral extension of
the myocoele (Fig. 29), and the splanchnocoele becomes cut up
by the gill- clefts into the sections of the coelom already described
as occurring in the primary pharyngeal bars (p. 24). The dorsal
and ventral regions of this part of the splanchnocoele furnish
the dorso-pharyngeal (sc) and endostylar coelom (ec) respect-
ively.
The first rnyotome is developed from
the somites of the anterior pair, the so-
called collar somites (p. 34), which retain
their communication with the enteron
longer than the others. This communi-
cation on the left side becomes elongated
and gives rise to Hatschek's nephridium,
(Fig. 9,20). These somites send back ven-
tral extensions which lie in the developing
atrial folds. It has been suggested that
these give rise to the metapleural lymph
canals, but this has been denied. The
origin of the metapleural lymph canals
is not certainly known.
Van Wijhe in his recent important
paper (op. cit.) states that the walls of
the collar cavity give rise to several
myotomes. It is not quite clear to us
whether this statement is based on em-
bryological study or not. He further
states that the second myotome of the
body is the anterior of these myotomes
which come from the collar-somite ; thus
implying that the walls of the head
cavities (preoral somite) give rise to a
myotome. So far as we know, the head
cavities do not give rise to myotomes.
The collar-coelom appears to give rise to
the stomocoel and cavum epipterygium
of van Wijhe, who states that the cavum epipte
the metapleural canals. This confirms MacBri
metapleural lymph canals are parts of the coll
epipterygium is also stated to communicate "with the endostylar cafbin.
through the coelom in the first branchial arch, which, being part m the
splanchnocoele, it might reasonably be expected to do. The arrangement
of the parts of the coelom about the mouth as explained by van Wijhe is
complicated.
The gonads are segmented in their origin. The generative
cells are first seen as the thickenings of the coelomic epithelium
at the ventral ends of the myotomes, on the anterior wall of the
FlG. 28. — Transverse section through
a young Amphioxus immediately
after metamorphosis, between the
atriopore and the anus, diagram-
matic (from Korschelt and Heider,
after Hatschek). 1 outer wall of
myotome (cutis layer) ; 2 muscles ;
3 fascia layer (outer wall of sclero-
toj»e ; 4 skeletogenous (inner)
w» of sclerotome ; 5 u 6 ventral
continuation of skeletogenous
layer and somatic wall of splanch-
nocoele ; 7 splanchnic ditto ; /
kj /' dorsal /* ventral fln-
! splanchnocoele.
communicates wit
statement that
coelom. The ca
42
PHYLUM CEPHALOCHORDA.
myocoele. They soon come to project into the cavity of the
somite in front, pushing the myosepta before them (Fig. 30).
FIG. 29.— Transverse section through the branchial region of Amphioxus showing on^the left
the condition of a secondary, and on the right that of a primary gill-bar, diagrammatic
(after Boveri and Hatschek, from Korschelt and Heiderj. ao aorta ; c cutis layer of
myocoele ; ec endostylar coelom ; / fascia layer ; fh dorsal fin canal ; p genital sac ; gl renal
vessels ; k vessel in primary bar ; kd pharynx ; Id ligamentum denticulatum ; mfmuscle-
plate ; mt transverse muscle ; n renal canal"; of metapleural lymph space ; p atrial ca\ :ty ;
sc dorsopharyngeal coelom ; si sub-pharyngeal vessel ; sk skeletogenous layer of sclerotome ;
«/ lymph canals of the atrial floor.
They lie therefore as small sacs in the preceding myocoele
attached to its hind wall by a pedicle (Figs. 30 (7, 31). Later, the
part of the myotome in which they lie becomes separated from
ENDOSTYLE.
43
the rest and forms the perigonadial coelom which lies in the
outer wall of the atrium (Fig. 10).
The club-shaped gland and endostyle. The club-shaped gland
B
FIG. 30. — A, B, C. — Three side views of the ventral end of a niyotome of a young Amphipxus,
showing the development of ihf genital rudiment and its projection into the cavity of
the preceding somite (from Korschelt and Heider, after Boveri).
is developed as a transverse groove on the floor of the pharynx
and continued on to the right and left walls. It becomes con-
stricted off from the pharynx, and acquires an opening to the
exterior on the left side of the body just in front of the mouth.
Later on the right end of it acquires an opening into the pharynx.
The club-shaped gland is of unknown function and eventually
atrophies. It has been suggested
without any obvious justification
that it is the metamorphosed an-
terior gill of the right side.
The endostyle is a ciliated tract
of columnar epithelium just an-
terior to the club-shaped gland
on the right side (Fig. 24). It
subsequently becomes bent on
itself in a V-shaped manner
(Fig. 25), and grows backwards
between the two rows of gill-
slits. It is at first, therefore,' on
the right side of the body, but
when the larva becomes sym-
metrical, it takes up its position
in the ventral middle line.
From the above account it is
clear that in the young larva
-bni
FIG. 31. — Transverse section through
the genital rudiment of a young
Amphioxus showing the separation
of the perigonadial coelom from
the myocoele. bm ventral muscle;
g blood-vessel ; gd gonad ; w fold
separating myocoele from peri-
gonadial coelom.
44 PHYLUM CEPHALOCHORDA.
the future ventral middle line of the pharyngeal region
is on the right side of the body as shown by the first
trace of the subpharyngeal vessel, the endostyle and the gill-
slits ; whereas in the buccal region later median structures are
on the left side. It results from this that, at the so-called
metamorphosis when the larva becomes symmetrical, the buccal
region of the body and the pharyngeal regions must rotate, so
to speak, in opposite directions.
No satisfactory explanation of this extraordinary larval
asymmetry has even been suggested. Though largely rectified
in the adult a 'trace of it persists in the slightly asymmetrical
position of the olfactory pit, the anus, and the continuity of the
cephalic fin with the right side of the preoral hood, and in the
innervation of the preoral hood (p. 18).
CHAPTER III.
PHYLUM VERTEBRATA* (CRANIATA).
Chordata in which the dorsal nerve cord extends some distance
in front of the notochord, and is expanded at its anterior end into
a brain. The axial skeleton is divided into an unsegmented
cranial portion, which surrounds the brain, and a segmented
vertebral portion which forms the axis of the body and protects
the spinal cord.
The various animals included in this phylum were first put
together by Aristotle, who called them " animals with blood " ;
he also recognized the possession of a bony or cartilaginous
skeletal axis as a common characteristic. But it was Lamarck
who first adduced the presence of a vertebral column, as a most
important character, and introduced before Cuvier the name
of Vertebrata into the science. This term, however, is not
entirely appropriate, for in some Pisces the sheath of the noto-
chord is not segmented, and there are no vertebrae (Marsi-
pobranchii, Dipnoi, some Ganoidei). Nevertheless, the term
may fairly be retained, for not only has it the sanction of long
usage, but the cases in which the vertebral column is not jointed
are few in number and unimportant in character. As already
pointed out, the segmentation of the vertebral column is corre-
* Stannius, Handbook der Anatomic ' der Wirbelthiere, 2nd ed., Berlin,
1854. Rathke, Beitrdge zur Bildungs und Entwickelungsgeschichte des
Menschen und der Thiere, Leipzig, 1833. Owen, The Anatomy of Vertebrates,
3 vols., London, 1866-68. Huxley, A Manual of the Anatomy of Verte.brated
Animals, London, 1871. Gegenbaur, Vergleichende Anatomic der Wirbelthiere,
Leipzig, 1898, 1901. Zittel, Handbuch der Palaeontologie, Munich, vols.
iii., iv., 1887-93 ; and Grundziige der Palaeontologie, Munich, 1895.
(English translation, Macmillan and Co., 1900). A. S. Woodward, Out-
lines of Vertebrate Palaeontology, Cambridge, 1898. Balfour, Comparative
Embryology, vol. ii., 1882. C. S. Minot, Human Embryology, New York,
1892.
40 PHYLUM VERTEBRATA (CRANIATA).
lated with its rigidity, and is therefore best developed in
those animals which have to support the body on land.
The integument consists of two distinct layers, the epidermis
externally and the cutis internally. The epidermis is composed
of many layers of cells, of which the upper and older layers are
worn off, while the lower layer (stratum malpighi) is actively
growing, and serves as a matrix for the continual renewal of
the upper layers, and sometimes contains pigment. The cutis
is principally formed of fibrous connective tissue, with which
muscular elements — striped and unstriped — come into relation
without however forming a dermo-muscular envelope, as in the
Annelids. Some of the appendages of the skin are epidermal
structures (hairs and feathers). Some are derived from ossi-
fications of dermal papillae, which sometimes may even give
rise to a hard and complete dermal armour (scales of fishes and
reptiles, carapace of armadillos and tortoises). The epidermis
is derived from the ectoderm of the embryo, the cutis or dermis
being mainly a mesodermal product.
The endo-skeletal tissue of the lower Vertebrata and of all
vertebrate embryos consists solely of cartilage (Marsipobranchii,
Elasmobranchii), but in most groups osseous tissue, supple-
menting or, in the higher forms, largely replacing the cartilage,
is present in the adult.
The muscular tissue may be divided into two categories :
They are (1) the somatic or myotome muscles, which are derived
from the epithelial wall of the myotomes or dorsal segmented
parts of the mesoblast of the embryo, and (2) the mesenchyma-
tous * muscles, which are developed from the ventral part of
the mesoblast (wall of the splanchnocoel). The myotome
muscles are innervated exclusively by the ventral roots of the
spinal nerves, and by the third, fourth and sixth cranial nerves,
which are the only ventral nerve roots found in the brain. The
mesenchymatous (visceral) muscles, which appear to be derived
from mesenchymatous mesoderm, are innervated by the ventral
roots in the trunk, but in the head by the fifth, seventh, ninth
and tenth cranial nerves, which are usually regarded as dorsal
nerve-roots, and which contain also afferent nerve fibres (see
account of nerves under Pisces). The somatic muscles are cross-
* Sometimes called visceral, but this is a bad name, as many of them
lie in the body-wall.
NERVOUS SYSTEM. 47
striped and voluntary. The mesenchymatous muscles for the
most part consist of unstriped fibres, but some of them are
cross-striped, and even voluntary. The muscles of the heart
and oesophagus are examples of cross-striped mesenchymatous
muscles in the trunk ; they are not under the control of the will.
In the head many of the mesenchymatous muscles are cross-
striped and voluntary ; e.g. the facial muscles, the mandibular
and the branchial muscles. The eye-muscles are myotome
muscles, and supplied, as stated above, by ventral roots ; but
they differ from the muscles of the great lateral sheet of myotome
trunk muscles in the fact that their fibres are directed dorso-
ventrally, and not longitudinally, as in the latter.
The dorsal nerve-cord extends in front of the notochord, and
is enlarged in front to form the brain, which is constructed on
the same fundamental plan in all classes. The posterior part
constitutes the spinal cord. The skeletal investment of the
brain is unsegmented, and constitutes the skull, while the spinal
cord lies in a tube of the vertebral column, which always shows
some sign of segmentation and is usually completely segmented.
The spinal nerves, which are segmentally arranged, possess
two roots, a dorsal and a ventral, which join. The dorsal of
these roots carries a ganglion and contains afferent nerve fibres ;
the ventral contains efferent fibres only. The brain possesses
ten pairs of nerves, which are very similarly arranged in all
Vertebrata. They differ from the spinal nerves in the fact
that except in the case of three of them, they have the dorsal
roots only. The third and sixth nerves may be regarded as
the ventral roots of the fifth and seventh nerves respectively,
and the fourth nerve must also be regarded as a ventral root,
though it arises from the dorsal surface of the brain. The ninth
and tenth nerves appear to be altogether without ventral roots.
In the higher Vertebrata there are two additional pairs of cranial
nerves, the eleventh and twelfth. Of the cranial nerves, the
fifth, seventh, eighth, ninth and tenth are usually regarded
as being serially homologous with the posterior roots of spinal
nerves, and are supposed to be related to a vanished segmenta-
tion of this part of the body.* They resemble these in having
* A short account of the modern views on the nature of cranial nerves
and of nerves in general, and of cranial segmentation is given in the
chapter on Pisces.
48 PHYLUM VERTEBRATA (CRANIATA).
a ganglion, but, with the exception of the eighth, they differ
from them in containing a fair proportion of efferent nerve
fibres. The first and second cranial nerves, which supply the
special sense organs of smell and sight respectively, appear to
differ fundamentally from the other cranial nerves.
In all Vertebrata there are three organs of special sense on
the head, the olfactory and visual, the innervation of which
has just been referred to, and the auditory, which is supplied
by the eighth cranial nerve. The connection of these organs
with the head has profoundly modified the structure of both
skull and brain.
A special visceral nervous system, known as the sym-
pathetic, is nearly always present.
The alimentary canal presents very similar features through-
out the series. It consists of a stomodaeum, pharynx, voeso-
phagus, stomach, intestine. The stomodaeum contains the
teeth and the openings of the salivary glands if present, and
passes without any line of demarcation into the pharynx, which
in all Vertebrata is at some time of life connected with the ex-
terior by lateral apertures, the pharyngeal apertures or visceral
clefts. These are never more (usually less) than eight in number
on each side.* In Fishes and Amphibia the first of these (spiracle)
is always smaller than the others and may be completely absent ;
in the Amniota (Reptilia, Aves, and Mammalia) it is always
present, and not smaller than the others. In Fishes and
Amphibia the visceral clefts are used for respiratory purposes
as in other Chcrdata, but they are never put to this use in the
Amniota, where they appear to have no function at all. In
such cases the respiratory organ of the adult is the lung, which
is developed as a median outgrowth of the ventral wall of the
pharynx. There are two other nearly constant features
of the vertebrate alimentary canal, viz. (1) the connection of
two large glands, the liver and pancreas, with the anterior part
of the intestine, and (2) the connection of the generative and
renal organs with the hind end of the intestine, which is com-
monly called the cloaca. The junction of the endoderm and
ectoderm appears to take place at the anus, and there is prac-
tically no proctodaeum in the Vertebrata.
* Except in some Marsipobranchs;
PHYLUM VERTEBRATA (CRANIATA). 49
The vascular system is well developed, consists of arteries,
capillaries and veins, and contains a red blood. There is a
median ventral subpharyngeal vessel, the hinder end of which
is especially muscular and contractile and differentiated as
the heart. The lymphatic system consists of vein-like
vessels containing a colourless fluid — the lymph — in which
float numerous amoeboid cells (lymph corpuscles). .These
vessels commence by blindly-ending fine tubes or sinuses in
the tissues, which gradually unite with one another to form
the main lymph vessels, which open into the venous system.
Special gland-like bodies, the so-called lymphatic glands, in
which the lymph corpuscles are produced, are inserted in the
course of the lymphatic vessels. The lymphatic system is a
draining system, for the purpose of carrying away from the
tissues the fluid which has exuded into them through the walls
of the blood-capillaries, and is undoubtedly a specially differ-
entiated part of the vascular system.
The body-cavity is a coelom, and has the usual relations
of that organ to the urinary and reproductive organs. It is
laid down early, making its appearance as a split (schizocoel)
in the mesoblast ; and in the Elasmobranchii, at any rate, a
certain resemblance between it at its first appearance and that
of Amphioxus can be detected (p. 33). But it differs from
that of Amphioxus in that the ventral portions of the trunk
somites are never distinct from one another, but form from
the first a continuous splanchnocoel. In the adult the
body-cavity is always divided more or less completely into
a pericardial division in front and a peritoneal division or general
body-cavity behind. In the mammals the latter is still further
subdivided, in that two anterior horns are cut off from it to
form the pleural cavities. There is no coelom in the head of
adult vertebrata.
The urinary organs consist typically, in their origin at
least, of segmentally arranged nephridia, which open internally
into the body-cavity. Externally they open into a longitudinal
duct which leads into the hind end of the intestine in almost
all cases. Both nephridia and ducts develop as special portions
of the coelom.
The generative organs develop from the lining of the
unsegmented ventral part of the coelom (splanchnocoel), and
z — TI E
.XTTiTAl
f^^ OF THE
I UNIVERSITY
50 PHYLUM VERTEBRATA (CRANIATA).
never present any trace of segmentation.* In the female they
retain this relation throughout life (except in Teleostei), but
in the male the generative part of the coelomic epithelium
always (except in Marsipobranchii) loses its relation with the
general body-cavity in the adult.
The ovum varies considerably in character in the different
classes. In Pisces (except Elasmobranchii) and in Amphibia
it is comparatively small and holoblastic,f and the young are
always hatched out in an immature condition as larvae. In
Elasmobranchii, Reptilia, and Aves the ovum is large and
meroblastic, and the young when hatched resemble the adult,
a larval stage being absent. In Mammalia the egg is smaller
than in any other Vertebrate, and except in one class under-
goes almost the whole of its development in the oviduct, the
young being born in a condition closely resembling the adult.
An amnion, allantois and primitive streak are found in the
embryos of all Reptiles, Birds and Mammals, but are absent
from all Pisces and Amphibia.
The division of the Vertebrata into the four classes — Pisces,
Amphibia, Aves, and Mammalia was first established by
Linnaeus, though it had already been indicated in the system
of Aristotle. The Pisces and Amphibia are cold-blooded
animals (i.e. animals with a varying temperature) ; Aves and
Mammalia are warm-blooded. Since Linnaeus' day, his group
Amphibia has been split up into the naked Amphibia and into
the scaly animals or Reptilia. Pisces and naked Amphibia
have many characters in common, e.g. the branchial respiration,
the frequent persistence of the notochord, the absence of an
amnion and allantois, etc. On these grounds and in con-
sideration of the many relations between Reptiles and Birds,
Huxley has distinguished three principal groups of Vertebrata
—the Ichthyopsida (Pisces and Amphibia), the Sauropsida
(Reptilia and Aves), and the Mammalia.
* See note on p. 88.
f In Teleostei the ovum though small is meroblastic.
CHAPTER IV.
CLASS PISCES.*
Aquatic vertebrata which breathe by means of pharyngeal gills
and possess typically two pairs of appendages which never present
any trace of a pentadactyle structure. Median fins supported, except
in Marsipobranchs, by dermal fin-rays (dermotrichia) are always
present. There are ten pairs of cranial nerves and paired posterior
cardinal veins.
Fishes are sharply marked off from all the other classes of
Vertebrata by the form of their pectoral and pelvic appendages.
These, which must be regarded as homologous with the limbs
of the higher groups, are cutaneous expansions supported by
skeletal structures, which, though presenting in their fan-like
arrangement some distant resemblance to the skeletal structures
of the pentadactyle limb, are yet never arranged on the penta-
* Lacepede, Histoire naturelle des Poissons, 6 vols.r Paris, 1798-1803.
G. Ouvier et Valenciennes, Histoire naturelle des Poissons, 22 vols.,
Paris, 1828-1849. Baer, Entwickelungsgeschichte der Fische, Leipzig,
1835. J. Miiller, Vergleichende Anatomie der Myxinoiden, Berlin, 1835-
45. Id. Ueber den Bau u. die Grenzen der Ganoiden u. d. natiirliche
System der Fische, Abh. d. Berlin, Akad, 1846. L. Agassiz, Recherche*
sur les Poissons fossiles, 5 vols. Neuchatel, 1833-44. Stannius, op.
cit. Heckel and Kner, Die Susswasserfische von der osterreischischen
Monarchic, Leipzig, 1858. A Dumeril, Ichthyologie, etc., 2 vols., Paris,
1866. Siebold, Die Susswasserfische von Mitteleuropa, Leipzig, 1863.
Blanchard, Les Poissons des eaux douces de la France, Paris, 1866. Cope,
" Classification of Fishes," Trans. Amer. Phil. Soc., 1870, and Proc.
Amer. Ass. for Adv. of Science, 1871. A. Gunther, Introduction to the Study
of Fishes, Edinburgh, 1880; and Catalogue of Fishes in the British
Museum, vols. i-viii., 1859-1870. A. S. Woodward, Catalogue of Fossil
Fishes in the British Museum, 3 vols. London, 1889-95. F. Day, The
Fishes of Great Britain and Ireland, London, 1881-83. Jordan and Ever-
man, Fishes of North and Middle America, Bull. U. S. National
Museum, no. 47, Pts. 1-4, 1896-1900. T. W. Bridge, Fishes in the Cam-
bridge Natural History, 1904. G. A. Boulenger, Poissons du Bassin du
Congo, 1901.
52 CLASS PISCES.
dactyle plan. The ichthyopterygium, though clearly homolo-
gous with the cheiropterygium, is sharply marked off from it,
and there are no intermediate forms connecting the two.
Though the structure of the limb skeleton, and possibly the
possession throughout life of the paired posterior cardinal veins,
are the only absolutely characteristic features of fishes, there is a
number of features which, while not distinctive, are highly
characteristic. We may enumerate some of these :—
1. Median unpaired folds of the integument, constituting
the unpaired fins and supported by dermal structures called
fin-rays or dermotrichia, would be absolutely characteristic
were it not for the fact that the fin-rays are absent from the
median fins of Marsipobranchii.
2. The absence of an internal opening of the nasal sac would
be absolutely characteristic of the class were it not for the
presence of internal narial openings in Dipnoi and of the pharyngo-
nasal duct in Myxinoids.
3. Respiration by means of lateral pharyngeal apertures and
gills is found in the adult in no other group excepting in a few
genera of the Amphibia.
4. The absence of a cloacal bladder might perhaps be cited
as a distinctive character, for it is present at least in the embryos
in all the higher Vertebrata.
5. Excepting in the Dipnoi the auricle is undivided, and the
ventral aorta is a tube of considerable extent.
6. Excepting in the Dipnoi there is nothing corresponding
to the median inferior vena cava of the other classes.
7. The absence of a tympanic cavity and membrane, and of
anything corresponding to the auditory ossicles of the higher
types may, we think, be cited as a distinctive character, for
these structures are very rarely, if ever, completely absent in
the other classes.
8. The presence of the peculiar sense organ known as the
lateral line might almost be regarded as a piscine character,
were it not for the fact that it is not clearly present in all
Marsipobranchii, and that it is found in some Amphibia.
9. The permanent division of the great lateral longitudinal
muscles of the body into segments (myotomes) corresponding
in number to the vertebral segments is only found outside
Pisces in some Amphibia, and in the tail of some Repbelia.
SCALES. 53
The epidermis contains large mucous cells which discharge
their contents on the surface. It may also contain pigment
cells and leucocytes. In many fishes the slime which is excreted
by the skin is poisonous.
The skin is seldom completely without skeletal structures
(Marsipobranchii). As a rule scales, formed as ossifications
of dermal papillae which are typically completely covered by
the epidermis, are embedded in it. Fish scales * are of three
principal kinds : (1) Placoid scales which consist of small
plates of bone in the dermis carrying an upstanding spine which
projects freely, and is formed of dentine capped with enamel.
These are found in Elasmobranchii and some Ganoids. (2)
FIG. 32.— Perca ftuviatttis (RSgne animal).
Ganoid scales are bony plates covered with a smooth layer of
a substance called ganoin. Ganoin f is a dermal product
allied to vitro-dentine. These scales are entirely dermal, and
if their surface is exposed, it is owing to the fact that the epidermis
has been rubbed off. Such scales are found in most Ganoids.
(3) Scales of varying thickness consisting of bone only, without
ganoin. They are found in most Teleosteans, and are there
called cycloid and ctenoid scales according to the nature of their
edges.
The unpaired fins arise as a continuous fold of skin extending
* A fuller account of the scales is given with the accounts of the orders.
For principal recent literature, see Klaatsch, Morph. Jahrb. 16, p. 258,
and 21, 1894, p. 153 ; F. Maurer Die Epidermis u. Hire Abkommlinge, Leip-
zig, 1895. 6. Hertwig, Morph. Jahrb., ii. and vii. C. Rose, Anai. Anz.,
14, 1897 ; pp. 21 and 33. Nickerson, "The development of the scales of
Lepidosteus," Bull. Mus. Harvard, 24, 1893.
f It was formerly supposed to be enamel and to be epidermal in origin,
but this has been proved to be erroneous.
54 CLASS PISCES.
along the middle dorsal line of the trunk, and continued round
the tail on to the ventral surface as far as the anus. It may
persist in this form, but as a rule it becomes broken up into a
variable number of dorsal fins, a caudal fin which consists of a
dorsal and ventral part, and an anal fin between the ventro-
caudal and the anus (Fig. 32). The unpaired fins are almost
always supported by the so-called fin-rays or dermotrichia.
These are horny fibres of the derm is (Elasmobranchii), or bony
rods (Teleostei, Ganoids, Dipnoi) which may be segmented, and
more or less soft and flexible (Malacopterygians) or stout and un-
segmented(Acanthopterygians). These dermotrichia are absent
only in Marsipobranchii. They are composed of two closely
approximated halves, and are carried except in the case of the
ventro-caudal fin, by the somactids or radialia. These are carti-
laginous or bony rods, placed as a rule in the basal part of the
fin-fold, and between the muscles of the back. They do not
necessarily correspond in number with the vertebrae. They
are usually segmented into two or three pieces, to the distal of
which the dermotrichia are attached. The basal piece is some-
times called the axonost ; in the Teleostei it is known as the
interspinous bone, because it occurs between the spines (neural
or haemal) of the vertebrae. The second piece is sometimes
known as the baseost. In a few fishes (e.g. Dipnoi), the
somactids articulate with the spines of the vertebrae.
The strong spine-like anterior fin-ray often found in Teleosteans and
bony Ganoids is formed of bone. In Elasmobranchii, the strong spines
which are sometimes found in connection with the fins are tooth -like in
structure.
The dermotrichia are of three kinds. *
1. In Elasmobranchii and Holocephali they are unjointed, occasionally
branched, fibrous rays of a horny consistency and without osseous tissue :
these are called ceratotrichia. Similar dermotrichia are found in the
larval fins and at the edges of the adult fins of Teleosteans and Ganoids :
in this case they are called actinotrichia. They are more numerous than
the somactids.
2. In adult Teleosteans and Ganoids the fins have jointed, branched,
bony dermotrichia developed between the actinotrichia and the skin.
They are supposed to be modified scales, which they sometimes resemble,
and are called lepidotrichia. They correspond in number with the
somactids except in the cartilaginous Ganoids, in which they are more
numerous.
3. In the Dipnoi the dermotrichia have been called kamptotrichia
* Goodrich, " Dermal fin-rays of Fishes," Q. J. M. S., 1904.
CAUDAL FIN. 55
They are branched, jointed bony rays, and appear to be merely modified
lepidotrichia. They are more numerous than the somactids.
In all fishes the ventral part of the caudal differs from the
other median fins in the fact that the dermotrichia (fin-rays)
are supported directly by the haemal arches. These are fre-
quently imperfectly segmented from one another, and may,
in the adult, have the form of two or three bony plates, or even
of a single plate. They are sometimes called, when ossified, the
hypural bones.
A few Teleostei (eel-like forms, some Gadidae, etc.) and the Dipnoi
constitute apparent exceptions to this rule as to the structure of the
caudal fin, but in the former of these it is probable that the anal fin
has fused with the ventral part of the caudal fin, for in a small por-
tion of the ventro-caudal fin a few dermotrichia are carried directly by
haemal arches. In the Dipnoi on the other hand, and in some Teleostei,
the caudal fin appears to be entirely unrepresented, for the tail gradually
tapers to its termination. What appears at first sight to be the ventro-
caudal fin is really the anal fin, and in no part of it are the dermotrichia
supported directly by the haemal arches. In the crossopterygian Ganoids,
in which there is a diphycercal tail, the ventral dermotrichia of the caudal
fin are clearly supported by haemal arches and not by somactids.
Considerable importance has been attached to the form of the
tail and to the structure of the caudal fin in fishes. In the
simplest cases the vertebral column is continued straight to
its termination, and the dorsal and ventral part of the caudal
fin are equal and symmetrical with each other. This type of
caudal fin is called diphycercal or protocercal. In many fishes,
however, the posterior part of the vertebral column is bent
dorsalwards, and a special enlargement of the ventro-caudal
fin is formed at a short distance from the end of the tail. This
type of caudal fin is called heterocercal (Fig. 64), and is character-
istic of Elasmobranchs and chondrostean Ganoids. In such fishes
the tail may be said to be bifid, presenting a dorsal lobe and a
ventral lobe. The dorsal lobe consists of the real hind end of
the tail with the dorso-caudal (if present at all) and part of the
ventro-caudal fin, while the ventral lobe is the specially enlarged
part of the ventro-caudal fin above described.
In Teleostei, and bony Ganoids, and some Selachians, the
dorsal lobe thus defined shrinks and almost disappears relatively
to the greatly enlarged ventral lobe, which now forms the whole
of the tail fin, and becomes svmmetrical in itself. Such a tail
56 CLASS PISCES.
is called homocercal. In many Teleostei the tail fin of the larva
begins diphycercal then becomes heterocercal and finally assumes
the homocercal form. This correspondence between the develop-
mental history of the tail and the three forms of tail fin found
in living fishes is supposed to be highly significant from an
evolutionary point of view, for it is supposed that the diphy-
cercal tail is the most primitive, and that the homocercal is the
most specialised, the heterocercal tail intervening between
the two. This supposition is to a certain extent borne out by
palaeontology, which seems to show that Teleosteans are the
most modern group of fishes. Unfortunately for the theory,
however, the oldest fishes known to us had heterocercal tails and
not diphycercal, as the theory requires.
In addition to these three types of tail-fin, intermediate conditions have
been named. For instance, the term heterodiphycercal has been applied
to slightly heterocercal tails in which the fin is much less developed on
the dorsal side than on the ventral (some Crossopterygians, Fig. 104),
while tails, in which the tail fin is externally symmetrical, but the
hind end of the vertebral column is bent and extends some way
into the dorsal lobe of the fin (Amia, etc.), are called hemiheterocercal
(Figs. 107, 109). The true homocercal tail is distinguished from the
hemiheterocercal by the fact that the vertebral column, which is bent
dorsalwards, does not extend into the fin, but terminates in front of it.
As has already been mentioried, the dermotrichia of the ventro-caudal
fin of all Pisces are attached directly to the haemal arches (for apparent
exceptions to this see p. 55). In the homocercal tail of the Teleostean
these haemal arches are called the hypvral bones and are frequently fused
together to form a single broad plate of bone. In Ganoids with hetero-
cercal tails, when the upper lobe of the caudal fin (dorso-caudal) disappears
it is replaced by a series of ridge scales : the " fulcra " of palaeontologists :
in Elasmobranchs, when absent, it leaves no trace.
The pectoral and pelvic fins also possess dermotrichia (fin-rays)
and somactids (radialia). A certain number of the somactids
are directly articulated to the limb girdles, and are then called
basalia. There are usually three of these, which are then called
pro- meso- and meta-pterygium, but their number varies con-
siderably. The important point to notice is the arrangement of
the peripheral somactids.* In Cladoselache, a Palaeozoic fish,
these are parallel to one another (Fig. 83), and the fin-skeleton
may be termed orthostichous.^ In most fishes, and notably in
* Wiedersheim, Das Gliedmassenskelet der Wirbelthiere, Jena, 1892.
f The same feature is found in the pelvic fins of the Ganoid Psephurus
(Regan, Ann. and Mag. Nat. Hist (7), 13, 1904, p. 333.)
ORIGIN OF LIMBS. 57
Elasmobranchs they are arranged in a fan-like manner, and the
fin may be described as rhipidostichous. In Dipnoi the somactids
of the fin are represented by a basal piece, followed by a row of
them occupying the axis of the fin, with or without pre- and post-
axial pieces placed like the barbs of a feather (Fig. 138). Such
an arrangement may be termed rachiostichous and mesorachic.
In some sharks and in the extinct Pleuracanthidae there is a succession
of somactids forming a rachis, but the rachis is placed on one side of the
fin and carries peripheral somactids mainly on that side. * Such an arrange-
ment may be called rachiostichous and pleurorachic (Fig. 76).
A similar reduction in the number of" basal somactids is sometimes
found in the median fins of extinct fishes, e.g. in the anal fins of Pleura-
canthus (Fig. 87)..
In the discussion of the vexed question of the origin of the
vertebrate paired limbs, much attention is paid to the arrange-
ment of these somactids (radialia). According to Gegenbaur
the Ceratodus type (Fig. 138) of fin skeleton (rachiostichous) is
the most primitive, and this fin constitutes what he calls the
archipterygium. On this view the skeleton of the paired fin^
and their girdles have originated from a branchial arch and its
branchial rays ; the girdle being derived from the branchial arch
and the somactids from the branchial rays. One important
objection (among others) to this view is that the branchial arches
are in the gut-wall, whereas the limb girdles lie in the body wall.
On another and perhaps more acceptable view, if any view on
these insoluble questions can be regarded as acceptable, the
pectoral and pelvic fins are to be regarded as local specialisations
of a once continuous lateral fold of the body wall, containing
skeletal structures comparable to those of the unpaired fins, viz.
basal segmented somactids (radialia) and peripheral dermo-
trichia. This view was first suggested by Balfour. According
to it the fin-skeleton of Cladoselache would be appealed to with
its parallel somactids as being an obvious local specialisation of
a once continuous fold, with parallel somactids all along its
course.
It would be useless to study the skeleton except in detail,
* There appears to be some dispute as to whether this side is pre- or post-
axial. According to Wiodersheim and Fritsch, the side on which the
majority of the rays are placed is post-axial, but according to the more
generally received opinion it is pre-axial, the limb in the specimen from
which Fig. 87 is taken having been displaced.
58
CLASS PISCES.
not
and for that we refer the reader to the account of the different
sub-classes. We must content ourselves here with an account
of its more general features, to which it is desirable to call
attention.
The notochord forms the
basis of the axial skeleton. It
always persists in the adult,
though it is generally consider-
ably reduced. Its longitudinal
extent is from the pituitary
fossa of the skull in front to
the end of the vertebral column
behind. The notochord itself
rarely forms an important
element of the axial skeleton
of the adult. Its supporting
function — so conspicuous a
feature in Amphioxus — is taken
over by its sheath and by
cartilaginous structures de-
veloped around its sheatn.
In the trunk these structures
are, with few exceptions, seg-
mented, and constitute the
vertebral column ; in the skull
they are not segmented, and
are known in the embryo as
the parachordal cartilages.
': has
FIG. 33. — Transverse Section through
the vertebral column of an advanced
embryo of Scyllium in the caudal
region ; na skeletogenous tissue of
neural arch, ha of haemal arch ; ch
notochord ; sh notochordal sheath,
which has acquired nuclei (elastica
inter na) ; ne outer chordal sheath
(elastica externa) (After Balfour).
At an early stage in the embryo
a well defined structureless sheath
is formed round the notochord.
This is called the merribrana elastica
interna. A little later a second
sheath is formed round this. This
outer sheath, also structureless, is
known as the membrana elastica
externa. Cells of the skeletogenous mesoblastic layer, which surrounds
the notochord, appear now to penetrate the elastica externa and invade
the elastica interna (Fig. 33), which thus becomes nucleated.
The chordal sheath sometimes remains as a continuous
structure (Sturgeon, Dipnoi, etc.), but as a rule becomes seg-
VERTEBRAL COLUMN.
59
mented ; in other words it becomes differentiated into alter-
nately short fibrous and longer cartilaginous portions (Fig. 34).
The fibrous portions become the intervertebral ligaments, the
cartilaginous portions the
bodies or centra of the verte-
brae. The sheath thickens in
the central part of the verte-
bral regions and constricts the
notochord, so that the noto-
chord assumes a beaded form,
being narrowest in the middle
of the vertebral regions and
widest in the intervertebral
(Fig. 34). In this way a bi-
concave or amphicoelous cen-
trum — a form eminently
characteristic of fishes — arises.
When the centra are formed
entirely or mainly from the
chordal sheath they are called
chordo-centrous (Dipnoi, Elas-
mobranchii). But it frequently
happens that they are rein-
forced by cartilage derived
from the arch- tissue. The arch- tissue arises from the meso-
blastic tissue (skeletogenous layer), which surrounds the noto-
chord, and is continued dorsally round the spinal cord. Four
special concentrations of this tissue are
formed adjoining the notochord, two dor-
sal and two ventral. In these the
chondrifications which give rise to the
neural and haemal arches begin. The
neural arches do not always completely
enclose the spinal canal, but are supple-
mented by the intercalated pieces (Fig.
FIG. 35. — Three pos- 0~\ i • i i -, ••
terior trunk-verte- <*D) which are placed between them, i.e.
brae of CentTophorus • , , -i -,-, -m ,
(after Hasse from mtervertebrally. The haemal arches may
Gegenbaur). n neural i r i -, -,
arch with foramen for also be supplemented by intercalated
anterior root ; in in- • mi , .1
tercaiated piece with pieces. These cartilaginous arches may
haemafarch1 * spread out round the notochord outside
FIG. 34. — a Diagram of a longitudinal
section of the vertebral column of a
Teleostean with vertebral constriction of
the notochord (from Claus). b vertebrae
of a bony fish, ch notochord ; D neural
spine ; Dl haemal spine ; J interverte-
bral ligament ; k body of vertebra ; 06
neural arch : R rib : Wk vertebral body.
60 CLASS PISCES.
the membrana elastica externa and unite with each other, and
so reinforce the vertebral centra. When the chordal sheath is
inconspicuous, and the centra appear to be mainly derived
from the arch tissue, the vertebral column is said to be arci-
centrous (Ganoidei, Tdeostei).*
In this way a segmented vertebral column is established. In
Teleosteans and bony Ganoids a further complication is added
in the replacement of the cartilage by osseous tissue. The
centra in the trunk (Fig. 34) carry as a rule short transverse
processes, which may be called haemal arches, though they do
not meet ventrally except in the caudal region, where they en-
close a space containing the caudal artery and vein. The ribs
are never more than short pieces of cartilage or bone attached
to the outer ends of the transverse processes in the trunk
region. There is no sternum in fishes.
The primitive craniumf consists of a cylinder of continuous
cartilage, to which are attached anteriorly the nasal capsules
widely open below, and posteriorly the auditory capsules. It is
thus divided into four regions ; the occipital surrounding the
foramen magnum, the wide auditory region, the narrow sphen-
oidal or interorbital region, and the wide nasal or ethmoidal region.
The junction of the parachordal with the trabecular region of
the skull is marked externally by the foramen in the median
floor, which transmits the internal carotid arteries (Fig. 36, 13),
and internally by the posterior clinoid ridge which forms the
hinder wall of the fossa for the lodgment of the pituitary body
(Fig. 36, £). Yin the embryo two elongated cartilages — the para-
chordal cartilages — are developed on each side of the cranial part
of the notochord. They unite with each other around the
notochord and form the basilar plate which gives rise to the
occipital and part of the sphenoid regions. The auditory capsules
which are developed round the membranous labyrinth become
fused with this part of the skull. The anterior end of the skull
in front of the pituitary fossa is formed by a second pair of
embryonic cartilages, the trabeculae. To the front end of these
the nasal capsules become attached, thus giving rise to the
ethmoidal region. /
* Vide Gadow, Phil Trans., 186, 1895, p. 165.
t C. Gegenbaur, Untersuchunqen z. vergl. Anat. d. Wirbelthiere,
Heft 3. Leipzig, 1872. Id., "Ueb. d. Occipitalregion, etc. der Fische."
Kolliker's Festschrift, Leipzig, 1887.
CRANIUM.
61
The hinder ends of the trabeculae embrace the front end of the notochord,
so that the posterior clinoid ridge must be regarded as being formed by
the hind end of the trabeculae. Moreover it must not be forgotten that the
internal carotid artery enters the skull in the embryo through the space
between the trabeculae before they fuse, so that the carotid canal also
belongs to the hind end of the trabecular region.
Though the roof of the cranium is largely cartilaginous in fishes
even when membrane bones are present on it, there is always a
considerable fontanelle in which cartilage is absent. The carti-
laginous cranium so constituted becomes in the Teleosts,
Ganoids and Dipnoi replaced by bone to a varying extent, and
reinforced by the development of osseous tissue in the adjacent
connective tissue. The membrane bones, formed in the latter
'is
14 13
FIG. 36. — Median section of the cranium of Hexanchus, inner view (after Gegenbaur). 1 Fora-
men for vagus, 2 glossopharyngeal, 3 auditory, 4 facial, 5 trigeminal nerves ; 6 posterior
clinoid ridge ; 7 foramen for oculomotor, 8 trochlear, 9 optic nerves ; 10 fontanelle ;
11 rostrum ; 12 lateral process of ethmoid region ; 13 foramen for carotid ; 14 transverse
canal in skull base ; 15 notochord ; 16 foramina for spino-occipital nerves ; 17 neural
arch of the first vertebra with nerve foramina.
manner, apply themselves to the subjacent cartilage and help in
forming the cranial wall. The occipital region of the cranium
is attached to the anterior end of the vertebral column, usually
without any special articulation (except in Batoidei and Chima-
era, etc.), the basioccipital region having the conical depression
and form of a vertebral body. The cranial part of the noto-
chord persists in the adult in some forms, but it more usually
undergoes atrophy. It occasionally happens, as will be men-
tioned in the special accounts, that a few of the anterior
vertebrae are fused with the occipital region of the cranium.
Visceral Skeleton. — The walls of the anterior part of the
alimentary canal (mouth and pharynx) are supported and
62 CLASS PISCES.
strengthened by incomplete cartilaginous rings, analogous to the
cartilaginous rings found in the trachea of the higher Vertebrata.
Like the tracheal rings, they serve to keep open the tube — in this
case the mouth and pharynx — through which the respiratory
medium passes to the respiratory organ, but they differ from
them in being divided up into segments which are movable upon
one another by means of muscles. The Visceral Arches, as
these structures are called, are placed in the splanchnic meso-
derm, as shown by embryology, and therefore have nothing to
do with ribs, with which they have sometimes erroneously been
compared. They may be described as consisting of a series of
cartilaginous rods on each side, joining one another ventrally,
but usually (except in the case of the first two) ending freely
dorsally without connection with other skeletal structures.
The first arch is called the Mandibular ; its skeleton lies near
the lips and constitutes the jaws. The second is called the
Hyoid Arch : it lies in the pharynx wall between the spiracle
and the first branchial cleft. The remainder ^ of which there are
usually five,- are the Branchial Arches : they lie in the pharynx
wall between the branchial clefts, the last always occurring
behind the last cleft. In Heptanchus there are seven branchial
arches and seven clefts ; in Hexanchus and Chlamydoselachus
there are six.
The mandibular arch becomes closely associated with the
cranium. It always becomes divided into two pieces : of these
the dorsal piece forms the skeleton of the upper jaw and is called
the palato- quadrate bar, while the ventral piece constitutes the
cartilage of Meckel. The dorsal piece is longitudinally directed
beneath the skull from the auditory to the ethmoidal region ; it
gives articulation at its posterior (quadrate) end to Meckel's
cartilage. This upper segment of the mandibular arch presents
two principal arrangements in fishes. In the one of these, that
which is generally called the hyostylic, its hind end is not attached
to the skull directly but is held up by the stout dorsal segment
of the hyoid arch, which is for this reason called the hyo-mandib-
ular. This is the arrangement found in most fishes. In
Chimaera and Dipnoi, however, a different arrangement is found.
In these and in some extinct fishes the palato- quadrate bar is
fused with the skull not only posteriorly in the auditory region,
but anteriorly in the ethmoid region and in the intermediate
ALIMENTARY CANAL. 63
sphenoid region. It is indeed fused all along with the side of
the cranium and has the form of a laterally projecting tri-
angular shelf, the projecting angle of which is the quadrate
region and gives articulation to Meckel's cartilage. This
arrangement is called Autostylic ; * the hyoid arch taking no
part in the suspension of the upper jaw.f It has been proposed
to divide fishesi nto two great groups based upon the condition
of the primitive upper jaw skeleton — the Autostylici and the
Hyostylici ; but as we shall explain in the sequel, there appear to
be good reasons for adopting a different arrangement.
In the Teleostei, Ganoidei and Dipnoi cartilage bones are
developed in both the mandibular and hyoid arches to a varying
extent and membrane bones may come to overlie them, largely
supplementing them and even replacing them.
The digestive organs vary much in structure. The mouth,
which is placed at, or near, the anterior end of the head, usually
has the form of a transverse slit, and can sometimes be extended
forward by means of the movable supporting bones of the upper
and lower jaws. The buccal cavity is distinguished by its width,
and by the great number of teeth it contains, which are developed
from the papillae of the mucous membrane by dentinal ossifica-
tion. There are often two curved parallel rows of teeth on the
upper jaw ; an outer row on the premaxilla, and an inner row
on the palatine, and there may also be a median unpaired row on
the vomer. On the lower jaw there is only one curved row of
teeth. There may also be teeth on the* hyoid arch and on the
maxillae, pterygoids, and parasphenoid, and, as a rule, on the
branchial arches also, especially on the upper and lower pharyn-
geal bones. The teeth may be distinguished according to their
shape into pointed conical prehensile teeth, and grinding teeth.
They are developed in the mucous membrane and are attached to
the skeletal structures by ligament or by ankylosis. In a few
cases only are they implanted in sockets. .—
A small, hardly movable tongue is developed on the floor of the
* The so-called amphistylic arrangement which is found in a few Elasmo-
branchs (see below) would seem to be a variety of the autostylic.
t The suspension of the mandibular arch, found in the skulls of Am-
phibia and Sauropsida, in which the palato-quadrate bar is not attached
along its whole length, but only in the auditory and ethmoid region,
must be regarded as a more typical form of the autostylic arrangement
than that found in Chimaera and the Dipnoi .
64 CLASS PISCES.
buccal cavity, and the lateral walls of the pharynx are pierced by
the gill-slits. Following the pharyngeal cavity, there is a usually
short funnel-shaped oesophagus, and a large stomach, which is
frequently drawn out into a caecum of considerable size (Fig. 37).
Caecal appendages (pyloric appendages) are. not unfrequently
met with at the entrance of the lower mid-gut (small intestine)
which is marked off by a valve ; they probably serve the purpose
of increasing the extent of the secreting surface of the alimentary
canal. The intestine is usually several times coiled, and its
internal surface is remarkable for the longitudinal folds of the
mucous membrane ; villi such as are found in the higher Verte-
brates are only rarely present ; but in the Selachians, Ganoids,
and Dipnoi there is a peculiar spirally-coiled longitudinal fold —
I'd
FIG. 37. — Alimentary canal and generative organs of Clupea harengus (after Brandt). A
anus ; Ap pyloric appendages ; Br gills ; D intestine ; Dp pneumatic duct ; Gp genital
pore ; Oe oesophagus ; S spleen ; T testis ; V stomach ; Vd vas deferens ; Vn swimming
bladder.
the so-called spiral valve — which contributes essentially to the
enlargement of the absorbent surfaces. A rectum is not always
clearly marked off, and when present is always short, and in the
Selachians it is furnished with a caecal appendage. The anus is
usually situated far back, and is always ventral, and in front of
the urinary and generative openings, when the latter do not
lead unto the rectum (cloaca). In fishes with jugular pelvic
fins, and in some Teleosteans without pelvic fins, it is situated
very far forward, and may even be on the throat.
Salivary glands are absent in fishes, but there is a large liver
which is rich in fat and is usually provided with a gall-bladder ;
there is also usually a pancreas, which is by no means replaced
in Teleosteans by the pyloric appendages as was formerly be-
lieved.
AIR-BLADDER. RESPIRATION. 65
In many fishes the swimming bladder, an organ which by its
mode of origin corresponds to the lungs, is developed as a diver-
ticulum of the alimentary canal : it is sometimes closed, but
sometimes remains in communication with the interior of the
alimentary canal by the pneumatic duct (Physostomi) (Fig. 37 r
Dp}. Its walls are formed of an external elastic membrane
which is sometimes invested with muscles, and an internal
mucous membrane. Glandular structures are sometimes pre-
sent in the internal coat, and these may exert an influence
on the enclosed air. The internal surface is usually smooth r
but is sometimes provided with reticulated projections which
lead to the origin of cellular cavities (some Ganoidei). Physio-
logically the swimming bladder is a hydrostatic apparatus,
the function of which seems to consist essentially in rendering
the specific weight of the fish variable. When it is present
the fish must have the power of compressing it, partly by
the muscles in its walls and partly by the muscles of the
body, thus rendering the body specifically heavier so that
it sinks. When the compression of the muscles is removed
the compressed air will again expand, the specific gravity di-
minish and the fish will rise. If the anterior and posterior parts
are separated and the pressure on them is unequal, then that
half of the fish which is rendered specifically heavier will sink.
Still more complicated relations, however, seem to exist.*
Respiration is in all cases effected by gills, which may be
supplemented by other structures, e.g. the lungs in the Dipnoi,
and in Teleostei by vascular folds found in cavities (Fig. 38) in
connection with the gill passages themselves or with the
cavity beneath the operculum into which the gill-slits open.
For a description of these we refer the reader to the special
account of the Teleostei. The gills themselves are folds, con-
taining many blood-vessels, of the mucous membrane of the
passages which lead outward between the branchial arches to-
open on the side of the head. These passages, which may be
short and slit-like, or long and tubular, open either directly to
the exterior (Elasmobranchii] or their outer openings are covered
by a fold of skin generally containing cartilaginous or bony
supports and called the operculum. In this case they may be-
said to open into a branchial cavity which itself opens to the
* See account of Teleostei.
F
66 CLASS PISCES.
exterior. The gills are either lamelliform (Elasmobranchii) and
attached along their whole length to the interbranchial septa,
or filiform and projecting (so-called pectinate gills of Teleostei,
etc.). They are arranged in a row on each side of the branchial
arch, so that each branchial arch carries two rows of gills (holo-
branch), one on its anterior and one on its posterior face.
Sometimes there is only one row (hemibranch), and some-
times gills are absent on each side, or present only as a vestigial
structure called a pseudobranch.
The general arrangement is as follows. The branchial passage
between the mandibular and hyoid arches is called the spiracle.
It is always reduced and is present only in most Elasmobranchs
and some Ganoids. Behind this there follow typically five
branchial passages or gill-
clefts. The mandibular arch
never carries more than a
vestige of a gill, which is called
the mandibular pseudobranch
v-^v \SNHJBHOHB I \ or pseudobranch of the spir-
acle. The hyoid arch never
carries more than a demibranch
and that on its posterior face.
The first four branchial arches
carry typically holobranchs,
while the last branchial arch
is always without a gill. It
thus happens that, if the hyoid arch carries a hemibranch
on its hinder surface, the first four branchial passages have
gills on both anterior and posterior walls, while the fifth
branchial passage has a gill only on its anterior wall, the fifth
branchial arch being always gill-less. In most fishes, however,
the hyoid demibranch is reduced to a vestige, and is then known
as the hyoidean or opercular (because the hyoid arch carries
the operculum) pseudobranch. Externally projecting gills are
found in the embryos of Elasmobranchs and a few Teleostei. They
are not true external gills, but are much elongated internal gills.
In the young Polypterus and some Dipnoi there appear to be
true external gills.
The brain of fishes is small and does not fill the cranial
cavity. It presents all the parts of the typical vertebrate brain.
BRAIX. 67
It is perhaps chiefly characterised by the small development of
the cerebral or prosencephalic part of the fore-brain. The anterior
end of the medullary tube becomes at an early embryonic stage,
when its walls are still epithelial, differentiated by two constric-
tions into three vesicles, the fore, mid, and hind cerebral vesicles.
Of these the posterior vesicle or hind-brain gradually tapers
behind into the spinal cord, and the portion of the medullary
canal contained in it gives rise to the fourth ventricle of the adult.
Its walls become transformed into the medulla oblongata, which
is a development of the floor and sides of the hind-brain and is
frequently called the myelencephalon. The cerebellum (meten-
cephalon) is a special development of the anterior part of the
dorsal wall of the hind-brain. The greater part of the dorsal
wall remains throughout life at the epithelial stage and never
develops nervous tissue. The mesoblast (pia mater) overlying
this permanently epithelial wall becomes especially vascular
and gives rise to the choroid plexus of the fourth ventricle.
The middle vesicle or mid-brain (mesencephalon) gives rise by
its roof and sides to the optic lobes or corpora bigemina, and by
its floor to a stout nervous mass consisting largely of strong
bundles of nerve fibres which in the mammalian brain constitute
the crura cerebri or peduncles of the cerebrum. The portion of the
medullary canal in the mid-brain is the iter a tertio ad quartum
ventriculum or aqueductus sylvii.
The anterior vesicle or fore-brain becomes early differentiated
into three parts ; a posterior part, the thalamencephalon, the
central canal of which constitutes the third ventricle ; a ventral
part usually described as part of the thalamencephalon, the
infundibulum ; and an anterior part the proscncephalon or cere-
brum, the ventricle of which is the second ventricle. The cere-
brum is usually divided into a right and left lobe by a longitu-
dinal vertical constriction, but this happens rarely (Dipnoi,
Marsipobranchii) in fishes, though there are sometimes indica-
tions of this division in the form of a longitudinal surface
groove, and in Elasmobranchs the contained ventricle is ac-
tually divided into a right and left ventricle which open be-
hind into the third ventricle by the foramen of Munro and
are termed the lateral ventricles.
The anterior end of the cerebrum is always marked off as two
lobes of varying size and shape into which the second ventricle
68 CLASS PISCES.
is continued (as the first ventricle) and which give off from their
anterior ends the olfactory nerve fibres : they are called the
olfactory lobes or the rhinencephala. In the embryonic brain
before the differentiation into thalamencephalon and prosen-
cephalon has been effected, the fore-brain becomes bent ventrally,
forming an angle with the posterior part of the basi-cerebral
axis. This bend in the cerebral axis constitutes the cranial
flexure ; it takes place, roughly speaking, at the junction of the
fore-brain and mid-brain and a short distance behind the front
end of the notochord, the anterior end of which is under the pos-
terior part of the fore-brain. The notochord is therefore in-
volved in the cranial flexure and its front end becomes hook-
shaped. The other organs of the anterior end of the head
are also affected as is shown by the somewhat longi-
tudinal disposition of the anterior gill-slits and arches (Fig. 39)
as compared with the transverse disposition of those behind. In
consequence of this bend in the nerve axis the anterior end of the
neural tube becomes eventually directed ventralwards and, by a
posterior outgrowth, backwards beneath the floor of the mid-
brain : it constitutes the infundibulum, which has already been
mentioned as one of the three divisions into which the fore-brain is
differentiated. In addition to the infundibulum, a fourth divi-
sion of the fore- brain has to be distinguished. At an early em-
bryonic stage, before the prosencephalon is marked off, the
anterior cerebral vesicle gives off a right and left lateral
outgrowth : these are the optic vesicles. They at once become
applied externally to the lateral skin of the head, and their con-
nection with the brain becomes constricted to form a stalk-like
structure which eventually becomes solid and forms the optic
nerve. At the same time the cavity of the optic vesicle becomes
obliterated by the invagination of its outer wall next the skin
upon the inner wall on the brain side. This collapse of the optic
vesicle, if not caused by, takes place in connection with the
formation of the lens from the outer ectoderm at the point where
the optic vesicle before its collapse touched the skin ; it gives
rise to the formation of a two-walled optic cup, the mouth of
which is occupied by the lens and the double wall of which
becomes the retina of the eye.
To return to the fore-brain. When the cranial flexure is
established, the posterior part of its dorsal wall looks forward.
CRANIAL FLEXURE. FORE-BRAIX. 69
This part becomes greatly developed and produced forwards
into a large vesicle, the front part of which soon becomes
marked off as the rudiment of the cerebrum or prosencephalon.
This forward growth is shown by the subsequent relations of the
optic nerve to have taken place behind (in the original position of
the parts) the attachment of that structure (optic chiasma) to the
cerebral roof (Fig. 113). If this interpretation of the complex em-
bryonic growths is correct, it would appear that the cerebrum is
derived from a dorsal extension of the original fore -brain just behind
the point of origin of the optic nerves, and that the olfactory nerves
which are developed from the front end of the cerebrum and are
usually described as the first pair of cranial nerves, are in reality
the second, the optic nerves being anterior to them in position.
The optic nerves then are attached to the roof of the original
fore-brain at about halfway between its front and hind ends.
A ganglionic mass is formed on each side at this point in the
side wralls of the fore-brain ; these great ganglia are the optic
thalami and lie in the adult brain at the side of the third ven-
tricle, constituting the chief bulk of the thalamencephalon.
Immediately in front of the optic thalami two great ganglionic
developments are formed in the ventral wall of the cerebral out-
growth : these are the corpora striata found in the adult on the
floor of the second ventricle or, if it is divided, of the lateral
ventricles.
The front end of the cerebral outgrowth also gives rise to
nervous tissue of the olfactory lobes.
We now come to the roof of the reconstituted fore-brain, after
the cerebral outgrowth has been formed.* This roof is divided
into two parts by the velum transversum (see below). Of these
the posterior part, the part overlying the third ventricle, remains
in all Vertebrates almost entirely in an epithelial condition. It
gives rise by its posterior part to the epiphysis or pineal body.
To this we shall return shortly. The anterior part, the part
belonging to the cerebral rudiment, is called the pallium. It is
marked off from the posterior part by a transversely directed
fold of the epithelial roof. This fold dips down into the ventricle
at the junction of the thalamencephalon and prosencephalon
and encloses between its two laminae a vascular development
of the pia mater, which is always present and gives rise in the
* Mino; , American Journal of Anatomy, 1, 1901, p. 81.
70 CLASS PISCES.
higher brains to the choroid plexuses of the lateral ventricles.
It is called the velum transversum.
This folded-in part of the roof is generally regarded as belong-
ing to the cerebrum : in all Vertebrata it retains throughout
life its epithelial condition. In front of it, the roof of the brain
(pallium) behaves in a different way in different animals. In
Elasmobranchs, Marsipobranchs, Dipnoi, and in all Vertebrata
above fishes, it loses its simple epithelial condition and develops
nervous tissue, forming the dorso -lateral part of the cerebral
hemispheres above the lateral ventricles. In most other fishes,
Teleosteans, and Ganoids, the pallium retains its epithelial
condition throughout life, so that in these groups the roof of
the lateral ventricle remains permanently thin and epithelial,
as does the roof of the third ventricle and that of the posterior
part of the fourth ventricle, and in Lampreys of the aqueductus
sylvii as well.
Curiously enough — for what reason it is difficult to under-
stand— the condition in which the cerebral pallium consists of a
thin epithelial layer is regarded as secondary. By all the or-
dinary tests which are applied in speculations of this kind — viz.,
embryonic development and general diffusion of the character
in the lower Vertebrata and absence in the higher, it should surely
be regarded as a primitive character. Indeed, if we may be
allowed to indulge in a little speculation of this kind, it would
appear from development that the whole medullary canal at
one time had purely epithelial walls, and there appears to be a
tendency to the retention of this character along the middle
dorsal line throughout life in all Vertebrata.
To return to the pineal body. It is developed as a divert-
iculum of the hinder part of the roof of the thalamencephalon.
Its terminal portion becomes the pineal body or epiphysis ; its
proximal part is the pineal stalk. The terminal part sometimes
gives rise on its anterior wall to an outgrowth which is called
the parietal organ. The parietal organ may be developed
separately from the brain roof just in front of or by the side
of the epiphysis.* It is not always formed, and usually van-
ishes with later growth ; but in Lampreys and Lizards it
* On account of this fact it has been suggested that the epiphysis is
really a paired organ, one of the pair becoming the actual epiphysis
(pineal body) of the adult, and the other either degenerating or becoming
PARIETAL ORGAN.
71
persists and assumes a peculiar structure resembling that of the
retina of the eye. For this reason it has been called the pineal
eye. In Lampreys the pineal body also assumes the same
structure. A great deal of significance has been attached to
the curious eye-like structure which is assumed by the parietal
organ. It has been regarded as the vestige of an unpaired eye.
In our opinion the resemblance to an eye is accidental, but for a
discussion of the question we refer the reader to the account of
the parietal organ in the section devoted to Reptilia.
Fia. 39. — Heads of young Elasmobranch embryos (Scyllium canicula) (after Sedgwick).
A. Ventral view of head of embryo, 7 mm. in length, with two open pharyngeal clefts.
The mouth is present as a longitudinal groove in the ectoderm of the buccal depression.
B. Same view of a slightly older embryo ; the buccal groove has become a longitudinal
slit. C. Side view of head of embryo, 9 mm. in length, with three open slits. D. Side
view of head of embryo, 11 mm. in length ; rudiments of external gills have appeared on
the hyoid and on the first and second branchial arches. E. Side view of head of embryo
of 16 mm. ; external gills have appeared on mandibular arch and the angle of the jaw is
marked. 1 mandibular arch ; 2 angle of jaw ; 3 second pharyngeal cleft ; 4 nasal pit ;
5 eye ; 6, midbrain ; 7, auditory sac ; 8 hyoid arch ; 9 spiracle.
The superior commissure is a small nervous development in
the otherwise epithelial roof of the third ventricle just in front
of the attachment of the pineal stalk. The posterior commissure,
the so-called parietal organ (pineal eye). See Dendy, Q. J. M. S., 42,
1899, p. 111. This view is supported to a certain extent by the arrange-
ment in the lamprey (see p. 106).
72 CLASS PISCES.
which probably belongs to the mesencephalon, is just behind the
attachment of the pineal stalk.
The paraphysis is the recess in the roof of the cerebrum caused
by and just in front of the velum transversum. By some mor-
phologists it is regarded as a special glandular organ, the
secretion of which passes into the ventricle. It is not always
present as a distinct structure.
The pituitary body or hypophysis develops as an evagination
of the front part of the buccal cavity. It is indeed the anterior
part of this cavity. In Elasmobranchs the original buccal slit —
for the vertebrate mouth perforation has at first the form of a
longitudinally extended slit (Fig. 39) — is continued into it.
It is applied to the infundibulum and eventually becomes cut
off from the mouth, except in Polypterus and Calamoichthys in
which the buccal opening is retained throughout life. At the
point in the embryo where the pituitary rudiment meets the
infundibulum there is a close approximation and partial fusion
of three other organs, viz., the front end of the gut, the anterior
end of the notochord, and the median part of the premandibular
somite (preoral coelom). The lobi inferior es and saccus vas-
culosus are parts of the infundibulum, very generally present
in fishes. The former are lateral diverticula or thickenings of
the infundibulum ; while the saccus vasculosus, or infundibular
gland, is a glandular dilation of its end, where it is in contact
with the pituitary body.
With regard to the cranial nerves, it ought to be noticed that
they all arise from the walls of the mid- and hind-brain, except
the olfactory and optic nerves. These come off from the pre-
notochordal part of the fore-brain, and it is doubtless to them
that the fore-brain owes its relatively enormous development in
all Vertebrata. The other cranial nerves, from the third nerve
onwards, probably all belong to the series of nerves which is
continued along the spinal cord as the spinal nerves. Indications
of this are shown by a careful study of the early stages of their
growth, particularly in Elasmobranch embryos, in which they
appear to be associated with the cephalic segments of the coelom.
These segments, for a knowledge of which we are indebted to Balfour*
and to the later researches of Van Wijhe.f are as follows : The first cranial
* A Monograph of the Development of Elasmobranch Fishes, London, 1878.
f " Ueber die Mesodermsegmente und die Entwickelung der Nerven des
Solachierkopfes," Verhandl. der k.Acad. d. Wissensch. zu Amsterdam, 1882.
CRANIAL SEGMENTS. 73
segment is represented by the premandibular somite* — an unpaired sac
with epithelial walls, immediately in front of the notochord (preoral
head cavity, vide p. 8). The walls of this sac give risa to all the eye-
muscles except the superior oblique and external rectus, and to mesen-
chyme. Its cavity vanishes, as do the cavities of all the cranial segments.
The nerves are the ram us ophthalmicus profundus, which develops from
the nerve crest immediately in front of the trigerninal and represents
the dorsal root, and the third nerve which represents the ventral root.
These two roots are both connected to the ciliary ganglion (see accoimtof
cranial nerves under Ela.smobranchii).
The second segment is the mandibular somite which is dilated in its
dorsal muscle-plate region and extends ventrally to the lower end of the
mandibular arch (collar-somite, vide p. 7). The walls of this sac give
rise dorsally to the superior oblique muscle and ventrally to the mesen-
chyme and muscles of the mandibular arch. The nerves are the trigerninal
and the fourth, the latter being regarded as an abnormally situated anterior
root. The first two cranial somites were discovered by Balfour.
The third and following segments are represented only by their dorsal
muscle-plate sections, the ventral portions being merged in the continuous
splanchnocoel (pericardial division). These segments may be regarded as
the anterior of the trunk series of Amphioxus. They do not apparently
communicate with the ventral splanchnocoel, which in this region under-
goes a pseudo-segmentation in consequence of the formation of the gill-
pouches. These pseudo-segments, or hyoid- and branchial- arch cavities,
open ventrally into the pericardium, of which they are a part, and were
taken by Balfour for the posterior cranial segments. The first of these
muscle-plates, which may be called, from its position, the hyoid myotome,
is better developed than the rest and gives rise to the external rectus
muscle. It was observed by Balfour. The next three, which were
discovered by v. Wijhe, are very faintly marked and transient and give
rise to no muscles, in correspondence with which fact may be noted the
absence of ventral roots. The next three segments (seventh-ninth) are
represented by well-developed muscle plates which persist and give rise to
muscles. The nerves of the hyoid segment (third) are the facial (dorsal
root) and sixth (ventral root). The nerves of the next three segments
are supposed to be represented by the auditory, glossopharyngeal and
vagus and are without ventral roots in correspondence with the absence of
myotome muscles. In the last three (or sometimes more) cranial seg-
ments, dorsal roots are present only in the embryo for a short time, but
ventral roots are developed, supplying presumably the myotome muscles
of this region and called the occipito-spinal nerves. These were mistaken
by Gegenbaur, who did not study the embryo and observe the transient
dorsal roots belonging to them, for ventral roots of the vagus. The
following table represents in brief the view of cranial segmentation
which has just been described. f
* There is in some forms a pair of head cavities in front of the pre-
mandibular somite. These are sometimes in communication with and
developed as diverticula of the premandibular somite, but in Acanthias
they are said to be independent of it (J. B. Platt, Journal of Morvholoav .
5, 1891, p. 79).
t The view here given takes no account of the scheme given on p. 77,
according to which the cranial nerves were originally tripartite, consisting
of dorsal, lateral and ventral roots. It was formulated before the modern
74
CLASS PISCES.
Coelomic Sac
Nerve
Dorsal Root
Ventral Root
Cranial segment 1
Premandibular so-
Ramus ophthal-
Third nerve.
mite. Its walls
micus profun- ,
give rise to all the
dus.
eye muscles sup-
plied by the third
nerve.
2
Mandibular somite. Trigeminal. Fourth nerve.
The walls of its
dorsal part give
rise to the superior
oblique muscle.
3
Hyoid muscle plate Facial.
Sixth nerve.
giving rise to ex-
ternal rectus mus-
cle.
4
Muscle plate (tran-
Auditory.
None.
sient).
5
Muscle plate (tran- Glossopharyn- None.
sient). geal.
6
Muscle plate (tran-
Vagus.
None.
sient).
7
^ Muscle plate per-
'j
(Spino-occipital
8
^ sistent and giving
-None.
nerves (so-
9
j rise to muscles. IJ
called ventral
and sometimes more
J
vagus roots).
The spinal nerves have two roots, which unite, and the dorsal
of which has a ganglion. The ganglion may, however, be placed
at the junction of the two roots. The cranial nerves are in ten
pairs, but there are often some small nerves — the spino-
occipital nerves (miscalled ventral vagus roots) — arising from
the ventral side at the hind end of the medulla. They pass
out through foramina in the skull, but are perhaps better
regarded as anterior spinal nerves (see above) the dorsal roots
of which are not developed.
analysis of the cranial nerves, which is due to Gaskell and is there referred
to, was fully developed. The later work, which is still incomplete, may
very possibly necessitate a new scheme of cranial segmentation, and the
groups of cranial nerves expressed by the terms fifth, seventh, ninth and
tenth may possibly be found to be connected with the ventral segmenta-
tion (pseudo-segmentation of the text) of the branchial pouches, and to be
independent of the mesoblastic segmentation which is so conspicuous
a feature in the trunk.
CRANIAL NERVES. SYMPATHEMIC. 75
For an account of a typical arrangement of the cranial nerves
the reader is referred to the section on Elasmobranchii. Their
arrangement in fishes differs from that in higher types, mainly
on account of the presence of the lateral line sense organs. The
nerves to these appear to arise from a special part of
the brain, the tuberculum acusticum, from which the auditory
nerves also arise. They are associated in their course to the
periphery with the seventh and tenth nerves, and constitute
the acustico-lateralis system. The fibres of this system which
run with the fifth and ninth are derived from these two nerves.
The nerves which pass from the facial roots to the fifth nerve
cause an intermingling of the roots of these two nerves, which
is not easy to unravel, and which is characteristic of fishes.
A sympathetic nervous system appears to be present. In
Marsipobranchii, in which all the nerves are without a medullary
sheath, it cannot be fully traced, but the spinal nerves give off
branches which pass to the viscera, where small ganglia are
found. In other Pisces there is a series of sympathetic ganglia
which develop as outgrowths of the spinal nerves, becoming
detached from the rudiments of the spinal ganglia at an early
stage. These ganglia are usually connected by longitudinal
commissures, but though regularly developed, their arrange-
ment is not easy to trace in the adult. In Elasmobranchii *
the system tends to take a plexiform structure, and lies in the
neighbourhood of the cardinal veins. There is an especially
large ganglion at about the level of the ductus cuvieri ; this is
supplied by a number of spinal nerves, and gives off several
branches, which are distributed to the viscera with the coeliac
artery. The system appears not to extend into the head. In
Teleostei there is a definite chain of small ganglia on each side
of the vertebral column. In these forms it is continued into
the head, where it is connected with the trigeminal nerve and
ciliary ganglion, and into the tail, where it runs in the caudal
canal.
The analysis of the nerves, which is the outcome of the recent work f
of morphologists and physiologists, is beyond the scope of this work,
but the following points may be noted here :
* R. Chevrel, " Surranatomiedusystemenerveuxgrandesympathetique
des Elasmobranches et des poissons osseux." Arch. Zool. Exp. (2) 5,
supplement.
| W. H. Gaskell, "The structure and function of the nerves which inner.
iO CLASS PISCES.
Five kinds of nerve fibres, characterised by their structure, function
and distribution, may be distinguished.
1. The system, of the somatic sensory (afferent) fibres. These include
the largest heavily medullated fibres which terminate in the skin and
myotome muscles. They pass out by the dorsal roots in the cord, and by
the roots of the trigeminal in the brain ; * their ganglia being the posterior
root ganglia (spinal), and the gasserian.
2. The somatic motor (efferent) system. The fibres of this system are
also large and heavily medullated : they terminate in the myotome
(somatic) striated muscles ; i.e. the muscles derived from the muscle-
plate?, including those derived from the dorsal part of the mandibular
and from the premandibular somites. They pass out by the anterior
roots in the cord, and by the third, fourth, and sixth cranial nerves, and
are without peripheral ganglia.
3. The visceral sensory (afferent) system (communis system}. Tho
fibres of this system are smaller, and they are distributed to the internal
mucous surfaces. They leave the cord by the posterior roots, their ganglia
here being posterior root ganglia. The cranial fibres of this system are
present in the roots of the fifth, seventh, ninth and tenth nerves ; the
ganglia being the gasserian (in part), geniculate, glossopharyngeal and
jugular ganglia. Their destination is mainly the mucous surfaces of the
anterior part of the alimentary canal.
4. The visceral motor (efferent) system. The fibres of this system may
be subdivided into (a) those which innervate the striated voluntary
muscles (mesenchymatous) of the anterior part of the alimentary canal
(mandibular, branchial, and facial muscles), are fairly large, and are non-
ganglionated, and (6) those which supply the unstriped muscles through-
out the body (blood-vessels, gut-wall, skin, etc.). The latter are small
fibres, all of which pass through peripheral ganglia. The true motor-
fibres to the muscles of the small intestine and anterior part of the alimen-
tary canal and its appendages (lungs, etc.) are derived from cranial nerves,
whereas the fibres to blood vessels, skin, walls of Miillerian and kidney
ducts come from the spinal cord by anterior roots. The cranial nerves
contain no vaso-motor fibres.
5. The acustico-lateral system (see p. 75). This system consists of
large fibres and passes out exclusively in the roots of the seventh, eighth,
tenth and possibly ninth cranial nerve. It is absent in the trunk and in
higher Vertebrates, except in the auditory nerve, and is distributed only
to the membranous labyrinth and the lateral line sense organs (lateral
line, ampullae and pit organs).
From this account it will be gathered that in the head the visceral
motor (efferent) fibres travel out with the visceral sensory fibres and in
the case of the fifth with the somatic sensory fibres as well, the somatic
motor fibres being distinct ; whereas in the trunk they leave the cord
with the somatic motor fibres.
vate the visceral and vascular systems." Journal of Physiology, 1, 1886;
and "On the cranial nerves" in Journal of Physiology, 10, 1889. O. S.
Strong, " The cranial nerves of Amphibia," Journal of Morphology, 10, 1895;
C. J. Hernck, " The cranial and first spinal nerves of Amphibia," Journal of
Comp. Neurology, 9, 1899, p. 157.
* The third nerve appears to contain fibres belonging to this system
(muscular sense), and it is possible that a few of them may be contained
in the vagus (Arnold's nerve).
SENSE-ORGANS. 77
To summarise the matter Gaskell has suggested that in the primitive
condition, both in brain and spinal cord, there were three rows of nerve
roots : (1) a dorsal containing somatic sensory fibres, (2) a ventral with
somatic motor fibres, and (3) a lateral row containing both visceral sensory
and visceral motor. This condition is modified in all existing forms in the
cord by the splitting of the lateral roots in such a way that the visceral
sensory roots have joined (1) and the visceral motor roots (2) ; whereas in
the brain the roots of the lateral row have persisted and the somatic sen-
sory roots (restricted to one) have joined them, the somatic motor roots
(three in number) remaining distinct. This scheme does not, however,
take account of the acustico -lateral system.
The Eyes have a flat cornea, and a large almost spherical
lens, the anterior part of which projects far out of the pupil.
Movable eyelids are present in ElasmobranchiL but are absent
from most other fishes. There are no lacrymal glands. The
usual eye muscles are present. There is frequently a rete
mirabile, the choroid gland, on the ophthalmic artery as it enters
the eye near the entrance of the optic nerve. The processus
falciformis and campanula halleri are described below under
Teleostei. The eyes are much reduced and functionless in most
adult Marsipobranchs and some cave-dwelling and ; abyssal
Teleosteans. The Auditory Organ consists of the otocyst
or membranous labyrinth, which is embedded in the side walls
of the auditory region of the skull. It lies in a cavity which
is closed from the cranial cavity in most Elasmobranchs, but
communicates with the latter in Chimaera, and Teleosteans,
Ganoids and Dipnoi. It consists (Fig. 40) of a central
chamber, the vestibule, and of three semicircular canals opening
into the vestibule. The vestibule is divided into two parts
by a constriction ; of these the upper is the utricle, the lower
the saccule. The semicircular canals open into the utricle
while the saccule in some fishes gives off from its posterior end
a process called the lagena, which is an incipient cochlea. In
Chimaera and the Squall the ductus endolymphaticus which
is given off by the saccule opens on the surface of the head.*
Both saccule and utricle contain a chalky mass of otoliths. When
the lagena is well marked its papilla acustica (pi) becomes
separate from the macula acustica sacculi and receives a separate
nerve (vide account of membranous labyrinth under Teleostei}.
The membranous labyrinth enters into peculiar relations with
* This is the remains of the aperture of invagination of the embryo.
78
CLASS PISCES.
-ha,
B
the air bladder in some Teleostei, which are fully described in
the account of that sub-class.
The Olfactory Organs are a pair of simple pits or sacs, in the
lining of which the
fibres of the olfactory
nerve terminate. In
the Marsipobranchii
the olfactory organ
is partly single and
presents peculiar re-
lations (see account
of Marsipobranchii ) .
In other fishes each
sac usually has two
openings, both of
which are external
except in Dipnoi.
In Elasmobra n c h s
there is usually only
one opening. The
internal surface of
the sacs is generally
increased by folds of
the mucous mem
brane.
We know practi-
cally nothing about
FIG. 40. — Right membranous labyrinth of Chimaera, seen f,hp <;f»nsf» of taste
from the median side (from Wiedersheim, after Retzius).
aa ampulla of anterior vertical canal ; etc auditory nerve ; The tactile Sense is
ade opening of ductus endolymphaticus ; ae ampulla of "
horizontal canal ; ap ampulla of posterior vertical canal ; J^Q doubt Specially
ass process of the sinus utriculi ; ca, anterior, c-p posterior
vertical canal ; ce horizontal canal ; cr crista acustica served bv the lips
ampullae ; de ductus endolymphaticus, which opens at ade •*
through the skin ha ; mn macula acustica neglecta ; ms and their appendages,
macula acustica sacculi (the macula ac. utr. rec is on the
other side and not properly visible) ; pi papilla acustica and bv special parts
lagenae (the lagena, however, can hardly be said to be J
present in this form) ; branches of auditory nerve rota to of the appendages
anterior ampulla, rae to horizontal ampulla, rap to pos-
terior ampulla, rec to macula acustici utriculi, rs to which are riclllv
macula sacculi and lagenae, ru to macula recessus utriculi ;
s saccule ; sp sinus utriculi posterior, ss sinus utriculi innervated (e.g.
superior ; u utricle.
Trigla.)
The system of embedded epidermal* sense organs which are
found in all fishes requires a detailed description.
* Levdig, Lehrbuch d. Histologie des Menschen u. d. Thiere, 1857. Solger,
rec
rs
LATERAL LINE.
79
In Elasmobranchs four kinds of organs are included under
this head : (1) the lateral line proper, or mucous canals, with its
cephalic ramifications ; (2) the ampullary canals, or Lorenzini's
ampullae ; (3) Savi's vesicles ; (4) pit organs. The essential
C$0 sot om
Flo. 41. — Diagram illustrating the distribution of the dorsal branches of the cranial nerves
and of the lateral line canals, and the position of the groups of ampullae in an Elasmobranch
(after Ewart,.from Gegenbaur). A auditory nerve with labyrinth ; it also points to the
groups of Lorenzini's ampullae ; Bu buccal branch of facial ; bu inner branch to part of
infraorbital canal, and to the inner buccal group of ampullae, bu' its outer branch which
supplies part of the infraorbital canal, and the outer buccal group of ampullae ; ch post-
branchial branch of facial to mucous membrane, and giving off motor branches to some
jaw muscles ; CSO, CSO supraorbital canal ; CJO, CJO infraorbital canal ; Fa, Fa'
roots of facial nerve ; Gp glossopharyngeal, arising under cover of the lateralis branch of
the vagus nerve ; Hm hyomandibular canal arising from the infraorbital, and giving off
the mandibular canal, the mandibular group of ampullae is in the angle between these two ;
Hm' branch of the hyomandibular nerve to the hyoid group of ampullae ; in intestinal
branch of vagus with ganglion, where it separates from fourth branchial branch ; In lateralis
branch of vagus nerve ; m mouth ; N nasal sac ; om deep branch of oculomotor giving off
short root of ciliary ganglion (shown, but not marked), the long root is also shown, as
are the short ciliary nerves to the eye ; opr root of ophthalmicus profundus ; opv dorsal
branch of same, giving off long ciliary nerves ; pol second branch of lateralis supplying some
lateral line sense organs and a row of pit organs, the first branch supplies the commissure
connecting the two lateral canals, and some sense organs of the main canal ; sof ophthalmicus
superficialis facialis, which supplies the supraqrbital canal, and the superficial ophthalmic
group of ampullae ; sot ophthalmicus superficialis trigemini ; it arises from the gasserian
ganglion ; sp spiracle ; Tr trigeminus ; V1, V2, V3 the first three branchial branches of
the vagus nerve, each with a ganglion and with pharyngeal, prebranchial and post-branchial
branches ; V* the united fourth branchial branch of vagus and intestinal branch ; 1-5
gill-slits.
part of these organs seems in all cases to be sensory patches
of the epidermis, consisting of sensory cells, bearing short
sensory hairs, and of supporting cells.
Neue Untersuchungen zur Anatomie der Seitenorgane der Fische, Arch.
f. mic. Anat., 1879-80. Allis, Anatomy and Development of Lateral
Line system in Amia, Journ. Morphology, 2, 1889. Fritsch, Die electrischen
Fische, Leipzig, 1890. Ewart, The sensory canals of Laemargus, Trans.
Roy. Soc. Edinburgh, 37, p. 59, 1891 ; and The sensory canals of the
skate, Ibid. Pollard, The lateral line system in Siluroids, Zool. Jahrb.
5, 1892. Cole, On the cranial nerves and lateral sense organs of fishes,
Trans. Linnean Soc., 1898.
80 CLASS PISCES.
In the lateral line system these sensory patches are modifi-
cations of the lining epithelium of a canal, which extends the
whole length of the body and on to the head, where it branches
in a somewhat complicated manner. The canals lie in the dermis
or deeper in the subcutaneous tissue, and their walls contain
either stiff connective tissue or cartilage (skates) for the purpose
of keeping them permanently open. They communicate at
intervals with the exterior by tubules. The trunk section of the
canal usually lies at the junction of the dorsal and ventral
divisions of the lateral muscles. The sense organs and the
tubules seem to be usually metamerically arranged in the trunk,
and the sense organs and tubules correspond, but in the head
the metameric arrangement is of course out of the question,
and the sense organs appear to be more numerous than the
tubules.
That this system has originated from a skin groove is indicated
by its development and by the fact that in some Elasmobranchs
it has the form of an open groove throughout life. In Chlamy-
doselachus it has the form of a groove guarded by overlapping
scales. In Chimaera it is also an open groove, though in the
head the lips of the groove tend to approximate over the sense
organs (Fig. 42.) In Heptartchus it is a groove in the greater
part of the trunk, but closes into a canal in front and on the
head. The course of the cephalic portion in a typical case is
shown in Fig. 41. The lateral 'canal on reaching the head is
connected with its fellow of the opposite side by a cross canal —
the commissural canal — which may pass in front of or behind
the openings of the otocysts. A short distance in front of this
it branches into a canal passing above the eye — the supraorbital
canal (CSO] and one passing below the eye, the infraorbital
canal (CJO). The supraorbital canal extends to the front end
of the snout and then passes back to join the infraorbital canaL
The infraorbital canal gives off a branch back to the hyoid region,
called the hyomandibular canal (Hm), which itself gives off a
branch to the mandible. In Chimaera (Fig. 42) the arrangement
is very similar.
In skates the hyomandibular canal is enormously extended backwards
in a loop which lies partly on the dorsal and partly on the ventral surface
of the pectoral fin, and communicates with the exterior by rather long
tubules. In the same animal the lateral line canal near the head gives off
LORENZINl'S AMPULLAE. 81
two long canals which pass backwards and outwards on the dorsal side o
the fin ; the anterior of these anastomoses with the dorsal part of the
above described extension of the hyomandibular canal.
The whole of this system of canals is in Elasmobranchs
supplied by the facial nerve and the lateralis branch of the vagus,
which probably belongs to the facial system (see account of
cranial nerves under Elasmobranchii and Fig. 41).
The ampullary canals or Lorenzini's ampullae, are un-
branched canals (Fig. 43), opening, usually in groups, on the
surface of the head and ending internally in vesicles — the
ampullae — which are beset with radial dilatations (Fig. 44).
The ampullae are placed in groups, the position of which in
a typical case is shown in Fig. 41.
FIG. 42. — Cephalic lateral line of Chimaera (from Gegenbaur). a lateral
groove of trunk, b, e" infraorbital, c supraorbital groove, c' supraorbital
grooves ; passing back to join infraorbital ; x frontal appendage. .
The sensoiy epithelium is confined to the ampulla to which the
nerves, in all cases branches of the facial, are distributed. The
tubes and ampullae contain a gelatinous matter.
Savi's vesicles are found in Torpedo round the electrical organs
They are completely closed.
The pit organs, found in many Elasmobranchs are sense
organs sunk in pits on different parts of the head and trunk, and
are supplied by the facial nerve, the lateralis of the vagus, and
the trigeminal.
In Teleosteans, Ganoids and Dipnoi the lateral line system
and the pit organs alone are present. The lateral line has an
arrangement very similar to that described for Elasmobranchs,
z — ii G
82
CLASS PISCES.
FIG. 43. — A portion of the snout of Scyllium in section, show-
ing ampullary tubes (from Gegenbaur). N nerve ; a ampullae ;
c epidermis ; t tubes ; c' dermis ; o openings of the tubes ;
a' passage of a tube through the dermis.
but the canal wall is sometimes ossified, especially on the head,
and the ossifications may be fused with the dermal and cranial
bones. Very often the canal traverses the scales and bones, and
the sense organs
are contained in
the osseous tissue.
In such cases the
lateral tubules,
which are in some
cases branched,
their openings
forming so-called
cluster pores, per-
forate the bone,
as does the nerve
going to the sense
organs. In this way certain scales on the body and bones of the
head may acquire a special relation to these organs. Pit organs
are present both on the trunk and head and often lie along the
course of the main canals. In a few cases (Esox, Gobius, Liparis,
etc.) the cephalic canals are alone present, the sense organs in
the trunk being isolated and not connected by a longitudinal
canal. In a few cases the longitudinal canal
may have the form of a groove for a part
of its extent. The openings of the lateral
tubules may occur between the scales as
well as upon them.
In addition to the innervation found
in Elasmobranchs the glossopharyngeal
frequently sends a branch to a few of the
posterior cephalic sense organs ; and it has
been stated that the ophthalmicus super-
ficialis trigemini also takes part, but this
must be regarded as doubtful. In any
case the nerves innervating this system of
lateral line sense organs can always be FIQ
traced to the special centre in the brain
from which the auditory nerve arises. The
pit organs are innervated by the trigemi-
nal as well as by the facial and lateralis of the vagus.
44. — Lorenzini's am-
pulla. A from the side
with nerve n and portion
of tube c ; B in section
(from Gegenbaup).
ELECTRICAL ORGANS.
8B
EO
Electrical organs,* the function of which is to develop con-
siderable quantities of electricity, are found in some fishes.
They occur in different parts of the body and in fishes belong-
ing to quite different groups (e.g. Torpedo and Hypnos among
Elasmobranchs, and Gymnotus and Malapterurus among
Teleoste a n s ) .
They differ
both in struc-
ture and po-
sition in the
body, but they
always consist
o f peculiarly
modified cross-
striped muscu-
lar tissue.
In Torpedo
(Fig. 45) they
are placed be-
tween the bran-
chial pouches
and the anterior
cartilages of the
pectoral fins,
and occupy the
whole space be-
tween the dor-
sal and ventral
integument.
They consist of
vertically ar-
ran g e d col-
umns, sup-
ported by walls
of connective tissue, and divided by horizontal septa of the
same material into a number of compartments placed one
FIG. 45. — Torpedo with electric organ EO and brain exposed (after
Gegenbaur), dorsal view. On the right side the dorsal surface
only of the organ is exposed ; on the left the nerves which supply
it are shown, br branchial sacs ; Gr sensory canal tubes of the
skin ; Le electric lobe of the brain ; o eye ; Tr trigeminal nerve ;
V vagus nerve.
* Fritsch, Die electr. Fische, Abt. 1 and 2, Leipzig, 1890. Ballowitz,
Electr. Organ v. Torpedo, Arch. f. mic. Anat., 42, 1893. Sanderson
and Gotch, Elect. Organ of Skate, Journ. Physiology, 10, 1889. Ewart,
Electric Organ of Skate, Phil. Trans., 1888 * 1892.
84
CLASS PISCES.
above the other. Each compartment is filled with gelatin-
ous tissue, through the middle of which runs a horizontal plate
composed of a finely granular nucleated substance and of numer-
ous nerve-endings. This is the electrical plate. The electrical
plates correspond to a certain degree to the copper and zinc ele-
ments of the voltaic pile, the gelatinous matter representing the
moist intermediate layers ; while the connective tissue frame-
work serves to hold the parts together and to carry the blood-
vessels and nerves. The face of the plate on which the nerves
ramify is the same in all the columns of the same organ, and is
always electro -negative, the other surface being positive. In
Torpedo the nerve enters on the lower surface of the plates, the
upper surface is therefore electro-
positive. The organ is supplied
by five strong nerves, of which
the anterior is a branch of the
facial, the four posterior being
branches of the vagus group.
In the electric Teleostei the
electric organs are placed in the
trunk and tail, and are supplied
by spinal nerves. They are simi-
larly constituted, but the col-
umns are horizontally placed. In
Malapterurus they lie along the
body beneath the skin, and the
posterior surface of the plates, the surface on which the nerve
enters, is electro-positive. This apparent exception is explained
by the fact that the nerves pass through the plate and
are distributed on the anterior surface, which is electro-nega-
tive. In the electric eel (Gymnotus electricus) the electric
organ lies at the side of the tail, and consists of long horizontal
columns (Fig. 46).
The so-called pseudo-electric organs found in the tail of Raja
and of Mormyrus have a similar structure, but manifest only
feeble electric phenomena. They constitute a very good example
of an organ which is practically of no use to its possessor, and
which we should entirely fail to understand the meaning of were
it not for the cases in which the electric organ is fully developed.
VASCULAR SYSTEM. — The blood is generally red ; it is white
FIG. 46. — Longitudinal section through
two columns of the electric organ of
Gymnotus. a horizontal partition ;
I transverse partition walls, convex
headwards ; e electric plates (from
Gegenbaur, after Max Schultze).
VASCULAR SYSTEM.
85
only in the Leptocephalidae (larvae of the eels) ; it circulates in a
closed vascular system, in which a muscular pulsating region or
heart is present. The heart (Fig. 47) is placed far forward on
the throat, ventral to the branchial
framework, and is enclosed in a
pericardium, the cavity of which
communicates with the body cavity
in some Plagiostomes, Chimaera,
Acipenser, etc. It is a simple
venous branchial heart, and is
composed of a sinus venosus, a
thin-walled large auricle and a very
powerful muscular ventricle. The
sinus venosus receives the venous
blood returning from the body, and
the ventricle forces it through the
ventral aorta to the respiratory
organs. The aorta begins with a
bulbous swelling (bulbus arteriosus}
which in the Ganoids, Plagiostomes
and Dipnoi is replaced by an inde-
pendently pulsating part of the
heart, with rows of semi-lunar
valves (conus arteriosus}. While
the fishes with a simple non-mus-
cular bulbus arteriosus have but
two semi-lunar valves at its origin,
the above-mentioned orders usually
have two or four, or rarely five,
rows of three, four, or more valves
each, in the conus
The aorta at once divides into a
number of paired vascular arches,
corresponding to the embryonic
aortic arches. These are the bran-
chial arteries ; they pass into the
branchial arches and give off branches to form the capillary net-
works of the gills. From the capillary networks small vessels
pass out which unite to form a larger vessel in each branchial
arch (epibranchial or efferent branchial artery). The arrange-
arf-Arin«n« Fm- 47.— Diagram of the circulation of
US< a Teleostean. Ab arterial arches;
Ao aorta descendens into which the
epibranchial arteries passing out from
the gills unite ; Ba ventral aorta with
the arterial arches which carry the
blood to the gills ; D intestine ; Lk
portal circulation ; N kidneys ; V
ventricle. The branchial capillary
system is omitted.
86 CLASS PISCES.
ment of these vessels corresponds to that of the afferent
branchial arteries ; they unite to form the large aorta descendens
or dorsal aorta. Before they unite the cephalic arteries pass off
from the efferent vessels of the anterior arch.
The arrangement of the principal venous trunks in fishes is
most nearly related to the embryonic condition. Corresponding
to the four cardinal veins of the embryo, two anterior and two
posterior cardinal veins bring back the blood from the anterior
and posterior part of the body respectively. These veins unite on
each side to form two transverse veins — the ductus Cuvieri —
which enter the sinus venosus of the heart. The course of the
returning venous blood is complicated by the insertion of a double
portal circulation. The caudal vein does not pass directly into
the posterior cardinal veins, but breaks up into capillaries in the
kidneys, from which the blood passes into the posterior cardinal
veins. There is thus a renal-portal circulation. For the hepatic
portal circulation on the other hand the venous blood of the
intestine is used ; this blood after passing through the capillaries
of the liver is returned to the heart by one or more veins, which
open into the sinus venosus between the two ductus Cuvieri.
Such capillary systems must be a considerable hindrance to the
circulation of the blood and explain the development of the so-
called accessory hearts on the caudal vein of the eel and on the
portal vein of Myxine.
The urinogenital organs are described under the different sub-
classes. With regard to them the following general remarks may
be made. A pronephros is present and functional in the larva of
all fishes except Elasmobranchii, in which there is no larval stage.
It has been maintained, and a great deal has been written on the
subject, that there is a vestige of a pronephros in the embryos of
Elasmobranchs ; but if there is it is very feebly developed and
never possesses a glomerulus.
The pronephros is the anterior and first developed portion of a
longitudinal gland, which extends, in the embryo at least, the
whole length of the body cavity from the pericardium to the
hind end. This extended excretory organ consists of nephridia,
which in Elasmobranchs are developed, as was first shown by
Sedgwick,* from the portions of the body cavity which connect
the lower ends of the muscle plate cavities with the general body
* Q. J. M. S., 20, 1880, p. 164.
EXCRETORY ORGAXS. 87
cavity. These portions of the body cavity are called nephro-
tomes, and accurately correspond at first with the segments of
the embryonic muscular system. The pronephros is the anterior
end of this excretory organ, which is developed before the rest
to meet larval needs. The serial homology between the prone-
phros and the hinder part of the excretory system was for many
years denied, partly because of a certain difference in structure
and partly because there is usually a gap between it and the
front end of the rest of the organ. But the differences in struc-
ture are very small, in some cases indeed (e.g. Lepidosteus) do
not exist ; and vestigial nephridia have been found in the gap
between the two organs (cf. especially Price's researches on the
development of the excretory organs of Bdellostoma). Finally,
Brauer's recent researches on the development of the excretory
organs of Gymnophiona remove all doubt on the point.
The hinder part of the excretory system differs from the
pronephros mainly in the fact that the glomerulus — the vas-
cular tuft which secretes the fluid part of the urinary excre-
tion— is segmented into portions, one for each nephridium (or
kidney tubule), instead of forming a continuous structure as in
the pronephros ; and the portion of the body cavity containing
each of these is partly shut off from the rest to form the
malpighian body of the kidney tubule. This malpighian capsule,
however, frequently, though not always, retains its connection
with the rest of the body cavity by the so-called nephrostome.
The internal opening is retained in most Elasmobranchs, but
is lost in Teleostei, Dipnoi, Ganoidei and Marsipobranchii.
This hinder part of the excretory system becomes in
Elasmobranchii much reduced in front and largely developed
behind. In consequence of this it is described as consisting
of the mesonephros in front and the metanephros behind ; but
this differentiation is not found in other fishes.
As in all Vertebrates, the longitudinal duct (archinephric duct)
is the first part of the excretory organs to appear. The prone-
phros is developed in connection with the front end of this duct,
so that the duct is at first the pronephric duct. The Miillerian
duct is found in all Pisces with the probable exception of the
Marsipobranchii and the Teleostei, and in all cases it becomes
the oviduct in the female, but is reduced in the adult male. In
Ganoids the longitudinal duct joins the oviduct (Miillerian)
88 CLASS PISCES.
before opening externally, but in Elasmobranchii the two ducts
open separately into the cloaca. The development of the Miil-
lerian duct is known only in Elasmobranchii. It there arises
in connection with the first establishment of the longitudinal
duct as an evagination of the parietal mesoderm of one of the
anterior nephrotomes, so that it at first consists simply of a
funnel-shaped opening of the longitudinal duct into the body
cavity. It soon, however, by a process of gradual shifting,
comes to open further and further back into that duct until it
acquires an independent opening into the cloaca.
The female genital glands, which are, as is usual in Vertebrates,
specialised patches of the lining of the coelom, and of the unseg-
mented * portion of it called the splanchnocoel which persists
as the general body-cavity, dehisce their ova into the body
cavity, whence they escape by the Miillerian ducts — except
in Marsipobranchii and Teleostei. These exceptions however
are doubtful. In Marsipobranchs the genital pores by which
they escape may be Miillerian ducts, though it must be confessed
that there is not much to be said for so regarding them. In
Teleostei the ovaries are generally saccular and continued directly
into their ducts, but in some families they discharge into the body
cavity and the eggs are taken up by two funnel-shaped structures
which join each other and open behind the anus. It is quite
possible, though not definitely proved, that these funnels are
short Miillerian ducts, and that the ducts in the more usual con-
dition, in which they are continuous with the walls of the ovary,
are also Miillerian ducts, which have spread round the ovary or
fused with the edges of a peritoneal recess into which the ovary
has sunk.
The male gonads also are specialised patches of the coelo-
mic lining, but the Marsipobranchii alone retain the primitive
condition of testis dehiscing into the general body cavity,
escape being made by genital pores of unknown homology.
In all others the testis is continuous with its duct. In Teleos-
teans this continuity is very like the continuity found in the
female between the ovary and its duct, and the homology of the
male duct in these animals is not understood. It may be a per-
* The contention which has been put forward in some quarters that
the gonads of Elasmobranchs arise from the segmented part of the coelom
cannot be seriously maintained.
GENERATIVE ORGANS. 89
sistent Miillerian duct which has fused with the testis or it may
be something else. In other Pisces, with the apparent exception
of the Ganoid Polypterus, the testis has come to consist of tubules
which are connected by means of a network of tubes, called the
testicular network, with some of the kidney tubules. The con-
nection may take place along the greater part of the length^of the
kidney, as in Lepidosteus and Acipenser, or it may be confined to-
the anterior region (mesonephros), as in Elasmobranchs, or
finally, as in Dipnoi, it may only occur through the hind end of
the kidney. The connection is usually through the malpighian
bodies of the renal tubules, but in Amia the tubes from the testis
join the renal tubes beyond the malpighian bodies. In Poly-
pterus alone is there no connection with the kidney, the testis duct
passing directly back from the testis to join the longitudinal duct
near th? cloaca. This condition in Polypterus is not understood
any more than is the condition of the male Teleostean, though
theories have been put forward to account for it. It may be
that in these forms the Miillerian duct has acquired a connection
with the male gonad and persisted ; or it may be that the con-
nection is .really effected through a part of the kidney which has
lost all kidney structure, as has happened in some male Amphibia
and in the higher Vertebrata. A study of development can only
settle the question, and that has not yet successfully been
made.
To return to the longitudinal duct. This, as explained above,
is called at first the pronephric duct, except in Elasmobranchs,
in which it is called the segmental duct, there being no functional
pronephros. Later, when the kidney is formed and the prone-
phros has atrophied, it becomes the kidney duct. In Elasmo-
branchs, in which the kidney differentiates into meso- and meta-
nephros distinguished, not by any break in continuity, but by size
and by the course of the so-called collecting tubes of the nephridia
(see below), it is called the mesonephric duct, because it appears to
be related more especially to the mesonephric portion of the
kidney. Inasmuch as in the male Elasmobranch this meso-
nephric duct is chiefly concerned with carrying off the spermatozoa
which pass, as has been described above, through a part of the
mesonephros, it is also called the vas deferens. In the higher
classes of Vertebrata the mesonephric duct is called the Wolfnan
duct in the embryo, and persists in the male adult as the vas
90 CLASS PISCES.
deferens, but disappears or is reduced to a slight vestige in the
female.
In Elasmobranchs the longitudinal duct is at first called the
segmental duct on the view that the Miillerian duct is segmented
off it. As we have seen, this is not a good description of what
happens, and the name is not a happy one. After the Miillerian
duct has become distinct from it, it becomes the duct of the per-
sisting kidney, and eventually, owing to the shifting back of the
point of opening of the metanephric tubules, the mesonephric
duct.
The nephridia typically open directly by the so-called collect-
ing tubules into the part of the longitudinal duct opposite to
them, but with the differentiation of the metanephros the collect-
ing tubes of the posterior nephridia shift their point of opening
into the longitudinal duct backwards, so that they all come to
open close together into the longitudinal duct — now called
mesonephric duct — close to the cloaca. They are usually re-
ferred to as ureters.
The development of the nephridia of the part of the kidney
behind the pronephros. as direct transformations of a portion
of the coelom occurs only in Elasmobranchs. In other fishes
the development of these tubules is delayed until the myotomes
and adjacent tissues have become functional, and have lost their
primitive relations. The consequence is that the development is
modified and the nephridia (except of the pronephros) are de-
veloped from small nodules of growing tissue, which make
their appearance during larval life in the proper positions.
Abdominal pores, as distinct from generative pores, are pre-
sent in most Elasmobranchs, some Teleostei and in Ganoids,
but they are strangely variable in their occurrence. They never
act as generative outlets, and their function would appear to be
for the outlet of excretory substances of the body-cavity itself.
As Bles has pointed out, they are rarely present in forms in which
the nephrostomes of the kidneys are persistent.
Generative Organs. — Excepting in certain forms, such as
Serranus and Chrysophrys, which are hermaphrodite, fishes
are of separate sexes ; the two sexes sometimes present
external differences. The male and female reproductive
organs often resemble one another so closely in form and position
that it is necessary to investigate their contents in order to dis-
HABITS. 91
tinguish the sex, especially as external sexual differences are
frequently absent.
Copulatory organs are only found in male Elasmobranchs, in
the form of long grooved cartilaginous appendages (claspers) of
the pelvic fins.
Most fishes are oviparous ; only a few Teleosteans, as Ditrema,
Zoarces, the Cyprinodonta, etc., and a great number of the sharks,
bear living offspring, which for the most part undergo their em-
bryonic development in a dilated part of the oviduct, which
serves as an uterus. Reproduction usually takes place only once
in the year, most frequently in spring, more rarely in the summer,
and exceptionally, as in many of the Salmonidae, in winter.
Many fishes, especially the males, undergo changes of colour and
develop growths of skin at the spawning time. The two sexes
often assemble in great shoals and seek out shallow places
near the banks of rivers or near the sea coast (Herrings) for spawn-
ing. Some make more extended migrations and pass in large
shoals over great distances along the sea-coast (Tunny-fish).
Others leave the sea and pass up the mouths of rivers, and over-
coming great obstacles (Salmon leaps) make their way up into the
smaller streams, in which they deposit their spawn in sheltered
places where the food is plentiful (anadromous, as the Salmon,
Sturgeon, etc.). The Eels, on the other hand, migrate from the
rivers into the sea, and in the following spring the young Eels
enter the fresh waters by millions and pass up stream (kata-
dromous). The spawn is as a rule fertilized in the water, and
thus artificial fertilization and pisciculture are rendered possible.
In the viviparous fish, and in the Rays, Chimaera, and Dogfishes,
which lay large eggs enclosed in a horny shell, a true copulation,
and an internal fertilization of the egg takes place. It is worthy
of note that in a few exceptional cases the male undertakes the
charge of the brood (Hippocampus, Coitus, Gasterosteus).
The embryonic development of fishes is principally distin-
guished from that of most higher Vertebrates by the fact that
neither amnion nor allantois are developed. Both the small eggs
of the Teleosteans, which are provided with a micropyle, and the
large eggs of the Elasmobranchs, which are surrounded by a hard
horny case, contain a large quantity of food yolk, and undergo a
partial segmentation. The eggs of Cyclostomes, Ganoids and
Dipnoi, however, undergo a total segmentation. As a rule
92 CLASS PISCES.
the young fishes leave the egg- membranes tolerably early, with
more or less distinct remains of the yolk-sac, which still projects
externally, like a hernia. Although the body form of the just-
hatched fish differs essentially from that of the adult animal, no
sudden metamorphosis takes place save in a few exceptional cases.
Most fishes live in the sea, and the number of their species and
genera increases as we approach the equator. But they are not
all exclusively confined to fresh or salt water. Many, as the
Plagiostomes, live almost entirely in the sea ; others, as the
Cyprinidae and Esocidae, are confined to fresh water, but there
are also fish which periodically change their habitat, especially
at spawning time. Some fish live in subterranean waters, and
are blind, like the inhabitants of caves (Amblyopsis spelaeus).
Few fish are able to live any length of time out of water ; as a
rule the wider the gill-slits the quicker does the fish die on dry
land. Fishes with narrow gill-slits (Eels) possess an uncommon
tenacity of life out of water. According to Hancock, a species of
Doras migrates in great shoals over the surface of the ground
from one piece of water to another, Except the Dipnoi, certain
East Indian freshwater fish, the upper pharyngeal bones of
which are hollowed out into the form of a labyrinth (Fig. 38)
and form a multicellular reservoir for water, are capable of living
the longest time out of water (Anabas scandens). There are
even fishes which can float through the air (Exocoetus,
Dactylopterus) .
Marine fishes may be distinguished into shore fishes, pelagic
fishes, and deep-sea fishes, which, as in the case of marine and
fresh-water fishes, graduate into one another. Shore fishes live
near the surface, and do not descend to any great depth ; they
are comparatively restricted in range. Pelagic fishes inhabit
the surface waters of the ocean, where they usually spawn,
though some visit the shores for this purpose ; they are usually
strong swimmers and wide ranging, but a few (e.g. Hippocampus,
Antennarius, etc.) are poor swimmers, and infest floating sea-
weed, or drift on the surface. Some pelagic fishes come to the
surface at night only, descending in the daytime to a consider-
able depth (Brama, Sternoptychidae, Scopelus, Astronesthes).
The largest fishes belong to the pelagic fauna, e.g. Rhinodon,
Selache, Carcharodon, Myliobatidae, Thynnus, Xiphiidae, Ortha-
goriscus. The features of deep-sea fishes are referred to below.
DEEP-SEA FISHES. 93
Owing to the uniformity of the conditions of life in the abyss in
different parts of the world, they are probably for the most part
wide ranging.
The greatest depth at which fishes are known to exist is 2,900
fathoms. Many littoral fish descend periodically within the
limits of the deep-sea fauna, but these are not conspicuously
modified. Fishes which habitually live at a depth of 80-120
fathoms, have a black lining to the pharynx and large eyes.
Fishes which belong to the real deep-sea fauna all present very
similar characters, those from 300 fathoms being as much
modified as fishes from 2,000 fathoms. The principal changes
in external conditions to which deep-sea fishes are subjected
as compared with surface forms are (1) absence of light, (2) still-
ness of the water, (3) constant low temperature, and (4) increase
of pressure. With regard to the latter, it may be stated that
pressure increases by one ton on the square inch for every 1,000
fathoms of depth. The principal bodily characters are as
follows : The eyes are largely developed and luminous organs,
or, to speak more correctly, organs the function of which is
probably to supply luminosity are present. When the supposed
luminous organs are not present the lateral line canals are much
dilated, sometimes into wide cavities, and full of mucus. The
eyes are, however, in some cases reduced or absent. The osseous
and muscular systems are feebly developed ; the bones being
light and provided with little calcareous matter, and the muscles
thin. When the fish are brought to the surface the bones are
found to be but loosely bound together, and the body easily
falls to pieces. This is probably due to the expansion of gases
within the body. The air-bladder presents no special modifica-
tions, and appears to be always without a pneumatic duct, even
in Physostomous forms. It is generally ruptured in fishes brought
up from the deep sea, and in fishes from 80 fathoms it is much
distended, and the eyes protrude and the stomach is everted.
Deep-sea fishes are sometimes found floating on the surface in
a dead or dying condition, and often with the stomach distended
with recently swallowed prey. It is conjectured that such fishes
have accidentally ascended too far above their normal depth,
possibly during the struggle of swallowing their prey which
may be as large as themselves, and then owing to the expansion
of gases consequent on the diminished pressure have been
94 CLASS PISCES.
carried to the surface. Sharks, Rays and flat-fish (with one
exception in each case) cease below 500 fathoms. Twelve
hundred fathoms is the limit for Holocephali. The eggs of some
deep-sea fishes ascend to and develop at the surface, but in
other cases the development undoubtedly takes place in the
abyss.
Fishes are of great importance to our knowledge of the develop-
ment of animal life on the earth, owing to the frequent appearance
of their fossil remains in all geological periods. In the palaeozoic
formations very singular fish-forms, as the Cephalaspidae
(Cephalaspis, Coccosteus, Pterichthys), constitute the oldest
representatives of the Vertebrata. From the palaeozoic forma-
tions to the chalk we find almost exclusively cartilaginous fishes
and Ganoids, amongst which the forms with persistent notochord
and cartilaginous skull predominate. Ganoids, with a fully
developed bony skeleton, round scales and an externally homo-
cereal caudal fin, appear for the first time in the Jurassic rocks,
where we also find the first Teleosteans. From the chalk
onwards, in the more recent formations, the Teleosteans increase
in number and variety of forms the nearer we approach to
the fauna of the present time.
The class Pisces is divided into the five sub-classes,
Marsipobranchii, Elasmobranchii, Ganoidei, Dipnoi, and
Teleostei.
CHAPTER V.
SUB-CLASS MARSIPOBRANCHII
(CYOLOSTOMATA).*
Vermiform fishes with smooth scaleless skin, cartilaginous
skeleton and persistent notochord ; with suctorial mouth, single
nasal organ, and straight intestine ; without jaws, paired appen-
dages, generative ducts, sympathetic system, and conus arteriosus.
The unpaired fins are without actinotrichia (dermal fin-rays).
The Marsipobranchii are vermiform in appearance, varying in
length from two feet or more (Bdellostoma) to a few inches
(Petromyzon fluviatilis). The skin is smooth and without scales,
and the skeleton is cartilaginous and notochordal. They are
without paired fins, but possess an unpaired caudal fin (Myxi-
nidae, Fig. 62), to which may be added a dorsal unpaired fin
in the posterior region (Petromyzontidae, Fig. 48). In the
* J. Miiller, Vergleichende Anatomie der Myxinoiden, Berlin, 1835-45.
A. Giinther, Catalogue of the fishes in the British Museum, London, 1870.
C. Kupffer, Die Entwickelung der Petromyzon planeri, Arch. f. mic. Anat.,
35, 1890. P. Furbringer, Unters z. vergl. Anat. d. Muskulatnr. d.
Kopfskelets d. Cyclostomen, Jena. Zeitsch, 9, 1S75. W. K. Parker,
Skeleton of Petromyzon and Myxine, Phil. Trans., 1883, p. 373. P.
Langerhans, Unters. ub. Petromyzon planeri, Ber. d. naturf. Gesellsch.
zu Freiburg, 1873. A Schneider, Beitrdge, z. vergl. Anat. etc. d. Wirbe.l-
thiere, Berlin, 1879. T. H. Huxley " On the Cranio-facial apparatus
of Petromyzon." Journal of Anat. and Physiology, 10, 1876, pp. 412-28.
F. Ahlborn, Das Gehirn v. Petromyzonten. Z. f. w. Z., 39, 1883,
pp. 191-295, and Hirnnerven v. Petromyzon Z. f. w. Z., 40, 1884, pp.
286-308. G. C. Price, Ontogenie d. Myxinoiden Bdellostoma stouti, Sitz. ber.
Math.-phys. Idasse d. k. bayer. Akadl d. Wiss, 26, 1896, Munich. Id.
Development of excretory organs of Bdellostoma stouti, Zool. Jahrbnch.
Anat., 10, 1897, p. 207. W. F. Pv. Weldon, The head-kidney of Bdellos-
toma, Q. J. M. S., 24, 1884, p. 171-182. J. W. Spengel, Die Excretions-
organe von Myxine, Anat. Anz., 13, 1897, p. 49-60. F. C. Studnicka,
Sur les organes parietaux de Petromyzon vlaneri, Vestnik Ceske Spol. Nauk
Prag, p. 1-50, 1893. J. D. Ogilby, "A Monograph of the Australian
Marsipobranchii," Proc. Lin. Soc. N. S. W., 21, 1896, p. 388-426.
96
SUB-CLASS MARSIPOBRAXCHII (CYCLOSTOMATA).
Petromyzontidae and in the tail of myxinoids the fins are sup-
ported by cartilaginous somactids. They possess a suctorial
mouth, which is without jaws, but is provided with horny teeth.
By means of it, with the assistance of a suctorial tongue-like
structure they attach themselves to and suck their prey.
Myxine indeed bores its way into the body cavity of other fishes,
and is truly parasitic. The nasal aperture is single, and leads
into an unpaired nasal sac. In this and in other features of
their anatomy, which will be described later, they are unique
amongst Vertebrates. Nevertheless, we shall not follow the
example of some zoologists who have established the Marsipo-
branchii as a separate class of the Vertebrate, distinct from the
class Pisces. We hold them, in spite of the remarkable and
unique features of their organization to be true Pisces, not only
FIG. 48. — a. Petromyzon fluviatilis (after Heckel and Kner). b, c, d, stages in the transforms'
tion of Ammocoetes branchialis into Petromyzon planeri (after v. Siebold) ; b head of an eye-
less larva, side view ; c the same, ventral view ; d later stage with small eyes, side view.
by their aquatic habit of life, but by the characters of their
respiratory and vascular organs. They possess a simple tubular
heart, which distributes the blood by means of a ventral aorta
to the walls of the gill pouches ; and these open to the exterior
on the sides of the body in the ordinary piscine manner. In
the structure of their mouth parts they present some resemblance
to the larvae of anurous Amphibia, but the resemblance is too
vague to permit of any definite approximation to that group
in classification.
The Marsipobranchii fall into two main groups which present
marked points of difference from one another. These are the
Petromyzontidae or lampreys, and the Myxinidae or hag-fishes.
In the Petromyzontidae the nasal sac does not communicate with
the mouth, the eyes are normally developed, and possess eye-
muscles with their corresponding nerves, the pericardium does
LATERAL LINE. MUSCLES. 97
not communicate in the adult with the abdominal part of the
body cavity, and the pronephros does not persist. In the
Myxinidae the nasal sac does communicate with the alimentary
canal by an aperture which perforates the roof of the mouth, the
eyes are much reduced and without the muscles and the cor-
responding cranial nerves, the pericardium communicates with
the general body cavity by a wide opening on the right side,
and the pronephros is persistent in the adult. Moreover, the
Myxinidae possess a contractile dilatation on the portal vein
(portal heart) which is not present in the lampreys.
The skin is slimy, and has the usual vertebrate structure. It
possesses unicellular glands which secrete the mucus. In the
Myxinidae there is in addition on each side of the body and
embedded in the subcutaneous tissue, a row of segmentally
arranged slime-glands, which open on
the surface and pour out a mucus
containing an immense, number of
threads. These threads arise in special
cells of the gland and unwind them-
selves when the mucus is discharged.
They were discovered by Retzius and
described and figured by Mfiller.
Nothing of the nature of lateral line
sense-organs has been observed in FIG. 49.— Thread-
n/r • "j i> •j.'ui n alutinosa with unwinding
Myxinidae, but in the lampreys small thread (after Muiier).
sensory eminences, partially sunk in pits,
are found on the head and in two double rows on the body.*
The great lateral muscles are divided up by septa, which have
a zig-zag course, into myomeres of the usual piscine type. The
myomeres extend on to the head to just behind the eyes. In
the Myxinidae there is in addition a ventral sheet of obliquely
directed muscle-fibres which is unsegmented. There is a
complicated system of muscular bands connected with the
mouth, tongue, and pharynx.
In Petromyzon the portion of the lateral muscles dorsal to the gill-sacs
is continued to just behind the eye and contains a greater number of seg-
ments than the corresponding ventral portion. The ventral part reaches
to just in front of the first gill opening. In Ammocoetes there is one
myomere anterior to the first gill aperture ; this in the adult divides up
into nine or ten myomeres (Schneider).
* Langerhans, op. cit.
z — II H
98 SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
The skeleton consists of cartilaginous, notochordal, and mem-
branous tissue ; there is no bone. There are two kinds of
cartilage at least, the hard with considerable intercellular
matrix, and the soft with but little.
The vertebral column consists of a persistent notochord with a
tough sheath, which is formed of two layers, an inner somewhat
fibrillated chordal sheath (or membrana elastica internet,) and an
outer thin elastic coat (membrana elastica externa) ; both are
devoid of nuclei. The notochord so constituted is surrounded
by a nucleated membranous sheath (the so-called skeletogenous
tissue, or membrana reuniens), which extends dorsalwards on
each side so as to enclose the spinal cord. Small cartilaginous
FIG. 50. — Cartilaginous skeleton of the anterior part of the body of Petromyzon fluviattiis ;
side view (after A. Schneider). 1 Foramen for sensory, 2 for motor root of spinal nerve ;
3 eleventh dorsal arcualium ; 4 first '.dorsal arcualium, pierced by the first anterior root,
which passes into the ligament between the fourth and fifth myomere ; 5 foramen for
vagus ; 6 auditory capsule ; 7 foramen for trigeminal ; 8 foramen for optic ; 9 nasal
capsule ; 10 posterior dorsal cartilage ; 11 anterior dorsal cartilage ; 12 annular lip carti-
lage ; 13 anterior lateral cartilage : 14 styliform cartilage of 12 ; 15 unpaired lingual
cartilage; 16 posterior lateral cartilage; 17 subocular arch; 18 styloid process; 19
cornual cartilage ; 20 branchial basket-work ; 21 the seventh gill aperture (the first and
sixth gill apertures are omitted) ; 22 pericardial cartilage.
pieces are developed on the membrana reuniens on each side :
these, the dorsal arcualia (dorsalia), are roughly segmentally
arranged.
In Petromyzon there are in the branchial and trunk region two pairs of
arcualia in each segment, while in the tail they are fused to form on each
side a continuous ridge, with which the cartilaginous fin -rays (somactids)
here present are continuous. Ventralia, fused to a continuous ridge, are
also present in the caudal region, and are continuous ventrally with ventral
somactids. In myxinoids cartilaginous elements are restricted to dorsalia
and somactids in the caudal region, and to some somactids in the trunk.
Anteriorly the notochord extends into the base of the skull,
ending just behind the pituitary body.
The skull consists of cartilage and membrane. The roof is
entirely membranous in myxinoids, but in Petromyzon there is a
narrow bar of cartilage passing across the posterior part of the
SKULL.
99
otherwise membranous roof. In the floor there is a basi-cranial
fontanelle (Fig. 52, 9} in the anterior (trabecular) region just in
front of the anterior end of the notochord ; this transmits the
pituitary pouch or posterior nasal canal, which, passing back
from the nasal capsule, ends blindly in the Petromyzontidae
(Fig. 51, 1], but opens into the mouth in the Myxinidae. This
canal lies between the basilar plate and the roof of the mouth.
The olfactory capsule is single and attached to the anterior part
of the cranium by fibrous tissue (Fig. 50, 9}- The auditory
12
11 10 9
14
13
15
FIG. 51. — Longitudinal vertical section through the anterior end of Petromyzon fluviatUis
(after Huxley). 1 Blind end of posterior nasal canal; 2 hinder margin of hard palate (inter-
trabecula) ; 3 cartilaginous roof of skull ; 4 brain ; 7 nasal capsule ; 8 posterior wall of
nasal capsule ; 9 the anterior portion of the subocular arcade ; 10 postero-lateral carti-
lage : 11 postero-dorsal cartilage (ethmovomerine plate) ; 12 tongue ; 13 anterolateral
cartilage ; 14 anterodorsal cartilage ; 15 annular lip cartilage ; 16 median ventral carti-
lage ; 17 lingual cartilage ; 18 ventral division of fifth nerve coming through the sub-
ocular foramen; 19 cornual cartilage; 20 posterior part of subocular arch ; 21 styloid
process (hyoid) ;
opening of
tube ; 27 oesophagus ; 28 notochord ; 29 spinal cord.
yoid) ; 22 tentaculate branchial valve ; 23 pharyngeal velum ; 24 internal
first branchial pouch ; 25 ditto of second branchial pouch ; 26 suboesophageal
capsules (Fig. 50, 6) are attached laterally in the posterior region
on each side of the basilar plate. The subocular arch (Fig. 50, 17)
is a ventro-lateral continuation of the basilar plate and trabe-
cular region on each side ; it contains a fenestra and is supposed
to correspond to the subocular or palato-quadrate arcade of the
Amphibian skull. At the point where the posterior part of this
arch joins the basilar plate, there is given off ventral wards the
styloid process (Fig. 50, I'S, and Fig. 51, 21), the end of which in
Petromyzon extends horizontally as the cornual cartilage (Fig.
50, 19). The styloid process and cornual cartilage have been
100
SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
compared to the hyoid arch of the higher forms. In the
Petromyzontidae the following additional cartilages are present.
Attached to the anterior end of the base of the skull is a large
median plate of cartilage — the posterior dorsal cartilage
(Fig. 50, 10, and Fig. 51, 11}. Immediately in front of this,
and overlapped by it, is the anterior
dorsal cartilage (Fig. 50, 11, and Fig.
51, 14)- Just below the latter there
is an annular cartilage (Fig. 50, 12,
and Fig. 51, 15), which lies within the
lips, and from which there projects
back on each side the so-called styli-
form cartilages (Fig. 50, 14). The
anterior lateral cartilages are paired
rods (Figs. 50 and 51, 13} in relation
with the anterior dorsal cartilage, and
the posterior lateral (Fig. 50, 16, and
Fig. 51, 10} are similarly in relation
with the posterior dorsal.
Finally, in the tongue in the floor
of the mouth there is a median
i1-T,fT11Ql oartilarm /TTifr ^O 7o nnH T^icr
lingual Cartilage (JJ Ig. OU, lO, and
KI 1?\ QTirl TTanfral +n +Vii« tVif* <an
^l> U), ana Ventral
no]]^ rnorlian Tr^ntral r>artilao-^ fTTio-
called median ventral cartilage ^ig.
61, ^; not shown in Fig. 50). The
lingual cartilage is also present in
Myxinoids, in which it is very largely
8
FIG. 52.— Ventral view of skull of
Petromyzon marinus (after W,
K. Parker). 1 posterior dorsal
cartilage (ethmoyomerine plate),
formed by union of cornua
trabecuiae, passing behind into
(formed by union of parachorial
cartilages), showing contained
notochord ; 9 basi-cranial fonta-
Snfuesed°rpo8sPtaedor ^pSn *? It is probable that the posterior dorsal
trabecuiae ; 10 cartilage formed cartilage is derived from the fused anterior
&£& t-SSVa^aVg end of the trabeoula* and it has been
of J. Miiller) ; it lies between suggested that the posterior lateral cartil-
SS*SM?torfirSSS& ages are the homologues of Meckel's cartil
intertrabecula of myxinoids. age. The anterior dorsal> and the anterior
laterals, and the annular cartilages are
generally regarded as labials, while the lingual cartilage has been compared
to the basi-hyal ; it is connected with the styloid process (supposed hyoid)
in Myxinoids (Fig. 53).
The foramen for the optic nerve is in the side wall of the skull
above the subocular arch (Fig. 50, 8), that for the fifth nerve
just in front of the auditory capsule (Fig. 50, 7), while the seventh
SKULL OF MYXIXE.
101
fs. CD
01 01
"S ° s p,-"^ a °^»
-a«ilaiil
3 p.
4illlii
ilftr-in
- S|i«tl£!*
« g-s s ..a &•
f-*r'STO . _ i ,—
--sits
O ~
102 SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
nerve passes out through the auditory capsules. The vagus
nerve passes out behind the skull, between it and the first dorsal
piece of the vertebral column (Fig. 50, 5}.
In its general features the chondro -cranium of Maraipdbranchii resembles
that of other fishes, but is more largely supplemented by membranous
structures, nearly the whole of the roof, the entire occipital region and
the basicranial fontanelle being membranous. From what is known of
the development of the lamprey's skull, it would appear that the basilar
plate is formed by two parachordals between which the notochord lies
(Fig. 52), that these become continuous above and below the notochord
(below only in Myxine), and that to their outer sides the auditory capsules
become attached. In front of the parachordals and continuous with them
are the trabeculae cranii which always remain separate posteriorly, leaving
the basicranial fontanelle, but unite in front to form in Petromyzon (Fig. 52)
the hard palate, the ethmoid and the posterior dorsal plate (ethmovomerine
plate), and in Myxine (Fig. 53, 13) a small median piece in front of the
large basicranial fontanelle. In front of the latter there is in Myxinoids a
pair of cartilaginous horns (Fig. 53, 17) which may be regarded as the
homologues of the posterior lateral cartilages of the lamprey. Moreover
in Myxinoids there are two median cartilages, called intertrabecular car-
tilages not present as separate structures in Petromyzon ; one of these —
the posterior intertrabecular — is a spoon-shaped cartilage lying in the basi-
cranial fontanelle and underlying the naso-palatine canal ; the other,
the anterior intertrabecular, extends in front of this and lies beneath the
nasal canal. In all Marsipobranchs there is a ventro -lateral process of
the hinder part of the trabecular region (anterior lateral process) which
meets and fuses with a corresponding process of the anterior end of the
basilar plate or auditory cartilage (posterior lateral process, said to be
comparable to the pedicle of the Amphibian suspensorium, Fig. 53, 7) ;
thus forming the so-called subocular arcade. The subocular arcade closely
resembles the same structure in the Amphibian skull, but against the
comparison of the two is the fact that the ventral division of the fifth
nerve passes dorsal to the arcade in Amphibians, whereas in Marsipo-
branchii it passes through the fenestra (Fig. 51, 18)- In Myxinoids the
hinder part of the subocular arcade contains two fenestrae (Fig. 53,6, 21),
which are not present in lampreys. The supposed hyoid arch arises in
all Marsipobranchs from the hind end of the subocular arcade (Fig. 50, 18 ;
Fig. 53, 23)- In lampreys it ends in the expansion of the cornual cartil-
age (Fig. 50, 19) and is not connected with the lingual (15) which is the
supposed median element of the hyoid arch. In Myxinoids it joins the
great lingual cartilage (Fig. 53, 18) which consists of several parts. In
the same group the hinder part of the subocular arcade also gives off
close to the point of origin of the hyoid a bar of cartilage which passes
ventral wards just within the hypoblastic epithelium to join the subocular
arch lower down (Fig. 53, 24). This structure is not represented in
lampreys and is supposed to be the first branchial arch. The velum in
Myxine is supported by some pieces of cartilage which are in connection
with the upper end of this supposed branchial arch (Fig. 53, 2, 3).
In Myxinoids the brain lies entirely above the cartilaginous skull, which
is a mere floor, the side walls and roof being entirely formed of membrane.
Moreover in Myxinoids the angle of the subocular arcade is posterior (Fig.
BRANCHIAL SKELETON. 103
53), i.e. the palatine process of the trabecular region is directed backwards
and not merely outwards as in lampreys (Fig. 50). Further the labial
cartilages of the lamprey, viz. the anterior dorsal, the anterior laterals and
the annular are not present in Myxinoids. On the other hand the oral
barbules of the Myxinoids contain a cartilaginous axis and the lingual cartil-
age is enormously developed (Fig. 53), and connected with the styloid
process (supposed hyoid arch).
In the Petromyzontidae there is a branchial basketwork of
cartilage placed superficially, near the skin and supporting the
outer parts of the branchial passages. It consists (Fig. 50) of
eight irregularly curved bars of cartilage placed between the
successive gill sacs.* They are connected dorsally by a longi-
tudinal band of cartilage, which lies along the notochord sheath
and is continuous with the hind end of the skull, and by three
other longitudinal bands, of which two are lateral, one being
above and one below the branchial apertures, and one is ventral
and partly fused with its fellow. The branchial basket is con-
tinuous posteriorly with a cartilaginous cup which supports the
wall of the pericardium (Fig. 50, 22). The first branchial aper-
ture is behind the first bar, and the seventh or posterior in front
of the last bar.
The branchial basketwork is supposed to be developed in the somato-
pleure and not to be homologous with the branchial arches of other fishes
which lie in the gutwall. The only representative of these structures in
Myxinoids (in addition to the supposed traces of mandibular and hyoid
arches) is the structure described above as the first branchial arch (Fig. 53,
24).
The alimentary canal. The mouth, or buccal funnel (Fig.
54), is suctorial and armed with horny epidermic teeth ; in the
lamprey it is surrounded by a lip carrying short papillae, in
Myxinidae by eight barbules (Fig. 61). On the ventral side of
the mouth is the tongue, which, moving backwards and forwards
like a piston, enables the animal to attach itself by its mouth as
by a sucker. The tongue carries teeth (two rows in the myxinoids
on the supralingual cartilages), which enable it to inflict con-
siderable wounds upon its prey. The buccal funnel leads into a
tube, which is supposed to be stomodeal, and may be called the
buccal cavity. This is continued behind into the oesophagus,
* There appears to be some variation in the details of the arrangement
of the branchial basketwork in the different species (cf. W. K. Parker's
account with Schneider's figure).
104 SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
which passes back through the pericardial cavity to become
continuous by a valvular aperture with the straight intestine,
which opens at the anus. The anterior end of the intestine is
slightly dilated, and receives the opening of the bile-duct, and
in Petromyzon the intestine is provided with a longitudinal fold
or valve, which takes a slightly spiral course.
In Myxinoids the naso-palatine canal (pituitary pouch) opens into the
hinder part of the buccal cavity. This may be taken to mark the junction
of mouth and pharynx. The opening is guarded by an epiglottis-like
valve and directly behind there is a velar membrane of a peculiar form
hanging from the dorsal wall and supported by the so-called pharyngo-
branchial cartilages (Fig. 53, 2, 3). The part of the alimentary canal
immediately succeeding the mouth and receiving the internal gill aper-
tures should be called pharynx, though it is
commonly termed oesophagus. In Petromyzon
a velar fold marks the junction of thesuboeso-
phageal tube or bronchus with the hinder part
of the mouth.
There is a gall bladder, but in the
adult Petromyzon the bile-ducts and gall-
bladder atrophy and the liver cells be-
come filled with fat (Schneider). A
pancreas and spleen appear to be absent,
and the mesentery is very imperfectly
developed. The anus is placed in the
median ventral line in a shallow pit im-
mediately in front of the urogenital
FIG. 54. — Head of Petromyzon rmcminn-
marinus, seen from below u-Hei
showing the lip and horny Thp rpsniratnrv nrtranc r>nn«i«t r»f
teeth of the buccal funnel. ICbpirdlOry orgdllb C
number of branchial sacs, in which the
branchial lamellae are contained. In Petromyzon there are
seven pairs of these sacs, and each of them opens independ-
ently to the exterior in the anterior region of the body, by
a short external branchial passage (Fig. 48), but internally
they open into a longitudinal suboesophageal tube (bronchus),
which opens into the buccal cavity in front (Fig. 51), and ends
blindly behind. The anterior opening of the suboesophageal
tube is guarded by a membranous velar fold.
In Myxine there are six pairs of branchial sacs (seven have
been observed in rare cases). In Bdellostoma the number is more
variable ; seven pairs appear to be the usual number, but
RESPIRATION. 105
there may be six pairs, or seven on one side and six on the
other (heterotrema), or there may be more than seven (up to
fourteen pairs). In both genera the sacs are connected directly
with the oesophagus (pharynx) by internal branchial tubes, and
with the exterior by external branchial tubes, but whereas in
Bdellostoma each of the external branchial passages opens separ-
ately by a small aperture (Fig. 61), in Myxine all the external
branchial tubes of the same side are directed backwards, and
unite together before opening to the exterior by a common
opening at the hind end of the branchial region. In both genera
there is on the left side a tube, the oesophageo-cutaneous duct,
which leads directly from the oesophagus behind the last gill
sac, to open with the external branchial tube of the last left
gill sac in Bdellostoma, and with the left gill aperture of
Myxine. The oesophageo-cutaneous duct is much wider than
the external branchial tubes.
In all Marsipobranchs respiration can be effected while the
animal is adhering to foreign objects by the suctorial mouth.
In Petrom'yzon respiration is effected by taking in water through
the external branchial openings into the branchial sacs, and
then expelling it again by the same way. In Myxinoids the
water is said to enter through the nasal tube, which communi-
cates with the mouth through the posterior nasal passage, and
passes out by the branchial sacs ; but the nasal passage is a
narrow one, and perhaps hardly sufficient to supply all the
respiratory water. Moreover, it would not be available when
the animal's head is buried in the tissues of its prey. It would
appear more probable that some at least of the inspiratory water
enters through the oesphageo- cutaneous duct.
In Petromyzon the branchial basket plays an important part
in respiration. In expiration it is compressed by the trans-
verse muscles ; in inspiration it recovers by its own elasticity.
In Myxinidae it is possible that the huge lingual apparatus may
play some part in bringing about inspiratory dilatation of the
pharynx, but it has been asserted that the inflow of water in
these animals is effected through the nasal canal by ciliary
action.
In the respiration of Ammocoetes water is taken in through the
mouth and passed out by the clefts. The expulsion of the water
is effected by muscular constriction of the branchial region ; the
106
SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
inspiration by the dilatation of the branchial region caused
by the elasticity of the branchial basketwork. The double
valve (velar fold) at the junction of the mouth and branchial
portion of the alimentary canal prevents the regurgltation of
water in expiration.
In Petromyzon it has been ob-
served that in every inspiratory
and expiratory movement of the
muscles of the branchial region
water is at the same time taken
in and expelled from the nasal
opening.
The central nervous system
is constructed on the usual
vertebrate type. The brain of
Petromyzon (Fig. 55) is unique
amongst Vertebrate, for the fact
that the median part of the roof
of the sylvian aqueduct (iter)
is epithelial and covered by a
choroid plexus. Moreover, the
cerebellum is very small, and
the thalamencephalon of some
length. The third ventricle di-
vides in front into a right and
left Canal> each °f which, passing
FIG. 55,-Dorsal view of the brain of
Petromyzon fluviatUis (after Ahlborn).
1 olfactory nerves : 2 left ganglion
habenulae (the two pineal bodies
have been removed) ; 3 continuation
off n
Wflrrj« into
War<
anrl
of 2 along the roof of the third ven- forwards inrn flip nlfaofn™-
tricle; 4 swollen termination of 3 Jliaciory
which is connected with the ventral
of the two pineal bodies ; 5 fourth
ventricle; 6 edge of thin roof of fourth
ventricle; 7 cerebellum; 8 optic
lobes ; 9 edge of thin roof of iter ;
10 posterior commissure ; 11 right
ganglion habenulae ; 12 cerebral
hemisphere ; 13 olfactory lobe.
pineal body, or
consists of two
the one dorsal to the other, over
the anterior part of the thala-
mencephalon. The larger dorsal
vesicle is the pineal body proper, the ventral smaller one being
called the parietal organ. The dorsal vesicle lies close beneath
the skull-wall, and is the so-called pineal eye. The ventral
part of its walls contains a white, sometimes a black, pigment,
and presents a structure which recalls that of the retina. It is
connected by a solid stalk (pineal stalk) containing nerve-
BRAIN. CRANIAL NERVES.
107
fibres with the right of two thickenings on the superior com-
missure, called the right ganglion habenulae. The ventral and
smaller vesicle also presents in its lower wall, though not so
markedly, features which recall retinal structure. It is hollow
and is connected with a small solid body on which it lies, and
which is the anterior part of the small left ganglion habenulae
(Fig. 55, 3). These two bodies, though in contact, are apparently
not connected. The pineal stalk is connected to the roof of the
brain just in front of the posterior commissure, while the
parietal organ is attached just anterior to the superior com-
missure. The pineal body lies close to the roof of the skull,
and the skin above it is not pigmented (Fig.
56).
The hypophysis or pituitary body is dorso-
ventrally flattened and follicular in structure.
It lies beneath the infundibulum.
In Myxinoids the corpora bigemina are present in
the normal form and there is no thin place in the
roof of the iter. The thalamencephalon is not nearly
so prominent, the optic lobes being approximated to
the cerebral lobes. The anterior part of the brain is
solid, the central canal not extending beyond the mid-
brain. A small space in the region of the thalamen-
cephalon may be made out but it is quite isolated
from the iter. A pineal body, has, so far, not been
found in the myxinoid brain.
-No,.
FIG. 56.— Dorsal view
of the head of Pe-
tromyzon planeri
(after Ahlborn). Na
external nasal aper-
ture ; Ep position of
the epiphysis (the
non-pigmented char-
acter of the skin at
this spot is not clearly
shown).
The cranial nerves are fairly normal in
their arrangement. There are ten pairs, but
in Myxinoids the third, fourth and sixth
appear to be entirely absent, in correspond-
ence with the absence of eye- muscles. The optic nerves, which
are very small in Myxinoids, appear not to cross, the chiasma
being hidden in the substance of the brain. In Petromyzon the
sixth nerve arises close to the fifth, and supplies the inferior
rectus as well as the external rectus. There is said to be no
lateral line branch of the vagus in Myxinoids, but in the lam-
preys this nerve is well developed and reaches to the end of
the tail. It is, however, in an unusual position, being placed
far from the skin close to the neural sheath of the vertebral
column, and it appears to be connected with the posterior
roots of the spinal nerves dorsal to which it passes.
108
SUB-CLASS MARISPOBRANCHII (CYCLOSTOMATA).
The fifth nerve divides into two branches, the ophthalmic * which is
purely sensory and passes to the skin on the head, and the ventral
branch, which is both motor
anci sensory. The ventral
branch divides into an ex-
ternal and internal branch,
which do not correspond to
the superior and inferior
maxillary branches of other
fishes, for they both supply
muscles which in Selachians
are supplied by the inferior
maxillary branch, t The
seventh nerve is in Petromy-
zon a purely sensory nerve ;
in Myxinidae it is mainly
sensory.
The vagus arises by eight
roots, of which the four an-
terior group themselves to-
gether as a nerve which by
its distribution to the tissue
between the first and second
branchial pouches must ob-
viously be compared to the
glossopharyngeal (Fig. 57,
Br^). The other four vagus
roots unite in a ganglion
which is joined by a com-
missural branch from the
seventh nerve (vii.-x.) and
gives off dorsally the lateralis
(lateral line branch ) and ven-
trally the visceral branch.
The latter supplies the bran-
chial region and the whole
length of the intestine, in the
wall of which it lies. In the
branchial region in Petromy-
zon, and possibly in the intes-
tinal region as well, the vis-
ceral branch of the vagus is
connected with the posterior
roots of the spinal nerves.
As suggested by Miiller, it
very possibly represents the
sympathetic which is other-
wise absent in Marsipo-
branchs.
FIG. 57.— Diagrammatic dorsal view of the pos-
terior cranial nerves of Petromyzon (after
Ahlborn). a Sensory root of hypoglpssal
from the glossopharyngeal ; Au auditory
capsule; Brl glossopharyngeal; 6. sp. 1,
O.sp 2 etc., ganglia on postrior roots of spinal
nerves ; Lot, lateral branch of vagus ; N.X.
vagus roots (including those of the glosso-
pharyngeal) ; N. sp. spinal nerves ; Ophth.
ophthalmic branch of trigeminal ; Pn vagus ;
rd dorsal, r.v ventral ramus of ventral root
of spinal nerve ; vm motor, vs sensory root
of trigeminal ; w.d. dorsal, w.v. ventral roots
of spinal nerves ; VII facial nerve ; VII-X
branch connecting facial and vagus ; VIII
auditory nerve ; XII hypoglossal ; XII rd.
dorsal branch of XII to muscles of head.
Some ventral roots arise
behind the vagus (so-called ventral vagus roots) and unite to form a nerve
* A motor branch is mentioned by some authors.
f Furbringer, foe. cit.
SPINAL CORD. NOSE. EYES. 109
(xii.) which supplies the tongue muscles. It is called the hypoglossal, and
gives off near its origin a branch which supplies the anterior part of the
dorsal muscles.
The spinal cord is flattened ; it has neither dorsal nor ventral
fissure, though traces of a dorsal fissure may be represented by
a fine tract of connective tissue which passes from the dorsal
side of the central canal to the dorsal surface of the cord.
The spinal nerves have dorsal and ventral roots which unite
in Myxinoids, but not in Petromyzon. The posterior roots
possess a ganglion, which lies just outside the skeletogenous
wall of the neural canal. All the nerves are without the medul-
lary sheath and the motor fibres are larger than the sensory.
In Petromyzon the dorsal root of the first spinal nerve enters the septum
between the fourth and fifth myomeres,the ventral root divides and supplies
the fourth and fifth myomeres. The motor root of the second spinal
nerve supplies the fifth and sixth myomeres, while the third and subse-
quent spinal nerves each supply one myomere only.
Sense Organs. The external nostril and the nasal sac are
single and median, though the olfactory nerves are double.
From the ventral side of the nasal sac a tube — the nasopalatine
canal — is continued backwards between the brain and the skull
floor, passes through the basicranial fontanelle and ends
blindly on the ventral side of the anterior end of the notochord
in Petromyzontidae, whereas in Myxinidae the same tube opens
posteriorly into the mouth. The palatal opening of this
canal has nothing to do with the posterior nares of higher
vertebrates. It appears to be derived from the pituitary
invagination of the embryo, which arises in Marsipobranohs,
not as in most Vertebrates from the mouth, but as an
ectodermal invagination in front of the mouth, which secondarily
becomes connected with the nasal pit. It is for this reason
sometimes called the pituitary pouch.
The eyes are normal in Petromyzon, and possess the usual
eye muscles.
In the Myxinoids they are extremely reduced and without
eye-muscles. In Bdellostoma they are embedded in a spherical
fatty mass, and placed beneath the skin which is without
pigment immediately over them. In Myxine they lie deeper
within the muscles close to the skull wall.
110 SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
The eye in Myxine is without any trace of lens and appears to have but
little if any pigment.* It consists of little more than the much degener-
ated optic cup. According to Miiller the optic nerve in Myxine passes
dorsal to the ophthalmic branch of the fifth.
The auditory organ differs from that of other Vertebrata.
In Petromyzontidae it consists of a vestibule and two semi-circular
canals, in Myxinidae of a single semicircular canal only.
The body cavity is divided into two parts, the pericardial
cavity and the general body cavity. These two cavities com-
municate by a wide opening on the right hand side in Myxinidae ;
in Petromyzontidae they communicate in the larva, but not in
the adult. The general body cavity opens into the urinogenital
sinus by two genital pores (one in Myxine}, through which
the generative products escape.
In the anterior part of the body there is a system of spacious
venous sinuses. These are specially developed round the
branchial sacs, and in Myxinoids round the ventral aorta, thus
constituting a kind of haemocoelic body cavity for these parts.
The vascular system is arranged essentially in the manner
usually found in fishes. The heart consists of sinus venosus,
large auricle, and ventricle. There are only two valves at the
junction of the ventricle and ventral aorta, and the base of the
ventral aorta (bulbus) is much swollen owing to the large amount
of elastic tissue in its walls. This bulbus is without any muscular
tissue. There is no conus arteriosus. The branches of the
ventral aorta are distributed one to each branchial sac, and the
efferent branchial vessels are collected into two aortic roots
which are continued forward as carotids, and unite behind to
form the dorsal aorta. The dorsal aorta is also continued
forward in the middle line as a carotid. In Myxinidae the
genital vein and some veins from the anterior part of the body
wall fall into the portal. Moreover, in Myxinidae the portal
vein is dilated into a contractile sinus, which, contracting about
as rapidly as the heart, drives the blood through the liver. It
is a remarkable fact that no muscular fibres can be found in the
walls of this portal sinus (J. Miiller). The portal vein extends
for some distance in the intestinal wall and has been called the
subintestinal vein.
* C. Kohl, " Rudimentare Wirbelthieraugen," Bibl. Zool. (Leuckart &
Chun.), 4, heft 13, 1892.
KIDNEYS.
Ill
The kidneys are not divided into meso- and meta-nephros.
They are placed along the dorsal side of the body cavity for the
middle of its length, being absent at the anterior and posterior
ends. The longitudinal ducts (pronephric ducts) extend along
their whole length and join together posteriorly in Petromyzon
to open by a single opening into the
urogenital sinus. The urogenital sinus
which also receives the two genital pores
opens at the end of a papilla just be-
hind the anus into a depression of the
skin into which the anus also opens.
In Ammocoetes the kidney ducts open
into the hind end of the intestine
(cloaca). The separation of the uro-
genital sinus and the formation of the
genital pores takes place just before
the metamorphosis.
In Myxinidae * there is a shallow
cloaca which receives the opening of the
intestine in front, the wide genital pores
(single in Myxine) on the dorsal side of
the anus, and the two urinary ducts,
opening close together at the end of a
papilla behind.
In Myxine the kidneys have an ex-
ceedingly simple structure. The longi-
tudinal ducts give off at segmental
intervals short lateral tubes which open
into large malpighian bodies. The
glomeruli are multipolar, i.e., are con-
nected at several places with the wall
of the capsule. In Petromyzon the
structure is very similar but more
complicated, though the malpighian
capsules of successive tubules are separate, the vascular tissue
of the glomeruli is continuous.
The tubules of the kidney do not open into the body cavity
by nephrostomata.
B repr
A highly magnified ; a pro-
nephric (longitudinal) duct ;
b kidney tubule ; c glome-
rulus ; d afferent, e efferent
artery.
* R. H. Burne, " Porus genitatis in Myxinidae" Journ. Linn. Soc., 26,
1898, p. 487.
112 SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
Abdominal pores as distinct from the genital pores appear
to be absent.
In Myxinidae the pronephros persists as a lobulated organ
in the pericardial cavity of the adult, and was called by Miiller
the suprarenal body. In Petromyzon it is quite absent in the
adult through present in the larva.
The pronephros of Petromyzon is developed in the embryo and has three
or four body-cavity openings and a continuous glomerulus. It is in rela-
tion with the pericardium and atrophies during the Ammocoetes stage.
The kidney is developed in the young larva posteriorly, its anterior
end being a short distance behind the pronephros. The tubules arise
as excavations in the mesoblastic tissues. This larval kidney of the
Ammocoetes atrophies after the metamorphosis and is replaced by an
exactly similar structure placed further back.
The pronephros of the adult Myxinoid consists of a large number of
nephrostomes which end blindly internally in a mass of lymphoid tissue,
or possibly in some cases, perhaps in young specimens, open internally
into an isolated anterior portion of the pronephric (segmental) duct. There
is also at the hind end of this organ a glomerulus of some size projecting
into an open recess of the pericardial cavity.
The whole excretory system of Bdellostoma * appears to develop in the
same way in which the pronephros does in other types, that is to say the
longitudinal duct (pronephric) and the excretory tubules (segmental
tubules) arise in continuity with each other from the body-cavity epithe-
lium. The parts of the body-cavity into which the segmental tubes open
soon become separate from the rest and form a series of small vesicles each
communicating with a segmental tube. These vesicles become the malpi-
ghian bodies and the segmental tubes become the renal tubules. It is
not known how the pronephric part of the system acquires the peculiar
structure which it exhibits in the adult.
As stated above the persistent kidneys of Marsipobranchs show no
differentiation into meso- and meta-nephros and the testes are not con-
nected with them.
The generative organs are unpaired. They are attached to
the dorsal wall of the body cavity by a broad membrane, and
the generative products, both male and female, are shed into the
body cavity, whence they escape by the genital pores. Myxine
is hermaphrodite, and the reproductive gland produces sper-
matozoa before ova f (protandrous). Petromyzon is dioecious,
but ova have been observed in the testis.
* Price, op. cit.
f J. T. Cunningham, "Reproductive elements in Myxine glutinosa"
(Q. J. M. S., 27, 1887), and " Spermatogenesis in M yxine " (Q. J. M. S., 33,
1891). The hermaphroditism of Myxine is denied by Dean (Journ. Coll.
Sci., Tokyo, 19, 1904).
DEVELOPMENT
The development has been fully worked out in Petromyzon planeri.*
The egg is small, about 1 mm. in diameter. It is enclosed in a membrane
formed of an inner perforated and an outer structureless layer. Outside
there is a mucous envelope which causes the egg to adhere to foreign objects.
The male adheres to the female during oviposition and the ova are depos-
ited in a hole previously made and subsequently covered up, the fish moving
stones for this purpose by means of their suctorial mouths. The eggs are
laid in April and May. Segmentation is unequal but complete ; the gastrula
is formed by a combination of invagination and epibole, and the blasto-
pore persists as the anus. The central nervous system is formed by a solid
keel-like ectodermal ingrowth, in which the central canal arises by excava-
tion, and there is a solid cord of cells connecting the hind end of it with the
dorsal hypoblast. The pituitary body is formed from an invagination of
the ectoderm and subsequently becomes connected with the nasal pitr
with which its proximal part remains in communication throughout life,,
as the naso -palatine canal or pituitary pouch.
The young are hatched as larvae which soon become Ammocoetes. These
live for three or four years, developing and increasing in size until they
become as large as or larger than the adult. They then undergo a sudden
(in three or four days) metamorphosis (from August to January) and
become adult (Fig. 48). The adult possesses ripe generative organs and
spawns in April-May. After spawning the lamprey (in the case of P. ftuvi-
atilis at least) dies.
Ammocoetes was formerly regarded as a distinct genus of
animal, and separate species were distinguished. The fact that
it becomes metamorphosed into Petromyzon was discovered two
hundred years ago by L. Baldner, a fisherman of Strasburg,
and rediscovered by Aug. Miiller.t
In Ammocoetes the buccal cavity is without the annular lipr
but possesses a semicircular upper lip (Fig. 59), and a small
separate lower lip. There are no teeth, but several fringed
barbels surround the mouth. The eyes are imperfect and
hidden beneath the skin. The gill openings are placed in a
groove on each side. The median fin extends all along the back,
as a continuous structure. The branchial pouches open into
the pharynx directly, and there is no suboesophageal tube or
bronchus distinct from the pharynx. In Ammocoetes there is
a gall bladder and bile duct, which opens into the intestine.
In the lamprey both these structures are absorbed, and the
intestine itself undergoes partial atrophy. The eye in Ammo-
* F. M. Balfour, A Treatise on Comparative Embryology, vol. ii. 1881
(with literature to date). A. E. Shipley, Q. J. M. S., 27, 1887. C. Kupffer,
Arch. mic. Anat., 35, 1890. P. Bujor, " Metamorphose de 1' Ammocoetes
branchialis," Rev. Biol. Nord. France, iv. 1891, p. 41.
t Miiller's Arch., 1856, p. 325.
114
SUB-CLASS MARSIPOBRANCHII (CYCLOSTOMATA).
coetes is only partly developed and lies be-
neath the skin. In the lamprey it becomes
fully developed and travels to the surface. The
pericardium of Ammocoetes opens into the
general body cavity, but the two become
completely separate in the adult. The an-
terior part of the kidney which had been
developed in the Ammocoetes disappears, and
a fresh posterior part is formed. The prone -
phros had already begun to disappear dur-
ing the Ammocoetes stage, and the portion
of the cloaca into which the urinary ducts
open becomes separated off as a urogenital
sinus shortly before the metamorphosis.
The skeleton undergoes very considerable
change at the metamorphosis. The Ammo-
coetes is without the cartilaginous dorsalia or
neural arches in the trunk region. These
appear at the metamorphosis as do cartilages
of the mouth, and the side walls and roof of
the skull. The spinal cord, which is nearly
round in section in Ammocoetes, becomes
flattened at the metamorphosis.
The head muscles of Ammocoetes are entirely
destroyed and reformed at
the metamorphosis.
The thyroid body arises in
the embryo as a groove in
the branchial region of the
g pharynx. The opening soon
becomes narrowed to a pore
placed between the second
and third permanent* branch-
ial pouches (Fig. 60). In Am-
mocoetes the tube so formed
becomes divided and assumes
FlQ/59. — A. Ammo-
coetes of Petromy-
zon planeri, 2 ins.
long, side view
(after W. K. Park-
,er) brl first, br7
seventh branchial B Ventral view of
* There is said to be a trace of an
eighth pouch, in front of the first
permanent one, in the embryo and young larva. It is supposed to repre-
sent the hyomandibular cleft of other fishes, but it never acquires gill folds
or an external opening.
aperture ; na na-
sal aperture; £eye.
the head of the
same larva.
HABITS. AFFINITIES. 115
a very complicated glandular form. After the metamorphosis
it is less conspicuous and appears to be without the opening
into the throat.
In Myxinidae the eggs are very much larger (19 mm. x 7 mm,
in Myxine, 31 mm. x 9-5 mm. in Bdellostoma] and contain a
considerable quantity of yolk. They are enclosed in a horny
case with hooked processes proceeding in tufts from each end.
The egg case appears to be the vitelline membrane.
The Ammocoete lives buried in mud and sand and likes
dark places. It lives on small aquatic organisms (Infusoria;
Daphnia, Rotifers, etc.). The marine lamprey ascends rivers
at spawning time, sometimes carried by the salmon or shad
(Alausa vulgaris), to spawn. They eat worms and small aquatic
animals. The Myxinidae live exclusively on other fishes. They
are able by their t,Y N
formidable dental
armature and
powerful lingual
muscles to make
0 KS^—*^^ K °
their prey, in which FIG. 60.— Diagrammatic longitudinal s-ction through the
head of a larva of Petromyzon (after Balfour). Ab optic
they are Sometimes vesicle; C heart.; Ch notochord ; H thyroid involution ;
Ks branchial pouches ; N nervous system ; 0 mouth ;
lOUnd em beaded. Ol olfactory pit; Ot auditory vesicle (represented .as
_ _ . visible) ; Ve velum.
The Marsipo-
branchii are sometimes spoken of as a degenerate group.
We do not think that there is any evidence of degenera-
tion. The most important points in which they differ from other
fishes relate to the skeleton, and to the nasal organ. But these
are precisely the organs which show the greatest amount of
variation within the group as at present constituted. This
seems to point to the fact that they separated off from other
fishes at a time when these two organs were in a highly indeter-
minate condition, and had not attained to that fixity of structure
which characterises on the whole the general arrangement of the
skeleton, and nasal and pituitary sacs in other fishes.
The condition of the eyes in Myxinidae might be held to be evidence of
degeneration, but we should rather be inclined to regard it again as the
survival from a time when the visual organ was more variable and had
not obtained that fixity of character which it has at the present day. No
J16
SUB-CLASS MARSIPOBRAXCHII (CYCLOSTOMATA).
doubt many individuals were then produced with imperfect visual organs.
Most of these naturally died out in competition with their more highly
endowed brethren, but in some cases compensating advantages in other
organs enabled them to hold their own in spite of their defective sight.
To hold that a free-living animal, and a myxinoid must after all be regarded
as such, can lose its eyes through disuse would seem to be an impossible
position. The absence cannot be considered as other than a disadvantage
to it.
Fam. 1. Petromyzontidae (Hy-
peroartia), lampreys, nine-eyes.
With seven external gill apertures
on each side which lead into a sub-
pharyngeal tube opening anteriorly
into the pharynx and ending
blindly behind, and with a com-
plete branchial basket-work. The
suctorial mouth is surrounded by
a circular lip and is provided writh
horny, simple or multicuspid teeth,
without barbules. The single nasal
opening is in the middle of the up-
per side of the head, and the nasal
duct (pituitary sac) ends blindly
behind. Eyes are present. With
two dorsal fins, and a spiral valve in
the intestine ; gall-bladder absent.
The eggs are small, and there is a
prolonged larval stage in which
the young are known as Ammo-
coetes. Fresh waters and coasts
of the temperate regions of both
hemispheres. Petromyzon Art.
coasts and fresh-waters of the
northern hemisphere ; P. marinus
L., sea-lamprey ; P. ftuviatilis L.,
river-lamprey. Ichthyomyzon Gir-
ard, west coast of North America ;
Mordacia Gray, without gular
pouch, coasts of Chile, south-east
Australia and Tasmania, entering
fresh-water to breed ; Geotria, Gray,
with gular pouch, rivers of Chile,
mal). south and south-east Australia and
New Zealand ; Velasia Gray, with-
out gular pouch, is an immature
stage of Geotria.
Fam. 2. Myxinidae (Hyperotreta). Nasal aperture single, at the anterior
end of the body ; the nasal duct (pituitary sac) opens posteriorly into the
pharynx and has cartilaginous rings ; mouth suctorial, without lips, with
barbules, with one median palatal tooth and two rows of lingual teeth ;
branchial openings far behind the head, lead directly into pharynx ; branch-
ial basket-work not present ; a series of mucous sacB on each side of the
body ; eyes hidden under the skin, and very imperfect, without lens or
d.KC
FIG. 61. — Ventral view
of anterior end of
Bdellostoma forsteri
(after W. K. Parker)
br p. external aper-
tures of branchial
sacs ; d. oe c opening
of ductus oesopha-
geus cutaneus.
FIG. 62. — Myx-
MYXIXIDAE.
117
muscles ; intestine without spiral valve ; gall bladder present ; egg large
with horny case provided with threads for adhesion ; marine in temperate
regions of both hemispheres. Myxine L., hag-fish, with six pairs of bran-
chial sacs opening by one external opening on each side. Bdellostoma
J. Mull. (Homea Fleming), with six or more (up to fourteen) branchial
FIG. 63. — Palaeospondylus gunni ventral view of head and side
view of vertebral column. tp trabeculo-palatine part of
skull ; pa, parachordal part of skull ; d c, Ic, vc oral cirri ; a, b, c,
n markings of more uncertain significance ; x post occipital
plates (from S. Woodward).
apertures on each side, each leading to a branchial sac ; the number of
branchial sacs may be different on the two sides of the body ; southern
hemisphere. Palaeospondylus Traquair, from the old Red Sandstone of
Scotland, is supposed to be a fossil Marsipobranch with calcified cartila-
ginous endoskeleton (Fig. 63). The notochordal sheath appears to have
contained rings.
CHAPTER VI.
SUB-CLASS ELASMOBRANCHIL*
Fishes with a cartilaginous endoskehton, placoid scales, and
abdominal pelvic fins -provided with claspers in the male. There
is a conus arteriosus, an optic chiasma and a spiral valve in the
intestine. There is no air-bladder. The eggs are large, and, except
in Laemargus, provided with a horny case. In the embryo the
gills ^woject^from the gill clefts as filaments.
The Elasmobranchii or cartilaginous fishes include the sharks
and rays. With the exception of one or two sharks and a few
rays they are entirely marine forms. They are remarkable for
possessing more features which are embryonic in the higher
purely terrestrial Vertebrata than any^ other group of fishes.
Of such may be mentioned the oro-nasal groove, the opening
between the membranous labyrinth and the exterior, the un-
covered gill apertures, the open spiracle, the cartilaginous
skeleton, the opening between the pericardium and the body
cavity. Lastly they are the only fishes which possess eggs
containing so much yolk that the whole development is embryonic.
Only two species of shark are known to be exclusively
inhabitants of fresh-water (Carcharias nicaraguensis and gan-
geticus), but several ascend large rivers, e.g., the Tigris and
Ganges, to a considerable distance. Most Selachians are pelagic
or shore forms, and some descend to great depths (Scyllium has
been taken at 700, Chlamydoselachus at 100-150, Centroscyllium
at 245, Pnstiurus at 500, and Centrophorus at 345-500
* See Giinther, Day, Jordan and Evermann, Bridge, Boulenger, cited
under Pisces ; J. Miiller and J. Henle, Systematische Beschreibung der
Plagiostomen, Berlin, 1839. F. M. Balfour, Development of Elasmobranch
Fishes, London, 1878.
EXTERNAL FEATURES. 119
fathoms). Their flesh is not usually esteemed as food, but some
of them are eaten by poor people.
The body is elongated and spindle-shaped in the Squall^. the
anterior part being somewhat broad and depressed dorso-ven-
trally as compared with the narrower posterior region ; in the
Raji it is strongly compressed dorso-ventrally. In some forms,
mostly in the Raji, the snout is prolonged to a greater or less
extent. This is most markedly the case in the saw-fish shark
and in the saw-fish Pristis. In the hammer-
heads the anterior part of the head is_elongatedjtransversely,
the eyes being placed at the ends of the prolongations. The\
median fins are typically two dorsal, a _caudal, the ventral
part of which is divided by a notch into two parts, and^an^anal/
placed between the caudal and the anus. The paired fins are,
well-developed : the pelvic being smaller than the pectoral,^
FIG. 64. — Acantffl&s vulgaris. spl spiracle ; ks gill slits (from Claus).
and abdominal in position. In the males the pelvic fins are
provided, each with a copulatory appendage — the clasper
(pterygopodmm, mixipterygium), which is grooved on its dorsal
side, the groove leading into a cavity at the base of the appendage.
In the Raji the pectoral fins are very large and their line of
attachment to the body has a considerable antero-posterior
extension. The muscular system is on the usual piscine type.
The great lateral muscle is divided into a dorsal and ventral half,
the myomeres of which alternate. There is the usual system
of branchial and mandibular muscles.
The gill-clefts are tubes usually five on each side (in Chlamy-
doselachus and Hexanchus there are six, in Heptanchus seven),
and their external openings which are placed laterally in Squall,
ventrally in Raji, are not covered by an operculum (Fig. 64).
Internally they open into the pharynx and their walls are pro-
120 SUB-CLASS ELASMOBRAXCHII.
vided with a number of Jamellate folds of the mucous mem-
brane, which are placed on their anterior and posterior walls
(except in the last tube, which has no branchial lamellae
on its posterior wall), and are attached through their whole
length (Fig. 118), not projecting freely as do the pectinate gill
processes of Teleostci. In addition there is usually an anterior
tube leading outwards from the pharynx and opening exter-
nally on the dorsal surface close behind the eye. This opening
is called the spiracle and the tube itself must be regarded as
belonging to the series of branchial tubes of which it is the first.
It differs from these, however, in never possessing branchial
lamellae, though it often, has traces of these as a few small folds
of the lining of its anterior wall, which constitute the pseudo-
branch or mandibular gill of these fishes. In the embryo long
filaments — the so-called external gills — project from all these
openings including the spiracle ; they are in reality externally
projecting internal gills.
|F IirRaji the spiracle is much larger than in Squali and it doubtless allows
of the entrance of water into the pharynx when the animal is lying flat upon
the ground or partly buried in sand. In Squali, in which it is very variable,
being sometimes absent and nearly always small, its function is not clear.
In some species in which it is very small it may be present or absent in
•different individuals. It is sometimes present in embryos of forms in which
it is absent in the adult (Carcharias), but whether this is always the case
is not known. From the fact that it is smaller than the posterior branchial
apertures even at its first appearance (which is subsequent to that of the
others) it may be presumed that it is usually absent in such cases, but the
matter wants looking into. When it is absent in the adult and present in
the embryo, it is without projecting gill filaments in the embryo (Miiller);
In Scyllium, Pristiurus, Mustelus, etc., the spiracle gives off a diverticulum
to the auditory cartilage of the skull.
The nasaLapertures and mouth are almost always placed
on the ventral surface of the head (in Chlamydoselachus the mouth
is anterior and the nasal apertures are dorsal), usually at a
considerable distance from the front end. The nasal apertures
are frequently connected with the mouth by a groove, the orc-
nasaLETOove, and sometimes they are so close that their open-
ings are confluent with the mouth. In other cases they are at
some distance from the mouth and there is no oro-nasal groove.
The anus (cloacal opening) is placed between the pelvic fins,
and there are two abdominal pores, one on either side of the
anal opening, which lead into the body- cavity.
SENSE ORGAXS. SKIX.
121
»v
Abdominal pores vary considerably.* In some species they are absent
altogether, in others they are present in the adult, while in yet others
they are present in some individuals and not in others. Their external
opening is always on an ectodermal surface, either just outside the
cloacal boundary, or into a cloacal pouch, which is a diverticulum of
the proctodeal part of the cloaca.
The eyes are usually provided with upper and lower cutaneous
folds which represent eyelids, and in some forms there is a third
inner eyelid or nictitating membrane which can be drawn over
the eye.
The otocysts retain their communication with the exterior
by means of a canal, the
aqueductv^ vestibuli, which
opens on tJie dorsal surface
throughout life (p. 77). The
latejral line is a canal which
extends in the skin from the
very hind end of the body to
the head, where it branches
out to different parts in the
usual piscine manner (p. 80).
It opens to the exterior at
intervals. In addition to the
system of the lateral line,
there are the openings of the
so-called ampullary canals.
These are placed in groups in
the head (Lorenzini's ampul-
lae, p. 81). Luminous or-
gans | irregularly scattered
over the body are found in many pelagic msmbsrs of the
Spinacidae (e.g., Spinax, Laemargus, Isistius) in the form
of minute cutaneous patches which probably secrete a
luminous mucus.
The skin is tough and rough owing to the presence of a vast
number of placoid scales. These are rhombic bony plates
embedded in the cutis and carrying a small spine, which
* Bles, " Correlated Distribution of Abdominal Pores and Xephrostoni33,"
Journ. Anat. and Phys., 32, 1898, p. 484.
t B. Burckhardt, "Luminous Organs of Selachians, Ann. and Mag. Nat.
Hist. (7) 6, 1900, p. 558-568.
FIG. 65.— Placoid scales of an adult Scyllium
in surface view (after Klaatsch). The
anterior end of the figure is uppermost.
The spines are omitted from some of the
scales. Ck the central canal (pulp cavity)
of the spine as it perforates the basal
plate Sb of the scale ; Sa spine of the
scale.
122 SUB-CLASS ELASMOBRANCHII.
projects freely on the surface in a backward direction and
consists_of__dentine containing a^pulp_£aYijty and capped by
enamel. The placoicLacales though numerous are not in con-
tact, and fresh scales are continually being developed between
them, to replace those worn off. The presence of these spines
enables the skin of Plagiostomes to be used by polishers
(shagreen). The spines are sometimes much enlarged, e.g. the
peculiar spines on male skates, the caudal spine of the
sting ray (Trygon), the large spines often present on the
dorsal fins, etc. The fa^th in T,V>A mouth are special modifi-
cations of placoid scales.
The endoskeleton is entirely cartilaginous, but the cartilage
is frequently more or less calcified.
It is possible that
t _^~t^ perichondriai ossifi-
:<jjj/ cation takes place
X- in some forms in
the bodies of the
y£ J3I vertebrae between
the arches (see p.
mSL* 124), but the tissue
resulting is without
9H| cells. This does
', -'.--— '-~^i2 n()t however pre-
FIG. 66. — Longitudinal section through the vertebral column
of Squatina vulgaris (after Hasse from Gegenbaur). a verte- bone» for m -leleos-
bral body, showing concentric calcined lamellae (cyclospondy- tei etc. undoubt-
lous) ; iv intervertebral ligament ; ch notochord ; fc attenu- ,
ated part of notochord. The double calcified cones^d are
shaded dark. without any bone
cells, or haversian
canals. Anatomists are divided on the point, but the preponder-
ance of opinion is in favour of the absence of osseous tissue in Elasmo-
branchs. Kolliker * takes this view. Gotte f on the other hand holds
that the calcined cartilage is true bone. There can be little doubt that
bone is quite distinct from cartilage and always arises from elements out-
side it, possibly as dermal plates. These elements may invade the cartilage
and bring about so-called cartilaginous ossification or they may always lie
outside it, giving rise to membrane bones proper. $
The vertebraL column § (p. 58) presents the most remarkable
* Ueb. d. Wirbel der Selachier, Abh. Senckenb. Ges. 5.
t Arch. /. mic. Anat., 1878.
j Stephan, Bull. Sci. France et Belgique, 1900, p. 281.
§ For a detailed account of the vertebral column of Plagiostomes see
C. Hasse, Das naturliche System der Elasmobranchier, etc., Jena, 1879, 1882
and 1885, and especially A. Kolliker " Uber die Beziehung der Chorda zur
Bildung der Wirbel der Selachier, " etc., Verhandl. der physik. medic.
Oesellsch. zu Wurzburg, 10, 1860, and " Weitere Beobachtungen," etc.,
Abhdlg. der Senckenberg. Oesellsch. zu Frankjurt, 5.
VERTEBRAL COLUMN. 123
variations which would, in any other group, be regarded
as of great morphological importance. It varies in the
extent and uniformity of its segmentation, in the arrangement
and number of the cartilaginous pieces which enclose the spinal
canal, and their mode of attachment to the vertebral central
and in the extent of the calcification of the cartilage. It con-
sists typically of a series of amphicoelous vertebrae, through
the centra and intervertebral ligaments of which runs the per-
sistent but reduced notochord. The neural arches of each
vertebra always consist of more than one piece of cartilage on
each side ; and the haemal arches extend outwards in the trunk
region where they carry short ribs, and downwards, meeting
each other ventrally below the caudal artery and vein, in the
caudal region. The vertebral column is
formed of hyaline and fibro-cartilage,
which tissues pass into one another
quite gradually.
A^ tough ; fibroua membrane, containing
cells and surrounded by the elastica externa, J &
is formed (see p. 58) at a comparatively j
early stage, round the notochord and is L j/,^
called the chordal sheath (Fig. 33). This in FIG. 67.— Three pos-
most Plagiostomes becomes differentiated terior trunk verte-
into alternately short fibrous and longer (aftL HasJeTom^g!
cartilaginous portions, i.e. segmented (Fig. enbaur). n neural arch,
66). The fibrous portions become the inter- ^^SS^d^aS-
vertebral ligaments, while the cartilaginous calated piece with
portions form the bodies or centra of the ST^ haemafa^h'
vertebrae ; so that the vertebrae are described
as being chordo-centrotis. The centra are, however, frequently reinforced
by the arch tissue in the manner described on p. 59.
The cartilaginous arches (neural and haemal), which appear in the neural
and haemal ridges of the skeletogenous tissue, may, as stated above, spread
out round the notochord outside the elastica externa (which may persist or
disappear) and unite with each other and so reinforce the vertebral centra;
or they may remain separate from one another. In the latter case the
neural and haemal arches are separate from the centra ; in the former
they are continuous with the centra. Kolliker states that in some cases
the centra are reinforced by calcified fibro-cartilage which proceeds from
the perichondrium of the centra between the insertion of the neural and
haemal arches (Carchariidae, etc.). In this case we get the cruciform
figure in section described below.
In Chlamydoselachus, Echinorhinus, Hexanchus and Heptan-
chus, the cartilaginous notochordal sheath is not definitely seg-
mented : it consists of continuous cartilage, though in the centre
124 SUB-CLASS ELASMOBRAXCHII.
of the vertebral regions (as shown by the arches) it has thickened,
become firmer, and has encroached upon the notochord (Fig. 68) .
(In Chlamydosdachus this only happens in front, the notochord
is unconstricted behind, and in Heptanchus the chordal sheath
has segmented in the caudal region.)
In other Plagiostomes the notochordal sheath is segmented
into alternately cartilaginous portions which constitute the bodies
of the vertebrae and fibrous parts which are the intervertebral
ligaments (Fig. 66). The sheath thickens in the centre of the
vertebral portions and constricts the notochord ; moreover its
tissue consists of three layers, forming the inner, middle and
outer zones. The middle zone is fibrous and is nearly always
calcified, forming the so-called double calcareous cone (Fig. 66, _c).
In Hexanchus and Laem-
^ c d °f e argus borealis the verte-
brae are entirely uncalci-
fied.
Centra (Fig. 69) in which
the internal calcareous mat-
c £ $ ter is confined to the middle
FIG. 68.— Longitudinal section through the hinder zone (double cone) have been
part of the vertebral column of Heptanchus, show- pollpH riirln^nnndtilnu^ Tn
ing incipient vertebral bodies (e)f and extensive cycLospona^us.
intervertebral ligaments (a), a ftbro-cartilage some, however, there are
of chorda-sheath ; b notocaord ; c calcified double arlrJitirmnl pnnpAntrin pnlpnr-
cone; d external calcification; e hyaline cartilage
of the incipient centrum external to the double eous rings outside the double
cone (after Kolliker). cone . such vertebral centra
are called tectospond/ylous.
In others again there are radiating calcareous lamellae proceeding from
the double cone through the outer zone of the chordal cartilage. Such
are termed asterpspondylous.
The amount of calcification varies from the cyclospondylous condition
of the simple double cone with soft tissue outside and inside, to the condi-
tion found in many Raji and in the Lamnidse in which the whole of the
chordal sheath is calcified both inside and outside the double cone. The
first calcification is always in the chordal sheath in the fibrous tissue of the
middle zone (double cone). Later arise the concentric rings of the Tecto-
spondyli or the radiating lamellae of the Asterospondyli ; these are calcifica-
tions of the hyaline cartilage of the chordal sheath. When skeletogenous
tissue is developed outside the elastica externa either by an extension
of the cartilage of the arches over the centra (many Cyclospondyli), or
(Carchariidae, etc.) by development on the inside of the perichondrium of
the centrum, it frequently becomes calcified as four wedges, which extend a
certain distance into the body between the insertion of the arches. These
hard wedges may or may not reach the double cone (sometimes they do
so at the end and not at the centre of a vertebral body) ; they give rise to
the cruciform radiating figure seen in the section of some vertebrae. In
such cases the uncalcified cartilaginous arches appear to be continued like
VERTEBRAL COLUMN'.
125
wedges into the centrum. These calcified wedges are formed in a fibrous
cartilage or fibrous tissue and contain blood vessels. Calcifications are
sometimes found on the surface of the arches or even in their tissue.
It is often difficult to determine in any given vertebra whether the arches
grow round and reinforce the centrum unless the elastica externa persists,
and there seems to be considerable variation in this respect in different
animals and even in different parts of the vertebral column of the same
animal. In Hexanchus, Heptanchus (anterior), Myliobates (posterior part),
Rhinobatus (posterior part), Trygon and Squatina the arches remain separate
and do not grow round the chordal sheath. In Heptanchus (posterior),
Centrophorus, some Spinacidae and Scymnidae, Squatina, many Rajidae
the arches grow round and reinforce the centrum. In the Carchariidae
and Lamnidae the centrum is strongly reinforced by perichondrial calcifi-
cation and the cruciform appearance in section is very marked, but it is
not clear whether the arches contribute to the centrum.
The neural and haemal arches are always segmented. The
neural arch is
generally incom-
plete, being sup-
plemented by the
intercalated pieces
(Fig. 67), and there
are often some
special supra- dorsal
pieces which form
the actual roof. In
some cases (Alo-
pecias] both neural
arches and /""intercalated pieces extend across the roof .
of the spinal canal (Fig. 70). ( The anterior root of a spinal
nerve frequently perforates the neural arch, the posterior
root the intercalated piece, or the nerves may pass out
between the arch and the intercalated piece^ In the trunk
region the vertebrae carry short dorsal spinous processes, but
in the caudal region these may attain some length. There is a
longitudinal elastic ligament extending along the ridge of the
upper arches ; it may be embedded in the cartilage.
Sometimes (Fig. 71) more than one pair of intercalated pieces may occur
in each vertebra, and the number may vary in different parts of the verte-
bral column of the same animal. In Zygaena there are two. It frequently
happens that in the caudal region there are two complete vertebrae (cen-
trum, arch, intercalated pieces, etc.) for every spinal nerve (diplospondyly).*
* W. Ridewood, " Caudal diplospondyly of Sharks," Journ. Linn.
Soc., 27.
FIG. 69. — Diagrammatic transverse sections of vertebrae, to
illustrate A the cyclospondylous ; B the tectospondylo'us ;
and C the asterospondylous condition. C notochord;
I) central calcareous ring ; £ elastic externa ; S neural,
H haemal arch (from Hasse).
126
SUB-CLASS ELASMOBRANCHII.
In the middle part of the trunk region in the Notidanidae, each centrum
carries two sets of neural arches and intercalated pieces, and corresponds
to two pairs of spinal nerves, and therefore to two segments.
The haemal arches, which are sometimes supplemented by
intercalated pieces, are in the trunk directed outwards, and
carry very short ribs ; in the tail they are directed ventral wards,
and meet below the caudal artery and vein.
In the Raji the anterior vertebrae are not separate, but form a continuous
cartilaginous structure into which the notochord extends only for a short
distance and which articulates with the occipital region of the skull. In
Notidg/nidae the anterior part of vertebral column has fused to the skull.
The cranium, of which a general description is given on p. 60,
consists of continuous cartilage, which may be partially calcified.
7Z-
---in
FIG. 70.— Three trunk vertebrae of
Alopecias vulpes (from Gegen-
baur, after Hasse). iv inter-
vertebral ligament ; n neural
arch ; in intercalated piece of
neural arch, m of haemal arch
(h).
FIG. 71. — Lateral view of a portion of the
caudal vertebral column of Rhinoptera
(Zygobates) (after Hasse), showing large
number of extra dorsal pieces above the
intercalated pieces in and the neural
arches n. The neural arches are con-
tinued into the haemal h round the centra.
The notoakoid^niay be entirely atrophied in the parachordal
region (Raji, etc.) or it may persist to a greater or less extent
(Heptanchus, Centrophorus, Acanlhias, Squatina, Prionodon).
In Raji there is a distinct articulation between the occipital
region and the anterior vertebral plate of the vertebral column
by means of two occipital condyles and an ' odontoid process ' of
the vertebral plate. In the Squali there are also usually two
occipital condyles, but no regular joint between the first vertebra
and the skull. In the Notidanidae, in which the anterior end of
the notochordal sheath is not segmented, the latter structure
runs continuously into the cartilaginous region of the skull.
CRANIUM.
127
The occipital region is more sharply marked off from the vertebral
column in the Raji than in the Squali. In correspondence with this the
occipito-spinal nerves (p. 138) are reduced or absent in Raji. In a few
cases the occipital cartilage extends back over the anterior vertebrae and
envelopes them (Car char ias), while in Mustelus one vertebra is fused with
the skull.
The greater part of the roof of the skull is formed of cartilage,
but there is a well -marked median fontanelle in the roof of the
ethmoidal region. The space^in the auditory cartilage in which
the otocyst lies communicates with a canal which contains the
aqueductus vestibuli and opens on the dorsal surface, either into a
depression in the cartilage which receives the opening of the
10
14
FIG. 72. — Median section of the cranium of Heianchus, inner view (after Gegenbaur). Fora-
men for 1 vagus, 2 glossopharyngeal, 3 auditory, 4 facial, 5 trigeminal nerve ; 6 pos-
terior clinoid ridge ; foramen for 7 oculomotor, 8 trochlear, 9 optic nerve ; 10 fontanelle ;
11 rostrum ; 12 lateral process of ethmoid region ; 13 foramen for carotid ; 14 transverse
canal in skull base ; 15 notochord ; 16 foramina for spino-occipital nerves ; 17 neural
arch of the first vertebra with nerve foramina.
corresponding canal of the other side (Squali) or on the surface
separately from the latter (Raji).
The ethmoidal region is frequently prolonged in front of the
nasal capsules. In the Raji and a few Squali this continuation
is a well-marked process, the rostrum (very largely developed in
Pristis). ; in Squali it is, if present, usually confined to a slender
process, the prenasal process, with which two processes of the
nasal capsules may be connected.
The labial cartilages are small cartilaginous rods in folds of
skin at the sides of the mouth, near the angle ; there are usually
two pairs above and one pair below. They are less developed
and less constant in the Raji.
Visceral Arches (p. 61). — The mandibular arch is always
128
SUB-CLASS ELASMOCBRAXCH1I.
/divided into two pieces ; of these the -dorsal-farms the skeleton
of the upper jaw, and is called the palato-jpiadrate bar, while the
ventral constitutes the lower jaw and is called the cartilage of
Meckel. The dorsal posterior end of Meckel's cartilage articulates
with the hind and ventral end (quadrate portion) of the palato-.
quadrate bar, while the ventral anterior end meets its fellow at
the symphysis of the lower jaw. Anteriorly the palato-quad-
rate bar joins its fellow beneath the ethmoid region but its rela-
tion to the skull varies in the most remarkable manner throughout
FlG. 73. — Skull of Hexanchus with mandibular and hyoid arch (after Gegen-
baur). P-Q palato-quadrate ; Hm hyomandibular ; Md Meckel's cartilage ;
C basihyal, L, L' labial cartilages ; p palatine process of palato-quadrate ;
M lateral process of ethmoid ; JV nasal sac ; Po postorbital process ; Gp fora-
men for glossopharyngeal nerve.
the group. In the Notidanidae (Fig. 73) it articulates with
the skull at two points ; anteriorly it has a process, the palatine
process, which is connected with the skull between the exit of the
optic and trigeminal nerves, while posteriorly it articulates with
the postorbital process of the auditory cartilage, i.e. anterior to
the spiracle. In these skulls the hyoid arch, which bears
branchial rays, is attached to the auditory region and is
segmented into two pieces on each side and a median piece,
the hypohyal or copula.
In other Selachians the palatine process is present, though the
VISCERAL ARCHES.
1'
connection is further forwards with the ethmoid region (ethmo-
palatine ligament), but the posterior articulation, viz. with
the postorbital process is not present. On the other hand the
posterior end of the bar is attached to the dorsal element of
the hyoid arch by ligaments.
In such Selachii the condition of the hyoid is very similar to
that in the Notidanidae, (already described), excepting that tl
dorsal piece is much stouter and assists to a marked extent by
means of ligamentous bands, attaching it to both the quadrate
end of the palato-quadrate bar and to Meckel's cartilage, in
supporting the mandibular arch. This dorsal piece is for this-
reason called the hyomandibular, the other piece being called
the ceratohyal. In Raji the palatoquadrate bar is withoi
FIG. 74. — Diagram showing the principal modifications in the arrangement of the hyoid arch
in Plagiostomes (after Gegenbaur). A in Notidanus ; B in pentanchal Selachians; C
Torpedo; D in Raja. Hm hyomandibular; p process of Hm ; hy lower part of hyoid
arch ; r branchial rays.
the palatine process, and the mandibular arch is entirely sup-
ported by the hyomandibular. This structure is without gill-
rays and has developed a process for the support of the mandibu-
lar arch (Fig. 74, p). It has almost lost its relation to t]
lower part of the hyoid arch, which is connected only to i
dorsal end, or is attached dorsally direct to the auditory cartilage
(many Rajidae, etc.). The hyoid arch of such forms is only
equivalent to the ventral part of the hyoid of the Notidanidae
and Squali generally. It is a comparatively slender, jointed
structure, closely resembling the posterior branchial arches,
like which it bears branchial rays. There are frequently two-
or three small cartilages, the prespiracular cartilages, in the
anterior wall of the spiracle.
Is
130 SUB-CLASS ELASMOBRANCHII.
In the Holocephali the autostylic arrangement (p. 63) prevails,
the palate-quadrate bar being continuous with the skull.
The branchial arches are typically and usually segmented
into four pieces on each side and a median piece, the basibran-
chial_or_copula. The dorsal of the four pieces is called the
pharyngobranchial, the second the epibranchial, the third the
ceratobranchial, while the ventral and smallest piece is called
the hypobranchial.
The hypo- and basi-branchial pieces are somewhat variable, the hypo-
branchial of the anterior arches being often undeveloped (some Raji) and
the basibranchial being often absent from the anterior arches. In the
latter case the last basibranchial (cardiobranchial) which is always larger
than the others, is much developed and has several arches attached to it.
The hypobranchial of the first arch is frequently attached to the basihyal.
(The last arch is always smaller than the others ; its pharyngobranchial
is fused with the pharyngobranchial of the preceding arch and its hypo-
branchial is not developed.) In Raji the last arch articulates with the
shoulder girdle. In Squalr the dorsal elements are not closely attached
to the vertebral column, but in Raji there is a firm attachment. All the
branchial arches except the last bear branchial rays on the egi- and cerato-
branchial segments ; and in most Squali cartilaginous rods called extja-
branchials are placed close beneath the skin near some of the external
branchial apertures ; they are absent in Raji.
The supporting^jstnictures of the median fins are, as in the
case of the paired fins, of twojkinds ; the cartilaginojis-somactids
and the horrj^jiermotrichia. In the dorsal fins, in the
dorsal part of the caudal, and in the anal fin the dermotrichia
are carried by somactids which are usually imbedded in the
muscles and not attached to the neural or haemal spines. In
the ventral lobe of the caudal fin there are no somactids and the
dermotrichia are carried by the haemal spines.
The pectorjLgirdle consists of two dorso-ventrally directed
cartilaginous rods, placed one on each side of the body, and
each divided by the surface (glenoid) for the articulation of
the skeleton of the pectoral fin into a dorsal portion, the scapula,
and a ventral portion, the coracoid. The two coracoids are
continuous with one another ventrally, beneath the pericardium,
but the scapulas end freely dorsally, except in Raji, in which
the dorsal portion, sometimes partly marked off as a supra-
scapula, is attached to the anterior vertebral plate (p. 126) of the
spinal column.
The skeleton of rthe pectoral fin consists of a number of
PECTORAL FIN.
131
somactids, which carry peripherally the dermotrichia. * There
are generally three basal somactids which articulate directly
with the pectoral girdle (Fig. 75, B) : these are called respective^
the pro- meso- and meta-pterygium. They carry the peripheral
radialia. The metapterygium is the largest of the basal pieces
and carries the greatest number of peripheral somactids. These
are placed mainly on its preaxial side (Fig. 75), there being
few, if any, on its postaxial side.
FIG. 75. — Skeleton of pectoral fin A of Scymnus, B of Acanthias vulgaris (after Gegen-
baur). p pro-, ms mesp-, mt meta-pterygium ; B postaxial (median) side of fin. (The
line drawn through mt in B indicates what some anatomists regard as the axis of the
so-called archipterygium ; on the same view the dotted lines R, R indicate the preaxial
radii, R' the postaxial radii). »
The metapterygium appears to be the most important basal, and when
there is only one basal somactid, as in Scymmis (Fig. 75, A), it is supposed
to be the metapterygium.
In living forms the fin-skeleton is always rhipidostichous (p. 57), but
in some extinct forms (Cladoselache, Fig. 83) it is orthostichous, and in
others (Pleuracanthus , Fig. 76) it is rachiostichous (and unibasal) and on
the whole pleurorachic (p. 57). In Raji the propterygium and mesoptery-
gium are elongated and segmented, and the propterygium is attached to
the olfactory region of the skull. Moreover in the Raji there are sometimes
additional basals inserted between the meso- and meta-pterygium.
The pelvic, girdle is not attached to the vertebral column ;
it consists of a transverse bar of cartilage placed just ventral to
* Dermotrichia are absent from the paired fins of some Raji (e.g. Tor-
pedo, etc.}, -i
132
SUB-CLASS ELASMOBRAXCHII.
the cloaca and carrying at its outer end the skeleton of the
fin. The main portion may be called the ischio-pubic portion,
the short process external and anterior to the limb being all
that can be compared to an ilium.
The fin presents two basal cartilages of which the larger
is the metapterygium and carries most of the peripheral somac-
tids ; the propterygium is small. In the male the metaptery-
gium is continued to form the skeleton of the clasper.
Here as in the fore-limb there is some variation in the number of basal
cartilages, mainly manifested in extinct forms.
// The brain * (Figs. 77.. 78) of
jy Plagiostomes presents great varia-
tions but is always characterised by
the following features : (1) The
olfactory lobes, which may be
placed some distance in front of
the cerebrum and connected with
the latter by a long stalk, or may
be placed quite close to the cere-
brum, are connected with the cere-
brum laterally and somewhat
dorsally ; (2) the cerebrum is
unpaired though internally it
possesses two lateral ventricles, each
of which is usually continued into
FIG. 76.— skeleton of right pectoral its olfactory lobe ; it is not sharply
marked off from the thalamencepha-
lon ; (3) the epiphysis is elongated,
its front end lying over the cerebrum either beneath or
just behind the cranial fontanelle (in Raja in the sub-
cutaneous tissue above the fontanelle) ; (4) the optic
nerves form a chiasma, and the infundibulum has lobi
inferiores and an infundibular gland (saccus vasculosus) ;
(5) the cerebellum is large and its surface is frequently con-
voluted. There is said to be a paraphysis, but there is
* N. v. Miklucho-Maclay, Beitrdge zur vergL Neurologic d. Wirbelthiere,
Leipzig, 1870. J. V. Rohon, " Das Centralorgan des Nervensystems der
Selachier," Denkschr. d. Wiener Akad. Math., etc., 38, 1877. L. Edinger,
'.' Unters. iib. d. vergl. Anat. des Gehirns, Abh. d. Senckenbergischen naturf.
Gesellschaft, i. and ii. 1888 and 1892.
fin of Pleuracanthus
thus) decheni (after A. Fritsch,
from Gegenbaur).
BRAIX.
133
no pineal eye (parietal organ). The pituitary body lies along
the ventral side of the infundibulum ; it is said to open in the
adult into the cranial cavity within the dura mater (Haller),
but this must be regarded as doubtful.
-Fa
FIG. 77. — Brain and anterior part of the spinal cord and nerves of Hexanchus griseus (after
Gegenbaur, from Claus). The nerves are exposed on the right side, and the right eye is
removed, a terminal branches of ophthalmicus superficialis trigemini ; Bo olfactory lobe ;
Br branchiae ; Ce cerebellum ; Fa seventh nerve (facial) ; Hm hyomandibular ; Gp ninth
nerve (glossopharyngeal) ; J intestinal branch of vagus ; L lateralis of vagus nerve ; Mh
optic lobes (mid brain) ; Mo medulla oblongata ; N nasal capsule ; Os superior oblique
muscle of eye ; P spinal nerves ; Pq palatoquadrate ; R branchial rays ; Re external, Ri
internal, Rs superior rectus muscle of eye ; S spiracle ; tr fourth nerve (trochlear) ; Tr'
ophthalmicus superficialis trigemini ; Tr" superior, Tr'" inferior maxillary branch of the fifth
nerve ; Vg tenth nerve (vagus) ; Vh cerebrum (forebrain) ; 1-6 branchial arches.
The cerebrum is generally marked by longitudinal grooves
indicating the internal division, but in Carcharias (Fig. 78),
Sphyrna, etc., there are no traces of these. Plagiostomes
134
SUB-CLASS ELASMOBRAXCHII.
-TTlfl
-Hh,
differ considerably as to the length of the thalamencephalon.*
In some, this part of the brain is much elongated, being com-
pletely exposed in its dorsal part and passing without break
into the anteriorly-placed cerebrum (Notidanidae, Spinacidae,
Scymnidae and most Plagios tomes). In others the thala-
mencephalon is very short and its dorsal surface is almost com-
pletely covered by the cerebrum, the hinder part of which
almost, if not quite, touches the optic lobes (Carcharias, Sphyrna,
Oxyrrhina, Galeus, Trygon). It would
appear that the latter condition is develop-
mentally the most primitive, for brains with
a long thalamencephalon in the adult, e.g.
Scyllium, have in the later embryonic
stages a short thalamencephalon with the
cerebrum and optic lobes in contact over it.
The cerebellum in some forms is very
large and may reach forward to the cere-
brum. The restiform tracts, or sides of
the medulla are much developed, and folded
or even convoluted. This is ascribed by
Burckhardt to the enormous development
of the sensorial centres in the dorso-lateral
parts of the spinal cord and brain in conse-
quence of the insertion of the nerves of
the lateral line organs.
The dorso -median tract of non-nervous tissue
which is so often found along the central nervous
system of the Vertebrata and was first mentioned
by the physiologist Haller (Opera Minora, 1768,
bd. 3) has been detected as a septum in the cere-
bellum of many Plagiostomes. It is of course also present, as in all Ver-
tebrates, over the third and fourth ventricles and on the posterior wall
of the lateral ventricle. Very possibly the very thin dorsal wall — at
the bottom of the dorsal fissure — of the central canal of the spinal cord is
to be regarded as part of it, though there is here a little nervous
tissue.
Cranial nerves t (see p. 72). There is nothing special to
* This and other features of the brain seem to be influenced by the size
and position of the eyes, vide Burckhardt, British Association Reports, 1900.
t H. Stannius, Das peripherische Nervensystem der Fische, Rostock, 1849.
J. C. Ewart, " On the Cranial Nerves of Elasmobranch Fishes," Proc. Roy.
Soc., 45, 1889, p. 524. Id., Supplementary note on the cranial nerves of
Elasmobranchs, Edinburgh, 1892. A. M. Marshall and W. B. Spencer, " On
FIG. 78. — Brain of Car-
charias from above
(after Miklucho-Mac-
lay) . SI olfactory lobe ;
Vh cerebrum ; Mh
optic lobe ; Hh cere-
bellum ; N restiform
tract ; Vag vagus.
CRANIAL NERVES. 135
note about the first, second, third, fourth, and sixth cranial
nerves.
The ophthalmicus profundus (Fig. 79, opv) is a well marked
and distinct nerve in most Elasmobranchs, but in some (e.g.
Scyllium} it is less marked. It arises either with or just in
front of (Laemargus) the main root of the trigeminal. After
emerging from the skull wall with the trigeminal it presents a
ganglion — the profundus ganglion, and passes forwards in the
orbit, dorsal to the external and internal recti, but ventral to
the superior rectus and superior oblique. It penetrates the
anterior wall of the orbit, and is distributed to the skin of the
front of the snout. In the orbit it gives off long ciliary nerves
to the eyeball, and one or more nerves which anastomose with one
or more filaments from the ventral branch of the oculomotor
(om), a small ganglionic swelling being found at the point of
junction. This small ganglion is the ciliary or oculo-motor
(lenticular, ophthalmic) ganglion ; it gives off some ciliary
nerves (short ciliary) to the eyeball. The filaments connecting
this ciliary ganglion with the ophthalmicus profundus (some-
times with the profundus ganglion) constitute the radix longa,
while those passing to the oculomotor represent the radix
brevis. The filaments passing from the ciliary ganglion to the
eyeball represent the short ciliary nerves.
The ciliary ganglion of Plagiostomes seems to be variable in its size and
position ; it is sometimes absent, sometimes close to the profundus nerve,
sometimes approximated to the ventral branch of the third nerve. In the
embryo the oculomotor nerve passes directly from its origin to the pro-
fundus ganglion ; later it becomes detached, the connecting cord being
the radix brevis. The ciliary ganglion is probably a detached portion of
the profundus ganglion, in which case its relation to this ganglion is exactly
that of a sympathetic ganglion to the ganglion of a posterior root of a
spinal nerve. The ophthalmicus profundus itself probably corresponds
to the nasal nerve of the M ammalia. The third nerve must be regarded
as the ventral root of a nerve of which the ophthalmicus profundus
is the dorsal (see p. 73).
The trigeminal nerve arises usually by a single root from the
sides of the medulla. It swells either inside or outside the
cranium into the gasserian ganglion and there gives off the
the cranial nerve? of Scyllium," Q, J. M. S., 21, 1881, p. 469. C. Gegen-
baur, " Die Kopfnerven von Hexanchus," Jena. Zeitsch., 6, 1871, p. 497.
F. J. Cole, " On the cranial nerves of Chimaera, " Trans. Roy. Soc. of Edin-
burgh, 38, 1896, p. 631. Also literature cited on p. 75.
136
SUB-CLASS ELASMOBRANCHII.
superficial ophthalmic (ramus ophthalmicus super ficialis, sot).
This nerve, which is quite inconspicuous in Raji and in forms
in which the ophthalmicus profundus is well developed (at once
joining the ophthalmic branch of the facial), runs close to or in
conjunction with the superficial ophthalmic of the facial ; it
is distributed to the subcutaneous tissue and skin of the snout.
The main nerve passes on and divides into the superior
and inferior maxillary branches. Of these the inferior maxillary
is a mixed nerve ; the superior being mainly sensory but con-
taining motor fibres in some forms (e.g. Chimaera).
CSO sot cm
A'
FIG. 79. — Diagram illustrating the distribution of the dorsal branches of the cranial ne/ves
of the lateral line canals, and the position of the groups of ampullae in an Elasmobranch
(after Ewart, from Gegenbaur). A auditory nerve with labyrinth ; it also points to the
groups of Lorenzini's ampullae ; Bu buccal branch of facial, bu inner branch to part of
infraqrbital canal, and to the inner buccal group of ampullae ; bu' its outer branch which
supplies the part of the infraorbital canal, and the outer buccal group of ampullae ;
ch postbranchial branch of facial to mucous membrane, and giving off motor branches
to some jaw muscles ; CSO, CSO supraorbital canal ; CJO, CJO infraorbital canal ;
Fa, Fa' roots of facial nerve; Gp glossopharyngeal, arising under cover of the lateralis
branch of the vagus nerve ; Hm hyomandibular canal arhing from the infraorbital and
giving off the mandibular canal ; the mandibular group of ampullae is in the angle
between these two ; Hm' branch of the hyomandibular nerve to the hyoid group of
ampullae ; in intestinal branch of vagus with ganglion, where it separates from fourth
branchial branch ; In lateralis branch of vagus nerve ; m mouth ; N nasal sac ; om
deep branch of oculomotor giving off short root of ciliary ganglion (shown, but not
marked), the long root is also shown, as are the short ciliary nerves to the eye ; opr
root of ophthalmicus profundus ; opv dorsal branch of same, giving off long ciliary nerves ;
pol second branch of lateralis supplying some lateral line sense organs, and a row of pit
organs, the first branch supplies the commissure connecting the two lateral canals, and
some sense organs of the main canal ; sof ophthalmicus superficial facialis, which
supplies the supraorbital canal, and the superficial ophthalmic group of ampullae ; sot
ophthalmicus superficialis trigemini ; it arises from the gasserian ganglion ; sp spiracle ;
Tr trigeminus ; F1, F2, F3 the first three branchial branches of the vagus nerve, each
with a ganglion and with pharyngeal, prebranchial and postbranchial branches ; V* the
united fourth branchial branch of vagus and intestinal branch; 1-5 gill-slits.
The facial nerve with its ganglion, the geniculate ganglion,
has three or four roots which after communicating with one
another separate into three nerves, the ophthalmicus superficialis
CRANIAL NERVES. 137
portio facialis (sof), the buccal (Bu), and the hyomandibular nerves
(Fa', ch, Hm'}. The two first of these and the external mandi-
bular branch of the last innervate the sense organs of the sensory
tubes. The hyomandibular * excluding the external mandi-
bular branch may be called the facial proper (ch) ; it is a mixed
nerve for the hyoid arch with branches to the roof of the mouth
(palatine) and mandibular arch (prespiracular).
The three roots of the facial are as follows: a dorsal root (Fa), from
which probably most of the lateral-sense organ nerves are derived, and
two ventral roots, of which the anterior is just behind the root of the
oth and is possibly double, while the posterior is just in front of the root
of the auditory.
The ophthalmicus superfecialis freely communicates with the
buccal nerve as it passes through the cranial wall which it does
by a foramen dorsal to that for the trigeminal. Outside the
cranium it presents a ganglion and passing along the dorsal side
of the orbit is distributed to the supraorbital branch of the ceph-
alic lateral line and to the ampullae of the ampullary canals of
the snout.
The buccal nerve (bu, bu') after passing through the cranial
wall with the trigeminus becomes closely applied to the gas-
serian ganglion and swells into a ganglion. It runs along the
floor of the orbit close to the maxillary nerve. It supplies the
inner and outer buccal groups of ampullae, and the sense organs
of the orbital and suborbital lateral line.
The hyomandibular nerve, after leaving the skull by a foramen
which is generally through the auditory cartilage, behind and
distinct from the trigeminal, dilates into a ganglion where it gives
off forward the palatine nerve (indicated but not marked in the
figure). The palatine nerve at once gives off the prespiracular
nerves which are supposed to be homologous with the chorda
tympani of mammals, and is continued to supply the roof of the
mouth. It is homologised with the great superficial petrosal
of mammals. The hyomandibular then gives off a branch to
the mandibular and hyoid group of ampullae and lateral line —
the external mandibular — and is continued to the muscles, etc.,
of the hyoid arch (internal mandibular of Stannius, ch).
The auditory nerve arises by a root immediately behind
* In the figure the hyomandibul ar nerve (ch) is smaller than the external
mandibular which runs with it, so that it appears as a branch of the latter.
138 SUB-CLASS ELASMOBRANCHII.
those of the trigemino -facial group and is distributed to the
walls of the otocyst.
The glossopharyngeal (Gp) arises just in front of the vagus by
three or four rootlets. It passes out by a canal below the audi-
tory capsule, dilates into a ganglion and gives off a small dorsal
nerve which in some cases is said to supply a part of the cephalic
lateral line. The nerve continues to the first branchial arch
giving off a prebranchial branch to the hyoid and a pharyngeal
branch.
In the vagus the root of the lateral line nerve (lateralis) must
be distinguished from the roots of the rest of the nerve. The
lateralis nerve (In) arises by a root dorsal to and slightly in front
of the glossopharyngeal. It leaves the skull with the rest of the
vagus to which it is closely applied and dilates into a ganglion.
It is continued to the end of the body and supplies the trunk
portion of the lateral line canal, and a small portion of the cranial
lateral line. The remaining vagus roots, which are numerous,
unite to form five nerves each of which has a ganglion. These
are at first closely connected together and are distributed in the
typical manner, the first four to the four hinder branchial arches
and the last is continued as the intestinal branch (in).
A variable number of anterior roots of spinal nerves * of which
the posterior roots though present in the embryo are absent in
the adult, arise from the medulla ventral to the vagus roots.
They were formerly mistaken by Gegenbaur for ventral roots of
the vagus and were called ventral vagus roots. They are absent
in some Raji. They leave the skull wall by special foramina in
the occipital region and innervate some muscles of the fore-limb
and some ventral branchial muscles. They are called the spino-
occipital nerves.
It has been shown in Amphibia that the superficial ophthalmic
of the facial, the buccal and external mandibular of the facial
and the lateralis of the vagus arise from the acustico-lateralis
nucleus in the brain (see p. 75). All these nerves are developed
from the surface ectoderm and sink inwards to their adult posi-
tions and when in Amphibia the lateral line sense organs dis-
appear the whole of these nerves disappear also.
* M. Fiirbringer, Ueb. d. Spino-occipitalen N erven der Selachier, etc.,
Leipzig, 1897.
ALIMENTARY CAXAL. 139
In Chimaera a small portion of the supraorbital canal is supplied by
the ophthalmicus profundus, and in some if not all Plagiostomes (Mus-
tdus, Laemargus], Teleosts, Ganoids, the dorsal branch of the glosso-
pharyngeal innervates a small portion of the cephalic lateral line.
For an account of the sense organs the reader is referred
to p. 121, and to the section dealing with Pisces (pp. 77-82).
For the sympathetic, see p. 75.
The alimentary canal is fairly similar throughout the order.
The mouth is usually ventral. Teeth varying considerably in
shape are present in several rows on the palato-quadrate bar and
cartilage of Meckel. As those in the row next the mouth
opening are worn away, those of the next row advance, and a
new row is added internally. The basihyal projects in a tongue-
like manner from the floor of the mouth. There are no salivary
glands. The hinder part of the mouth passes without demarca-
tion into the pharynx which receives the internal openings of
the spiracle and gill-slits.
The oesophagus leads into the stomach, wThich is U-shaped,
the pyloric limb of the U being narrow and opening into the short
somewhat swollen anterior end of the intestine (duodenum, bursa
entiana). Into this open the bile duct and the pancreatic duct.
It is followed by the rest of the intestine which is provided with
a spirally disposed longitudinal valve. The intestine ends behind
in a narrow rectum, which receives a dorsal gland, the rectal
gland, and opens into the cloaca. The cloaca opens externally
between the pelvic fins. The alimentary canal is supported by
a mesentery which is defective in part. The liver is well devel-
oped and usually provided with a gall bladder. The pancreas
is also large. There is a well-developed spleen in the neighbour-
hood of the stomach.
In Laemargus borealis two large caeca open into the commencement
of the intestine. In some forms (Zygaena, Carcharias) the longitudinal
valve is not spirally arranged, but is rolled upon itself.
There is no air-bladder.
A thyroid is present between the rami of the mandibles. It
frequently has a pyriform shape and lies over the bifurcation
of the ventral aorta.
The thymus is represented by an elongated lobed gland placed
over the dorsal ends of the branchial arches and derived, as usual,
140 SUB-CLASS ELASMOBRAXCHII.
from epithelial outgrowths of the embryonic branchial passages.
Body cavity. The pericardia! cavity communicates with
the general body-cavity by a canal which leaves it dorsal to the
sinus venosus and passing along th3 ventral side of the oesophagus
opens behind by a slit-like aperture into the body-cavity. This
canal may divide in a Y-shaped manner behind, but usually only
one of the limbs is complete.
The body-cavity may communicate with the exterior by abdo-
minal pores, with the kidney-tubules by persistent nephrostomes
and with the cloaca by the oviducts.
Abdominal pores are -usually present, though there is consider-
able variability as to these openings in closely allied species or
even in the same species at different periods of life. They are
placed on each side of the cloacal opening, either on the surface
or at the bottom of a pouch (cloacal pouch). They lead into
that part of the body cavity which is placed on each side of the
cloaca (peritoneal canals).
The vascular system is arranged in the usual piscine manner.
The pericardial cavity is placed dorsal to the median union of
the coracoid cartilages of the shoulder girdle. Its walls are
stiffened by that skeletal structure and by the basibranchial
plate which lies dorsal to it. It thus happens that its walls are
unyielding and when the ventricle contracts, blood flows from
the great venous sinuses outside the pericardium into the large
auricle. The ventricle is provided with a muscular conus arteri-
osus in which there are from two to five or even more rows of
semilunar valves. The ventral aorta sends branches to the hyoid
arch, which has a demibranch on its hinder face, and to all the
branchial arches except the last. The carotids arise from the
dorsal system and the internal carotids anastomose as they enter
the cranial cavity. The efferent vessel coming from the hyoid
demibranch gives off near its ventral end an artery which passes
forward ventrally to the spiracle on to the mandibular arch. It
passes near the front wall of the spiracle, giving off vessels to the
pseudo branch and then pierces the cranial wall to join the internal
carotid artery within the skull.
The great veins are much dilated into sinuses as they approach
the heart. This applies to the anterior and posterior cardinals
and to the hepatic veins. Moreover the anterior cardinal is
dilated round the eye-ball forming the space (a kind of hsemo-
URIXOGEXITAL ORGANS. 141
coelic body-cavity) in which the movements of the eye occur.
There is a renal-portal system furnished by the caudal vein which
branches when it reaches the kidney, and the posterior cardinals
arise in the kidney.
The kidney (Fig. 81) of each side is a single gland but by the
arrangement of the collecting tubules may be divided into an
anterior thin part, the mesonephros (almost absent in the adult
female), and a posterior thick well -developed portion the meta-
nephros. The longitudinal duct extends along the whole length
of the gland and posteriorly joins its fellow to form an unpaired
tube — the urinary sinus — which opens into the cloaca. This
duct has various names none of which are entirely satisfactory.
It is called the pronephric, the mesonephric, and the wolffian
duct (p. 89). We shall call it usually the longitudinal duct.
The collecting tubes of the mesonephros are directed transversely
and open at once into the longitudinal duct ; the collecting tubules
of the metanephros, the so-called ureters, are directed back-
wards and after a certain amount of union amongst themselves
open into the hinder part of the longitudinal duct close to the
urinary sinus by one or more openings.
The ovaries and testes are slung to the dorsal wall of the body-
cavity by the mesovarium and mesorchium respectively, mem-
branes which are either attached close to the mesentery or to
the mesentery itself. In some few cases the ovaries of the two
sides are united into one body which is placed slightly on the
right side. The testes are connected with the anterior end of the
mesonephros by a network of tubules — the testicular network
(Fig. 80), which is not visible (Fig. 81) without special prepara-
tion, and which typically consists of the longitudinal canal of
the testis, the longitudinal canal of the mesonephros (wolffian
body) and the vasa efferentia connecting these two. The longi-
tudinal canal of the mesonephros (wolffian body) is connected
with the malpighian bodies of a number of the anterior meso-
nephric tubules. The number of tubules implicated varies very
considerably in different species, and very possibly in individuals
of the same species. In Scyllium canicula it appears frequently
to be four, in Squatina vulgaris five. The sperm therefore passes
through anterior kidney tubules into the longitudinal duct which
is in the male much convoluted and functions as the vas deferens.
The hind end of the longitudinal duct is dilated to form the vesi-
142
SUB-CLASS ELASMi >BRANCHII.
cula seminalis (Fig. 81, vs). The two vesiculse seminales join
to form the urogenital sinus and just before their union each
receives the opening of the seminal bladder (ss), which is a
pouch lying on the ventral side of the vesicula seminalis, and
the openings of the ureters, usually four or five in number in
Scyllium canicula. The urinary sinus which in the male is
common to the urinary and generative organs opens into the
cloaca through its dorsal wall by a median papilla — the urino-
genital papilla (ug.p.).
In the female the hind end of the longitudinal duct is dilated
(ub) and receives not far from its union with its fellow the ureters
(ur) by one or
5 more openings.
The oviducts
open close to-
gether through
the dorsal wall
of the cloaca
in front of the
urinary papilla.
They extend for-
ward to the front
end of the body
ca v ity into
which they open
close together
on the ventral
side of the
anterior end of the liver (fl.tf). Not far from their front end their
walls are much thickened owing to the presence of glandular
tissue constituting the oviducal gland (od.g).
Traces of the oviducts are often present in the male, particu-
larly near the abdominal openings.
The oviduct in the viviparous forms presents a uterine dilata-
tion and the oviducal gland is much reduced.
In many Selachii the nephrostomes of a certain number of
the primary kidney tubules persist into the adult as ciliated
openings. These are minute in Scyllium, but in some forms they
attain a considerable size.
The egg is large and heavily yolked. It receives a coat of
FlQ. 80. — Testis and anterior part of niesonephros (Wolffian
body) of an embryo of Squatina vulgaris (after Balfour) : to
show the testicular network. There are five vasa efferentia
connecting the longitudinal canal in the base of the testis
with a longitudinal canal in the mesonephros. From the
latter there pass off four ducts to as many malpighian bodies.
1 vasa efferentia ; 2 malpighian bodies ; 3 mesonephros ;
4 longitudinal or mesonephric duct ; 5 longitudinal canal of
the testis ; 6 testis.
PLEUROPTERYGII.
145
The Elasmobranchii are the most ancient of all known fishes.
They make their appearance in the Upper Silurian. They are
almost entirely active, carnivorous, predatory fishes and with
very few exceptions exclusively marine.
The following is the classification adopted in this work : —
Order 1. PLEUROPTERYGII (extinct).
2. ACANTHODI
3. ICHTHYOTOMI
4. SELACHII (PLAGIOSTOMI) .
Suborder l. Notidani.
2. Squall.
3. Eaji (Batoidei).
5. HOLOCEPHALI.
FIG. 83.—Cladoselache. A pectoral, B pelvic fins x $ ; B basal somactids within the body-
wall, D dermal fin membrane, R peripheral somactids. Left border preaxial (after Dean,
from Woodward).
Order 1. PLEUROPTERYGII.*
With unconstricted notochord and heterocercal caudal fin. Paired fins
with unsegmented parallel radials, reaching to the edge of the fin. Eyes
with a circle of thin dermal plates. Male without claspers on the pelvic
fins.
The skull is unknown, but the jaws are suspended by a slender hyo-
mandibular. The teeth have a principal cusp and several accessory
lateral cusps. They resemble teeth which have long been known from
the Carboniferous under the generic name Cladodus. There were certainly
* B. Dean, Contributions to the Morphology of Cladoselache, Journ.
Morph., 9, 1894. Jaekel, Ueber Cladodus, Sitzungsb. d. Gesellsch. naturf.
Freunde, Berlin, 1892. R. Traquair, Geol. Magazine, 1888, p. 83.
Z — II L
146
SUB-CLASS ELASMOBRANCHII.
five gill-arches but there may have been more. Two dorsal fins have
been seen (one only shown in Fig. 84), but no anal. The caudal fin
is strongly heterocercal ; the neural arches are continued to the end
of the tail, and carry stout somactids which extend to the edge of the
fin. The paired fins are horizontal expansions of the integument.
The peripheral somactids are parallel, unsegmented, and extend to the
margin ; between their distal ends are slender cartilages which are pos-
sibly displaced somactido. Thebasals are also parallel, and are contained
FIG. 84. — Restoration of Cladoselache newberryi Dean (from Woodward, after Dean).
ii
in the body wall. The skin is covered by minute denticles, not enam-
elled. Cladoselache Dean, Lower Carboniferous of Ohio ; Cladodus Ag.
for some tune known only by teeth ; Devonian, Carboniferous, and Per-
mian.
Order 2. ACANTHODII.*
With dermal calcareous plates on the skull and pectoral arch, and with
a mosaic of quadratic dermal scales on the body. All the fins except the
caudal, with a powerful dentine spine on their anterior margin. Without
claspers. There are no cranial bones, nor membrane bones connecting the
pectoral arch with the cranium.
This group, which was formerly placed with the Ganoids, is now placed
with the Elasmobranchs. The endoskeleton contains granular calcifica-
tions, and the dermal plates placed on the head, body and pectoral girdle
FIG. 85.— Acanthodes Wardi x i (after Woodward),
gill-frills are hypothetical.
The orbit is made too small and the
seem to have consisted of vaso-dentine or of structureless lamellae without
bone-cells. The most marked characteristic of the group is the large
* Huxley, Geological Survey of the United Kingdom, 10, 1861. Fritsch,
Fauna der Gaskohle in Bohmen, 2, 1889. Reis, Zur Kenntniss des Skelets
der Acanthodinen, Geognost. Jahreshefte,'Munchen, 1890, 1894. Traquair,
Geol. Mag., 1888, p. 511 ; 1889, p. 17.
ICHTHYOTOMI. 147
spines on the front of the fins. These appear to have consisted of dentine,
and are doubtless comparable to the spines found in similar positions in
the fins of Elasmobranchs. It is probable that a number of isolated
spines which have received special generic names (Onchus, Byssacanthus ,
Homacanthus, etc.) may have belonged to fishes of this group, and that
a number of quadratic scales, e.g. Thelolepis, Coelolepis, etc., from the
Upper Silurian, were part of the dermal armature of similar fishes. Pec-
toral and pelvic fins are always found.
FIG. 86.—Ciimatius scutiger, outline of fish with spines shaded. The pectoral fins pines pc
are the two large spines next the head ; then follows a double row of smaller spines i, the
last of which are the pelvic fin-spines plv. The large fin with spine a between the paired
spines and the caudal fin is the anal ; dl, d* dorsal fins.
The eye is surrounded by dermal plates ; the notochord must have been
persistent ; the supports of the fins are not preserved ; the tail is hetero-
cerca-1 and the caudal fin without any trace of upper lobe. Comparatively
small fishes. Acanthodes Ag. (Fig. 85), Lower Devonian to Lower
Permian ; Diplacanthus Ag., and Climatius Ag., Upper Silurian and
Lower Devonian, without teeth, with four or five pairs of spines between
the pectoral and pelvic fins (Fig. 86). Most of the sub-order do not
show teeth, but there is a powerful dental armature in Ischnacanthus.
Order 3. ICHTHYOTOMI.*
The cartilaginous endoskeleton is permeated by granular calcifications ;
notochord unconstricted, with slight calcifications in its sheath ; neural and
haemal arches calcified, with long spinous processes ; tail diphycercal ;
pectoral and pelvic fins with long segmented axis and biserial radii ; pelvic
fins with claspers in the male. The teeth have two large lateral cusps, with
one small median cusp. Lower Carboniferous to Lower Permian.
Pleuracanthus Ag. (Xenacanthus Beyr.) (Fig. 87). Body elongated,
to half a metre ; skin probably naked, with a long 3pine attached to the
occipital region of the cranium ; five, possibly seven, branchial arches ;
all the fins with dermotrichia ; pectoral girdle arch-like, united with its
fellow, composed of two pieces ; pectoral fin (Fig. 76) with segmented
axis ; rachiostichous and pleurorachic, or nearly so (p. 57) ; pelvic fir-
similar, but with no postaxial somactids, with claspers ; pelvic girdle of
two separate arches. The somactids of the long dorsal fin are segmented
* Fritsch, loc. cit. Davis, On the Fossil Fish Remains of the Coal
Measures in the Brit. Islands, I. Pleuracanthidae, Trans. Roy. Dublin
Soc.t 4, 1892.
148
SUB-CLASS ELASMOBRANCHII.
FIG. 87. — Pleuracanthus decheni,
restored by A. Fritsch, x i ;
Lower Permian, Bohemia (from
Woodward). A1, A'2 anal fins;
C dorsal part of caudal fin ; Z>
dorsal fin. The specimen from
which this figure was taken has
been crushed in such a way
that the paired fins appear to
have their postaxial sides
turned forward.
into three pieces, and are twice as numer-
ous as the neural arches, those of the
dorsal part of the caudal fin are similar,
but equal in number to the neural arches ;
the anal fin is double, and its supports
are partly fused, and branch peripherally.
Didymodus Cope, Permian of Texas, skull
shows symmetrical fissuring, to which the
name of the sub-order is due.
Order 4. SELACHII (PLAGIOSTOMI),
Elasmobranchii with characters of
the soft parts as defined for the sub-
class, with hyostylic skull (except
Notidanidae) and heterocercal tail.
The notochordal sheath is always
segmented, though sometimes imper-
fectly ; the pectoral fins with three
basal cartilages, and the pelvic fins of
the male with claspers.
The mouth is placed on the under
surface of the head, except in
Chlamydoselachus in which it is sub-
terminal, and Rhinodon and Rhina
in which it is terminal. The skin
has detached placoid scales only.
The body is either fusiform or flat-
tened dorsoventrally, and there is
usually a spiracle, but the pseu-
dobranch is absent in the Scym-
nidae, Lamnidae, Myliobatis, Trygon,
etc. In Carcharias and Zygaena, in
which the spiracles are absent, a
pseudobranch is present buried in
the flesh or placed on the front wall
of a recess of the mouth. They are
almost all marine, but a few ascend
American and Asiatic rivers, and a
few are confined to freshwater (some
Trygons, two species of Carcharias).
They have existed since Palaeozoic
times
XOTIDANI.
149
Sub-order 1.
NOTIDANI.
With six or
seven branchial
apertures and a
small spiracle
with one dorsal
fin without spine.
Vertebral col-
umn imperfectly
segmented. Cau-
dal fin without a
pit at its root ;
without labial
fold and nictitat-
ing membrane.
Fam. 1. Chlamy-
d o selac hidae.*
Body eel-like;
mouth anterior ;
nasal opening
divided and on side
of head ; lateral
line as an open
groove on the body,
but closed (with
openings left) on
the head ; with
six gill openings
and six branchial
arches ; opercular
fold (first gill- FIG. 88. — A. Chlamydoselachus angui-
neus Garman ; B. side view of the
head of the same (after Garman).
x f
cover) free across
the isthmus ; the
palatoquadrate is not articulated with the post-
orbital process of the skull and there is a large
hyomandibular ; notochord unconstricted pos-
teriorly ; teeth similar in both jaws, each with
three slender, curved cusps separated by a pair
of rudimentary denticles on a broad base; vivi-
parous. Chlamydoselachus Garman, from the deep
sea, 5-6 feet. Japanese seas, Atlantic and
Arctic.
* Garman, Bull. Mus. Zool. Harvard College, 12,
1885.
150 SUB-CLASS ELASMOBRANCHII.
Fam. 2. Notidanidae. Mouth sub-inferior; nostrils on lower side,
nearer snout than mouth ; dentition unequal in the two jaws ; in the upper
jaw one or two pairs of awl-shaped teeth, the next six teeth broader and
each provided with several cusps, one of which is the strongest ; lower
jaw with six large, comb-like teeth on each side, beside the smaller pos-
terior teeth ; viviparous ; sometimes reach a large size. The palato-
quadrate articulates with the postorbital process of the skull and the hyo-
mandibular is comparatively slender ; each segment of the vertebral
column of the middle part of the trunk region carries two neural arches
and corresponds to two pairs of spinal nerves (p. 126) ; the pseudobranch
is very large and has several M'ell-developed laminae. Temperate and
warm seas. Hexanchua Raf., with six pairs gill-apertures ; vertebrae
without calcification ; H. griseus Gmelin, 8-26 feet, Mediterranean,
W. coast Scotland ; Heptanchua Raf., with seven pairs gill-apertures,
vertebrae asterospondylous.
Sub-order 2. SQUALL
Vertebral column well segmented, vertebrae amphicoelous
with a double cone of calcified cartilage, outside which and
springing from it there may be radiating calcareous lamellae
(asterospondylous) or additional concentric calcified rings (cyclo-
spondylous) ; with two dorsal fins, and with or without anal fins.
With five gill apertures laterally placed, spiracle present or
absent, never large. The palatoquadrate is not articulated
directly to the skull except in Cestraciontidae.
This sub-order includes the great body of living sharks, and has
existed since the Silurian period. Some of the living genera have
existed since early times ; e.g. Cestracion, Upper Jurassic ;
Scyllium, and Scapanorhynchus (Mitsukurina) Cretaceous ;
Pristiurus, Upper Jurassic. Most of them are active predatory
creatures, and some attain a considerable size. The largest
are however harmless creatures, which like the whalebone
whales exist on small marine organisms which are detained on
their prolonged gill-rakers (Selache, Rhinodon).
Fam. 3. Cestraciontidae. Bull-head sharks; asterospondylous; the
palato-quadrate articulates by an extensive surface with the preorbital
region of the skull ; two dorsal fins with spines, the first dorsal opposite
the space between pectorals and pelvics, the second in advance of the
anal ; upper lip divided into seven lobes, the lower with fold ; spiracle
small, below posterior part of eye ; without nictitating membrane ; den
tition similar in both jaws, viz. small obtuse teeth in front, pointed and
provided in young individuals with three to five cusps ; lateral teeth
large, pad-like, twice as long as broad ; Pacific and East Indian Archi-
pelago ; size small ; oviparous, egg-case spirally twisted. Cestracion
Cuv. (Heterodontus Blainv.), C. phillipi Blainv., Port- Jackson shark.
SQUALL 151
Extinct genera are Orodus Ag., Campodus de Kon., Sphenacanthus Ag. ,
Carboniferous Limestone ; Hybodus Ag., Trias to Cretaceous ; Palaec-
spinax Eg., Lias ; Acrodus Ag., Trias to Cretaceous, etc.
Fam. 4. Scylliidae. Dog-fishes ; asterospondylous, dorsal fins
without spine ; first dorsal above or behind the pelvic ; an anal fin ; no
membrana nictitans ; spiracle distinct ; mouth inferior ; teeth small ;
nostrils near the mouth, sometimes confluent with it, sometimes with cirri.
Scyllium Cuv. (Scylliorhinus Blainv.), upper edge of caudal fin smooth ;
Sc. canicula Cuv. , small-spotted dog, single nasal flap, pelvic fins separated ;
eggs laid in April, hatched in December ; Sc. catulus Cuv., large-spotted
dog, nurse hound, nasal flap divided, pelvic fins almost conjoined ; Pris-
tiurus Bon., snout much produced, small flat spines along upper edge of
caudal fin, P. melanostomus Bon. ; Ginglymostoma M. and H., large sharks
of the warm seas, nostrils confluent with mouth ; Stegostoma M. and H.,
tiger-shark to 15 feet, India ; Parascyllium Gill, Tasmania, 2| feet ;
Chiloscyllium M. and H., nasal and buccal cavities confluent, Indian and
Australian, 2^ feet ; Crossorhinus M. and H., Australia and Japan to 10
feet, mouth nearly anterior, nasal and buccal cavities confluent,
Extinct genera : Palaeoscyllium Wagn., Upper Jurassic ; Mesiteia
Kramb., Cretaceous.
Fam. 5. Carchariidae. Asterospondylous ; first dorsal opposite space
between pectoral and pelvic, without spine ; an anal ; with nictitat-
ing membrane ; mouth crescentic, inferior ; spiracles present or absent.
Carcharias M. and H. (sub-genera, Scoliodon M. and H., Physodon M. and
H., Aprionodon Gill, Hypoprion M. and H., Prionodon M. and H.) com-
prises the true sharks ; no spiracle ; teeth with a single cusp, snout pro-
duced, pit at root of tail ; temperate and tropical ; C. glaucus Cuv.,
blue-shark, 25 ft. ; C. gangeticus of the Ganges and inland lakes of the Fiji
Islands, and C. nicaraguensis G. and B., Lake Nicaragua, only fresh-
water sharks known, 7 ft. ; Hemigaleus Bleek, East-Ind. Archipelago ; Loxo-
don M. and H., Ind. Ocean ; Galeocerdo M. and H., arctic, temp,
and trop. seas ; Thalassorhinus M. and H., Med. and Atl. ; Galeus
Cuv., small spiracle, teeth with single cusp, snout elongated, no pit at
root of tail, temp, and trop., viviparous ; G. canis Rond., tope,
whithound, penny dog, miller's dog, 7 ft. ; Zygaena Cuv. (Sphyrna
Raf.), temp, and trop., no spiracles, hammer-headed sharks, eyes at
extremity of head lobes ; Z. malleus Shaw, hammer-shaped head, vivi-
parous, balance fish ; Triaenodon M. and H., no spiracles, Red Sea,
Ind. Ocean ; Leptocarcharias Smith, no spiracles, S. Africa ; Triads
M. and H., Ind. and Pac. Oceans ; Mustelus Cuv., viviparous, teeth flat
and paved, temp, and trop. seas, spiracles small, no pit at root of tail,
bottom-fish ; M. laevis Risso, embryo attached to uterus by placenta ;
M. vulgaris M. and H., no placenta, 6 ft., smooth hound, skate-toothed
dog. Scylliogaleiis Blgr., Natal.
Fam. 6. Lamnidae. Mackerel sharks. Large sharks with large
teeth ; first dorsal opposite space between pectoral and pelvic, without
spine ; asterospondylous ;. an anal fin ; no nictitating membrane ; mouth
crescentric, inferior ; spiracles absent or minute, varying even in the same
species ; pelagic, attain large size. Lamna Cuvier, Porbeagles, teeth
lanceolate, large, with smooth edges, keel at side of tail, temperate and
tropical seas ; L. cornubica Gmelin, Porbeagle (porpoise and beagle) or
Beaumaris shark, viviparous, 10 ft. ; Carcharodon M. and H., C. rondeletii
M. and H., great blue-shark, man-eater, spiracle minute or absent, Med. to
152 SUB-CLASS ELASMOBRANCHII.
i
Australia, 36 ft. ; Odontaspis L. Ag., temp, and trop. seas ; Alopecias
(Alopias) M. and H., teeth triangular, flat, smooth edges, caudal fin
long, no keel at side of tail, temp, and trop. seas ; A. vulpes Gmelin,
thrasher-shark, fox ; Selache Cuv. (Cetorhinus Blainv.), teeth small,
numerous, conical and smooth, keel at side of tail, whalebone-like gill-
rakers consisting of dentine on the gill-arches, Arctic to Med. ; S. maxi-
mus Gunner, basking-shark, sun-fish, one of the largest of living fishes,
to 40 ft., large gill apertures, vertebrae appear to be tectospondylous,
owing to presence of a number of concentric lamellae in the adult ; in-
offensive, of great strength, has been known to tow a 70-ton boat against
a fresh gale ; a large fish yields 1£ tons of oil ; Pseudotriacis Capello.
Mitsukurina Jordan (Scapanorhynchus S. Wood), Japan. Extinct
genera : Orthacodus S. Wood, Jurassic and Cretaceous ; Odontaspis
Ag., Upper Cretaceous.
Fam. 7. Rhinodontidae. Whale-sharks ; asterospondylous ; origin
of first dorsai fin in front of pelvic ; the second small, opposite the anal,
both without spines ; a pit at root of caudal ; side of tail with keel ;
spiracle small ; membrana nic titans absent ; mouth and nostril near the
front of snout ; teeth small ; gill openings wide, with gill-rakers, Cape of
Good Hope, Seychelles, Japan. Rhinodon Smith ; a gigantic shark known
to exceed 50 ft., said to attain 70 ft.
Fam. 8. Spinacidae. Cyclospondylous ; spiracles present ; gill
openings narrow ; without nictitating membrane ; a deep groove along
either side of the mouth ; a spine on front side of each dorsal fin ; without
anal fin. Centrina Cuv. (Oxynotus Raf.), body somewhat three-sided
with a fold of skin at each angle, teeth in lower jaw triangular, erect and
with finely serrated edges, no membrana met., Med. and adjacent At-
lantic ; C. Salviani Risso, attains to 4-5 ft. ; Acanthias Risso (Squalus),
teeth rather small, their points placed so obliquely that their inner margin
which is smooth forms the cutting edge, no membrana nict., temp,
seas of both hemispheres ; A. vulgaris Risso, picked dog-fish, spur-, spear-,
or bone-dog, hoe, skittle-dog ; viviparous ; Centrophorus M. and H. ,
Eur. seas, Moluccas ; some species live at a great depth (400-500
fathoms) ; Scymnodon Boc and Cap. ; Spinax Cuv. (Etmopterus Raf.),
Eur. Seas, W. Indies ; Centroscyllium M. and H., Greenland, has been
taken 300-400 fathoms.
Fam. 9. Scymnidae. Like Spinacidae, but no spines on dorsal fins ;
Scymnus Cuv., Med. and Atlantic ; Laemargus M. and H. (Somniosus
Lie Sueur), teeth in upper jaw small and conical, those in lower jaw in several
rows, their points placed so obliquely that their inner margin, which is
smooth, forms the cutting edge ; L. microcephalies Kroyer (borealis M. and
H.), Greenland shark; notochordal sheath imperfectly segmented, un-
calcified (calcified and segmented in L. rostratus) ; attains 25 ft., bites
pieces out of whales ; with two pyloric caeca ; eggs large, soft, globular,
without shell, dropped in the ooze on the sea bottom, said to be fertilised
externally; they breed at considerable depths (100 fathoms); Euproto-
micrus Gill, Ind. Ocean ; Echinorhimis Blainv., skin with irregularly
placed round osseous tubercles, teeth large, oblique, with several small
cusps on each side of the main one, Med. and Atl., E. spinosus Blainv.,
to 8 ft. ; Isistius Gill.
Fam. 10. Rhinidae. Ray-like sharks. Tectospoiidylous ; spiracles
large, gill openings wide, lateral, and partly concealed from above by
pectoral fins ; body flat ; mouth anterior ; nostrils at front end of snout
BATOIDEI. 153
with skinny valvular coverings ; pectoral fins large, laterally expanded,,
but not attached to head ; dorsal fins spineless, in caudal region, no anal ;
males with claspers ; temperate and tropical seas ; intermediate between
the sharks and rays. Rhina Klein (Squatina Dum.), angel-fish, monk-
fish, viviparous, to 8 ft.
Fam. 11. Pristiophoridae probably here. Shark saw-fish. Rostral
cartilage produced into long flat lamina, armed along each edge with teeth ;
Pristiophoms M. and H., Japan, Australia.
Sub-order 3. RAJI (BATOIDEI).
Gill openings ventral, five in number : spiracle always present,
without anal fin ; dorsal fins, if present, on the tail ; vertebrae
tectospondylous. Skates and Rays.
The body is much flattened dorso-ventrally and the pectoral
fins are enormously expanded in an antero-posterior direction.
The five branchial apertures are entirely on the ventral surface
of the body. The spiracles are dorsally placed behind the eyes ;
they are wide and can sometimes be closed by a valve. It i&
probable that they are used for the intake of th3 respiratory
water when the fish is lying on the ground. The caudal region
is usually slender, and in some forms very much so. There is no
anal fin, and the dorsal fins when present are placed on the tail.
The Pristidae and Rhinobatidae, which have a well-developed
caudal region and are intermediate in the form of their body
between the sharks and rays, are powerful swimmers, but most
of the Raji lead a more sedentary life on the bottom, rarely
coming to the surface. They feed chiefly on Mollusca and
Crustacea. A few deep-water forms are known, but they are
rarely taken below 100 fathoms. Most are shore-forms.
The Myliobatidae, which include the largest forms in the sub-
order, are however met with in the open sea. Some species
are confined to fresh water. They are for the most part
oviparous. The flesh of many of the species is eaten. Some
of the living families have existed since the Jurassic.
Fam. 1. Pristidae. Saw-fishes. Snout much produced (rostral
process of cranium) with lateral saw-like teeth ; body somewhat shark-
like, the disc-like body gradually passing into the tail, which is com-
paratively thick, with two dorsal fins and a caudal fin, without serrated
caudal spine. Pristis Latham, tropical and sub-tropical, attain a con-
siderable size, with a saw 6 ft. long and 1 ft. broad at base.
Fam. 2. Rhinobatidae. Tail long and strong with two dorsal fins,
a caudal and a longitudinal fold on each side, without serrated caudal
spine ; rayed portion of pectoral fins not continued to snout ; no electric
154 SUB-CLASS ELASMOBRANCHII.
•organ ; viviparous. Rhinobatus Bl. and Schn., guitar-fishes, tropical and
sub-tropical, and fossil from the upper Jurassic ; Rhynchobatus M. and
H., Ind. Ocean to China ; Trygonorhina M. and H., Australia ; Zapteryx
Jor. and Gilb., Peru ; Platyrhinoidis Gar., California. Extinct genera :
Asterodermus Ag., Belemnobatis Thiol., Upper Jurassic.
Fam. 3. Torpedinidae. Trunk a broad, smooth disc ; tail with
rayed dorsal (absent in Temera) and caudal fins and a longitudinal fold
on each side, without serrated dorsal spine ; anterior nasal valves con-
fluent into a quadrangular lobe. An electric organ between the pectoral
fins and the head. Eocene to the present time. Torpedo Dum. (Narco-
batis Blainv.), large specimens (width from 2 to 3 ft.), can disable
a man. Med., Atl., Ind. Oceans ; T. nobiliana Bon., spiracles not
fringed at their margins ; on flat sands or mud, 40-50 fathoms ; T. mar-
morata Risso, spiracles fringed ; Narcine Henle, trop. and sub-trop. ;
Hypnos Dum., Australian ; Discopyge Tschudi, Peru ; Astrape M. and H.,
Ind., S. Afr. ; Temera Gray, E. Ind.
Fam. 4. Rajidae. Skates. Disc broad, rhombic, generally with
asperities or spines ; tail with longitudinal fold on each side ; pectorals
extend to snout ; no electric organ or serrated caudal spine ; oviparous ;
sexual differences are frequently observable, in colour, form of teeth and
arrangement of spines. Cretaceous to the present tune. Raja Art., tail
distinct from disc, pectoral fins not extended to front end of snout, caudal
fin rudimentary ; may attain width of 6-7 ft. ; in some species the teeth
of the male are sharper than in the female, and in all species the males
are armed with patches of claw-like retractile spines on the upper side
of the pectoral fin ; seas of both hemispheres ; R. batis L., skate, oviposi-
tion from May to September, to 6-7 ft. ; R. macrorhynchus Raf., flapper
skate ; R. alba Lacep., white skate, to 8 ft. ; R. oxyrhynchus L., long-
nosed skate ; R. fullonica L., Fuller's ray, shagreen skate ; R. clavata L.,
thornback ; R. maculata Montagu, homelyn ray, spotted ray ; R. micro-
cellata Montagu ; R. radiata, starry ray ; R. circularis Couch, sandy ray.
Psammobatis Giinth., South America ; Sympterygia M. and H. ; Platy-
rhina M. and H. Extinct genus : Cyclobatis Eg., Cretaceous.
Fam. 5. Trygonidae. Sting-Rays. Pectorals continued to and
confluent at end of snout ; tail long and slender, without lateral folds ;
vertical fins none or imperfect, often replaced by strong serrated spine.
Tertiaries to present time. Urogymnus M. and H., Ind. Oc. ; Ellipe-
surtis Schomburgk ; Trygon Adanson (Dasyatis Raf.), tail with long
serrated spine, temp, and trop. ; T. pastinaca, sting ray, sandy ground
near land, caudal spine causes severe wounds ; Taeniura M. and
H., Indian seas, fresh-waters of trop. America ; Urolophus M. and H.,
Australian and Caribbean seas ; Pteroplatea M. and H., temp, and
trop. seas.
Fam. 6. Myliobatidae. Eagle-rays. Disc broad with large pectoral
fins which are not present at the sides of the head, but reappear as at the
extremity of the snout as a pair of detached fins ; teeth hexagonal, flat,
tesselated ; tail long, thin, whip-like ; viviparous. Myliobatis Cuv.,
snout with a soft prolongation with fin rays ; temp, and trop. seas ;
M. aquila L., mill-skate, whip-ray, eagle-ray ; Aetobatis M. and H.,
tropical seas ; Rhinoptera Kuhl, trop. and sub-trop. seas ; Dicero-
batis Blainv. (Aodon Lac.) (Cephaloptera Dum.), head with a forwardly-
pointing horn-like projection on either side ; attain great size ; temp,
and trop. seas ; D. giornae. Ceratoptera M. and H. (Mania Bancroft),
HOLOCEPHALI. 155
temp, and trop. seas, attain great size, 20 ft. wide. Last two genera
often called sea-devils. Extinct genera : Ptychodus Ag., Cretaceous ;
Promyliobatis Jaekel, Eocene.
The following extinct Palaeozoic families are placed here : —
COCHLIODONTIDAE, with several genera, from the Carboniferous Lime-
stone ; PSAMMODONTIDAE, from the Carboniferous Limestone ; and
PETALODONTIDAE, also from the Carboniferous.
Order 5 — HOLOCEPHALI.*
Without spiracle, with four clefts covered by an opercular fold
which contains a cartilaginous plate. The skull is autostylic, and
the notochordal sheath is unsegmented. There are two dorsal fins
and an anal.
The Holocephali differ from the Plagiostomi in the fact that
there are only four gill clefts (though there are five branchial
FIG. 8Q.—Chimaera momtrosa (Rdgne Animal).
arches). Moreover the gill apertures are covered by an opercular
fold, and the palatoquadrate bar is continuous with the skull
in its whole extent. They have a cartilaginous skeleton and
claspers on the pelvic fins of the male.
The mouth is small, ventral, and bounded by lip -like folds
supported by labial cartilages. The nostrils are confluent with
the mouth. The urogenital part of the cloaca is separate from
the rectum and opens behind the anus. The anterior dorsal fin
has a strong spine, on its front border, which is attached to the
fused neural spines of the anterior vertebrae. The tail is hetero-
oercal and prolonged in Chimaera into a long filament. There
* G. Good and T. H. Bean, Oceanic Ichthyology, Memoirs of the Museum
of Comp. Anat. Harvard College, 22, 1896. A. A. W. Hubrecht, Kent-
•niss des Kopfskelet d. Holocephalen, Niederldnd Arch. ZooL, 3, 1877.
S. Garman, The Chimeroids, Bull. Mus. Harvard Coll., 43, 1904.
156 SUB-CLASS ELASMOBRANCHII.
is on each side in the male a peculiar structure consisting of
a plate carrying teeth and sunk in a pit just in front of the
pelvic fin.
The heapLof the male is provided with an erectile hook-like
process projecting forwards over a groove and armed on its lower
surface with small spines. The skin is usually naked except
in the young, in which small placoid spines are found principally
in a double row on the back. The lateraljine may be an open
groove (Chimaera) or a closed canal (Callorhynchus). In
Chimaera the lips of the groove are approximated on the
head (Fig. 42), but remain apart at intervals giving the appear-
ance of openings. Ampullary canals are present as in Plagio-
stomes. The eyes are without lids.
The notochordal sheath is thick, cartilaginous and unsegmented,
It contains in Chimaera numerous calcified rings (four or five to
each segment). The arch tissue is segmented, except in the
front and in the whip-like tail, and does not meet round the
notochord sheath, except again at the front end and in the tail.
The neural arches consist of two pairs of pieces and a dorsal
piece for each pair of spinal nerves. The neural spine of the
anterior fused arch tissue is large and carries the anterior dorsal
fin, the basals of which are fused into one piece.
The skull is autostylic (p. 63), has rostral continuations and is
without the prefrontal fontanelle. It has a well marked mem-
branous interorbital septum, which is placed dorsal to the brain.
It articulates with the vertebral column by two condyles. The
auditory capsule is incomplete internally so that the space for
the membranous labyrinth is open to the cranial cavity. There
are three pairs of labial cartilages and the hyoid arch which
carries branchial rays is attached by ligament to the skull.
There are five branchial arches. The hyoid arch carries a
demibranch (uniserial), the first three branchials each have a
holobranch (biserial), and the fourth branchial carries a demi-
branch. There is no gill-cleft between the fourth and fifth,
branchial arches. The gill filaments are attached as in Plagio-
s tomes and do not project.
The paired fins and their girdles are formed on the Plagiostome
type, except that the two halves of the pelvic girdle are united
only by ligament.
The tgetharelg/rge and few in number consisting of strong
HOLOCEPHALI. 157
plates with cutting edges. (There are two pairs in the upper
and one pair in the lower jaw. ) The intestine has a spiral
valve and the anus isjnjfront of the urogenital aperture. There
is a conus arteriosus with three rows of valves.
The brain is characterised by the great length of the thala-
mencephalon, and the cerebrum is very small. The olfactory
peduncles are long and there is an optic chiasma. The pineal body
is as hi Plagiostomes, and there is an extracranial part of the
pituitary body lodged in a pit on the base of the skull. The
cranial nerves* are arranged in the usual manner ; the roots of
the fifth and seventh are more distinct than in most fishes.
There is a pericardio-peritoneal canal.
The urogenital organs appear to be similar to those of Plagio-
stomes. In the female the shell gland is large. In the male
there is a large vesicula seminalis, and the miillerian ducts are
complete tubes opening at each end.
Thex-are, oviparous andJiayjpi la,rge_eggs. The eggshell is
covered with hair-like processes, and may attain a great size.
They are probably laid in deep water, where the young are for
the most part found.
They have existed since the Jurassic period.
In many points of structure these animals depart from other
Elasmobranchs, and they have by some authorities been removed
from that group and raised to the rank of a sub-class with
affinities to the Dipnoi by the characters of their skull and teeth.
There is much to be said for this view, for they present affinities
to more than one piscine sub-class : to Elasmobranchs by their
placoid scales, cartilaginous skeleton, absence of membrane bones,
their gill-laminae, the open otocyst, the ampullary canals, the
form of the brain, the structure of the urinogenital organs, their
fin skeleton and claspers, and by their large eggs and develop-
ment : to the Ganoids by the separation between the urinogenital
sinus, and the alimentary canal, and by the incomplete internal
wall of the auditory capsule : and to the Dipnoi by the last-
named feature, by their autostylic skull, their peculiar teeth, and
their vertebral column. They differ from Elasmobranchs and
resemble Ganoids and Dipnoi in having an operculum, but they
stand by themselves in having only four branchial clefts and a
* F. J. Cole, Cranial Nerves of Chimaera. Trans. Eoy. Soc. Edinburgh,
38, 1896, p. 631.
158 SUB-CLASS ELASMOBRANCHII.
demibranch on the fourth branchial arch. It is clear from this
that the Elasmobranch characters strongly predominate, and
in our opinion they may fairly be retained as an order of that
subclass.
Chimaera L., snout soft, prominent, without appendage ; tail produced
into a fine filament ; deep water (200 to 1,200 fathoms) of coasts of
Europe, N. Pacific, Cape ; C. monstrosa L., King of the Herrings ;
attains 3 or 4 ft.
Hydrolagus Gill, like Chimaera, but three dorsals and caudal, and tail
without filament ; surface waters, N. Pacific.
Callorhynchus Gronov. Snout with a cartilaginous prominence ending
in a cutaneous flap ; S. Pacific, Cape ; egg-case 9 or 10 in. x 3 in.
Hariotta Goode and Bean. Snout elongated, no frontal clasper, anal
fin as cutaneous fold, deep water 700 to 1,200 fathoms.
Extinct genera*: Ischyodus Eg., Upper Jurassic and Lower Cretaceous ;
Ganodus Ag. ; Edaphodon Buckl., Cretaceous, Eocene, Oligocene ; Pachy-
mylus Smith, Upper Jurassic, etc.
The extinct families PTYCTODONTIDAE, known by teeth from the De-
vonian ; SQUALOBAJIDAE, known by its skeleton, from the Lias ; MYRIA-
CANTHIDAE, also known by skeletons from the Lias and Upper Jurassic,
are placed here.
* E. T. Newton, Chimaeroid Fishes of the British Cretaceous Rocks,
Mem. Geol Soc. U. Kingdom, 1878.
CHAPTER VII.
SUB-CLASS GANOIDEI. *
Fishes with a conus arteriosus, optic chiasma, free pectinate gills
and an operculum, abdominal pelvic fins, a spiral valve in the intes-
tine, an air-bladder, and without a processus falciformis and
choroid gland. The oviducts and urinary ducts unite and open by
a common urogenital aperture behind the anus. The skull is hyo-
stylic and is without a supraoccipital bone. The segmentation of
the ovum is complete, a pronephros is present in the larva and
abdominal pores are always found.
Very few of the characters mentioned in the definition are pecu-
liar to Ganoids : they are almost all found in Teleostei or Elas-
mobranchii. This fact coupled with the great variations of
structure found in the group points to the conclusion that the
sub-classes, Elasmobranchii, Teleostei, Ganoidei and Dipnoi are
the survival of a once great and continuous group of animals, a
large number of which have become extinct, leaving three groups,
Elasmobranchii, Teleostei and Dipnoi, each fairly compact and
showing but little variety of organization, and one, the Ganoideir
loose and heterogeneous with large gaps between the individual
members. Although it may fairly be held that by such forms
as Lepidosteus and Amia the Ganoids more nearly approach the
Teleostei than the Chondrostei do the Elasmobranchii ; we cannot
* J. Miiller, Ueb. d. Bau u. d. Grenzen der Ganoiden, Abh. d. Berlin
Akad. d. Wiss. 1844; id. Myxinoiden, op.cit. J. Hyrtl, Ueb. den Harn-
werkzeuge bei den Ganoiden, Wien Denkschriften, 8, 1855. Liitken, Ueb. d.
Begrenzung und Eintheilung d. Ganoiden, Palaeontographica, 22, 1872,
Huxley, ' The systematic arrangement of the fishes of the Devonian.
Epoch,' Mem. Geolog. Survey. London, 10, 1861 ; and 12, 1866. Tra-
quair, Ganoid fishes of the British Carboniferous Formations, Palaeontogr.
Soc. 1877. V. Wijhe, Visceral Skel. u. Nerven des Kopfes der Ganoiden u.
Ceratodus, Nied. Arch. Zool., 5, 1882, p. 207. Zittel, Grundzuge d. Palaeon-
tologie, Leipzig, 1895 (English Translation, Macmillan, 1902). Smith-
Woodward, Outlines of Vert. Palaeontology, Cambridge, 1898.
160 SUB-CLASS GANOIDEI.
agree with those zoologists who wish to unite the Ganoids and
Teleosteans into a single group, distinct from other piscine orders.
In this opinion we are in company with two of the greatest ana-
tomists of the last century, J. Miiller and F. M. Balfour. The
latter has expressed his view in words, with which we are in
entire agreement and which we quote here, because they appear
to express in the most judicial form the state of the question.
He says, " We do not recommend such an arrangement (union
of the Ganoids and Teleosteans) which in view of the great pre-
ponderance of the Teleostei amongst living fishes would be highly
inconvenient, but the step from Amia to the Teleostei is certainly
not so great as that from the Chondrostei to Amia, and is un-
doubtedly less than that from the Selachii to the Holocephali."
The scales present some variation in arrangement and struc-
ture. In the living Chondrostei they may be almost absent on
the body as in Polyodon, or arranged in rows as in Acipenser ;
not, however, forming a continuous cuirass except in the caudal
region. They frequently carry bony spines, which are without
any enamel cap. In some extinct Chondrostei they form a con-
tinuous cuirass, and have often the rhombic form typical of the
order. In Crossopterygii they form a continuous armour and
are either rhombic or cycloidal ; in the living forms it can be
shown that they are coated externally by ganoin and that in
some cases they carry spines which consist of cones of dentine
capped with enamel. In Lepidostei there is also a continuous
armour of rhombic or cycloid scales, and in the living Lepidosteus
it has been shown that these scales are coated with ganoin
(yavos sheen) and may, especially in the young state, carry one
or a number of small spines having exactly the structure of
the spine of a placoid scale.
In Amia the scales, which form a complete armour, are
Teleostean in character and consist of bony plates without ganoin.
Moreover it has been shown from a study of living forms that
the scales save for the toothlike projections which occur in Poly-
pterus and Lepidosteus are purely mesodermal products, and that
the ganoin which was formerly thought to be enamel is really
of the nature of vitrodentin and is formed by the scleroblasts *
of the dermis.
* Scleroblasts are cells which secrete a hard skeletal substance.
VERTEBRAL COLUMX.
161
3
Although the scales are dermal structures, they are said to be
frequently exposed on the surface in the adult. This, if true,
must be due to the fact that the overlying epidermis and dermis
have been rubbed off. This may frequently happen in the hand-
ling of animals during their preservation.
Vertebral column. In the Chondrostei the notochord is
persistent and its sheath is stout but unsegmented and unossified.
The neural and haemal arches on the other hand are segmented ;
they are attached to the sheath but do not extend round it. In
other living Ganoids (for the vertebral column of extinct genera
the reader is referred to the special accounts), vertebral bodies
are formed by the extension of the arch tissue round the sheath,
its chondrification, segmentation and ossification. In Poly-
pterus and Amia the
vertebral bodies are
amphicoelous as in
Teleosteans ; in Lepi-
dosteus they are con-
cave behind and con-
vex in front (opistho-
coelous).
In some extinct Ganoids
(Fig. 90A) bony plates
are found, corresponding
to each arch, on the
ventral side of the noto-
chord. They are called hypoeentra, and carry the haemal arches.
A corresponding plate, which may be composed of two pieces, is
found on the dorsal side, and called pleurocentrum. Such incipient
vertebrae are called half -vertebrae. They may, each of them, extend
completely round the notochord (Fig. 90s), as in the tail of the
living Amia, in which case one of them only carries the neural and
haemal arches. Ring-vertebra is the term used when the pleurocent-
rum and hypocentrum are joined to form a ring round the noto-
chord, as in the amphicoelous vertebrae of Polypterus, Teleostei, etc.,
in which the bony ring has thickened so as to constrict the notochord
in the middle of each vertebra. In Lepidosteus the arches are continuous
with the bony centrum. In all other Ganoids with bony centra the
arches are separated from the centra by persistent cartilage.
The caudal fin is diphy cereal in Polypterus. In other living
genera it is heterocercal. In Amia it is hemiheterocercal (ex-
ternally homocercal, internally heterocercal), and the dorsal
lobe of the caudal fin is reduced to the covering of fulcra.
z.-n. M
A B
FIG. 90.— A. Vertebra of Caiurv.s furcatus. B. Caudal
vertebrae of Enrycormus speciosus (after Zittel). 1
neural arch ; 2 the bifurcated neural spine ;3 hypo-
centrum ; 4 pleurocentrum ; 5 rib.
162 SUB-CLASS GANOIDEI.
The structure of the skull is very varied, but the cartila-
ginous cranium always contains cartilage bones and is invested
by membrane bones. The dorsal membrane bones are dermal
structures and are frequently in the adult exposed on the surface
in consequence of the superjacent epidermis and dermis having
been rubbed off (see p. 161). The suspensorium is always
hyostylic.
The shoulder girdle and pectoral fin skeleton presents great
variation, but on the whole inclines to the Teleostean type of
structure. In the Chondrostei and in Amia the pectoral girdle
is cartilaginous. In the other orders it is ossified very much as in
Teleosts.
In the Chondrostei and Crossopterygii there are three separate
membrane bones in relation with the shoulder -girdle, the supra-
clavicle, clavicle and infra-clavicle,* while in the other orders the
infra-clavicle is absent. In the pectoral fin the skeleton of
Polypterus is on the Elasmobranch type (rhipidostichous), in
extinct Crossopterygians on the Dipnoan type (rachiostichous
and mesorachic). In other orders the arrangement on the
whole is Teleostean.
The other anatomical characters of the Ganoids are (1) the
possession of a conus arteriosus with more than one row of
valves ; (2) the very general presence of a gill on the hyoid
arch supplied by a branch of the ventral aorta, or of a spiracle
(see below) ; (3) the presence of an air-bladder with pneumatic
duct ; (4) the union of the urinary and Mullerian ducts and their
opening by a median urogenital pore behind the anus ; (5) the
testis appears to be connected except in Polypterus with the
kidney by a testicular network ; (6) a spiral valve is present in
the intestine (small in Lepidosteus and Amia) ; (7) the optic
nerves form a chiasma ; (8) the openings of the nasal pits are
double as in Teleosteans ; (9) the processus f alcif ormis and choroid
glands are absent in Polypterus, Lepidosteus, and possibly in
other Ganoids ; (10) the scales are bony plates embedded in the
dermis, and frequently covered by a layer of peculiar substance
called ganoin. Ganoin is probably vitro-dentin : it used to be
* These bones are now often called supracleithrum, clei thrum and
clavicle respectively, on the view that the last-named alone is homo-
logous with the clavicle in the Amphibia and Amniota, . the cleithral
elements not being represented in these groups.
BRAIX. GILLS.
163
regarded as enamel. These scales in the young state and some-
times throughout life bear spines which project through the
epidermis and are formed of dentine capped by enamel (Poly-
pterus, Lepidosteus}. (11) The fins frequently, not always, possess
a single or double row of spine-like scales, called fulcra, on their
anterior edge (absent in Polypterus, Polyodon and Amia). The
dermotrichia are soft and segmented, and the pelvic fins are
abdominal. (12) They lay relatively small eggs which undergo
complete cleavage, and the young are hatched out as larvae
which differ in many respects from the adult and possess a prone-
phros as in Teleosteans. In Lepidosteus the medullary canal
arises as a solid keel-like projection of the ectoderm which
sub sequently
becomes hol-
low.
The brain
is on the
whole Teleos-
tean - like .
There is a
thin pallium
(Fig. 91) and
a val vul a
cerebelli and
the cerebrum
is undivided ;
though it
may be grooved externally so as to suggest a division into two
lobes.
The branchial apparatus presents remarkable variation. In
Spatularia (Planirostra edentula) there is no hyoid gill, but a
pseudobranch in the spiracle as in Acipenser. In Polypterus
there is no hyoid gill, nor spiracular pseudobranch. The spiracle
is present in Acipenser, Polyodon and Polypterus, but absent in
Scaphirhynchus, Lepidosteus and Amia. The following table
summarizes the matter :—
Hyoid gill, pseudobranch and spiracle . Acipenser.
Hyoid gill, pseudobranch* but no spiracle Lepidosteus.
* It is doubtful if the structure identified by Muller as pseudobranch in
Lepidosteus is really such.
FIG. 91. — Median section through the brain of Acipenser ruthenus
(from Gegenbaur, after Goronowitsch). Cb cerebellum ; ch
optic chiasira ; cp pineal body ; hy pituitary body ; pi pal-
lium with choroid plexus projecting in between the" third ven-
tricle z and the ventricle of the cerebrum V ; pi' roof of fourth
ventricle ; Sv saccus vasculosus.
1G4 SUB-CLASS GAXOIDEI.
Hyoid gill, but no pseudobranch or
spiracle Scaphirhynchus.
Hyoid gill absent, pseudobranch and
spiracle present Polyodon
(Spatularia).
Hyoid gill and pseudobranch absent,
spiracle present ..... Polypterus.
Hyoid gill absent ; pseudobranch and
spiracle also absent (4 double gills) . Amia.
In those forms (Polypterus and Polyodon) without hyoid gill
the ventral aorta still gives a branch to the hyoid arch.
Abdominal pores* are present in all living Ganoids. Their
external openings are placed on each side of the anus and they
open internally into the body cavity.
Pericardio-peritoneal canals are present in the Sturgeons as
single unbranched tubes ; they appear to be absent in other
Ganoids.
Of these characters which on the whole suggest Elasmobranch
more than Teleostean affinities, it will be convenient to treat the
urinogenital organs more fully at this point.
The urinogenital organs present many features of interest,
and as they differ in important points in the different members
of the group it will be necessary to describe them at some length.
In all of those, the development of which is known, there is a
pronephros in the larva, constructed on the Teleostean type, i.e.
it consists of one large malpighian body (Fig. 92, v) connected
by a convoluted tube (pr.n) with the anterior end of the longi-
tudinal duct (sd) of the future kidney. In Lepidosteus and
possibly in others, this body is connected with the peritoneal
cavity by a ciliated canal (/). In none of them does the kidney
show any differentiation into a meso- and meta-nephros, and
in all the oviduct (mullerian) joins the kidney duct of its side
posteriorly. Moreover mullerian ducts appear to be in all classes
present, generally in both sexes, and they present the peculiarity
of being short and opening into the body cavity at a point much
nearer the anus than in other groups in which they are found.
We have full knowledge of the urinogenital organs in two
* Bles, "Correlated distribution of Abdominal Pores and Nephro-
stomes in Fishes," Journ. Anat. and Phys., 32, 1898, p. 484.
URINOGEXITAL ORGANS. 165
Ganoids ; one of these is Lepidosteus of which we have a
description from the pen of Balfour,* and the other Polypterus
in which their structure has been recently elucidated by
Budgett.f
In Lepidosteus the kidneys extend forward from the anus
about three-fifths of the length of the body cavity (Fig. 93, Jc).
Anteriorly they are continuous with a band of lymphatic tissue
of a very similar appearance. The ureters (sg), which lie on
their ventral side and receive the openings of numerous collecting
tubes, enlarge posteriorly, and approaching each other coalesce
to form an unpaired vesicle (bl) which opens by a median pore
FIG. 92. — Diagrammatic view of the pronephros of Lepidosteus (from Balfour),
isolated and seen from the side, pr.n Coiled tube ; sd longitudinal duct of kidney ;
v malpighian body of pronephros ; / tube leading from v to the body cavity (peri-
toneal funnel) ; bv blood vessel of glomsrulus oi v.
on a papilla (ug) behind the anus. The ovary is a hollow sac,
attached about its middle to the oviduct and continued back-
wards and forwards from this attachment into a blind process.
The oviduct is a thin- walled tube, continuous in front with the
ovarian sac and opening behind (od) into the dilated part of the
kidney duct of its side. In the male the testis is lobulated and
the vasa efferentia pass in the mesorchium to the kidney, where
they open into a longitudinal canal. From the longitudinal
canal pass off tubules which open into the kidney tubules them-
selves. Near the testis the vasa efferentia are united into an
* Phil. Trans., 1882.
f Trans. Zool. Soc., 15, 1901, p. 323.
16(3 SUB-CLASS GAXOIDEI.
irregular network. No trace of the oviducts has been observed
in the male.
In Amia* there is a testicular network, and the posterior part of
the kidney is provided with nephrostomes. In the female the oviduct
opens into the body cavity.
In Polypterus the oviduct is short and opens anteriorly into
the body cavity, and posteriorly into the kidney duct just before
its union with its fellow. In the male the kidney duct dilates
behind and joins its fellow to form a considerable sinus which
receives the testis duct of each side and opens to the exterior
behind the anus. The testis is an elongated body almost as long
as the kidney, to the ventral side of which it is attached. Two
parts may be distinguished in it — an anterior dilated portion
which forms spermatozoa and is the functional testis, and a
posterior streak-like portion — the testis-ridge. — in which the
ug „
bl
FlG. 93 — Diagram of the urinogenital organs of an adult female of Lepidosteus (from Balf our
and Parker), od Right oviduct ; the od which is placed on the upper side of the figure
points a little to the "right of the opening of the oviduct into the dilated lower end of the
kidney duct ; ov ovary ; bl urogenital sinus : uq urogenital aperture ; sg kidney duct ;
the reference line goes a little too far in the figure ; k kidney, ly lymphatic organ. The
organs of the right side only are shown.
testicular tubules are few in number and do not form sperma-
tozoa. The testicular tubules, both of testis and testis-ridge,
open by numerous short ducts into the testis duct which is a
longitudinal canal extending the whole length of the organ close
to the ureter. In Polypterus then the testis tubules do not
communicate with the kidney tubules, but there is a special testis
duct which opens behind into the kidney duct at the point at
which the oviduct opens in the female. No trace of oviducts has
been seen in the male and there are no nephrostomes in the adult.
In the Sturgeon there is a testicular network in the male, as was first
shown by Rathke, and there are short mullerian ducts in both sexes open-
ing widely into the body cavity and behind into the kidney duct. In
the female the miillerian duct is of course the oviduct. Open mullerian
ducts have been seen in both sexes of Scaphirhynchus and Polyodon, but
a testicular network has not yet been seen in those genera.
* Jungersen, Zool. Anzeiger, 23, 1900, p. 328. '
CHONDROSTEI. 167
The Ganoids reached their greatest development in the Palae-
ozoic, Triassic and Jurassic periods. From the Cretaceous
epoch onwards they have gradually become less numerous, until
at the present day they are represented by a few widely scattered,
extremely isolated, and for the most freshwater genera. The
Ganoids are here divided into four orders — Chondrostei, Cross-
opterygii, Lepidostei and Amioidei.
Order 1. CHONDROSTEI.
Endo-skeleton largely cartilaginous ; head covered with bony
plates. Body naked or with rows of bony plates, or with rhomboid,
rarely cycloid scales. Operculum weakly developed, branchio-
stegals numerous, few, or absent; teeth small or absent. Infra-
clavicle present. Caudal fin usually heterocercal. One dorsal and
one anal fin, with fulcra. Paired fins non-lobate. Pelvic fins
with a series of basal cartilages. Lower Devonian to present time.
So far as the facts which can be made out from a study of
the extinct forms are concerned, this order agrees with the
Crossopterygians in the feebleness of the ossification round the
notochordal sheath (except Polypterus), and in the presence of
infra- clavicles ; it differs from them in the absence or absorption
into the body of the basal lobe of the paired fins, in the
heterocercal tail, and in the absence of jugular plates between
the rami of the mandible.
There are two living families, the Acipenseridae and theSpa-
tulariidae. The following remarks apply to them : —
The tail is heterocercal. The notochord is persistent and un-
constricted. Its sheath is thick, unsegmented, and entirely within
the elastica externa. The neural and haemal arches are seg-
mented (except in front) and placed upon the sheath, but are not
continuous with one another round it (fig. 94). There are inter-
calated pieces both in the dorsal and ventral arches, and there is
a longitudinal ligament on the neural arches. The haemal arches
of the two sides meet ventrally and enclose the dorsal aorta. In
addition they carry lateral projections which must be regarded
as the transverse processes. These meet ventrally in the tail
to enclose the caudal vein, so that in the caudal region there are
two canals, one for the dorsal aorta and a ventral one for the
caudal vein. The anterior part of the column is continuous
with the skull, and here the neural and haemal arches are not
168
SUB-CLASS GANOIDEI.
segmented. The notochord is continued into the base of the
skull to the pituitary fossa in Polyodon, but not in Acipenser.
In the Acipenseridae there are five rows of large scales with
projecting spines, * one dorso-median and two on each side
(Fig. 96). Between these are numerous small scale-like plates,
which frequently carry one or more spines. In the caudal
region these smaller plates, also carrying spines, are rhombic,
in contact, and regularly arranged. In Polyodon (Spatularia),
which is often described as naked, there are also small spine-
bearing scale-like structures. The scales are placed in the sub-
cutaneous tissue and are composed of bone (with bone corpuscles
-and branched processes, and in the larger scales haversian canals).
The spines are composed of a
similar substance in layers,
either with bone cells in their
lower portions or without them.
There is no enamel and appar-
ently no ganoin.
The cranium^ is massive and
largely cartilaginous, there being
but slight traces of ossification
(in the periotic region). As in
other Ganoids and in Teleostei
the inner wall of the otic capsule
is not developed. The roof con-
sists of almost continuous cartilage, but the fontanelles though
not conspicuous are not altogether absent. It is completely
covered by membrane bones which lie in the dermis. There
is a large parasphenoid and a single or paired vomer in the
floor.
There is a partially ossified hyomandibular and a symplectic
cartilage (Fig. 95) which suspend the mandibular arch. The
anterior ends of the pterygoids meet in a symphysis. The
visceral arches are partially ossified but the meckelian cartilages
are unossified. The hyomandibular carries an opercular plate
and the hyoid arch a branchiostegal ray. Membrane bones (a
* H. Klaatsch, Morph. Jahrb., 16, 1890, p. 146. O. Hertwig, ibid., 2,
1876, p. 373,
f Bridge, Osteology of Polyodon. Phil. Trans. 1878, p. 683.
FlQ. 04.— Lcteral view of the vertebral
column of Spatularia (from Wieders-
heim). Cs sheath of notochord ;
Ic intercalated piece ; Ob neural
arch ; Ub haemal arch ; Ps neural
spine.
CHONDROSTEI. 169
maxilla and dentary) are developed in connection with the jaws.
Teeth are entirely absent in the adult, but small teeth are present
in the young Polyodon and possibly other genera. There are
five branchial arches.
In the unpaired fins the fin rays (dermotrichia) are more
numerous than the interspinous supports (somactids), and the
ca-udal fin has fulcra in a single row. The pectoral arch is un-
ossified and the^two halves are not united ventrally. They are
covered by membrane bones; supra-clavicles, clavicles, and infra-
clavicles being present. The pelvic arch is absent, its place being
taken by enlarged basal cartilages of the fins as in Teleostei.
The paired fins are without a basal lobe (non-lobate), their whole
free portion being supported by dermal fin-rays. These are
carried by a row of cartilages of which the posterior is possibly
FIG. 95. — Cephalic skeleton of the sturgeon (from Claus after Wiedersheim) . Ro Rostrum;
i_ Cn nasal pit ; 0 orbit ; H m hyomandibular ; S symplectic ; Pq palatoquadrate ; M d
lower jaw ; Hy hyoid ; V foramen for vagus ; R ribs.
a basal somactid (metapterygium) and the others peripheral
somactids which have become articulated to the pectoral arch.
The anterior dermal fin- ray is enlarged and directly articulates
with the pectoral girdle.
The branchial apparatus presents remarkable variability. In
Acipenser there is a spiracle with a pseudobranch, and a hyoid
demibranch ; in Scaphirhynchus there is no spiracle or pseudo-
branch, but a hyoid demibranch is present. In Polyodon spiracle
and pseudobranch are present, but there is no hyoid gill. Each
of the first four branchial arches carries a double row of gill-
filaments and there is a cleft behind the fourth gill arch. In
Acipenser the inter-branchial septa are fairly broad. In
the conus there are three longitudinal rows of valves with three
or four valves in each row.
170 SUB-CLASS GANOIDEI.
Fam. 1. Acipenseridae. Sturgeons. With five rows of keeled plates
in the skin, elongated snout, small mouth without teeth, with four barbels
in front of the mouth, opercular and four double gills. Stomach without
blind sac. With fulcra on the dorsal lobe of the caudal fin. Dorsal and
anal fin with two rows of supports (axonosts and baseosts). Large fishes
in the seas and rivers of the northern hemisphere, feeding on small
animals and plants. Most are migratory (anadromous). Caviare is the
ovary of the sturgeon. Acipenser L. with spiracle. Scaphirhynchus
Heckel, without spiracles. Fossil remains rare ; an Eocene species
(A. toliapicus Ag.) is known, and isolated remains of scales from the
Upper Lias of Whitby (Gyrosteus) and from the Upper Chalk of Kent
(Pholidurus).
Fam. 2. Spatulariidae. Skin with small isolated scales, tail scaled as
in sturgeons, snout prolonged into a thin flat blade ; without barbels ;
with spiracle, without hyoid gill ; gills, 4 ; gill-rakers long, in a double
series on each arch, except on the fifth, which has only one series.
Air-bladder cellular. Jaws with fine teeth in young individuals. Fresh-
FiG. 96. — Aciyenser ruthenus (after Heckel and Kner).
waters of N. America and China. Polyodon Lac., Mississippi ; Pse-
phurus Giinther, Chinese rivers ; a fossil genus Crossopholis Cope, from
the Eocene of Wyoming.
EXTINCT FAMILIES.
Fam. 1. Chondrosteidae. Parietals and frontals paired ; near the
parietal a great squamosal. Jaw edentulous. Branchiostegal rays
present. Operculum small, sub-operculum large. Body naked ; the
dorsal lobe of the caudal fin with fulcra and covered with rhombic ganoid
scales. Chondrosteus Egerton, Lower Lias, England.
Fam. 2. Belonorhynchidae. Trias, Lias, may be placed here.
Fam. 3. Palaeoniscidae. Body elongated with rhombic, rarely cycloid
scales ; with operculum, sub-operculum and branchiostegal rays. In no
single genus are the osteological characters well known. Devonian to
Jurassic. Cheirolepis Ag., Devonian ; Palaeoniscus Blv., Upper Per-
mian ; Coccolepis Ag., Jurassic.
Fam. 4. Platysomidae. Deep-bodied fishes from the Carboniferous
to the Permian ; very similar to the Palaeoniscidae. Cheirodus M'Coy,
Eurynotus Ag., Platysomus Ag., Benedeniits Traquair.
The Catopteridae, Triassic, may be placed here.
CROSSOPTERYGII.
Order 2. CROSSOFTERYGII.*
Vertebral column ossified, or unossi-
fied. Tail diphycercal or hetero-diphy-
cercal (upper lobe of caudal fin weaker
than the lower lobe, Fig. 103). Paired
fins with scaled basal lobe which is either
pointed or rounded. In the former
case it is unibasal, rachiostichous and
mesorachic, in the latter case, found only
in living forms, the pectoral fin is
tribasal and rhipidostichous . In place
of the branchiostegal rays are two large
jugular plates between the rami of the
lower jaw, near which there are in many
palaeozoic forms a number of smaller
lateral plates and a median anterior
plate. Ganoid scales, rhombic or
cycloidal, cover the whole body and
tail. Dorsal fin either two in number ;
or if single, long or multifid. Devonian
to present time.
This order which was established by
Huxley f in 1861, is mainly based on
the form of the fin, which is fringed
with dermotrichia on both sides. It
is difficult to state any other charac-
ters peculiar to the living and extinct
forms, unless it be the two jugular
plates between the rami of the lower
jaw.
The following remarks apply to the
living Polypteridae :—
The scales of Polypterus are very
similar to those of Lepidosteus (see p. 177).
171
FIG. 97.— Cheirolepis Irailli ; re-
stored (except margin of fins)
by Traquair (from Snrith-
Woodwara), quarter natural
size.
They are
" Traquair, Cranial Osteology of Polypterus, Journ. Anat. and
Physiology, 4, 1871. Pollard, " Anatomy of Polypterus," Zool. Jahrb.,5,
t Preliminary Essay upon the systematic arrangement of the fishes
of the Devonian Epoch, Mem. Geol. Survey United Kingdom, 1861.
172
SUB-CLASS GANOIDEI.
attached to one another in much the same way and are
arranged in oblique rows. They are rhombic in form
and similarly covered by ganoin. The canals in the
deeper part of them, containing blood vessels, open on the
surface, but differ from those of Lepidosteus in being branched.
They are without spines and the remains of spines, except at
the bases and on the hinder surface of the pectoral fins and on
the plates overlying the shoulder girdle. They are covered by
soft skin in the adult, but this is frequently rubbed off in pre-
served specimens, leading to the view
that the scales are freely exposed in
the adult.
The vertebral column is completely
ossified ; the vertebrae are amphi-
coelous, as in Teleosteans, and carry
in the body two pairs of ribs, of which
the shorter and ventral pass between
the muscles and the peritoneum and
correspond to the ribs of other forms,
while the dorsal and larger pair lie
between the dorsal and ventral lateral
muscles. The body of the first verte-
bra is united to the skull, but the
arch and ribs are separate. The
cranium consists mainly of persistent
cartilage (Fig. 98) with a large fon-
tanelle in the roof and in the floor
(pituitary) and a few cartilage bones, of
which the most important are exoc-
cipitals which completely surround
the foramen magnum, opisthothic (~),
sphenoid (? sphenethmoid), postfrontal (8), prefrontal (9) and
a median ethmoid (^). There is a slender arcade of car-
tilage passing forward from the postfrontal to the anterior part
of the sphenoid cartilage.
The whole is invested dorsally by membrane bones, while
ventrally there is a parasphenoid which extends back beneath
the body of the first vertebra, and two vomers (as in Lepidos-
teus). The mandibular arch is very like that of Teleosteans : in
the upper jaw arcade (Fig. 100) are palatine, ectopterygoid,
-7
FIG. 98. — Dorsal view of the
u cartilaginous cranium of
Polypterus with the mem-
brane bones removed (after
Traquair).- 1 Ethmoid, 2
nasal opening, 3 sphenoid,
4 optic foramen, 5 occipital
bone, 6 foramen magnum,
7 opisthotic, 8 post-frontal,
9 pre-frontal.
CROSSOPTERfGII.
173
entopterygoid, metapterygoid and quadrate ; the lower jaw has
an articular and mento-meckelian cartilage bone and an angular,
splenial and dentary, the two latter being dentigerous. On the
upper jaw
1C. 'I A
1312 n
: /\ ,• 10
16
15
24 25
19
FIG. 99. — Side view of skull of Polypterus with membrane bones
(after Traquair). 1 Nasal opening, 2 premaxUla, 3 ethmoid, 4
accessory nasal, 5 os terminale, 6 nasal, 7 anterior suborbital,
8 posterior suborbital, .9 postfrontal, 10 frontal, 11 prespira-
cular, 12 spiraoular bones, 13 parietal, 14 post-spiracular, 15
supratemporal, 16 post-temporal, 17 operculum, 18 sub-oper-
culum ; 19 preoperculum, 20 quadrate, 21 jugals, 22. articular,
23 angular, 24 dentary, 25 maxilla.
are premax-
illae, max-
illae and
jugals (two).
The hyo-
m a n dibular
is ossified
and bent ;
there is no
symplectic.
There is an
ope rculum,
s u b o p e r-
culum and
a large bone
called preoperculum. There are also circumorbital bones and
pre- and post-spiracular bones (Fig. 99), as well as two bones
(12) — the spiracular bones — in the flap which covers up the
spiracle.
There are also three supra- temporals (15) and a post-temporal
(16) on each side. The membrane bones are in the skin and their
outer surfaces are smooth and tuberculated, and not exposed in
uninjured speci-
mens. The pre-
maxillae and
maxillae bear
teeth, and the
vomers, ptery-
goid and para-
sphenoid are
covered with
fine closely set
teeth.
The cartilaginous shoulder girdle is small and contains a scapular
and coracoid ossification ; it is overlaid by a series of clavicular
bones, of which the supraclavicle is attached to the pos t- temporal;
FIG. 100. — Side view of palatoquadrate, hyoman dibular and
opercular bones of Polypterus (after Traquair). 1 vomer,
2 palatine (small and not appearing in palate), 3 ectoptery-
goid, 4 entopterygoid, 5 quadrate, 6 subopcrculum, Jf
operculum, 8 hyomandibular, 9 metapterygoid.
174
SUB-CLASS GANOIDEI.
there is an infraclavicle (clavicle, see note, p. 1G2). The skeleton
of the pectoral fin is tribasal as in
Elasmobranchs ; it consists of three
basal somactids, carrying two rows
of peripheral somactids (r, r"} to
which the dermotrichia are attached
(Fig. 101). The pro- and meta-
pterygium are ossified, the meso-
pterygium is mainly cartilaginous
but contains an ossification (o).
The pelvic girdle is represented
by a small piece of cartilage (Fig.
102) to which the large ossified
basal somactid is attached. The
latter carries a row of ossified peri-
pheral somactids to which the der-
motrichia are attached. There are
no fulcra. There is a number of
dorsal fins in Polypterus, each
with an anterior spine ; and the
tail is diphycercal.
In Polypterus there
are three main longi- ,*
tudinal rows of valves
in the conus arteriosus with nine valves in each
row, and between these there are three incom-
plete rows of smaller valves (about forty-five in
all). Both ductus Cuvieri open into the
auricle. The spiracle is present, but the hyoid
gill and pseudobranch are absent. The ventral
aorta sends off a branch to the hyoid arch which
supplies the external gill of the larva. The
fourth branchial arch bears only one row of
filaments and has no slit behind it. The
stomach has a caecum and there is one pyloric
appendage. The air bladder is double and cel-
lular and its duct opens into the ventral wall of
the pharynx ; its blood supply is from the last
efferent branchial vessel and its vein joins
the hepatic. According to Budgett Polypterus is capable of
FIG. 101.— Skeleton of pectoral fin
of Polypterus (from Gegenbaur).
R propterygium, R' metaptery-
gium ; o ossification in meso-
pterygium ; r', r primary radials
(basal somactids) ; r" secondary
radials ; s fin rays.
Fia.
102. —
Pelvic girdle
p and skele-
ton of pelvic
fin of Poly-
pterus (from
Gegenbaur,
after v.
Davidoff). 6
basal somac-
tid ; r peri-
pheral somac-
tids ; ft trace
of pelvic
girdle.
CROSSOPTERYGII.
175
breathing air. The pituitary body retains its opening into the
buccal cavity through life.* The young Polypterus has an
external gill, which is attached to the operculum.
Classification of Crossopterygii, living and extinct.
Sub-order 1. OSTEOLEPIDA.
Notochord more or less persistent. Pectoral fins rounded or pointed,
unibasal. Nares on the lower surface of snout.
Fam. 1. Tarrasiidae. Axonosts and baseosts of median fins in simple
regular series, much fewer in number than the dermotrichia. Tarrasius
Traquair, Calciferous Sandstones (Lower Carboniferous) of Dumfriesshire.
Fam. 2. Holoptychiidae. Body covered with overlapping cycloid
ganoid scales ; vertebral column unossified ; pectoral fin with long pointed
scaled axis (mesorachic) ; tail hetero-diphycercal. Axonosts of each of
the dorsal and anal fins fused into a single piece with a broad distal
end, bearing three to six rod-like baseosts, which are much fewer than
and overlapped by the dermotrichia in all the median fins. Lateral jugular
Fio. 103. — Holoptychius flemingi, Devonian, Scotland, after restoration by Traquair, from
Woodward.
plates, clavicles and infra-clavicles present ; the teeth have a compli-
cated folded structure. Holoptychius Ag. (Glyptolepis, Platygnathus Ag.)
Devonian ; isolated teeth have been described as Dendrodus, Lamnodus,
Apedodus.
Fam. 3. Rhizodontidae. Like the preceding but with shorter pec-
toral and pelvic fins. Devonian, Carboniferous. Ehizodus. Strepsodus
Rhizodopsis, etc.
Fam. 4. Osteolepidae. Ring vertebrae in the caudal region, Devonian.
Osteolepis, Thursius, Diplopterus, Megalichthys.
Fam. 5. Onychodontidae, known only by fragments from the Devonian,
is placed here.
Fam. 6. Coelacanthidae. Notochord persistent, vertebral column un-
ossified. Axonosts of each of the dorsal and anal fins fused into a single
piece ; a series of axonosts, equal in number to the neural and haemal
spines present in the caudal fin above and below, each axonost directly
connected with a single dermal fin ray. Caudal fin diphycercal ;
air-bladder with ossified walls ; paired fins with short, obtuse axis ; only
one opercular bone. Lower Carboniferous to the Upper Chalk. Coela-
canthus Ag., Undina Miinst., Macropoma Ag., etc.
* Bickford, Anat. Anz., 10, 1895.
176 SUB-CLASS GANOIDEI.
Sub-order 2. CLADISTIA.
Notochord more or less constricted and replaced by ossified vertebrae.
Baseosts in median fins rudimentary or absent ; axonosts of dorsal fins
equal in number to the apposed dermotrichia. Pectoral fins di- or tri-
basal. Nares on the upper surface of the snout.
Fam. 7. Polypteridae. Body covered with rhombic ganoid scales ;
vertebral column ossified ; tail diphycercal ; pectoral fins tribasal ; two
jugular plates only ; dorsal fins numerous ; pulp cavity of teeth simple.
Polypterus Geoffr. (Fig. 104), with pelvic fins, rivers of North and
Equatorial West Africa ; Calamoichthys Smith, elongated and without
pelvic fins, rivers of Old Calabar and the Cameroons.
FIG. 104.— Polypterus bichir (from Claus).
Order 3. LEPIDOSTEI.
Body covered with rhombic or rhomboidal scales arranged in
oblique rows and articulated together. Caudal fin hemi-hetero-
cercal. Vertebral column in the most different degrees of
ossification. Unpaired, and sometimes paired fins with fulcra.
Branchiostegal rays numerous, and often a median jugular plate
Always four opercular bones ; between preoperculum and orbit
at least one row of postorbitals. Infraclavicle absent. Somactids
of the unpaired fins as numerous as the dermotrichia. Teeth
pointed or conical. The pelvic fins are without baseosts.
This order, which appears to be closely allied to the Palaeonis-
cidae on the one hand and to the Amioidei on the other, in-
cludes the living genus Lepidosteus. With the exception of
the Permian genus Acentrophorus, the extinct members are
found in the Lias, Jurassic, Lower Cretaceous, and Tertiaries.
The following remarks apply to the living Lepidosteidae.
The body is covered by rhombic scales articulated together
(see p. 177). The tail is hemi-heterocercal. The paired fins
are non-lobate, and all the fins bear paired fulcra. The jaws
are much elongated, forming a snout ; the premaxillae form most
of the upper jaw. Both jaws bear teeth, small and large, and
there are fine close-set teeth on the palatines and vomers. The
vertebrae are well developed and ossified, and have opisthocoelous
centra. The chondrocranium is large and cartilaginous with
LEPIDOSTEI. 177
embedded cartilage bones much as in the salmon, and is com-
pletely invested by membrane bones. The vomer is double.
There is a symplectic in the suspensorum, several bony elements
are present in the mandible, and the maxilla is divided trans-
versely into many bones.
The pectoral girdle is as in Teleosteans, with scapula and
coracoid ossifications and overlying clavicle. The pectoral fin
has one row of basal elements carrying the dermotrichia. The
pelvic girdle is absent.
In Lepidosteus * the scales of the trunk are arranged in oblique
rows which pass from above and in front backwards and ventral-
wards. The scales of a row are more closely connected with each
other than with those of neighbouring rows, in consequence of a
peg and socket articulation. Each scale has its anterior and
dorsal angle produced into a pro-
cess which fits into an excavation
under the next dorsal scale of the
same row, where it is attached
by a ligamentous band. The
centre of the scale is bored by
one or several canals which pass Fm lp5 * 4 portion of th*armour of
right through it and transmit
blood vessels. The scale con-
sists in its deeper portions of
bone with bone corpuscles and vertically directed fibres, which
are prolongations of large scleroblast cells at the surface (so-
called odontoblasts, they do not become enclosed) and of a
superficial layer of structureless dentine or ganoin, as it was
called by Williamson, which is only found on the exposed part
of the scale, and was formerly taken for enamel. In some
parts of the body (ventral side of head, investing bones of skull
and shoulder girdle, the fin scales) the scales carry one or a
number of small teeth, which consist of enamel, dentine with
fibres, and a pulp-cavity. In the young animal all the scales
carry teeth, with the dentine of which the ganoin of the scale
is continuous. The scales are developed as plates in the dermis,
* O. Hertwig and Klaatsch, op. cit. ; see also W. C. Williamson, On
the microscop. structure of scales, etc., of fishes, Phil. Trans., 1849 and
1851. Nickerson, Scales of Lepidosteus, Bull. Mus. Comp. Zoology r
Harvard, 24, 1893.
z. — II. N
178
SUB-CLASS GANOIDEI
the scleroblasts of which become successively included in the
scale to form the bone corpuscles. The ganoin is formed later
(in a fish of fifty-two months) by the cells on the upper surface of
the plate. The teeth are developed as in Selachians on a papilla
of dermis projecting into the epidermis. The cells of the papilla
form the dentine and those of the epidermis the small cap of
enamel. Some of the scales possess processes which indicate
where teeth were formerly attached.
.....Olf
There is no spiracle in the
embryo or adult, though there
is a pouch-like trace of one in the
embryo ; but the hyoid bears a gill,
dorsal to which is a structure called
by J. Miiller the pseudobranch.
This so-called pseudobranch is not
found in the larva. There are
four double gills, and a cleft behind
the fourth branchial arch.
The conus arteriosus possesses
eight * equally developed longi-
tudinal rows of valves, five in
each row. The ventral aorta gives
off on each side posteriorly two
branches, one to the third and
fourth branchial arches, and one to
the second ; anteriorly it also
gives off two, the posterior of
which goes to the first branchial
and the anterior to the hyoid.
The so-called pseudobranch ap-
pears to be supplied by arterial blood from the efferent
vessel of the first branchial arch, as in other fishes.
The left ductus Cuvieri opens into the sinus, the right
into the auricle. The stomach is without a blind sac and
there is a number of pyloric caeca and a small but distinct
pancreas. The intestine is coiled and has a spiral valve pos-
* Boas states, Morph. Jahrb. 6, p. 323, that the valves of four of these
rows are smaller than those of the other four. There seems to be some
variation in the valves of the conus of Ganoids.
— ce
— op.
— -cb
m o
FlQ.\106. — Dorsal view of the brain
of Lepidosteus (after Balfour and
Parker), cb cerebellum ; ce, ce an-
terior and posterior lobe of cere-
brum ; TO o medulla oblongata ;
olf olfactory lobes ; op,l optic
lobes ; v,th vesicle of thalamen-
cephalon.
LEPIDOSTEI. 179
teriorly. The air-bladder is single and opens into the pharynx
dorsally. It has a continuous central cavity opening on each
side into lateral chambers which are placed in the thickness
of the wall.
In Lepidosteus the cerebrum (Fig. 106) is divided into two
parts, an anterior and a posterior. The anterior part tapers
in front into the olfactory lobes and is double ; the posterior
part is single and its ventricle possesses a thin roof like that
of the thalamencephalon, with wilich it is continuous. The
dorsal part of its side walls, where they pass into the roof are
everted and thickened and form the prominent posterior cerebral
lobes (Fig. 106). The anterior part of the roof of the thalamen-
cephalon is produced dorsalwards into a large thin-walled
vesicle which projects just in front of the pineal body. The
cerebellum is of medium size and has a forwardly projecting
lobe.
FIG. 107. — Dapediits politus, restored with scales removed, quarter natural size, Lower 'Lias
(from British Museum Catalogue).
Fam. 1. Lepidosteidae. Body covered with thick, rhombic, ganoid
scales, vertebral column completely ossified, vertebrae opisthocoelous ;
tail heterocercal ; the snout is much elongated. Lepidosteus Lac., gar-
pikes. Fresh-waters of N. America and Cuba, one species is known
from China. Sluggish habit, voracious, valueless as food.
Extinct families.
Fam. 1. Stylodontidae. All fins with fulcra. Jaws and vomer with
several rows of teeth. Vertebral column composed of half vertebrae or
of ring-vertebrae. Upper Permian to Cretaceous. Acentrophorus Tra-
quair. Semionotus Ag., Dapedius de la Beche, a deep-bodied fish
(Fig. 107).
180 SUB-CLASS GANOIDEI.
Fam. 2. Sphaerodontidae. Very similar to preceding ; with obtusely
conical or chisel-shaped teeth. Trias to Chalk. Colobodus Ag., Lepi-
dotus Ag. (Fig. 108).
Fam. 3. Eugnathidae. Very similar to preceding ; elongated bodies ;
caudal fin homocercal or hemi-heterocercal ; Trias to Cretaceous.
Eugnathus Ag., Ptycholepis Ag., Caturus Ag., Strobilodus Way.
Fam. 4. Macrosemiidae. Macrosemius Ag., Ophiopsis Ag., Prop-
terus Ag., Notagogus Ag.
Fam. 5. Pholidophoridae. Pholidopleurus Bronn.
Fam. 6. Pycnodontidae. Body laterally compressed, high, oval ;
covered by rhomboidal scales, articulated together and strengthened
by a vertical ridge ; scales sometimes absent in the caudal region, rarely
absent altogether. Notochord persistent, without ossifications in its
sheath, but ribs, arches and spinous processes ossified. Caudal fin inter-
nally hemi-heterocercal ; fulcra absent ; pelvics small, anal and dorsal
Jong ; fulcra absent ; somactids of the unpaired fins equal in number to
FIG. 108. — Lepidotus minor, restored, one-fifth natural size, Purbeck'JBeds (from British
Museum Catalogue).
the segmented dermotrichia ; opercular apparatus reduced, often only
one opercular bone present. Dentition of oval, crushing teeth. The
chondrocranium often well ossified. Infraclavicles absent. Jurassic,
Cretaceous, Eocene. Gyrodus Ag., Mesturus Wagn., Mesodon Wagn.
(Fig. 109), Pycnodus Ag., etc.
Fam. 7. Aspidorhynchidae. Very similar to preceding, but with
ring-shaped or complete and biconcave vertebrae (pleurocentra and hypo-
centra never distinct). Caudal fin homocercal ; snout elongated and
pointed ; scales rhomboidal, unequal ; lower jaw with movable pre-
mandibular ; fulcr.a weak. Lower Oolite to Upper Chalk. Aspidorhynchus
Ag., Belonostomus Ag.
Fam. 8. Lepidosteidae. See p. 179.
Order 4. AMIOIDEI.
Body covered with thin cycloid or rhombic scales, overlapping,
but not articulating, without ganoin. Caudal fin internally
heterocercal, externally symmetrical (hemi-heterocercal). Vertebral
column with either half -vertebrae or completely ossified amphi-
coclous vertebrae, or without vertebrae, ossification extending from
AMIOIDET.
181
the arches into the notochordal sheath. Fulcra present or absent.
Branchiostegal rays flattened ; a median jugular plate. Teeth
pointed, conical. From the Lias onwards.
This order, which is close to the Lepidostei, contains the
single living genus Amia. It approaches more closely to the
Teleostei than any other ganoid fish, but it differs from them
FIG. ] 09.— Mesofon macropterus, restored, with cheek-plates removed, two-thirds
natural size. Upper Jurassic (after Smith Woodward), fr frontal, meth mesethmoid,
md mandible, op operculum, orb orbit, p.op prcoperculum, pa parietal, pmx
premaxilla, socc supra occipital, sq squamosal, v vomer. (The caudal region is
destitute of scales in this fish.)
in important features of the urinogenital organs and structure
of the heart, and alimentary canal.
Fam. 1. Pachycormidae. Extinct. Ethmoid region more or less
produced in front of the mouth ; vertebral column variable as in the
order. Fulcra present, branchiostegal rays numerous. Lias to Lower
Cretaceous. Pachycormus Ag., Euihynotus Wagn., Hypsocormus Wagn.
Fam. 2. Amiidae. Vertebral column ossified with complete amphi-
coelous vertebrae. The caudal region consisting of vertically divided
182 SUB-CLASS GANOIDEI.
half -vertebrae, of which one half (variously described as the anterior and
posterior) carries the arches. Fulcra absent. Tail somewhat heterocercal,
more so in the young.
The scales of Amia, which are thin, elastic and cycloidal, consist of a
superficial layer containing bone corpuscles, and a deeper layer containing
fibres. They thus closely resemble the scales of Teleostei, and are without
a superficial layer of ganoin (Klaatsch, op. cit., p. 179).
The skull* is decidedly Teleostean in its structure. The chondrocranium
is well developed and contains a few widely separate cartilage bones.
As in Lepidosteus, it is without fenestrae in the roof. From the fact that
two neural arches are attached to the basioccipital bone, it would appear
that the centra of the two first vertebrae are fused to the skull. The
investing bones of the dorsal surface, though closely applied to the carti-
lage, are dermal structures, and are for the most part not covered externally
by soft skin in the adult. The vomer is double and bears teeth. The
suspensorial apparatus is almost exactly similar to that typical of Teleos-
teans. The premaxillae, maxillae, palatines, and pterygoids also bear
teeth. There are four opercular bones, numerous branchiostegal rays, and
a median jugular plate, The shoulder girdle is cartilaginous and is over-
laid by the large clavicle. It carries one basal cartilage (metapterygium),
to one side of which the somactids, which carry the dermotrichia, are
attached. Spiracle, pseudobranch and hyoid gill are absent. There are
four double gills and a slit behind the fourth arch. The conus arteriosus
has three transverse rows of valves with four or five valves in each row.
The base of the ventral aorta is slightly swollen into a kind of bulbus. The
air-bladder is cellular and lung-like and opens by a duct into the dorsal
wall of the pharynx. Stomach with a blind sac, pyloric caeca absent.
The intestine contains a spiral valve. For urinogenital organs, see p. 166.
A single living genus Amia L., with one species, in the fresh waters of the
United States ; flesh valueless as food ; species are known in the Lower
Tertiaries of Europe and N. America. Megalurus Ag., with fulcra, from
the Upper Jurassic may be placed here.
Fam. 3. Oligopleuridae. Upper Jurassic to Upper Cretaceous. Oenos-
copu» Costa, Spathiurus Davis.
* Bridge, Cranial Osteology of Amia calva, Journ. Anat. and Phys.,
., 1877, p. 605.
CHAPTER VIII.
SUB-CLASS (AND ORDER) TELEOSTEL*
Fishes with a bony endoskeleton, distinct, usually amphicoelous,
vertebrae, a supraoccipital bone, pectinate gills, a branchial oper-
culum and usually a hyoidean pseudobranch. Without spiracle,
conus arteriosus, optic chiasma, and intestinal spiral valve. An
air-bladder is often present. The gonads are usually continuous
with their ducts, and the testes are not connected with the kidney.
The eggs are heavily yolked, but usually small, and the young are,
with a few exceptions, hatched in an immature condition and
undergo a larval development.
The Teleostei include the vast majority of living fishes. They
are found in freshwater as well as in the sea, and in some cases
they possess organs which enable them to exist in or to breathe
air (Anabas, Periophthalmus, fishes which live in foul or muddy
water, e.g. many marsh fishes).
The form of the body is exceedingly variable, most often it is
typically piscine, but it may be elongated and snake-like as in
the eels, strongly compressed laterally in the ribbon-fishes
(Trichiurus, etc.) and in the flat-fishes (Pleuronectidae), or the
vertical axis may equal or even exceed the longitudinal in
length (Orthagoriscus). The tail which is usually the principal
organ of locomotion is in the last-named modification so much
reduced that it appears to be absent, and in the sea-horses
(Hippocampus) it is without caudal fin and is used as a pre-
hensile organ.
The body is divided into head, trunk, and tail ; the gill-
opening usually marks the boundary between the head and
* See, besides the works of J. Miiller, Gxinther, Day, Jordan and Ever-
mann, Boulenger, Bridge, already cited, G. B. Goode and T. H. Bean,
" Oceanic Ichthyology," Memoirs of the Museum of Comparative Anatomy
at Harvard College, 22, 1896.
184 SUB-CLASS (AND ORDER) TELEOSTEI.
trunk, and the vent that between the trunk and tail. The mouth
is usually at the anterior end of the head,but it varies considerably
in form and position ; it may be anterior or superior (on the upper
surface), or inferior or lateral (extending along each side of the
head). The upper jaw may be formed by the premaxillaries
(intermaxillaries) and maxillaries or by the premaxillaries only,
and both jaws may be provided with tactile appendages called
barbels. The nostrils are usually double on each side, and in a few
cases (some eels) the anterior or lower opening perforates the
upper lip. The eyes are large, are usually without lids, and the
cornea is flat. In cave-fishes and in abyssal forms they may be
much reduced and even hidden beneath the skin, but in some
deep-sea forms they are enormously enlarged. The branchial
slits are hidden by the gill-cover, which is a fold of skin, con-
taining dorsally four flat bones, the opercular bones or opercles,
and ventrally a number of bony rods called the branchiostegal
rays. The branchial aperture or aperture of the space bounded
by the operculum is usually a slit of considerable dorso- ventral
extent, but in some cases it is much restricted, and in Sym-
branchus, the openings of the two sides coalesce in the middle
line. The space on the throat between the gill apertures is called
the isthmus. There is no spiracle. The actual gill-openings
themselves, i.e. the openings leading from the pharynx into the
space below the gill-cover are not tubular but simply slits,
separated by the rod-like branchial arches. These carry the gills
which are usually filiform and project freely. There are usually
two rows of them (holobranchs) on each branchial arch, projecting
like the prongs of a comb ; hence they are said to be pectinate
(Fig. 118). There are usually five gill-slits, but the last is always
smaller than the others, and is sometimes absent, in which case
the fourth branchial arch bears only one row of gill-filaments
(hemibranch). They may be still further reduced. There are
five branchial arches, but the last never bears filaments.
The hyoid never carries true gill-filaments, but it generally
carries them in a reduced form as a pseudobranch. In some
cases the pseudobranch is without a trace of filaments and has
the form of a red glandular patch. The vent is usually at the
junction of the trunk and tail, but it may be shifted far back on
the tail or far forward on the trunk. It consists of at least two
openings placed close together, the foremost being the anus
FINS. 185
and the hinder one the urinogenital aperture. The genital
aperture may, however, in some forms be separate from and in
front of the urinary.
The median fins are subject to considerable variation.
There are usually two dorsal fins, a caudal and an anal fin, but
there may be a single dorsal fin continuous round the tail with
the anal, or there may be a series of finlets in place of the dorsal
fin, and the anal may be multiple or absent. The paired fins are in
two pairs, the pectoral and pelvic (sometimes called ventral}.
Of these the pel vies are small, vary considerably in position
and are sometimes absent (fishes which live in mud) ; they may
be behind the pectoral on the abdominal surface in which case
they are said to be abdominal in position, or they may be below
the pectorals (thoracic] or in front of them (jugular}. In some
cases they coalesce and form a suctorial organ (Gobies) and in
some Blennies they are adapted for walking. The pectorals
are usually close behind the gill-opening and vary much in size.
They assist the fish in balancing and enable it to execute back-
ward movements. In some forms (Periophthalmus, Trigla9
Lophius, etc.) the pectoral fins are used for walking, and in the
flying fish (Exocoetus) they are enlarged to form parachute-like
organs. All the fins are supported by osseous fin-rays
(dermotrichia) which are for the most part jointed and flexible
(sometimes they branch peripherally), but in some cases
(Acanthopterygian fishes) more or fewer of the anterior der-
motrichia in the dorsal (anterior dorsal if there are two), anal,
and pelvic fins are unjoin ted and generally stiffened. Such
dermotrichia are called spines. The caudal dermotrichia are
always jointed, as are all the dermotrichia in the Malacoptery-
gian fishes. In some Malacopterygian fishes the posterior
dorsal fin is without jointed dermotrichia, but contains adi-
pose tissue only and delicate unjointed horny dermotrichia
resembling the embryonic dermotrichia ( actinotrichia) :
this is the adipose fin of certain Siluridae, Salmonidae, etc.
The dermotrichia of the ventral part of the caudal fin are
carried by the haemal arches, those of the other unpaired fins
by special skeletal rods — the somactids (p. 54) — lying in the
median fibrous septum separating the dorsal parts of the muscles.
These somactids of the Teleostean unpaired fin are often called
inter spinous bones.
186 SUB-CLASS (AND ORDER) TELEOSTEI.
The spines of the dorsal fin of Acanthopterygians can be raised or de-
pressed at will. In the depressed position the spines may cover one
another completely (homacanth), or they may be turned slightly to one
side or the other alternately (heteracanth).
The skin usually contains pigment and may be very brightly
coloured. Many fishes possess the power of changing their
colour in a protective manner according to their surroundings,
and in almost all the dorsal surface is darker in colour than the
ventral. The body is usually covered with scales, overlapping
one another in such a way that the posterior part of the scale is
free and covers the anterior part of the next scale behind. The
scales are thin plates of bone imbedded in the dermis, and are
more frequently absent from the head and fins than elsewhere.
They are absent in most eels and in fishes with electric organs.
The epidermis is soft and contains many mucous and pigment
cells.
The scales have a concentric striation and are of two kinds, cycloid
and ctenoid. In ctenoid scales the posterior free margin possesses denti-
culations which may extend on to the surface, whereas in cycloid scales
such denticulations are absent. In some cases the scales are enlarged
into great scutes (Siluridae, Lophobranchii, Plectognathi) and in Balis-
tidae they have the form of ossified papillae which project in a shagreen-
like manner. In Siluridae the scales may carry movably articulated
dermal teeth.
The scales of most Teleostean fishes are thin calcified lamellae, without
bone corpuscles, lying in a dermal sac. They are surrounded by sclero-
blasts which, as in Lepidosteus, form them and add to them during growth.
The outer portion of the scales is structureless, the inner contains fibres.
In some forms, scleroblasts of the upper surface are included and become
bone corpuscles, so that the scales consist of an outer part showing ordin-
ary bone structure and an inner consisting of connective tissue impreg-
nated with calcareous matter by the scleroblasts.
The spines which are present on the scales of some Teleostei, e.g. some
Acanthopterygians and Plectognaths, frequently contain a cavity which
suggests a pulp cavity. They may possibly be regarded as homologous
with the spines of Elasmobranchs, but without the enamel cap. The
spines of the hinder part of the ctenoid scales are due to the sculpture of
the surface and are not denticles.
According to the recent and as yet (March 1904) unpublished researches
of Marett Tims, the scales of Gadus consist of a number of small plates of
structureless bone (vitrodentine) lying close together on a fibrous basis.
In the young state each plate carries a small spine which does not reach
the epidermis.
The sense organs * (nerve eminences) of the lateral line are
* F. Leydig, Integument u. Hautsinnesorgane der Knochenfische, ZooL
Jahrb. Anat., 8, 1894, p. 1-152. W. Collinge, Sensory Canal System of
Teleostei, Proc. ZooL Soc., 1895, pp. 274-299. R. McDonnell, Lateral
line in Fishes, Trans. P. Irish Acad., 129, 1862, pp. 161-187.
PHOSPHORESCENT ORGAN'S. 187
usually enclosed in canals, but they may be unenclosed and only
protected by flaps of skin (Batrachus, Lophius, etc). Their
distribution, whether they are enclosed or not, resembles that
found in Elasmobranchs and is indicated on Fig. 42. When
they are enclosed in canals, the tubes which leave the canal and
open on the surface are simple, ending in a single external pore ;
or they branch considerably before reaching the surface and open
by several pores. The trunk part of the lateral line canal is
placed in the dermis and is usually without osseous supports,
but on the head the canals are either enclosed in small bones
which lie outside the skull bones, or they burrow in and are
protected by the bones of the skull and visceral arches themselves.
There may be accessory lateral lines in the tru?ik, placed on
the sides of the body near the dorsal and ventral middle lines.
There are no ampullary canals.
Many deep-sea fishes possess numerous shining bodies in the
skin resembling in their general features eyes.* It appears
probable that they are phosphorescent organs. They are
found either on the head near the eyes, on the lower
jaw, at the end of barbels, under the gill-cover, or in
rows in which they may be segmentally arranged along
the sides of the body, and sometimes in connection with
the lateral line. They vary considerably in structure from
being simply glandular patches of the skin which are supposed
to secrete a phosphorescent mucus to a state in which they
are more eyelike in appearance and possess a lens-like body
which, it is suggested, acts like the lens of a bull's-eye lantern in
concentrating the rays proceeding from the internal parts of the
organ. In the latter case a kind of tapetum can often be made
out at the back of the organ which appears to act as a reflector.
They are probably in all cases modified skin glands. It appears
probable that in many cases these organs are for the purpose
of enabling their possessors, which are generally provided with
large eyes, to see in the dark abysses of the ocean, but in some
cases no doubt they act as lures (when placed at the end of
barbels or far back on the body). In the case of Ipnops in which
* F. Leydig, Die augendhnlichen Organe der Fische. Bonn, 1881.
M. Ussow, Ueber d. Bau der sogennanten augenahnlichen Flecken etc.,
Bull. Soc. Nat. de Moscou, 1879. A. Gunther, Deep-Sea Fishes, in Chal-
lenger Reports, 22, 1887, and appendices by H. N. Moseley and R. v.
Lendenfeld.
188 SUB-CLASS (AND ORDER) TELEOSTEI.
there is no trace of eyes, optic nerve or olfactory nerve, and in
which the supposed luminous organs have the form of two
broad laminae on the upper surface of the head, and in other
deep sea forms in which the eyes are imperfect (e.g. the
Pediculati) they can only be of use as lures.
In the endoskeleton the primitive cartilage is largely replaced
by bone, but some cartilage, varying in amount in the different
forms, may persist.
The vertebral column is usually completely ossified and consists
of amphicoelous vertebrae (Fig. 34). The vertebrae are con-
nected by articulating processes placed on the neural arches.
In the trunk the centra carry transverse processes, which are
directed outwards, and ribs which are articulated to the centra
or to the base of the transverse processes (Fig. 34). In the tail the
centra carry complete haemal arches, which enclose a canal
containing the caudal artery and vein and are prolonged like
the neural arches into a median spine. In some forms a pair of
small bony rods — the inter-muscular bones, are attached to the
centra near the neural arches.
The vertebrae are arcicentrous, the notochordal sheath remaining
thin, but the skeletogenous tissue develops very little cartilage being
rapidly replaced by membrane bone in the centra as well as in the arches.
In most Teleosteans the end of the vertebral column is bent
dorsalwards, and is unsegmented, though the notpchordal
sheath is ossified to form a bony urostyle. The haemal arches
of this part of the vertebral column persist in a modified form
as the hypural bones, which carry the dermotrichia of the ven-
tral part of the caudal fin (p. 55). In such cases the tail
though symmetrical externally, is internally asymmetrical,
and is said to be homocercal (see pp. 55, 56). In a few forms
(Gadidae, etc.), the end of the vertebral column is not bent
dorsalwards, and the tail-fin is symmetrical internally as well as
externally (diphycercal). In these fishes the dermotrichia of
the ventral part of the caudal fin are carried by interspinous
bones, and it seems highly probable that the true tail-fin has
atrophied completely, as it has in some Heteromi, Syngnathidae,
etc., in which the tail tapers to a point and is without any trace
of a caudal fin, and has been secondarily replaced by a backward
extension of the dorsal and anal fins (p. 55). Such tails are
therefore secondarily diphycercal.
SKULL.
189
The skull is always hyostylic and possesses both mem-
brane and cartilage bones. It differs considerably in the
extent to which the primitive cartilage persists. In
many forms, e.g. the salmon, pike (particularly in the less
specialised, more ganoid-like fishes), a considerable amount
of cartilage persists and the cartilage bones are separated
Ztkl
Ethi
Sse
FIG. 110. — Cephalic skeleton of Perca fluviatilis (Kegne animal). Ac post-clavicles ; '-A
alisphenoid ; An angular ; Ar articular ; Brs branchio-stegal rays ; Cl clavicle ; Cvr cora-
coid ; D dentary ; Ekp ectopterygoid ; Enp entopterygoid ; Ethi median ethmoid :,} EtM
lateral ethmoid (prefrontal) ; Fr frontal ; Frp posti'rontal (sphenotic) ; Hm hyomandibular ;
Htf hyoid arch ; Jm premaxilla ; JOp interpperculum ; Mt-p metapterygoid ; MX maxilla ;
Oex epiotic ; Op operculum ; Os supraoccipital ; Pal palatine ; Par parietal ; POp pre-
operculum ; PrO prootic ; Ps parasphenoid ; Q quadrate ; S symplectic ; Sc scapula ;
SOp suboperculum ; Sq pterotic ; Ssc supraclavicle ; Vo vorner.
by wide tracts of intervening cartilage. In others, e.g. the cod,
the cartilage is almost entirely ossified. The cartilage is usually
deficient in the roof of the skull except in the occipital region,
in which a basi-, two ex- and a supra-occipital are developed.
The auditory region usually presents five separate cartilage bones,
the epiotic, opisthotic, prootic, the pterotic and the sphenotic
(postfrontal). The sphenoid region is feebly ossified : there
is always a small basisphenoid and sometimes an alisphenoid
190 SUB-CLASS (AND ORDER) TELEOSTEI.
and orbit osphenoid, and the anterior part of it generally acquires
a considerable vertical extension forming an interorbital septum
(absent in Siluroids, Cyprinoids, etc.). The ethmoid region
remains unossified, or at most has two bones — the lateral eth-
moids or prefrontals (Fig. 110 EM}. The membrane bones of the
roof are parietals (Par], large f rentals (Fr) and a bone over the
ethmoid (supraethmoidal or median ethmoid, Ethi). There
may be other bones, called nasals, over the ethmoidal region.
The parietals may touch in the middle line between the f rentals
and supraoccipital, or be pushed apart and separated by the
junction of the f rentals and the supraoccipital. In the floor
there is a large and important parasphenoid strengthening
the base of the skull and a vomer (Vo) underlying the
ethmoid region. The orbit is surrounded by a ring of
circumorbital membrane bones (not shown in Fig, 110),
of which the anterior is called the lacrymal. Premaxillae
(Jm) and maxillae (Mx) are present, and there may be a
jugal, but the maxillae are usually toothless and frequently take
no part in the formation of the edge of the mouth. The palatine
bar of the mandibular arch always presents osseous palatine,
pterygoid and quadrate elements : in front is the palatine
(Pal) often dentigerous ; then follows the pterygoid region
usually presenting three elements — the pterygoid (ectoptery-
goid), the mesopterygoid (entopterygoid Enp] and the meta-
pterygoid (Mtp) ; lastly comes the quadrate (Q) which gives
articulation to the lower jaw. The front (palatine) end of this
bar is attached to the ethmoid region, while the quadrate is not
attached to the cranium directly, but is supported by the
strong dorsal element (hyomandibular) of the hyoid arch. In
the lower jaws Meckel's cartilage persists, being ossified proxi-
mally as the articular (Ar), and ensheathed by the dentary
bone (D) distally : in addition there is often an angular element
(An). In the hyoid arch there is a powerful dorsal hyomandi-
bular elemen,t which presents two bones, the hyomandibular
(Hm) and the symplectic ($). The hyomandibular bone
articulates with the auditory region of the cranium and passes
ventralwards behind the metapterygoid, while the symplectic
lies distally and is closely applied to the quadrate. The rest
of the hyoid arch consists of three ossified pieces on each side
(Fig. Ill) — the epihyal (c), ceratohyal (6) and hypohyal. The
VISCERAL SKELETOX.
191
epihyal is joined to the cartilage interval in the hyomandibular
element between the hyomandibular and the symplectic
bones by a small osseous piece the interhyal (d), while ventrally
the hypohyal joins the large median, sometimes toothed
glossohyal. In connection with the hyoid arch is a number of
membrane bones — the opercular bones supporting the opercu-
lum, and the branchiostegal rays in the branchiostegal mem-
brane. The opercular bones are in connection with the dorsal,
hyomandibular element and consist of the operculum (Fig. 110,
Op) and preoperculum (POp), and sometimes of a suboperculum
FIG. 111. Hyoid apparatus and branchial arches of Perca ftunatUis (R£gne animal).
a, b c, d segments of the branchial arches ; the upper joints Ops are the superior
pharyngeal bones (pharyngobranchials) ; VI, Opi the inferior pharyngeal bones (reduced
fifth branchials) ; Cop median pieces (copulae) ; Kb branchiostegal rays; I = Zbg
hyoid arch ; // — V branchial arches.
(SOp) and interoperculum (JOp). The branchiostegal rays
(Brs) are attached to the lower part of the hyoid arch, partly to
the inner and partly to the outer side (Fig. Ill Rb). There are
five pairs of branchial arches. Of these the anterior four are
usually segmented into four pieces (Fig 111), the pharyngo-
(Ops=d), epi-(c), cerato-(6) andhypo-(a) branchials. More or
fewer of the pharyngo-branchials, which are not joined to the
skull or vertebral column, are united with one another to form
the so-called superior pharyngeal bone which generally bears
192
SUB-CLASS (AND ORDER) TELEOSTEI,
teeth (Ops). The hypobranchials, which may be wanting
in the fourth arch, are attached to a varying number of median
elements, the copulae or basibranchials (Cop). The fifth bran-
chial arch is reduced to a single rod on each side which is usually
strongly toothed, and the pair are called the inferior pharyngeal
bones (Opi) ; they are sometimes ankylosed to form a single
bone. The four anterior branchial arches bear small tooth-like
projections, in one or two rows, which act as strainers ; these are
the gill-rakers.
Pectoral and pelvic* paired fins are present, but one or both of
them may be absent.
In the pectoral girdle,
which is usually present
even when the fin is
absent, the primitive
cartilaginous c o r a c o-
scapular elements are
but slightly developed
and relatively > unim-
portant, while the
membrane bones (clavi-
cles t) are largely de-
veloped.
Flo. 112. — Bight pectoral girdle and fin off Gadus
(after Gegenbaur). c clavicle (cleithrum) ; b
supraclavicle (supracleithrum) ; a post-temporal ;
d post-clavicle ; / scapula ; e coracoid ; g basal
somactids of the fin ; h bony dermotrichia.
The coraco-scapular arches do not join ventrally and are
attached to the inner sides of the clavicles. They present two
bony elements — the scapula and coracoid (by some regarded as
precoracoid) with persistent intervening cartilage. The scapula
usually has a foramen, and there is sometimes a third bony
element placed dorsal to the coracoid and in front of the scapula
and called the mesocoracoid. The clavicle (cleithrum) is a
large membrane bone meeting its fellow ventrally under the
throat. To its dorsal end there is usually attached a smaller
supraclavicle (supracleithrum) which is connected dorsally with
a forked bone the post-temporal. This bone is attached to the
auditory region of the skull, by one prong to the epiotic and
by the other to the pterotic bone. Projecting back from the
* The pelvic paired fins are usually called ventrals.
•j- Called cleithra by some anatomists, on the view that they are not
homologous with the clavicles of higher Vertebrates (see notes, p. 162).
BRAIN. 193
upper end of the clavicle is a bony rod, the post-clavicle. There
is no infraclavicle. The skeleton of the fin consists of usually
five basal ossified somactids which are articulated with the
corac o-scapula, and of a row of small cartilaginous pieces
representing distal somactids. These are followed by the
dermotrichia, the anterior of which is continuous with the an-
terior of the basal somactids.
The pelvic girdle is always absent, its place being taken by a
large osseous basal somactid, commonly called the basiptery-
gium ; to this are attached a few small, partly bony, distal
somactids, which carry the dermotrichia.
The brain * of Teleosteans presents the following features.
FIG. 113. — Median longitudinal vertical section through the biain of the trout (from Gegen-
haur, after Rab-Riickhard). Aq aqueductus sylyii ; Bo olfactory lobe ; Cbl cere-
bellum ; Cc central canal of spinal cord ; Ccn anterior commissure ; Cho. optic nerves ;
Ci inferior commissure ; Glp pineal body ; Hy, Hy' hypophysis ; J infundibulum ; Not
olfactory nerve ; Pa pallium ; pf velum transversum ; Sv saccus vasculosus ; Too pia
mater on the dorsal side of the mid-brain ; Tl dorsal wall of mid-brain between the two
optic lobes ; tr crossing of the fibres of the fourth nerve ; Vc valvula cerebelli ; Vcm ven-
tricle of the cerebrum ; Vq fourth ventricle ; Vt third ventricle.
(1) The olfactory lobes are usually much elongated and
slender ; they are swollen at their free ends against the nasal
capsules and at their origin. The cerebral ventricle is continued
into the swollen base.f
* Rabl-Ruckhard, Das Grosshirn der Knochenfische, etc., Arch. f.
Anat. und Phys., Anat. Abt., 1883, p. 279-322. E. Baudelot, Rtcherches
sur le sy steme nerveux des Poissons, Paris, 1883. A. Schafer, Die morphol.
u. hist. Entwick. d. Kleinhirns der Teleostei, Morph. Jahrb., 21.
f There seems to be some difference of opinion as to whether these basal
swellings alone constitute the olfactory lobes, the slender prolongations
being only olfactory nerves. It has been suggested that in some fishes,
e.g. Salmon, this is the case, whereas in others, e.g. Cyprinoids, the
whole elongated structure is also part of the olfactory lobe.
Z — II O
194
SUB-CLASS (AND ORDER) TELEOSTEI.
(2) The cerebrum is not clearly marked off from the thalamen-
cephalon, and its roof is entirely composed of a thin gallium.
The latero-ventral parts are thickened into the great corpora
striata, which were formerly taken for the cerebral hemispheres
themselves. The ventricle of the cerebrum is entirely un-
divided, and the pallium or dorsal wall of it is not marked by a
groove (Fig. 114).
(3) The thalamencephalon is very inconspicuous and the optic
thalami are hardly if at all developed. The anterior part of the
thin roof is folded inwards in the usual way (Fig. 113 pf.). The
pineal body lies in the skull over the pallium ; it has folded walls
and appears to open by a narrow pore at its point of attachment
to the roof just in front of the posterior commissure. There is
no parietal organ. The floor
presents the usual structure ;
in front is the thickening caused
by the optic nerves, which sim-
ply cross after leaving the brain
and do not form a chiasma.
The infuridibulum possesses
lateral lobi inferiores, and is
provided posteriorly with a
glandular sac, the saccus vas-
culosus, opening into it by a
minute pore. The pituitary
body is solid and is attached
to the infundibulum in front
of the saccus vasculosus.
(4) The mid-brain presents the two optic lobes (corpora
bigemina) dorsally and contains a projection formed by the
wall of the brain at the junction of the optic lobes and cerebellum.
This is the valvula cerebelli (Fc), or fornix of Gottsche.
(5) The hind-brain is in the usual form, the cerebellum being
large and containing a prolongation of the fourth ventricle. It
projects back over the medulla oblongata. In some Teleosteans
(e.g. Gymnarchus, Mormyridae) the brain attains a very large
size, the cerebellum and sometimes the optic lobes being
especially well developed.
The spinal cord frequently ends in an oval or spherical swell-
ing. In some forms (Plectognathi) it is much reduced in length ;
FlO. 114.— Transverse section through the
cerebrum of the trout, through the line
xx in Fig. 113. Vcm and Vt Ventricle of
the cerebrum ; Cst corpus striatum ; Sm
pallium ; Gp pineal body ; PI choroid
plexus (after Rabl-Ruckhard from
Gegenbaur) .
NERVES. SENSE ORGANS. 195
e.g. in Orthagoriscus mola it is barely as long as the brain and
hardly reaches beyond the skull. In such cases it ends in a
slender filum terminale.
The central canal usually contains a fibre * (Reissner's fibre), which
extends from the anterior end of the optic lobes, with which it is continuous,
backwards along the whole length of the central canal. It consists of a
bundle of nerve fibres, and communicates with the tissues of the spinal
cord throughout its course. It appears to be absent in blind fishes.
In some Teleosteans (Ctenoldbrus, Pleuronectes, etc.) giant nerve cells f
are found in the posterior fissure of the spinal cord, their neurites passing
into the substance of the cord.
The cranial nerves i resemble in their general arrangement
those of other fishes.
The ramus ophthalmicus profundus if present is
much reduced. There is a dorsal branch of the fifth
nerve — the ramus lateralis accessorius or r. recurrens
trigemini — which receiving branches from the facial
and vagus passes dorsalwards in the cranium to
perforate the frontal bone. It then travels backwards
near the skin to supply the skin of the trunk near the
dorsal fin (sense-buds and pit-organs). It appears
to be composed partly of so-called communis (afferent-
visceral) fibres (ramus lateralis accessorius), and partly FioT 115. — Hori-
of lateralis fibres supplying pit-organs and derived from through the^eye
the facial. of Esox Indus
(from Claus). Co
cornea ; L lens ;
Sense organs. The olfactorv organ is Pf rrocessus fai-
ciformis ; CH
usuallv provided with two openings. campanula Hai-
leri ; No optic
The eve is distinguished bv the possession nerve; se ossm-
. . , cations in the
of a flat cornea and a sclerotic which is sclerotic,
frequently more or less ossified. The lens
is closely approximated to the cornea, the anterior chamber
of the eye being small. Traversing the vitreous humour, some-
what on the lower side of the eyeball, and extending from the
entrance of the optic nerve to the eye, is a band of tissue (a
process of the choroid coat) containing blood vessels and smooth
muscular fibres ; this is the processus falciformis. At its point
of attachment to the lens it is swollen into the so-called cam-
panula halleri. One of the functions of this structure is said to
be that it assists in accommodation for vision of distant objects,
* Sargant, Anat. Anzeiger, 17, 1900, p. 33. A similar fibre has been
described in Petromyzon.
t Sargant, Anat. Anzeiger, 15, 1898, p. 212.
J Stannius, op. cit. Cole, Gadus, Trans. Lin. Soc., (2), 7. Herrick,
Menidia, Journ. Comp. N enrol., 9, 1899.
196
SUB-CLASS (AND ORDER) TELEOSTEI.
by drawing the lens nearer to the retina. The eyes of fishes
when at rest are accommodated for vision of near objects, i.e.
the opposite of the condition in the eyes of the terrestrial
Vertebrates. There is a layer of tissue between the choroid
and sclerotic which contains crystals, the argentea ; and round
the entrance of the optic nerve between the same coats there
is in many Teleosts (those with a pseudobranch) a vascular
plexus of unknown function, called the choroid gland.
ass
cp
The eye-muscles are the
usual four recti and two
obliqui ; the former often
arise from a subcranial bony
canal the floor of which is
formed by the parasphenoid.
Movable eyelids are not
present, though there may
be a circular fold of skin round
the eye. In Anableps the
cornea is crossed by a hori-
zontal stripe which divides
the pupil, so that there
appear to be two pupils one
above the other.
The auditory organ *
consists of the membra-
FlG. 116.— Membranous labyrinth of Perca fluvia- noUS labyrinth and is
tilis, inner view (from Wiedersheim). aa anterior ..,
ampulla; ac auditory nerve; ae external, ap WltllOUt accessory StrUC-
posterior ampulla ; ass apex sinus superioris ;
ca anterior, ce horizontal, cp posterior semi-
circular canal ; de ductus cndolyni.phaticus ; I
lagena cochleaeti mn macula acustica neglecta ;
ms macula acusca sacculi ; mu macula ac. re-
cessus utriculi ; o otoliths of the recessus utriculi,
the saccule and the lagena ; pi papilla acustica
lapenae ; raa, rap, rl, rs, nerves to the am-
pullae of the anterior, and posterior semi-
circular canals, to the lagena, and to the
saccule ; rec recessus utriculi ; s saccule ; ss
sinus utriculi superior ; u utricle.
tures except in those
forms (Ostariophysi) in
which a chain of small
bones connects it with
the air bladder (see
p. 202). The membra-
nous labyrinth is con-
tained in the auditory region of the skull wall, but the cavity
in which it is placed is not shut off from the cranal cavity by
bone or cartilage. It is constructed on the usual plan, con-
sisting of a central chamber or vestibule and three semicircular
canals (Fig. 116). The vestibule is divided by a constriction
into two parts, an upper, the utricle (u) into which the semi-
* G. Retzius, Das Gehororgan der Wirbelthiere, Bd. 1., Stockholm, 1881.
ALIMENTARY CANAL. 197
circular canals open, and a lower the saccule (s), which possesses
a small posteriorly directed process (lagena) representing the
cochlea. The otoliths vary much in form in different fishes.
They occur in the utricle, saccule and lagena. That in the
saccule (the sagitta) is generally the largest and of a crystalline
structure. There is another small one (asteriscus) in the lagena,
and a third in the utricle close to the ampullae of the anterior
and horizontal canals (o). The ductus endolymphaticus is
present as a process of the saccule, but does not open externally.
The lateral line has already been described (p. 187). Its
sense organs are probably innervated by branches of the facial
and lateral line branch of the vagus as in other fishes, but this
has not been shown in all cases.
The alimentary canal is distinguished by the very general
presence of an air bladder, which must be regarded as an appen-
dage of the oesophagus, though it is often in the adult separate
from this ; by the presence of more or less numerous appendages
— the pyloric caeca, opening into the first part of the intestine ;
by the inconspicuous character of the pancreas, which in some
cases is even said to be absent ; by the absence of a spiral valve
in the intestine ; and by the absence of a cloaca common to the
alimentary canal and urinogenital organs.
The teeth * are usually well -developed, but in some cases are al-
together absent (some Lophobranchii, Coregonus). They may be
borne by the maxillary, premaxillary, palatine, vomer, dentary
bones, by the glosso-hyal and by the branchial arches, and rarely
by the pterygoid and parasphenoid. The maxilla is usually with-
out teeth, and does not always form part of the edge of the mouth.
The teeth are generally ankylosed to the subjacent bony
structures, but in some cases there is a ligamentous connection
of such a kind that they can be bent inwards when food is being
swallowed, but not in the reverse direction (some Gadidae,
Lophius, Esox). In a few cases they are implanted in sockets
(Sphyraena, etc.). As a rule teeth continue to be developed
throughout life from new germs (not from pre-existing germs),
placed behind the functional teeth. These come into function
and position as the old teeth are worn down and cast off. When
the teeth are implanted in sockets, the new tooth, though
* R. Owen, Odontography, London, 1840-15. C. S. Tomes, Dental
Anatomy, London, 1898.
198 SUB-CLASS (AND ORDER) TELEOSTEI.
developed behind the old one, comes to lie beneath it, so that
the succession is vertical.
The teeth are generally conical, and may be minute, slender and sharp-
pointed (villiform, e.g. Perch), or longer but very fine (ciliiform, setiform,
as in Chaetodonts). Larger conical teeth are termed card-like (rasp-teeth,
raduliform). In Goniodonts the teeth are bent on themselves like a
tenterhook. They may vary in shape in different parts of the mouth,
the anterior teeth being conical, and the posterior broad and molar-like
for grinding the food, as in the wolf -fish (Fig. 117), and many Sparidae.
In Sargus indeed the anterior teeth are incisor-like, and in Dentex there
are canine-like teeth. Small molar-like teeth are called granular,
In Labrus crushing teeth are borne by the upper and lower pharyngeal
bones. Compound teeth, which are found in the Gymnodonts and the
Scari,* are made up of a number of teeth which are developed successively
but are joined by cement when full grown and functional. They thus
present the appearance of teeth which continue to grow throughout life.
Pharyngeal teeth may be present on the superior and inferior pharyn-
geal bones. In the Cyprinoids the mouth is edentulous, and teeth are
only found on the inferior pharyngeal bones, which bite against a tubercle
on the basi-occipital. They
are also present on the edges
of the branchial arches, but
except in a few cases, e.g.
Orthagoriscus, in which they
are long and sharp, these gill-
teeth are little more than
horny excrescences, which
however are sometimes elon-
gated into setiform horny
processes — the gill-rakers.
FIG. 117.— Teeth of the Wolf-flsh, Anarrhichas lupux
(after Gunther).
There is usually on the
floor of the mouth a small non-muscular elevation which
represents the tongue ; it is supported by the glosso-hyal,
and is sometimes toothed. The oesophagus is a wide
tube, hardly if at all marked off from the stomach. The
stomach, which varies in form, is usually but slightly dilated
and is either U-shaped as in Elasmobranchs, or is provided with
a caecal prolongation of its cardiac portion and a short pyloric
region placed near the junction with the oesophagus (Fig. 37).
The intestine is usually slightly convoluted, is without a spiral
valve (though a trace of one may be made out in some genera),
and opens to the exterior by the anus. In some forms (e.g.
Tinea, Cobitis] the striped muscles of the oesophagus are con-
tinued over the stomach and intestine outside the smooth
* J. E. Boas, Die Zahne der Scaroiden, Z. /. w. Z., 32, 1879, p. [189-215.
RESPIRATORY ORGANS.
199
muscles. The pyloric caeca are tubular structures opening
into the first part of the intestine just beyond the pylorus ;
they vary in number from one to two hundred, and are very
generally present. The liver is provided with a gall bladder
which opens just beyond the pylorus. It generally contains
much oily matter, but in some forms the oil occurs in all
the tissues of the body and is not only a feature of the liver.
The pancreas,* the presence of which in Teleostei used to be
denied, is not usually a conspicuous
structure, though functionally of great
importance, especially in those Teleosts
in which the stomach is without gastric
glands. It is either embedded in the
liver or diffused in the mesentery, and its
duct opens in close connection with the
hepatic duct. In some forms (Salmo,
Gadus, Perca, Platessa, Brama, etc.) there
is a small gland opening with the bile
duct, which is possibly pancreatic.
The Thyroid t body is represented by
small reddish masses lying ventral to the
ventral aorta, and the thymus f is placed
at the dorsal ends of the last pair of
branchial arches.
The respiratory organs. — There is no
spiracle. The branchial apertures are
narrow slits and the tissue between them
has the form of an arch, not of a sep-
tum. In consequence of this the gills
themselves are filamentous, not lamellar
(Fig. 118). The external openings of the
clefts are covered by the operculum.
The gill-filaments are borne in a double
row (holobranch) by the four anterior branchial arches, the
last gill-aperture is smaller than the others, and the fifth
branchial arch never bears gill-filaments.
E. Laguesse, Structure, etc., du pancreas d'apres les travaux recents,
Journ. Anat. Phys., Paris, 30, 1894, p. 591 and 731. E. Goeppert, Die
Entwick. d. Pancreas Teleost., Morph. Jahrb., 20, 1893.
f F. Maurer, Schilddriise u. Thymus in Teleostier, Morph. Jahrb.,
xi., 1886, p, 128-75.
FIG. 118. — Transverse sec-
tion through a branchial
arch of Zygaena (right
hand) and of Gadus (left)
(after B. Hertwig, from
Wiedersheim). a and v
afferent and efferent
blood vessels, b skeletal
branchial arch, bll and
fro^posterior and anterior
demibranch together con-
stituting a holobranch,
h septum between two
branchial apertures in
Zygaena, r cartilaginous
branchial ray supporting
the same, z small tooth-
like tubercle (sometimes
elongated as a gill-raker)
in a double row on the
branchial arch of Gadus.
200 SUB-CLASS (AXD ORDER) TELEOSTEI.
A pseudobranch * is generally present on the posterior side of
the hyoid arch. It contains a rete mirabile and usually has
the form of short filaments or ridges. In some cases it is con-
cealed below the mucous membrane, and the organ may have
the form of a red, lobed swelling (so-called glandular pseudo-
branch or vaso-ganglion). Sometimes it lies so far from the
surface that it is quite hidden : indeed it may be covered by
fat and muscles and even by bone. It is sometimes absent,
and its absence appears to be very generally correlated with
that of the choroid gland. The function of the pseudobranch
is unknown ; it lies in the course of the greater part of the blood
supply to the eye (see below), and it is generally regarded as a
vestige of a hyoid gill.
Certain fishes, e.g. eels, can exist for some time out of water,
but those with large gill-apertures usually perish rapidly. In
some active fishes, e.g. the Scombridae, the temperature of the
blood is considerably higher than that of the water ; probably
it is always slightly higher, but we know very little on this
subject.
The Teleosts have usually five gill-clefts, but the fifth is always smaller
than the rest and is sometimes absent. In this case the fourth branchial
arch bears one row of filaments only (demibranch) or may be gill-less.
In some forms the gill-apparatus, both arches and gills, may be still more
reduced (Symbranchidae, Malthe, etc. ; in Amphipnous cuchia the second
branchial arch alone bears gill-filaments). In some Lophobranchii the gills
have the form of curious tufted processes.
Accessory respiratory structures are met with, especially in cases in
which the gill-filaments are reduced. Thus in Amphipnous there is a
lung-like vascular-lined sac, opening into the first gill-cleft, for breathing
air. In Saccobranchus there is a very similar sac. In Anabas scandens,
in which the gill-apparatus is complete, the superior pharyngeal bones are
honeycombed so as to form a laminated organ covered with vascular
mucous membrane to enable it to breathe out of water (Fig. 38). Accessory
respiratory organs are also found in the Ophiocephalidae, certain Siluridae
(Clarias, Heterobranchus, Heterotis], and in Chanos.
The air-bladder is present in most but not in all Teleostei.
It presents great variety of structure throughout the group.
In the Malacopterygii, Ostariophysi, Apodes, and Haplomi it
usually, but not always, opens into the alimentary canal (usually
into the oesophagus) on its dorsal side by the pneumatic duct
(laterally in JErythrinus), which may however be partly or
* Joh. Miiller, Vergl. Anat. der Myxinoiden, loc. cit. Maurer, Morph.
Jahrbuch, 9, 1883, p. 229.
AIR-BLADDER. 201
entirely occluded. In other Teleostei there is rarely * a ductus
pneumaticus in the adult, though such may be present in the
young form ; and the air-bladder is a closed sac. Inasmuch as
it develops in the embryo as a diverticulum of the oesophagus,
this closed condition must be regarded as secondary. In the
Clupeidae the ductus pneumaticus opens into the fundus of the
stomach and in the Herring there is a second duct opening to
the exterior on the left side of the reproductive aperture.
The air-bladder always contains gas which consists of nitrogen,
oxygen and a trace of carbonic acid. It lies dorsal to the ali-
mentary canal, and is usually closely adherent to the ventral
surface of the kidneys, lying between those organs and the
peritoneum, and in many Siluroids it is partly enclosed in
osseous capsules formed by the vertebrae. In some cases
however it projects into the body cavity, lying more or less
loosely. Its walls consist of connective and elastic tissue and
yield isinglass. Tufts of blood vessels in the form of retia
mirabilia (red bodies) covered by a glandular epithelium are
often present on its walls, and sometimes project into it, like
huge vascular glomeruli. These vascular bodies are absent
from the Ostariophysi and from most fishes which have a
pneumatic duct. They are however present in some of the
latter, e.g. the eel. The air-bladder may be coextensive in length
with the body-cavity, but it frequently extends as a single or
double prolongation some distance beyond into the caudal region
beneath the caudal vertebrae (Gymnotus, Ophiocephalus, etc.),
or forwards into (see below) or towards the head (Gadus, etc.).
Sometimes it is much restricted (some Siluridae, Pediculati,
Plectognathi, etc.). In some cases it is partially or completely
divided transversely into two or even more compartments
(Cyprinidae, Characinidae) ; more rarely it is divided longi-
tudinally (Arius}. In some forms it is so much reduced in size
that it almost escapes notice (some Siluridae and Cyprinidae).
It frequently gives off diverticula, which in the Sciaenidae and
Polynemidae are numerous and branched. As a general rule the
internal cavity is unbroken except for the partitions complete or
* An open pneumatic duct is said to be present in Holocentrum, Pria-
canthus, Caesio, etc. See Kner, Einiges iib. die Thymus bei Fischen u. d.
Schwimmblase der Stachelflosser, Sitz. Mat. Nat. Classe Akad. Wiss.,
Wien, 49, 1864, p. 455.
202 SUB-CLASS (AND ORDER) TELEOSTEI.
incomplete just referred to, and the lining may be smooth or
cellular (Clupeidae, etc.), but sometimes it is much broken up
and has spongy, lung-like structure (Heterotis, Gymnarchus,
and other forms).
In the Ostariophysi the anterior end of the air-bladder is
connected by a chain of small bones, which are probably de-
tached portions of some of the anterior vertebrae and are
called the Weberian ossicles,* with the wall of a chamber in
the skull wall enclosing a diverticulum of the membranous
labyrinth ; and in other cases anterior prolongations of the air-
bladder reach the skull and come into immediate contact with
the wall of the space in which the membranous labyrinth is
contained.
In the simplest cases (Myripristis, Holocentrum, Sparus, Sargus, etc.)
the two anterior horns of the air-bladder apply themselves to membranous
spaces in the bony wall of the occipital region containing the membranous
labyrinth. In many Clupeidae the slender anterior end of the air-bladder
enters a canal in the basi-occipital and divides into two narrow branches.
Each of these dilates within the bone and divides again into two, each of
which forms a spherical swelling. A process from the vestibule (utricle)
of the membranous labyrinth comes into contact with these vesicles ;
moreover, the vestibules of the two sides are connected by a transverse
canal. In the Ostariophysi, in which the connection is effected by a chain
of ossicles, a few of the anterior vertebrae are ankylosed together and
modified in certain of their parts, some of which are partially detached
to form the auditory or Weberian ossicles. These are four in number,
of which three, the tripus (malleus, Fig. 119, 11), intercalarium (incus, 9)
and scaphium (stapes 8) form a chain connecting the air-bladder with
the membranous labyrinth. In addition there is a fourth — the claus-
trum — partly dorsal to and partly in front of the scaphium, which, how-
ever does not form part of the chain, but simply lies in the wall of the
atrium (see below).
The first vertebra is represented by the centrum only which is distinct
from but firmly connected to the skull and the next centrum. The second
centrum (10) although it shows no marked sign of being composite, con-
sists of the completely fused centra of vertebrae -2, 3 and 4-. It is
therefore called the complex centrum. To the hind end of the complex
centrum the three next centra may be united, but these remain distinguish-
able. The saccule (15) of the membranous labyrinth gives off a process,
the ductus endolymphaticus (4), which unites with its fellow in the middle
line, and gives off posteriorly from the point of union a median sac, the
saccus endolymphaticus (5). The saccule and saccus lie in excavations
of the basioccipital bone, called respectively the foveae sacculi (10) and
the cavum sinus imparis (14). These are partly separated from one
* E. H. Weber, De aureetauditu hominis etanimalium,Fars I.,De aure
animalium aquatilum, Leipzig, 1820. T. W. Bridge and A. C. Haddon,
The air-bladder and Weberian ossicles in the Siluroid Fishes, Phil. Trans.,
184, 1893, p. 65-333.
AIR-BLADDER.
203
another and from the cranial cavity by bony plates, but they open into
the cranial cavity in front. The foveae sacculi (16) end blindly behind,
but the cavum sinus imparis opens behind into two laterally-placed
chambers the floor of which is formed by the basioccipital, the sides and
roof by thick fibrous walls. These chambers are the atria sinus imparis
(13). To the outer wall cf these is attached a process of the scaphium (S),
the anterior of the three ossicles. Of these, the posterior or tripus (11)
is by far the largest, and is inserted behind into the fibres of the anterior
chamber of the air-bladder ; laterally it has a process articulating with
the complex centrum, and anteriorly it is connected by a strong ligament
— the interossicular ligament (12) — to the scaphium. In this ligament
and between the
tripus and scaph-
ium, is the inter-
calarium (8). The
tripus and inter-
calarium are partly
enclosed in a thin-
walled fibrous sac,
containing a deli-
cate fibrous net-
work and called
the saccus para-
vertebralis. The
air-bladder is
divided into a n
anterior and pos-
terior chamber, of
which the anterior
is usually especially
distensible, and in
the Siluridae comes
into close contact
with the skin on
each side. The pos-
terior division is
generally divided
into two by a
longitudinal septum
which frequently
gives off incomplete transverse septa,
into the anterior chamber.
FIG. 119. — A view from above of the cranial floor and anterior
vertebrae of Macrones ntmurus, semidiagrammatic (after
Bridge and Haddon). The brain has been removed, and the
bone cut awav, so as to expose more completely the mem-
branous labyrinth. 1 sphenotic, 2 prootic, 3 pterotic,
4 ductus endolymphaticus, 5 saccus endolymphaticus,
6 epiotic, 7 exoccipital, 8 scaphium, 9 intercalarium, 10
complex centrum, 11 tripus, 12 interossicular ligament,
13 atrium sinus imparis, 14 cavum sinus imparis, 15 sacculus,
16 fovea sacculi, 17 ductus sacculo-utricularis, 18 utricle.
The ductus pneumaticus opens
Striped muscles are frequently present in the wall of the air-
bladder (species of Trigla, Batrachus, Pogonias, Zeus, and others).
Sometimes there are extrinsic muscles passing from the ventral
surface of the vertebral column on to the air-bladder (species of
Gadus, Diodon, Tetrodon, etc.).
The blood supply of the air-bladder is arterial from the system
of the dorsal aorta, either from the efferent branchial vessels,
from the coeliac artery or from the dorsal aorta. In Gym-
204 SUB-CLASS (AND ORDER) TELEOSTEI.
narchus the efferent vessels of the third and fourth branchial
arches go exclusively to the air bladder (Hyrtl). The veins
join either the system of the posterior cardinal, or the hepatic,
or the portal.
The air-bladder is extraordinarily variable in its occurrence.
It is entirely absent in some families, e.g. Blennidae, Pleuro-
nectidae, Symbranchidae. It may be present in some genera of
a family and absent in others, or even in different species of
the same genus.*
Several functions f have been ascribed to. the air-bladder ; it
has been said to be hydrostatic, a resonator, sound producing,
and respiratory. There can be but little doubt that it is a
hydrostatic organ : J its function appears to be to keep the
weight of the fish equal to the weight of the volume of water it
displaces. Thus if the fish sinks, its body is compressed and
the specific gravity is increased. To meet this the air-bladder
slowly secretes gas, which distends the bladder and so restores
the specific gravity of the fish to its former point. Further,
when the fish rises, its air-bladder becomes distended and its
specific gravity diminishes. The fish consequently has some
difficulty in preventing its body rising to the surface. To meet
this, the superfluous gas is slowly absorbed and the air-bladder
becomes reduced in bulk so that the specific gravity of the fish
returns to its normal point. In the Ostariophysi the reduction
of pressure causes the fish to expel the gas through its pneu-
matic duct, but this does not always occur in other fishes with
pneumatic duct, though possibly it does so in some cases. In
fishes without pneumatic duct the only way in which the super-
fluous gas can be removed is by absorption. With regard to
the process of secretion, it takes place so slowly that it would
not be worth while for a fish to change its depth unless it meant
the change to be of some duration. Moreover, Biot,§ and more
recently Moreau, have shown that the gas secreted is mostly
oxygen. The gas in the air-bladder of fishes taken near the
surface contains nitrogen, oxygen, and a trace of carbonic acid
(not more than 1 or 2 per cent.). The nitrogen in such cases is
* See Stannius, Handbuch, 2nd edit. loc. cit., p. 221.
f Vide W. Sorensen, in Journal of Anatomy and Physiology, 29, 1895,
p. 109, et seq.
J A. Moreau, Recherches exp. s. 1. functions de la vessie natatoire,
Ann. d. Sci. Nat., 4, 1876.
§ Memoir es d. 1. Societe d1 Arcueil, 1, 1807.
AIR-BLADDER. 205
considerably in excess of the oxygen, which amounts to from
9 to 20 per cent. In fishes taken from deeper water the per-
centage of oxygen increases, to as much as 87 to 90 per cent, in
fishes taken from a great depth. Further, if the air-bladder
be artificially emptied, the fish sinks to the bottom, but it
slowly recovers by gas-secretion ; the gas so secreted is richer in
oxygen than air. At the same time nitrogen must also be
secreted, and sometimes appears to be the only gas secreted.*
Recently Bohr f has shown that section of the vagus prevents
the secretion of gas into the air-bladder.
The evidence that it acts as a respiratory organ is very slight.
Many fishes swallow air, but there is nothing to show that the
air is taken into the air-bladder. In some cases however it
has been shown (e.g. by Budge tt, op. cit., in young Gymnarchus)
that the fish dies if it is prevented from coming to the surface
to take in air. It has however been suggested with more
probability that the oxygen secreted into the bladder may
serve as a store when the fish enters water in which the supply
of oxygen is too small.
In some fishes, e.g. the Ostariophysi, in which the posterior
chamber is non-distensible and often enclosed by bone, while the
anterior chamber is distensible and connected by ossicles to the
membranous labyrinth, and in other fishes (see above) in which
the air-bladder is in connection with the ear, it has been surmised,
though not in any way proved, that the air-bladder acts as a re-
sonator in intensifying sound vibrations and transmitting them to
the auditory apparatus. On this view the Weberian apparatus
may be of use in increasing the acuteness of hearing. It has
also been suggested that it acts as a sound-producing organ, as
a consequence of the incomplete septa and membranes which
project into it being set in vibration by a movement of the con-
tained air, caused by contraction of the extrinsic and intrinsic
muscles which are contained in its walls. This suggestion rests
on observation, for many fishes possess the power of producing
sound (grunting, drumming, hissing, etc.), as many Sciaenidae,
some Siluridae (Doras, Platystoma, etc.), Trigla gurnardus,
Dactylopterus volitans, Malapterurus electricus, and many others ;
and in some cases the sound has actually been detected
* See Hiifner, in Arch. f. Anat. und Physiologic, 1892, p. 54.
t C. Bohr, Influence of section of vagus on gas secretion in air-bladder,
Journ. of Physiology, 15, 1894, p. 494-500.
206 SUB-CLASS (AND ORDER) TELEOSTEI.
proceeding from the air-bladder in fishes just removed from the
water and opened. It appears that sounds may be produced
in some fishes without special air-bladder muscles by the activity
of muscles, with the fascia of which the air-bladder is in close
connection (Peristedion cataphractum, Trigla lyra, Sciaena
aquila, etc.).
Vascular System. The heart is without a conus arteriosus,
and is usually separated from the ventral aorta by two semilunar
valves only, though there is sometimes a small third valve. In
some Clupeids it is said * that a trace of a small conus provided
with striped muscles may be made out, and in Butirinus (Albula)
there are actually two rows of valves (two large and two small
in the proximal, and two large in the distal row).
The ventral aorta presents at its ventricular end a swelling,
the bulbus arteriosus, due to the thickness (elastic tissue and
smooth muscular fibres) of its walls at this point. It gives off
branches to the four anterior branchial arches, which usually
bear gills.
The ventral aorta does not as a rule give off branches to arches which
are without gills, but in some cases with deficient posterior gills (Sym-
branchus, Amphipnous, etc.) the afferent vessel from the ventral aorta
is present and passes round directly into the efferent vessel, so that
venous blood is conveyed into the dorsal aorta. As an example, we may
mention Amphipnous, the first branchial of which has no gills ; the second
has a few filaments ; the third has a transparent fringed membrane, and
the fourth has no gills. The breathing organs are two sacs filled with
atmospheric air and placed over the upper ends of the branchial arches ;
they open into the branchial cavity between the dorsal end of the hyoid
and first branchial arches. The ventral aorta gives off a branch on each
side, which passes to the fourth branchial arch and joins its fellow to form
the dorsal aorta ; it then gives off small branches to the second and third
branchial arches and to the air-cavities, the blood from which is returned
in two trunks which join the dorsal aorta.
The blood after passing through the gills is collected by the
efferent branchial arteries, of which one leaves each gill-bearing
arch. These fall into the two roots of the dorsal aorta, which
anastomose in front dorsal to the parasphenoid bone and con-
stitute the so-called circulus cephalicus (Fig. 120, cc). The
circulus cephalicus gives off anteriorly the internal (at a) and
external (b) carotid arteries, and receives an anastomosing
branch from the hyoidean artery (vh) ; posteriorly it gives off the
* J. E. V. Boas, Morph. Jahrb., vi., 1880, p. 527.
VASCULAR SYSTEM.
207
two subclavian arteries, and on the right side the large coeliac
artery (r). The hyoidean artery (vh) is a continuation of the
ventral end of the efferent vessel of the first branchial arch on to
the hyoid, up which it runs in a dorsal direction to supply the
pseudobranch (/&). The efferent vessel of the pseudobranch
208 SUB-CLASS (AND ORDER) TELEOSTEI.
(ef) anastomoses with its fellow of the opposite side and then
passes round the external carotid to the choroid gland, a rete
mirabile in the choroid coat round the entrance of the optic nerve
into the eye. When the pseudobranch is not present, there is
no choroid gland. In Gymnarchus the efferent vessels of the
third and fourth branchial arches do not join the dorsal aorta
but pass to the air-bladder.
The blood of the choroid gland supplies the choroid coat. The iris
and sclerotic are supplied by the external carotid. The efferent bran-
chial vessels give off small vessels for the nutrition of the branchial arch
tissues, and near their ventral ends they give off vessels for the ventra
part of the body, the neighbouring parts of the head, and even in some
cases the heart. The hyoidean artery which supplies the pseudobranch
is an example of this system of arteries.
The dorsal aorta is frequently closely adherent to the ventral wall of
the vertebral column, so that the latter appears to form part of its wall.
It may be swollen at intervals, and in some forms (Esox, Clupea, Salmo,
Silurus, etc.) a fibrous elastic band projects into its cavity. The principal
branches are subclavian, which may come off from the circulus cephalicus,
the coeliaco-mesenteric which frequently gives off the air-bladder vessel
and a posterior mesenteric.
The veins are arranged in the usual piscine fashion. The left
posterior cardinal is often smaller than the right and appears as
a small branch of the latter coming from the anterior part of the
kidney ; or the right vein may alone be present, lying almost in
the middle line and receiving branchlets from each side. A
renal-portal system appears to be present in most Teleosteans.
The hepatic-portal vein may receive tributaries from the air-
bladder, the gonads (Perca, Bhnnius, Cyprinus, Osmerus, etc.),
and the ventral body wall (Salmo, Alosa, Clupea, etc.), though
these veins more generally open into the posterior cardinals.
The body-cavity has the usual piscine arrangement. The
pericardium is completely separated from the general body-
cavity. Paired abdominal pores opening at the sides of the
anus are absent in most Teleosteans, but they are found in the
Salmonidae and Mormyridae, though not universally. They
must not be confused with the pore-like oviducts of female
Salmonidae, etc. (see below).
The urinary organs are paired streaks of kidney substance
* M. Weber, Morph. Jahrbuch, 12, 1886, p. 336. Jungersen, Arb. a, d.
Zool. Inst. Wurzburg, 9, p. 93.
URINOGENITAL ORGANS.
209
D
R
placed oil the ventral side of the vertebral column between it
and the air-bladder.
They have a great longitudinal extension, frequently reaching
from the head to the end of the body-cavity, or even in some cases
extending into the caudal region. Their front ends are enlarged
into the so-called head-kidneys. The head-kidney, as was
shown by Balfour, consists of lymphatic tissue which occupies
the place of the pronephros of the larva. There are two
longitudinal urinary ducts which unite
posteriorly to form the single ureter.
This structure, which frequently has a
bladder-like dilatation, passes ventral-
wards on one side of the air-bladder
to open externally behind the anus, or
into the rectum, into which the genera-
tive duct may also open (some Sym-
branchii, Plectognatki, Pediculati), or, in
the Pleuronectidae, on a papilla placed
asymmetrically on the coloured side of
the body. Nephrostomata are never
present.
The generative and urinary open-
ings, whether separate or united, fre-
quently open on a papilla which may be
of some length (Blenniidae, Gobiidae,
etc.). In Rhodeus the opening of the
oviduct is prolonged in the breeding
season into a tube, by means of which
the female deposits her ova in the
shells of living bivalves (Fig. 123). The
ovaries are usually double, rarely single,
saccular bodies the walls of which are continued into the short
median oviduct which opens between the anus and the urinary
opening, or with the latter. In some Teleosteans the ovaries are
separate from their ducts, and the ova are dehisced into the body-
cavity whence they escape by two funnels which join to form a
short tube which opens to the exterior usually between the anus
and the ureter (Salmonidae, Muraenidae, etc.). In viviparous
forms development takes place in the ovaries or in the oviduct.
The testes are paired saccular bodies, and are apparently always,
z-n. p
7e
TIG. 121.— Kidneys of- Salmo-
iario (after Hyrtl). D ductus
Cuvieri; R kidneys; U
ureter ; Ur efferent duct of
bladder ; Vs bladder-like
dilation ; Vs subclaviau vein.
210 SUB-CLASS (AND ORDER) TELEOSTEI.
continuous with the short duct which either opens in the same
position as in the female, or joins the ureter, so that there
is a median porus urogenitolis behind the anus.
In the viviparous forms fertilisation is effected by an in-
tromittent organ, which is usually formed by the urogenital
papilla. A few Teleosteans (Serranus, etc.) are hermaphrodite.
The ova fall into the body-cavity and escape by porelike oviducts in the
Galaxiidae, Hyodontidae, Nolopteridae, Muraenidae and Salmonidae.
In Fierasfer there is said to be a pronephros in the adult, and the pos-
terior part of the kidney is not developed.
The ova are always provided with soft shells and vary con-
siderably in size ; amongst the largest are those of Gymnarchus
(10 mm.) and of Arms (5 to 18 mm.). They may be deposited
singly (salmon, trout, etc.), or they may be agglutinated to-
gether by a substance secreted by the walls of the oviduct. In
freshwater forms they either adhere to some foreign body or are
deposited in nests ; in marine forms they are either attached to
foreign bodies or float freely in the surface waters of the ocean,
or sink to the bottom as in the herring. Most fishes breed once a
year at a definite period, but some breed more than once, and
in some the breeding period is much prolonged — as in the cod
and herring.
Care of the brood by the female is often found (Aspredo,
Solenostoma, Cichlidae, see systematic part) ; in the male it is
more frequent (by nests in Gymnarchus,* Heterotis, Coitus,
Gafttrosteus, Cyclopterus, Antennarius, Ophiocephalus, Callichthys,
etc. ; in Arius the eggs are carried in the pharynx of the
male, in Lophobranchs in a pouch on the abdomen).
The segmentation is meroblastic and the germinal layers arise
by delamination. The cerebro-spinal cord is formed as a solid
keel-like thickening of the ectoderm,which subsequently becomes
hollow. The young are hatched at an early stage arid undergo
the remainder of their development as larvae. The larvae have
a pronephros and considerable remains of the yolk-sac. The
Teleostean pronephros is characteristic, in that the portion of
the body-cavity containing the glomerulus is quite cut off from
the rest and is in relation with the pronephric duct by one body-
cavity opening only.
* Budgett, Breeding Habits of some W. African Fishes, etc., Trans.
Zool. Soc., 16, 1901, p 115.
HABITS. 211
Teleosteans frequently undergo remarkable changes of form
in their growth. This is a marked feature of the group, and
leads to some difficulty in the recognition of species. As ex-
amples may be mentioned the Pleuronectidae, Cyttidae,
Muraenidae, Xiphiidae, Plectognathi. In many cases the young
are so different that they have been described as distinct genera.
Moreover, Teleostean fishes are often highly variable under
the influence of changed conditions (variation in acquired char-
acters), particularly with regard to colour, both of skin and flesh.
The change in the colour of the skin is due to the pigment cells
( chroma tophors).
Secondary sexual differences are usually present. The male
is generally smaller than the female, and some of its fin-rays or
fins may be prolonged. The male is often more brightly coloured
in the breeding season, or its skin may become warty.
Hybridism is also known to occur (Serramcs, Pleuronectidae,
Cyprinidae, Salmonidae, etc.).
Some fishes are very long-lived (carp and pike to beyond 100
years), and growth frequently appears to be somewhat indefinite
and to continue for a long time. Fishes which rapidly a,ttain to
their full size (e.g. sticklebacks) are said to be shortlived.
A few fishes have been domesticated and transported to
different parts of the globe (carp, Crucian carp, tench, goramy),
and certain species of salmon and trout have been acclimatised
in countries in which they are not indigenous (see accounts of
families).
Marine fishes are usually extremely sensitive to changes of
temperature, freshwater fishes much less so. It is said that the
carp will survive after being frozen in a block of ice. A modified
hibernation has been observed in some Cyprinoids and Muraen-
oids in cold weather, and many tropical fishes (Siluroids,
Labyrinthici, Ophiocephaloids, etc.) pass the dry season in a
torpid state in hardened mud.
The flesh of many fishes is poisonous, and in unknown waters,
especially in tropical seas, great care must be exercised in select-
ing fish for food.
The wounds caused by the spines of many fishes are poisonous.
This is generally due to the poisonous nature of the mucus which
covers the body, but it may be caused by special poison glands,
as in Synanceia, Thalassophryne.
212 SUB-CLASS (AND ORDER) TELEOSTEI.
There is a considerable number of marine fishes which occasionally
wander into freshwater and ascend rivers (e.g. Sciaenidae, Pleuronectes,
species of Clupeidae), and a smaller number of freshwater fishes which
occasionally descend into the sea (some species of Salmo, of Siluroids,
of Coregonus, and pre-eminently the Gastrosteidae and Cyprinodontidae) ;
but most of these are inhabitants of the brackish water. They must be dis-
tinguished from those fishes which migrate for the purpose of spawning.
Such are of two kinds ; there are the anadromous fishes which ascend
rivers to spawn in freshwater, as the salmon and the salmon-trout, some
Clupeids, etc., and katadromous fishes, like the freshwater eel, which
descend to the sea to spawn. There are many clear cases of marine fish
which by geological changes have been retained in freshwater basins ;
such are Coitus quadricornis, in the large lakes of Scandinavia ; species
of Gobius, Blennius and Atherina in the lakes of N. Italy ; Comephorus
in the depths of Lake Baikal.
The classification of the Teleostei adopted here is essentially
that of Mr. G. A Boulenger, F.R.S., to whom I am greatly in-
debted for having allowed me to see proofs of his work before
its publication. It is as follows :*—
Sub-order 1. MALACOPTERYGII (SALMONICLUPEIFORMES).|
2. OSTARIOPHYSI (CYPRINISILURIFORMES).
„ 3. SYMBRANCHII (SYMBRANCHIFORMES).
„ 4. APODES (ANGUILLIFORMES).
„ 5. HAPLOMI (ESOCIFORMES).
.. 6. HETEROMI (DERCETIFORMES).
,: 7. CATOSTEOMI (GASTROSTEIFORMES).
Tribe A. Selenichthyes.
,, B. Hemibranchii.
„ C. Lophdbranchii.
„ D. Hypostomides.
„ 8. PERCESOCES (MUGILIFORMES).
„ 9. ANACANTHENI (GADIFORMES).
10. ACANTHOPTERYGII.
Tribe A. Perciformes.
„ B. Scombriformes.
„ C. Zeorhombi (Zeirhombi formes).
„ D. Kurtiformes.
. „ E. Gobiiformes.
,, F. Discocephali (Echinei former).
„ G. Scleroparii (Trigliformes).
,, H. Jugulares (Blennii formes}.
* Boulenger, Ann. and Mag. Nat. Hist. (7), 13, 1904, p. 161.
t The names in brackets are those used in the fish-gallery of the
British Museum.
M ALACOPTERYGII. 213
Tribe I. Taeniosomi (Lophotiformes).
Sub-order 11. OPISTHOMI.
„ 12. PEDICULATI (LOPHIIFORMES).
„ 13. PLECTOGNATHI (BALISTIFORMES).
Tribe A. Sclerodermi.
,, B. Gymnodontes.
The old group Physostomi (with a ductus pneumaticus to the air-
bladder), which is sometimes referred to in the preceding pages,
included, roughly speaking, the Malacopterygii, Oslariophysi,
Symbranchii. Apodes, Haplomi, Heteromi (in part), and Perce-
soces (in part), of the above classification.
Sub-order 1. MALACOPTERYGII (SALMONI-CLUPEIFORMES)-
Soft-rayed fishes with the anterior vertebrae simple, unmodi-
fied, and without auditory ossicles ; symplectic present or absent ;
opercular bones distinct ; pharyngeal bones simple above and
below, the lower not falciform. Pectoral arch suspended from the
skull ; mesocoracoid always well developed. Maxillary bone
forming part of margin of upper jaw ; no barbels. Supra-
occipital sometimes separated from the frontals by the parietals.
Gills 4, a slit behind the fourth. Air-bladder if present with
a pneumatic duct. Dorsal and anal fins without true spines.
Pelvic fins abdominal, sometimes absent ; scales usually cycloid,
sometimes ctenoid ; occasionally absent. No developed photo-
phores. Adipose fin present or absent. This sub-order of
Teleostei is nearest to the Ganoids.
Fam. 1. Leptolepidae. Extinct. Upper Lias to Lower Cretaceous;
vertebral centra nearly complete, pierced by the notochord ; without
fulcra ; scales cycloid. Leptolepis Ag., Thrissops Ag.
The Pholidophoridae (p. 180), Oligopleuridae (p. 182), and the Archaeo-
maenidae, all extinct, are placed here by Smith Woodward and Boulenger.
Fam. 2. Mormyridae.* Body and tail scaly ; head scaleless ; upper
jaw formed by the two premaxillaries which are fused, and by the maxil-
laries. Sub- and very small inter-operculum present ; supraoccipital
separated from frontals by parietals. On each side of the skull there is a
large cavity leading into the interior and covered by a thin bony
lamella. They are without pharyngeal teeth. All the fins are well
developed in Mormyriis, caudal, anal and pelvic fins are absent in Gym-
narchus. No adipose fin. Pectorals directed upwards. Pseudobranch
absent, gill-apertures reduced to a short slit. Air-bladder simple, com-
municating with the ear. Two pyloric caeca. A series of pores along
* Kolliker, Bericht v. d. zootom. Anstalt zu Wurzburg, 1849. Hyrtl,
Denkschr. Akad. Wiss. Wien, 1856, xii. p. 1. ErdL, Munchner Gelehrte
Anzeigen. Boulenger, Poissons du Bassin du Congo, 1901.
214 SUB-CLASS (AND ORDER) TELEOSTEI.
the base of the dorsal and anal (if present) fins. f. w. of tropical
Afr. They possess an electric organ on each side of the tail with feeble
electric functions, consisting of modified muscle- tissue. The snout fre-
quently of strange shape ; eyes often reduced. The brain is remarkable
for its size ; 10 genera. Mormyrus L., teeth in rows along
the middle of the palate and the tongue ; M. oxyrhynchus Geoff., venerated
by the ancient Egyptians ; Hyperopisus, Mormyrops ; Gymnarchus Cuv.,
Nile and W. Afr. rivers, eel-like, each jaw with incisor-like teeth ;
air-bladder cellular, very extensible, duct with sphincter at oesophageal
opening ; lays very large eggs ; the gills of the embryo project beyond
the gill-openings. Gnathonemus.
Fam. 3. Clupeidae. Body covered with scales, head naked ; supra-
occipital in contact with frontal. Abdomen frequently compressed into
a serrated edge. Maxillaries (of three pieces) and premaxillaries both
enter into upper jaw. Opercular apparatus complete. Adipose fin
absent, dorsal not elongate, anal sometimes very long. Stomach with
blind sac, pyloric caeca numerous. Gill openings usually wide. Pseudo-
branch usually present. Air-bladder simple, large, communicating with
the ear. Principally coast fishes ; none from the deep sea ; may enter
f. ws. communicating with sea ; temp, and trop. zones. Many
fossil forms. Engraulis C. et V., anchovies, upper jaw prominent ;
mouth with a very deep cleft ; eyes covered by skin ; E. encrasicholus L.
(Anchovia J. and E.), the anchovy, abundant in Med., also
taken in E. Channel ; Cetengraulis Gthr. ; Stolephorus Lac. ; Coilia
Gray ; Dussumieria ; Etrumeus ; Chatoessus C. et V. (Dorosoma Raf.%
C. Amer., Aust., E. Ind., Japan. Clupea Cuv., herrings, upper
jaw not projecting, eyes with free lateral adipose lids, more than
60 species, most used as food, but some trop. species poisonous ;
C. harengus L., the herring, incredibly prolific, whitebait consists
chiefly of the young of the herring (and sprat), the air-bladder opens
into the stomach, and also on the left side near the anus,* the eggs are
attached to stones, etc.; C. pilchardus Walb. (Clupanodon Lac.), the
pilchard (the young is the sardine), equally abundant in Brit. Channel,
on coast off Portugal and in Med. ; C. sprattus L., the sprat,
in Norfolk sold as anchovies ; C. alosa L. (Alausa, Alosa), the shad or
allice-shad, coasts of Eur. ascending rivers ; C. finta, the twaite-shad.
Other Clupeoid genera are Clupeoides, Pellonula, Clupeichthys, Pellona,
(Ilisha), Pristigaster, Chirocentrodon, Pomolobus, Sardinella, Opisthonema,
Brevoortia, Opisthopterus, Odontognathus, Pristigaster ; Chanos Lacep.
wi£h accessory branchial organf in a cavity behind the gill-cavity, Indo-
Pac., 4 ft., edible.
The following genera may be placed here : Elops, Megalops (M. atlan-
ticus, the tarpon), Albula (Butirinus) with a trace of the conus (with two
rows of valves) in the heart ; Pterothrissus (Bathythrissa), deep sea, Japan.
Fam. 3a. Hyodontidae (moon eyes), f. w. fish of N. America,
no oviducts ; Hiodon, Le Su.
Fam. 4. ' Alepocephalidae. Deep-sea fishes approaching the Sal-
manoids ; without adipose fin or air-bladder. Phosphorescent spots
none or small. Stomach curved, without blind sac ; pyloric caeca in
moderate number. Pseudobranch present. Alepocephalus, Mitchillina,
Bathytroctes, Talismania, Conocara, Platytroctes, Aleposomus.
* Weber, " De aure et auditu," 1, 1820, vii., 63.
f J. Miiller, Bau u. Grenzen d. Ganoiden, p. 75.
MALACOPTERYGII. 215
Fam. 5. Notopteridae, with one genus Notopterus, f. w. of E. Ind.
and W. Afr.
Fam. (5. Osteoglossidae. Body covered with large mosaic-like scales ;
head scaleless, its integument confluent with the bone ; dorsal fin on tail
and opposite anal ; gill openings wide, pseudobranch absent ; air-
bladder simple or cellular, stomach without caecal sac, pyloric append-
ages two. Eggs fall into body cavity. Large f. w. fishes of the
tropics. 4 genera. Osteoglossum Vandelli, S: Amer. ; Ara-
paitna Mull., Brazil and Guyanas ; Heterotis Ehr., trop. Afr.; Sclero-
pages, Australia, E. Ind. Arch. Excluding the E. Ind. Archipelago,
the distribution of this family is the same as that of the Dipnoi.
Heterotis niloticus forms a nest and the young larvae have external gills.
Fam. 7. Pantodontidae. One genus, f. w.,W. Afr., pectorals very large.
Fam. 8. Ctenothrissidae. Extinct, Cretaceous.
Fam. 9. Phractolaemidae. One genus, W. Afr.
Fam. 10. Saurodontidae (Ichthyodectidae). Extinct, Cretaceous ;
Portheus, Ichthyodectes.
Fam. 11. Chirocentridae. One genus, Ind. Ocean and Seas of China
and Japan.
Fam. 12. Salmonidae. Body generally covered with scales, head
scaleless ; margin of upper jaw formed by maxillaries and premaxillaries ,
a small adipose fin behind the dorsal ; pyloric caeca generally present
and numerous ; air-bladder large and simple with a pneumatic duct ;
pseudobranch present ; no oviducts. Inhabitants of sea and f. w. ;
most of the mar. genera are from the deep sea ; most of the f. w.
forms are peculiar to the temperate and arctic region of the Northern
Hemisphere, one occurring in New Zealand ; many f. w. species are
anadromous ; no fossils of f. w. species known. Osmerus and other
genera from the Miocene.
Salmo Art., trout, salmon and charr, inhabitants of f. w., many
species descending to the sea after spawning (anadromous), the young
of all are barred, the bars vanishing in adult except in small varieties ;
many of the species are highly variable and capable of considerable adapta-
tion to their surroundings ; the marine forms usually silvery with or
without black spots, the f. w. forms more or less speckled with
black and red. Some individuals of full size are sterile, but this is pro-
bably only a temporary condition ; overgrown individuals are sterile ;
anadromous fish, generally return to their native river. River and sea
trout have been acclimatised in Tasmania and N. Zealand, and appar-
ently in India. As these species are highly variable in response to change
of condition the observation of these acclimatised races will afford an
extremely interesting study.
S. salar L., salmon, N. Hemisphere between latitudes 45° and
75° ; does not occur in rivers opening into Med.,* the last Thames salmon
was caught in 1833 ; a marine fish ascending rivers to spawn (Sep. to Jan.
in Britain), the nest or redd is dug out by the female in gravel
and the eggs are buried ; young salmon of the first and second
year are called parr or pink (4 to 6 in.) ; they then become smolts,
which descend to sea, and reascend the rivers as grilse, which having
spawned go to the sea and return as salmon ; a salmon which has spawned
is a kelt, kelts go to the sea, and probably reascend next year ; kipper
is a male kelt, or a salmon which has been detained in f. w. and got
* Not even in those of Macedonia, notwithstanding Fluellen (Henry
V., Act 4, Sc. 7) !
216 SUB-CLASS (AND ORDER) TELEOSTEI.
lean ; male parrs may become sexually mature and fertilise the eggs of a
full-grown female ; will hybridise (artificially) with the trout and charr ;
not a highly variable species and change of conditions is fatal. The
various kinds of British trout are probably all varieties of the same species,
as they will freely cross, but three species may for convenience be dis-
tinguished : S. trutta Flem., sea- or salmon-trout, phinok, sewin, a migra-
tory species ; S. jario L., the brook trout ; and S, levenensis Walker,
Loch Leven trout. To these the bull-trout, S. eriox, and great lake-
trout, S. ferox, may possibly be added.
S. alpinus L., the charr, breed Nov. to Dec. ; redd usually in
gravelly shallows in the lakes (the Windermere charr is known as S.
willughbii) ; the charrs are migratory or non-migratory and inhabit
the deep waters of lakes ; there appears to be one British species
with several varieties. S. fontinalis Mitchell, f. w. of Brit. N.
Amer., acclimatised in Britain. Oncorhynchus Suckley, anadromous fish
in American and Asiatic rivers flowing into the Pacific ; O. tschawytscha,
the Calif ornian salmon ; Brachymystax Gthr., Siberian rivers ; Lucio-
trutta Gthr. (Stenodus Rich.), Arctic N. Amer. ; Plecoglossus Schley.,
f. w. of Jap. and Formosa. Osmerus L., smelts, migratory,
ascending rivers to spawn and frequently becoming resident in them,
Atl. coasts of N. Eur. and N. Amer. ; O. eperlanus L., the
smelt, sparling, irregular in its migrations, spawning in rivers near
high-water mark, generally found in rivers from Aug. to May, spawns
about March or April, when fresh exceedingly good eating, but deteriorate
in a few hours ; allied genera are Hypomesus and Thaleichthys from the
Pacific coast of N. Amer., the latter, known as Oulachan, has so
much oil it will burn like a candle ; Mallotus Cuv. ; Coregonus Art. (Argy-
rosomtis Ag.), whitefish, mostly lacustrine, a few anadromous, northern
parts of temp. Eur., Asia, and N. Amer. ; C. oxyrhynchus L.,
houting, marine entering f. w. Holland, Germany, Denmark ; C.
clupeoides Lac., schelly, f. w. of Lake District and Wales ; C. vande-
sius Rich., vendace, f. w. lochs of Scotland ; C. pollan, Thomps.,
pollan, f. w. of Ireland ; Thymallus Cuv., graylings, clear streams
of Eur., Asia, and N. Amer.; Th. vulgaris Nilss., grayling, flesh
good, in best condition Oct. and Nov. ; Salanx Cuv. ; deep-
sea genera are Argentina, Microstoma, Bathylagus.
Fam. 13. Stomiatidae. Scales absent or thin ; a hyoid barbel ; eyes
large ; luminous spots more or less developed ; no pseudobranch ; ovi-
ducts present. Deep-sea fishes descending to the greatest depths and
distinguished by their barbel and formidable dentition. Astronesthes
Rich., Stomias Cuv., Echiostoma Lowe, Grammatostomias G. and B.,
Photonectes Gthr., Malacosteus Ayres, Bathyophis, Chauliodus Bloch
and Schneider, Bathylaco, Maurolicus, Sternoptyx, etc.
Fam. 14. Gonorhynehidae, one genus, Aust. and Japanese seas.
Fam. 15. Cromeriidae, with one genus Cromeria, recently discovered
in the White Nile.
Sub-order 2. OSTARIOPHYSI (CYPRINI SILURIFORMES).
The anterior vertebrae are co-ossified and have some of their
lateral elements detached to form a chain of small bones, the
Weberian ossicles, which connect the air-bladder with the ear
(p. 202). The air-bladder is probably always present though
OSTARIOPH7SI. 217
it may be very small. When well developed it has a pneumatic
duct. Pectoral arch suspended from the skull, mesocoracoid
present. The great majority of freshwater fishes are included
in this sub- order.
Fam. 16. Characinidae. Body scaly, head naked; barbels absent,
margin of upper jaw usually formed by the premaxillaries and maxillaries,
rarely by the premaxillaries only ; jaws usually toothed ; parietals
distinct from supraoccipital ; symplectic present ; generally a small
adipose fin behind the dorsal ; pelvics abdominal ; pyloric appendages
more or less numerous ; air-bladder divided into two portions ; pseudo-
branch absent or much reduced. Freshwaters of Africa and of tropical
America. In America they replace the Cyprinoids ; unknown as fossils.
Erythrinina. Adipose fin absent ; trop. Amer. The genera
are Macrodon, Erythrinus, Lebiasina, Nannostomus, Pyrrhulina,
Corynopoma.
Curimatina. A short dorsal and an adipose fin ; dentition im-
perfect ; trop. Amer. ; Prochilodus, Caenotropus, Hemiodus,
Saccodon, Parodon.
Citharinina. A rather long dorsal and an adipose fin ; minute
labial teeth ; trop. Afr. Citharinus Cuv., attaining to 3 ft.
Anastomatina. Short dorsal and an adipose fin ; teeth in both
jaws well developed ; the gill membranes grown to the isthmus ;
nasal openings remote from each other ; trop. Amer. Lepo-
rinus, Anastomus, Rhytiodus,
Nannocharacina. Like the last, except that incisors are notched, and
nostrils close together. Nannocharax.
Tetragonopterina. Short dorsal and an adipose fin; teeth well
developed, notched or denticulated ; gill-membranes free from the
isthmus ; nasal openings close together ; S. Amer. and trop.
Afr. Alestes M. and T., trop. Afr. ; Tetragonopterus Cuv.,
trop. Amer. Of the other genera Nannaethiops and Bryconae-
thiops are African, the rest are S. American, viz., Chirodon,
Megalobrycon, Gastropelecus, Piabucina, Scissor, Pseudochalceus,
Aphyocharax, Chalceus, Brycon, Chalcinopsis, Bryconops, Creagrutus,
Chalcinus, Piabuca, Paragoniates, Agoniates.
Hydroeyonina. Short dorsal and adipose fin ; teeth well developed
and conical ; gill-membranes free from the isthmus ; nasal openings
close together. S. Amer. and trop. Afr. Fishes of prey.
Hydrocyon Cuv., trop. Afr., and Cynodon Spix., S. Amer.,
both to 4 ft. Except Sarcodaces from W. Afr. the other genera
are trop. Amer., e.g., Anacyrtus, Hystricodon, Salminus, Oligo-
sarcus, Xiphorhamphus, Xiphostoma, etc.
, Distichodontina. Dorsal fin rather elongate, adipose fin present ;
gill-membranes attached to the isthmus ; belly rounded. Trop.
Afr. Distichodus M. and T.
Ichthyborina. An adipose fin ; dorsal rays 12 to 17 ; gill-mem-
branes free from the isthmus ; belly rounded ; canine teeth ; trop.
Afr. Ichthyborus Giinth., Nile ; Eugnathichihys , Phago, W. Afr.
Crenuchina. Dorsal fin rather elongate, an adipose fin ; gill-
membranes free from the isthmus ; belly rounded ; without canine
teeth. Crenuchus Giinth., Brit. Guiana; Xenocharax, W. Afr.
218 SUB-CLASS (AND ORDER) TELEOSTEI.
Serrasalmonina. The caribe. Dorsal fin rather elongate ; an adipose
fin ; gill-membranes free from the isthmus ; belly serrated ; trop.
Amer. ; exceedingly voracious, they assail persons entering the
water. Mylesinus, Serrasalmo, Myletes, Catoprion.
Fam. 17. Gymnotidae (yvfwds naked, vuros back). Head scale-
less ; barbels none ; body eel-shaped ; scales small or absent ;
margin of upper jaw formed by premaxillaries and by maxillaries ; an-
terior vertebrae united, modified, with Weberian ossicles ; dorsal fin
absent or reduced to adipose strip, caudal generally absent ; tail ending
in point, can be regenerated ; anal long, pelvics absent ; anus on or
near the throat ; shoulder girdle attached to skull ; ribs well developed ;
gill-openings narrow ; air-bladder double ; stomach with caecal sac ;
pyloric caeca present ; ovaries with oviducts. Eel-like f. w.
fishes from S. America. Sternarchus Cuv., Rhamphichthys M. and
T., Sternopygus M. and T., Carapus M. and T., Gymnotus Cuv. (Electro-
phorus), electric eel, Brazil and Guyanas, electric organ along each side
of the tail ; Giton Kaup, Eigenmannia J. and E.
Fam. 18. Cyprinidae. Body generally covered with scales ; head
naked. Anterior 4 vertebrae modified and joined, margin of the upper
jaw formed by the premaxillaries. Belly
rounded or if trenchant without ossifi-
cations. No adipose fin ; a dorsal and
anal fin, pelvic fins abdominal. Stomach
without blind sac. Pyloric appendages
absent. Mouth toothless ; lower pharyn-
geal bones well developed, falciform,
sub-parallel to the branchial arches, pro-
vided with teeth in one, two, or three
series. Air-bladder large, divided into an
anterior and posterior portion by a con-
Fio. 122.-Lower pharyngeal bones striction> or into a right and left portion,
of a carp (after Heckel and Uner, enclosed in an osseous capsule. Ovarian
from Claus). gacs closed. About 200 genera and 1,200
species ; freshwaters of the Old World
and N. America. The fossil forms can be referred mostly to living
genera.
I. Catastomina. Pharyngeal teeth in a single series, numerous ;
dorsal fin long, anal short ; barbels none. Lakes and rivers of N.
Amer., 2 spec, from N.-E. Asia, generally known as
suckers. Ictiobius Raf., Carpiodes Raf., Cycleptus Raf., Panto-
steus Cope, Catostomus Le Sueur, Chamistes Jordan, Xyrauchen
Eig. and Kirsch, Erimyzon Jordan, Minytrema Jordan, Moxo-
stoma Raf., Placopharynx Cope, Lagochila Jord. and Bray.
II. Cyprinina. Anal fin short with not more than 5 or 6,
rarely 7, branched rays. Abdomen not much compressed. Barbels
often present, never more than 4. Three branchiostegals. Air-
bladder without osseous covering.
Cyprinus Art., carps ; large scales ; dorsal fin long with its last un-
divided ray osseous and serrated ; pharyngeal teeth in three rows,
molar-like (Fig. 122); four barbels. C. carpio the carp, indigenous
in Persia and China, introduced into Europe (known 1258 A.D.), into
England (known 1496); food vegetable and animal ; bury themselves in
mud in winter, will live for some time out of water, may attain a large
OSTARIOPHYSI. 219
size (20-50 lb.), and great age (50-100 years, Gesner, Buffon), very
prolific, spawn on weeds about May, said to form hybrids with
the Crucian carp with the tench and the bream. Carassius Nilsson,
without barbels ; C. vulggaris Nilss., the Crucian carp, Prussian
carp, Eur. and Siberia ; C. auralus L., gold-fish, China and Japan,
introduced into Eur. and Amer. as an aquarium fish and natural-
ised in many streams ; very variable under domestication in
colour and otherwise, brilliancy generally decreases when turned
into the open, in the wild state greenish ; so-called telescope-fish
is a variety ; breeds in May and June. Catla C. and V., E. Ind. ;
Labeo Cuv., Afr. and E. Ind. ; Discognathus Heck., Ind.,
Ceylon, S.-W. Asia, Afr. ; Capoeta C. and V., W. Asia ; Barbus
Cuv., barbels, 200 species, Eur., Asia, Afr., dorsal fin with the
(third) longest simple ray sometimes enlarged and serrated
only exceptionally with more than nine branched rays commencing
opposite or nearly opposite the root of the pelvic fin ; eyes without
adipose eyelid ; mouth arched without inner folds ; lips without
horny covering, barbels 4, 2 or 0 ; B. vulgaris Fleming,
Europe, to 50 lb., as food coarse, roe scmetimes poisonous. Thynn-
•>'chthys Bleek, E. Ind. Oreinus ; McClell, Himalayas ; from
same region Ptychobarbus , Gymnocypris, Schizopygopsis, Diptychus ;
Gobio Cuv., Eur. a small maxillary barbel; dorsal fin with few
rays, without spine; G. fluviatilis Flem., the gudgeon. Allied are
Ladislavia and Pseudogobio , E. Asia; Ceratichthys Baird and Gerard,
N. Amer., called chub in the U. S. ; similar genera of
N. Amer., and generally called "minnows," are Pimephales
(black head), Hyborhynchus, Hybognathus, Campostoma (stone-
lugger), Ericymba, Cochlognathus, Exoglossum (stone-toter or cut-
lips), Rhinichthys (long-nosed dace). Other Old World genera are
Cirrhina, Dangila, Osteochilus, Barynotus, Tylognathus, Abrostomus,
Crossochilus , Epalzeorhynchus, Barbichthys, Amblyrhynchichthys,
Albulichthys, Aulopyge, Bungia, Pseudorasbora.
III. Rohteichthyina. Anal fin very short, with not more than
six branched rays ; dorsal fin behind pelvic ; abdomen compressed ;
no barbels ; pharyngeal teeth in triple series. Rohteichthys Bleek,
East Ind. Arch.
IV. Leptobarbina. Anal fin as in last ; dorsal opposite pelvic ;
abd. not compressed ; barbels present, not more than 4 ; phar.
teeth in triple series. Leptobarbus Bleek, E. Ind. Arch.
V. Rasborina with Rasbora, from E. Ind. Cont. and Arch, and
E. Afr. ; Amblypharyngodon, Luciosoma, Nuria and Aphyocypris,
from E. Ind. Cont.
VI. Semiplotina with Cyprinion from Syria, Persia, Semi-
plotus from Assam.
VII. Xenocypridina with Xenocypris and Paracanthobrama from
China, Mystacoleucus from Sumatra.
VIII. Leuciscina. Anal fin of short or moderate length, with
8-11 branched rays, not extending forwards below the dorsal,
which is short and without osseous ray. Barbels generally 0 ;
pharyngeal teeth in a single or double series. Leuciscus Klein,
white-fish, north temperate zone of both hemispheres ; species
found in England are L. rutilus Flem., the roach, said to form hybrids
with the bream and ludd ; L. cephalus Flem., the chub; L. vul-
220 SUB-CLASS (AND ORDER) TELEOSTEI.
garis Flem., the dace ; L. erythrophthalmus Flem., the rudd or red-
eye ; L. phoxinus Flem., the minnow ; L. idus, the id or nerfling,
found in Europe, is domesticated in Germany, assuming the golden
hue of semialbinism like a goldfish. Tinea Cuv., Eur. and Asia
Minor, has been acclimatised in India, T. vulgaris Cuv., the tench,
golden tench as a variety, due to albinism, as in the id and gold-
fish. Leucosomus Heck., N. Amer., L. pulchellus (fall-fish, dace
or roach), L. corporalis (chub), Chondrostoma Ag., Eur. and W.
Asia; other Old World genera are Myloleucus, Ctenopharyngodon,
Paraphoxinus ; N. American are Mylopharodon, Meda, Orthodon,
Acrochilus.
IX. Rhodenia with genera Achilognathus, Acanthorhodeus,
Rhodeus, Pseudoperilampus, roach-like fishes in East. Asia and
Japan ; in the females a long external urogenital tube is developed
externally in the breeding season ; this deposits the large eggs into
the mantle cavity of the pond mussel where they develop. Rh.
amarus, the bitterling (Fig. 123), extends into Europe.
X. Daninina. Small fish from E. Ind. Cont., Ceylon, E. Asiatic
Islands, and a few from Afr. rivers ; Danio, Pteropsarion,
Aspidoparia, Barilius, Bola, Scharca, Opsariichihys, Squaliobarbus,
Ochetobius.
XI. Hypo-
phthalmichthyina.
With H y p o-
phthalmic hthy s
from China.
XII. Abra-
midina. Anal fin
elongate ; abdo-
men or part of
the abdomen
FIG. 12S. — Rhodeus amarus, female (after comnressed A-
v. Siebold, from Claus).
oramis Cuv., the
breams, temper-
ate parts of both northern hemispheres; A. abr amis Flem., A.blicca
Ag., both in Britain and Europe, hybrids between these two species
and even other cyprinoids are not rare (Giinther) ; A. ballerus L.,
the zope, A. vimba L., the zarthe, Europe ; A. crysoleucas Mitchill,
shiner, bream, United States. Aspius Ag., E. Eur. to China ;
Alburnus Heckel, bleak, Eur., W. Asia ; A. lucidus Heck. u. Kner,
Britain, Eur. north of Alps, absent in Scotland and Ireland ; other
genera are Leucaspius and Pelecus, Europe ; Pelotrophus, E. Afri. ;
and the rest, Rasborichthys, Elopichthys, Acanihobrama, Osteobrama,
Chanodichthys, Hemiculter, Smiliogaster, Toxabramis, Culter, Eustira,
Chela, Pseudolabuca, Cachius, from E. Ind. or temp. Asia.
XIII. Homalopterina. Air-bladder absent, hill streams in E.
Ind., genera Homaloptera, Gastromyzon, Crossostoma, Psilorhynchus.
XIV. Cobitidina. Loaches. Barbels 6 or more ; dorsal fin
short or of moderate length, anal fin short ; scales small or absent ;
pharyngeal teeth in single series ; air-bladder partly or entirely
enclosed in bony capsule ; pseudobranch absent. Misgurnus Lacep.,
Eur. and Asia, M. (Cobitis) fossilis Lacep., largest European
loach ; Nemacheilus v. Hass., Eur., Asia, Abyssinia, without spine
OSTARIOPHYSI. 221
near orbit ; N. barbatula Giinth., groundling, stone-loach, etc.,
Britain and ^Europe; Cobitis Artedi, Eur., E. Ind. ; C. taenia
L., spined loach, with preorbital spine, Britain (rare) and Europe ;
Botia Gray, E. Ind. ; from tropical India are Lepidocephalichthys,
Acanihopsis, Oreonectes, Paramisgurnus, Lepidocephaltis, Acanth-
ophthalmus, Apua. >.v*»:j
Fam. 19. Siluridae. Cat-fishes. Skin naked or with osseous scutes,
without scales. The 4 anterior vertebrae joined. Barbels always pre-
sent ; maxillary bone small, almost always forming a support to a maxillary
barbel. Margin of the upper jaw formed by the premaxillaries and
maxillaries or by the premaxillaries only. Parietal bones confluent
with the supra-occipital. Sub-operculum absent. Adipose fin present or
absent. Pyloric appendages absent. Mostly inhabitants of the fresh
waters of all the temperate and tropical regions, some entering the salt
water, but keeping near the coast ; some are said to be able to cross land
in search of other waters (Callichihys, Clarias, etc.). Over 100 genera
and upwards of 1,000 species known. Clarias Gronov., Africa and S.
Asia, muddy and marshy waters, an accessory branchial organ is attached
to the convex side of the second and fourth branchial arches ; Nilotic
species known as Carmoot. Heterobranchus G. St. Hil., Afr. and E. Ind.
Arch., ace. gills as in Clarias ; Plotosus Lacep., brackish waters of
Indian Ocean and Aust., brackish waters of Aust. ; Copidoglanis Giinth.,
Cnidoglanis Giinth, Chaca C. and V., East Indies ; Saccobranchus C. and V.,
E. Ind., gill-cavity with accessory posterior sac with contractile walls,
vessels from last branchial artery and delivering into aorta. Silurus
Art., temperate palaearctic rivers, S. glanis L., the wels, Europ. rivers
east of the Rhine, to 300-400 Ib. African genera are Schilbe, Eutropius ;
E. Indian are Silurichthys, Wallago, Belodontichthys, Eutropiichthys,
Cryptopterus, Callichrous, Hemisilurus, Siluranodon, Ailia Schilbichthys,
Lais, Pseudeutropius, Pangasius, Helicophagus, Silondia. Hypophthalmus
C. and V., S. Amer., eye behind and below angle of mouth, Helogenes
Giinth., Bagrus C. and V., Nile, B. bayad; African genera are Chry-
sichthys, Clarotes ; E. Indian are Macrones, Pseudobagrus, Liocassis,
Bagroides, Bagrichthys, Rita, Acrochordonichthys, Akysis. Amiurus
(Ameiurus) Raf., horned pout, cat-fishes of N. Amer., one sp. in
China; from N. Amer. also are Hopladelus, Noturus. Platystoma Ag.,
S. Amer. snout long, spatulate ; allied are Sorubim, Hemisorubim,
Platystomatichthys, Phractocephalus, Piramutana, Platynematichthys ,
Piratinga, Bagropsis, Sciades, all from S. Amer. Pimelodus Lacep., 40
S. Amer. sp., 2 W. Afr. sp. ; allied are Pirinampus, Conorhynchus,
Notoglanis, Callophysus, Lophiosilurus, all from S. Amer. Aucheno-
glanis, trop. Afr. ; Arius C. and V., 70 sp., in all trop. countries and seas ;
allied are Galeichthys, S. Afr. and Amer., mar. ; Genidens, Paradiplomystax
Brazil ; Diplomystax Chili ; Aelurichthys C. and S. Amer. ; Hemipi-
melodus, Ketengn^, Osteogeniosus, Batrachocephalus E. Ind. ; Atopochilus
W. Afr.
Bagarius Bleek, E. Ind. ; Euglyptosternum Bleek, Syria ; Glypto-
sternum, Hara, Ambliceps E. Ind.
Doras C. and V., Oxydoras Kner, Rhinodoras Kner, these three
genera travel over land in the dry season in search of a pond of greater
capacity, they make nests and both sexes tend the eggs, tropical S.
Amer. in rivers flowing into the Atlantic ; the following also are S.
American, Ageniosus, Tetranematichthys, Euanemus, Auchenipterus,
222 SUB-CLASS (AND ORDER) TELEOSTEI.
Glanidium, Centromochlus, Trachelyopterus, Cetopsis, Astrophysus ; Syno-
dontis C. and V., trop. Afr.
Callomystax Giinth., Bengal, Mochocus Joannis. Rhinoglanis Giinth.,
Upper Nile.
Malapterurus Lac., electric cat-fish, trop. Afr., electric organ extends
over whole body beneath the skin.*
Stygogenes, Arges, Brontes and Astroplebus in the lakes and torrents
of the Andes, Humboldt thought they lived in subterranean waters
and were ejected by volcanoes ; Callichthys, similar in dist. and habits
to Doras (p. 221) ; Chaetostomus with the allied Plecostomus, Liposarcus,
Pterygoplichthys ; Rhinelepis, Acanthicus, Xenomystus, from f. w. of S.
Amer. ; Hypoptopoma ; Loricaria L., trop. Amer., Acestra Kn., Brazil,
Surinam ; Sisor, N. India ; Erethistes M. and T., Assam ; Pseudecheneis
Blyth, Himalayas ; Exostoma Blyth, E. Ind. continent.
Aspredo L., Guiana, the female attaches the eggs to the spongy integu-
ment of its belly by pressing against them ; Bunocephalus, Bunocephal-
ichthys and Harttia from trop. Amer.
Heptapterus, Nematogenys, Trichomycterus, Eremophilus, Pariodon
are small S. American forms from f . w. of high altitudes to 14,000 ft.;
they resemble the loaches of the N. Hemisphere in appearance and
habits.
Stegophilus Rein., and Vandellia C. and B., small fishes from Brazil,
the latter are said to ascend urethra of persons bathing, but there is no
doubt that they enter the gill-cavity of larger fishes.
Cathorops Jordan and Gilbert, Panama ; Ictalurus Raf., f. w. of N. Amer.
Sub-order 3. SYMBRANCHII.
Body eel-shaped. Shoulder-girdle usually joined to the skull ;
no mesocoracoid. Scales minute or absent. No paired fins.
Unpaired fins reduced. Anus far from head. No air-bladder ;
gill-openings confluent in a single slit. Stomach without cae-
cum and pyloric caeca. Ovaries with oviducts. Widely dis-
tributed in warm seas and fresh waters.
Fam. 20. Symbranchidae. Eel-like, without paired fins, scales
minute or absent ; gill-openings confluent into one slit on the ventral
surface ; anus far from head ; no air-bladder, stomach caecum or pyloric
caeca ; with oviducts ; f. w. and brackish w. of trop. Amer. ; 3 genera,
and one marine genus (Chilobranchtis) from Australia. Amphipnous Mull,
Bengal, 3 branchial arches of which the second alone possesses gills, and
narrow slits, with a lung-like branchial sac on each side opening between
hyoid and first branchial arches and supplied by branchial arteries ; A.
cuchia ; Monopterus Lacep., 3 branch, arches and small gills, no branch,
sac, East Ind. Arch, and Cont. ; Symbranchus Bl., 4 branch, arches and
large gills, trop. Amer. and E. Ind.
* Ballowitz, Das elect. Organ des afrikanischen Zitterwelses- Jena
1899.
APODES. 223
Sub-order 4. APODES (ANGUILLIFORMES). The Eels.
The premaxillaries small or absent, the maxillaries lateral,
the body eel-like and without pelvics. Symplectic absent ;
operculum and palatine arch reduced ; scales absent or
feeble ; pectoral arch not attached to skull ; fins with-
out spines, median fins if present confluent ; no pseudobranch ;
tail protocercal ; no pyloric caeca ; no generative ducts. Air-
bladder, when present, with a ductus pneumaticus.
The eels are spread over the f. ws. and seas of the
trop. and temp, zones ; some descend to the greatest
depths. The young of some have a limited existence and are
known as Leptocephalus (see below). Fossil Anguilla in chalk
of Aix and Oeningen, Anguilla, Sphagebranchus, Ophichihys
at Monte Bolca and Urenchelys S. Wood., with homocercal
tail, from the chalk.
The breeding * of the common eel was until a short time ago a mystery.
During their sojourn in freshwater they do not develop reproductive
organs, and it was not known how they originated. Aristotle thought
that they came from the " entrails of the earth." It is now known, thanks
to the researches of Grassi and Calandruccio, that they breed in the depths
of the sea, that the eggs float but remain near the bottom, and that they
hatch out as a larva, which soon becomes transformed into a ribbon-
shaped, transparent creature, which has long been known and called
Leptocephalus. There are several kinds of Leptocephalus. That of the
common eel is L. brevirostris. It appears to remain at the bottom, pro-
bably hiding under stones or burrowing in sand and mud until it meta-
morphoses into the elver. Elvers (see below) are the young of eels which
ascend rivers in great numbers.
The Italian naturalists worked at Catania in the Straits of Messina,
where specimens of the Leptocephalus brevirostris are common in certain
years at the surface, and at all times in the stomach of Orthagoriscus mola,
a deep-sea fish, and they showed that this particular kind is the larva of the
common eel. That it should be taken here and nowhere else is a curious
fact, considering that the common eel is widely distributed. The probable
explanation is that it is brought to the surface by the currents and whirl-
pools which abound in this locality, while elsewhere it has escaped observa-
tion by lurking at considerable depths (300 fms.) in mud and under stones.
Several species of Leptocephalus, which doubtless belong to different
Muraenidae, are known as pelagic forms, especially in the tropics, so that
it is probable that all Leptocephali are not confined to deep water during
their development. Speaking generally it appears that female Murae-
noids cannot mature their ova except in deep water, while the male can
* B. Grassi and S. Calandruccio, Ulteriori recerche sulle metamorfosi
dei Murenoidi, Rend. Ace. Lincei (5), vi., p. 43, 1897 ; also Q. J. M. S.,39,
1897, p. 371, and Proc. Roy. Soc., 1896. Cunningham, Journal of Marine
Biological Assoc. (2), 3, 1895, p. 278, and (2), 1, 1891, p. 16.
224 SUB-CLASS (AND ORDER) TELEOSTEI.
arrive at maturity at a less depth, but has to migrate to a greater depth
to fertilise the eggs. The eggs float, but at a considerable depth and only
exceptionally mount to the surface. The characteristics of typical Lepto-
cephali are the transparent ribbon-shaped body with colourless blood,
vent near the tip of the tail, small head, and large eyes.
It has long been suspected that certain Leptocephali were the larvae
of the conger, but many held that they were abnormal overgrown larvae
incapable of further development, on the ground that they attained a
size larger than that of the youngest conger, and because of the great
variability of their form and dentition. The first naturalist who definitely
observed the metamorphosis of a Leptocephalus into a young conger was
Delage in 1886 (Comptes Bendus, 103, 1886, p. 698). In this metamor-
phosis the skin became pigmented, the blood coloured, the air-bladder
developed, and the body cylindrical and shorter.
Grassi has shown that L. stenops (in part), L. morrisii and punctatus
belong to the life-cycle of Conger vulgaris ; that L. haeckeli, yarrelli, bibroni,
gegenbaurii, kdllikeri, stenops (in part) belong to Congromuraena mystax ;
L. taenia, inornatus, and diaphanus to Congromuraena balearica, etc.
Fam. 21. Derichthyidae. Body eel-like, from the abysses of the
Atlantic ; Derichthys Gill.
Fam. 22. Muraenidae, with the characters of the sub-order. (This
family is now usually divided into several.)
Group 1. Eels in which the branchial openings in the pharynx are
wide slits.
Nemichthys Rich., jaws produced into long slender bill, eyes large, with
Serrivomer, Spinivomer, Avocettina, Labichthys are deep-sea (500-2,500
fms.) forms. Anguilla Cuv., eels, small scales imbedded in the skin,
upper jaw not projecting beyond the lower ; gill-openings narrow, at the
base of the pectoral fins ; dorsal fin some distance from head ; they freely
ascend rivers, descending to the sea for purposes of reproduction ; f . w.
and coasts of temp. and trop. zones, not yet found in S. Amer., W. coast of
N. Amer. and W. Afr. A. anguilla L., the common Eur. and Brit,
species, they descend rivers in the autumn and spawn in the deep sea ;
the larva is known as Leptocephalus brevirostris ; the young eels are
called elvers, and ascend rivers in incredible numbers in spring (April
and May), overcoming all obstacles and even crossing land ; such migra-
tions are known as eel-fares (of which elver may be a corruption), they
bury themselves in mud and become torpid in winter, do not develop
their generative products in freshwater ; the adult eels are said not to re-
ascend rivers and to die soon after spawning.
In eels migrating down the rivers to the sea the reproductive organs
are enlarged, and the skin has a silver colouration. The eyes also are
enlarged. All these peculiarities are observed in the sexually mature
forms taken from the deep water. Young elvers are not known of a less
size than 5 cm., while the larva, L. brevirostris attains a length of 8 cm.
Simenchelys Gill, and Ilyophis Gilbert, are deep-sea eels ; Synapho-
branchus Johns., gill-openings united into a longitudinal slit, deep-sea
congers ; Conger Kaup., congers or marine eels, scaleless (Leptocephalus,
Oxyurus, Helmictis, are all said to have priority over Conger), C. conger
L., prefers deep waters with rocky bottom, attains to 8 ft., almost cosmo-
politan ; allied genera are Poeciloconger, Congromuraena, Uroconger,
Heteroconger ; Muraenesox McClell., scaleless, trop. seas ; Nettastoma
Kaf., scaleless, deep-sea, the leptocephalid form is Hyoprorus ; Sauren-
HAPLOMI. 225
chelys (Chlopsis), Oxyconger, Hoplunnis, Neoconger, all with superior or
lateral nostrils, and Myrus, Ahlia, Myrophis, Paramyrus, Chilorhinus,
Muraenichthys with nostrils in the upper lip, may be placed here. Oph-
ichthys Gthr. (Ophichthus), nostrils labial, extremity of tail free, more than
eighty species known, very numerous in trop. seas, formidable den-
tition in jaws and palate ; Sphagebranchus, Verma, Letharchus, Myr-
ichthys, Pisoodonophis, Callechelys, Bascanichthys, Quassiremus, Mystri-
ophis, Scytalichthys, Brachysomophis, are other allied genera ; Moringua
Gray, E. Ind., Fiji, Japan.
Group 2. Eels in which the branchial openings in the pharynx are
narrow slits.
Muraena Gthr., scaleless ; teeth well developed ; pectoral fins absent,
are as abundantly represented in tropical and sub-tropical waters as is
Ophichthys ; more than eighty species ; most of them with formidable
teeth, attain a length of 8 ft. and attack man, most are highly coloured.
M. helena L., the muraena of the ancient Romans, can be domesticated,
will live in fresh-water, Mediterranean, etc. ; other genera are Gymno-
muraena, Myroconger, Enchelycore, Pythonichthys, Rabula, Lycodontis,
Echidna Forster 1778, Uropterygius, Channomuraena.
The family Saecopharyngidae may be placed here. They are eel-like
deep-sea (Atlantic) fishes with feeble muscular system, but little earthy
matter in their bones, and branchial arches far behind the skull, without
palato-pterygoid bar, narrow tail ending in filament, and with pedunculated
appendages in place of the lateral line. Sacco pharynx, Gastrostomus, Eury-
pharynx.
Sub-order 5. HAPLOMI (ESOCIFORMES). Pike-like fishes.
Soft-rayed fishes with the mesocoracoid wanting, the cora-
coids normally developed, and the post-temporal normally at-
tached to the cranium. Parietal bones separated by the supra-
occipital. Symplectic present, opercular bones well developed.
Anterior vertebrae unmodified. Air-bladder with duct ; pelvic
fins abdominal, rarely absent. First ray of dorsal fin occasion-
ally stiffened and spine-like ; no adipose fin. Chiefly f . w.
Fam. 24. Galaxiidae. Xaked, without barbels ; margin of upper
jaw chiefly formed by premaxillaries. Dorsal fin opposite anal ; pseudo-
branch absent. Without adipose fin ; with air-bladder. Ova dehisced
into abdomen F. w. and seas of temperate parts of S. hemisphere
(S. Afr., Patagonia, N. Zealand, Tasmania), some are katadromous ;
Galaxias Cuv.
Fam. 25. Haplochitonidae, representing the salmonoids in the S.
hemisphere. Haplochiwn Jen. ; Prototroctes Gthr.
Fam. 26. Enehodontidae. Extinct, Cretaceous. Enchodus Ag., etc.
Fam. 27. Esocidae. Body covered with scales ; margin of upper
jaw formed by premaxillaries and toothless maxillaries ; barbels and
adipose fin absent ; unpaired fins far back ; stomach without blind sac ;
pyloric caeca absent ; pseudobranch glandular hidden ; air-bladder
simple ; gill-opening very wide ; noted for their voracity. Esox (L. )
Cuv. (Lucius Raf.), the pikes, f. w. of temp. Eur., Asia and Amer.
z. — ii. Q
226 SUB-CLASS (AND ORDER) TELEOSTEI.
E. lucius L., common pike, pickerel, jack, luce, hake, Eur., N.
Asia and northern parts of North America ; extremely voracious, does
not refuse frogs, voles, house rats, puppies, kittens, weasels, foxes, ducks,
geese, has been found with a human infant in its stomach, has been
known to lay hold of a swan, a tame cormorant, and to attack otters,
dogs, asses, mules, oxen, horses, men, and to catch swallows, dislikes
sticklebacks. Umbra Kramer, Austria, Hungary (Hundsfisch), and
United States (mud-minnow).
Fam. 28. Dalliidae, f. w. fishes from Alaska and Siberia.
Fam. 29. Scopelidae. Naked or scaly. Margin of upper jaw formed
by premaxillary only ; opercular bones thin but complete. Barbels none.
Pseudobranchs usually well developed. Air-bladder small or none.
Adipose fin present. The eggs are enclosed in the sacs of the ovary and are
extruded by oviducts. Intestine short. All marine, mostly inhabiting
shore waters, some descending to the deep sea. The following fossil forms
are probably allied here : Hemisaurida, Parascopeltis, Anapterus. Saurus
Cuv., Med., trop. Atl. and Pac. ; Bathysaurus Giinth., deep sea,
Pac., 1,100-2,400 fms. ; Harpodon Les., Ind. and China Seas, H.
nehereus, Bombay duck ; Scopelus Cuv., lantern-fishes, luminous
spots along sides of body, pelagic fishes, taken at any depth to
2,500 fms. ; Ipnops Giinth., 1,600 to 2,150 fms., phosphorescent
organs extending along the median line of the snout, have been regarded
as modified eyes, which are otherwise absent, pseudobranch absent ;
Paralepis Risso, small, pelagic, from Med. and Atl. ; Sudis Raf. ;
Plagyodus Pall. (Alepidosaurus or Alepisaurus Lowe), one of the
largest deep-sea fishes ; other genera are Aulopus, Chlorophihalmus,
Scopelosaurus, Odontostomus, Nannobrachium, Bathypterois ; Trachino-
cephalus Gill, Synodus Bloch and Sch., Benthosaurus Goode and Bean ;
Myctophum Raf., pelagic fishes coming to surface at night, taken at any
depth to 2,000 fms.
Fam. 30. Cetomimidae. Rondeletia Goode and Bean, deep sea ; Ceto-
mimus, Goode and Bean, deep sea.
Fam. 30 a Chirothricidae. extinct.
Fam. 31. Kneriidae. Small loach-like fishes from f. w. of trop.
Africa. Kneria.
Fam 32. Cyprinodontidae (Poeciliidae J. and E.). Head and body covered
with scales ; barbels absent. Margin of upper jaw formed by premaxil-
laries only. Teeth in both jaws ; upper and lower pharyngeals with
cardiform teeth. Adipose fin absent ; dorsal fin on the hinder half of the
body. Stomach without blind sac ; pyloric appendages absent. Pseudo-
branch absent ; air-bladder simple. Sexes usually unlike, the fins being
larger in the males, which however are often much smaller in size than
the females ; mostly viviparous, the young being well developed at birth.
The anal fin of the male is frequently modified as a copulatory organ.
Freshwater fishes of S. Eur., Asia, Afr. and Amer., some of them
occurring in arms of the sea. Some are carnivorous and some live on
organic substances in mud. Fossil remains in tertiary strata.
I. Carnivorae. Bones of each ramus of the mandible firmly
united, intestine short or but little convoluted ; carnivorous. Cyprin-
odon Lacep., in Mediterranean region and N. Amer., are able
to live in brine pools, e.g., of Dead Sea and Sahara, and at high tem-
peratures ; sometimes lose their ventral fins and then known as
Tellia ; oviparous. Allied are Fitzroyia from Monte Video, and
HETEROMI : 227
Characodon from Central Amer. Haphlochilus M'CL, E. Ind. trop.
Afr., temp, and tropical Amer. Fundulus C. et V., killifish, abundant
in New World, one in Spain and one in E. Afr. ; allied are the South
American Limnurgus, Lucania, Rivulus and Cynolebias ; Orestias
C. et V., East Peru and Bolivia, at an elevation of 13,000 to 14,000
ft. ; Jenynsia Gthr., Madonado ; Gambusia Poey, W. Indies, and
S. Amer. ; allied are Pseudoxiphophorus and Belonesox of Cent.
Amer. ; Andbleps Art., four-eyed fishes, iris with two pupils, swims
with part of head out of water, trop. Amer.
II. Limnophagae. Mandibular bones but loosely joined, intestine
convoluted, sexes differentiated, mud-eating, trop. Amer. Poecilia,
Mollienesia, Platypoecilus, Girardinus.
Fam. 33. Amblyopsidae (Heteropygii). Head naked, body with very
small scales, barbels absent. Villiform teeth in jaws and on palate.
Adipose fin absent. Pelvic fins small or absent. Vent in front of pectorals.
Stomach caecal ; pyloric caeca present. Pseudobranch absent (con-
cealed). Fishes of small size living in the swamps and subterranean streams
of the United States. Aniblyopsis De Kay, the blind fish of the Mammoth
Cave of Kentucky, colourless, 5 inches, eyes and optic nerve very
imperfect * ; viviparous ; allied species without pelvic fins are known as
Typhlichthys Gerard. Chologaster Ag., with normal eyes and coloured ;
swamps and entering caves.
Fam. 34. Stephanoberycidae, deep sea.
Fam. 35. Pereopsidae. F. w. of N. Amer. ; adipose fin present ; dorsal
and anal with a few spines, pelvics abdominal with more than five soft
rays, with a trace of pneumatic duct and with pseudo-branch ; body
covered with ctenoid scales. Percopsis Ag., Columbia Eigenm.
Sub-order 6. HETEROMI (DERCETIFORMES).
Air-bladder without open duct ; parietals separating the
frontals from the supraoccipital ; no mesocoracoid. Pelvics
abdominal if present.
Fam. 36. Dercetidae. Eel-shaped fishes without ordinary scales.
Body generally with four series of sub triangular scutes and intermediate
scale-like smaller scutes. Head long and jaws produced. Extinct, Cre-
taceous. Dercetis Ag., Pelargorhynchus v. d. Marck.
Fam. 37. Halosauridae, deep-sea forms. Halosaurus, Aldrovandia.
Fam. 38. Notacanthidae, deep-sea, pelvics abdominal, air-bladder
with duct. Notacanthus, Macdonaldia.
Fam. 39. Lipogenyidae. Deep-sea.
Fam. 40. Fierasferidae.f Without pelvic fins, vent at the throat ;
eel-like, small, shore-fishes of tropical seas, often living as lodgers
in cavities of other animals, e.g. Holothurians, starfishes and bivalve
molluscs ; often commensal with the pearl oyster ; are harmless to their
hosts. Fierasfer Cuv., Encheliophis. Lycodapus Gilbert may be placed
near here.
* Eigenmann, Arch. f. Entwick. Mech., 8, 1899, p. 545.
t Emery, Fauna und Flora d. Golf. v. Neapel, 1880.
228
SUB-CLASS (AND ORDER) TELEOSTEL
Sub-order 7. CATOSTEOMI (GASTROSTEIFORMES).
Air-bladder, if present, without open duct. Parietals, if pre-
sent, separated by supraoccipital. No mesocoracoid. Ventral
fins abdominal
if present.
Mouth bordered
by the premax-
illaries or by
them and a small
portion of the
FIO. 124;— Gasterosteus aculeatus (after Hockel and Kner, maxillarieS.
A. SELENICHTHYES
Preoperculum and symplectic distinct ; branchial apparatus fully
developed ; mouth terminal, toothless ; post-temporal forked, free ;
pelvic bones connected with the scapular arch ; pelvics with fifteen to
seventeen rays ; ribs long, sessile ; fins without spines.
Fam. 41. Lamprididae.
Body short and deep, with
minute scales. Lampris
Retzius ; L. luna Gmelin,
the opah or king-fish, to
4 ft., N. Atl. and Med.
B. HEMIBRANCHH.
Gills pectinate. Post-
temporal furcate. Superior
pharyngeal bones reduced in
number, the bones of the
gill-arches also reduced ex-
cept in Gasterosteidae ; in-
ferior pharyngeal bones pre-
sent, not united. Pelvic
fins abdominal. Mouth
bounded above by premax-
illaries only. Basis of cra-
nium simple and without
tube. Mouth small, at the
end of the snout which is
usually produced.
Fam. 42. Gasterosteidae.
Sticklebacks. Body elon-
gate, compressed, cleft of
the mouth oblique, villiform
teeth in the jaws. Opercular
bones not armed. Scales
none, but generally large scutes along the side
FIG. 125. — Nest of Gasterosteus punQitius (from Glaus
after Landois).
Isolated spines in
CATOSTEOMI.
229
front of the soft dorsal fin. Pelvics abdominal, joined to the scapular
arch. Branchiostegals 3. Pseudobranch and air-bladder present. Small
fishes inhabiting f. w. and arms of the sea in Eur., As. and Amer. ; noted
for their pugnacity ; they are very destructive to the spawn and fry
of other fishes. In many species the males build nests for the eggs
with blades of grass, etc., cemented together by cutaneous mucus ; the
male defends the eggs. They are extremely variable and susceptible
to change of conditions. Gasterosteus Artedi, probably only 3 Brit,
species, though many varieties have been described as such, G. aculeatus,
the 3-spined, f . w., G. pungitius, the 9-spined, f . w., and G. spinachia, the
marine stickleback ; Eucalia Jordan, Pygosteus Brevoort, Apeltes De
Kay ; Aulorhynchus Gill.
Fam. 43. Protosyngnathidae. Extinct.
Fam. 44. Fistulariidae. Gigantic marine
sticklebacks, flute-mouths, pipe-fishes, trop.
and sub-trop. Atl. and Indo-Pac. Fistu-
laria, Aulostoma, Auliscops.
Fam. 45. Maerorhamphosidae. Bones of
the skull much prolonged anteriorly forming
a long tube which bears the short jaws at
its end ; two dorsal fins, the spinous short ;
pelvics truly abdominal, imperfectly devel-
oped ; the 4 anterior vertebrae much elon-
gated. Macrorhamphosus Lac. (Centriscus
Cuv.), snipe fishes, M. scolopax L., the
trumpeter bellows-fish, rarely occurs on S.
coast of England ; Amphisile Klein, body so
thin as to be semi-transparent, trunk part
of vertebral column composed of 6 verte-
brae, and four times as long as the caudal,
which consists of 14, with a dorsal cuirass
formed by portions of the skeleton
C. LOPHOBRANCHII.
Fl<J. 126— Male of Hippocam-
pus with the brood-pouch.
Bit, (from Claus).
Gills composed of small rounded lobes
attached to the branchial arches ; gill-cover a
large simple plate ; air-bladder simple, usually
without duct (present in Syngnaihus acus) ;
skin with bony plates ; muscular system
feeble ; snout prolonged, bearing the small terminal toothless mouth,
bounded above by premaxillaries only ; scapula attached to skull bv
post-temporal ; bad swimmers, carried about by currents.
Fam. 46. Solenostomidae. Gill-openings wide, two dorsal fins, the
rays of the anterior not articulated ; all the other fins well developed ;
in the female the eggs are retained in a brood pouch formed by the broad
pelvic fins. Solenostoma Lac., Ind. Ocean, preceded in the tertiary epoch
by Solenorhynchus. \
Fam. 47. Syngnathidae. Gill-openings very small, near the upper
posterior angle of the gill-cover ; one soft dorsal fin ; no pelvics ; males
with an egg-pouch placed on the ventral side of the tail or abdomen
usually formed of two folds of skin ; eggs are retained here till some time
after hatching ; small fishes found in all warm seas, sometimes entering f . w.
230 SUB-CLASS (AND ORDER) TELEOSTEI.
A. Tail not prehensile, generally with caudal fin. Pipe-fishes.
Siphonostoma Kaup ; S. typhle L. coasts of Eur. Syngnathiis
Art. ; S. acus L. greater pipe-fish. Doryichthys. Nerophis Kaup.,
eggs glued to abdomen, no folds of skin ; N. aequoreus L. ocean
pipe-fish, N. ophidian L. straight-nosed pipe-fish, JV. lumbrici-
formis Yarr. little pipe-fish common on British coasts ; Protocampus,
Ichthyocampus, Nannocampus, Urocamptis, Leptoichthys, Coelonotus,
Stigmatophora.
B. Tail prehensile, without caudal fin. Sea-horses. Oastrotokeus,
Solenognathus . Phyllopteryx Swainson, provided with prominent
spines on the edge of the body, some with cutaneous filaments
giving them a close resemblance to the seaweed which they frequent ;
Hippocampus Raf. sea-horse (Fig. 126), H. antiquorum Leach, Brit,
seas, etc.
D. HYPOSTOMIDES.
With one Fam. 48. Pegasidae, Body entirely covered with bony
plates ; preoperculum and symplectic absent ; the pectorals are broad
FIG. 127. — Exocoetus rondeictii (after Cuv. and Vah., irom Glaus).
and horizontal ; and the upper part of the snout is produced into a pro-
cess ; without air-bladder and pseudo branch. Small fishes living in
sandy shoal-places near the coast. Indian Ocean, Chinese and Australian
coasts. Pegasus draco and volans.
Suborder 8. PERCESOCES (MUGILIFORMES).
Air-bladder, if present, without open duct. Parietals separated
by supraoccipital. Pectoral arch suspended from skull, no
mesocoracoid. Pelvic fins, if present, often with 1 spine and 5
rays ; pelvic bones not attached to shoulder girdle. Connects
the Haplomi with the Acanthopterygii.
Fam. 49. Scombresocidae. Body covered with scales ; a series
PERCESOCES 231
of keeled scales along each side of the belly ; maxillae entering
border of upper jaw ; lower pharyngeals united into a single
bone ; no adipose fin ; pelvics without spines, with 6 rays ; air-
bladder generally present without duct ; pseudobranch hidden glandu-
lar ; stomach not distinct from intestine, which is quite straight, without
appendages. Chiefly marine, but some acclimatised in f . w. ; many
of the latter are viviparous. All trop. and temp, zones (Holosteus in
the strata of Monte Bolca is allied here). Belone Cuv., with
green bones, both jaws elongated into a beak, no finlets ; B. vulgaris
Flem., Brit, coast, gar-fish, gar-pipe, sword-fish. Scombresox Lac., the
saury or skipper, both jaws elongated into a beak, finlets behind
anal and dorsal fins ; S. saurus Rond., Brit, coast. Tylosurus, Ath-
lennes, Hemirhamphus, Arrhamphiis, Chriodorus, Hyporhamphus ; Exo-
coetus Art., flying fish (Fig. 127), both jaws short, pectoral fins elongated
into organs for floating through the air (parachute-like), they live in shoals
in trop. and sub-trop. seas, E. volitans L., has been taken off Brit, coast ;
flying fish do not fly, but leaving the water by a powerful tail movement
they float rapidly through the air in a straight line supported by their
expanded pectoral fins. Fodiator, Parexocoetus, Halocypselus.
Fam. 50. Ammodytidae. Sand-eels. Small carnivorous fishes swim-
ming in shoals near the shore and burying themselves in the sand ; pelvics
absent ; vent remote from head, long dorsal and anal fins destitute
of spines ; pelvics without spine, with 6 rays ; no air-bladder. Ammo-
dytes L., A. lanceolatus, greater sand-eel ; A. tobianus, lesser sand-eel.
Fam. 51. Atherinidae. Lateral line indistinct, with a silvery band
along the sides ; valued as food ; the fossil Mesogaster allied here. Ather-
ina L., littoral fishes living in shoals, like smelts ; the newly hatched
young are called nonnat in S. France. A. presbyter Jenyns, silverside,
and A. boyeri are British ; Lethostole J. and E. ; Chirostoma Swains.
(Atherinichthys Bleek), pesce rey ; Kirtlandia ; Menidia ; Leuresthes ;
Eur y stole ; Thyrina ; Atherinella ; Labidesthes ; Atherinopsis ; Atherinops.
Fam. 52. Mugilidae. Grey mullets. Lateral line absent ; large cycloid
scales ; anterior dorsal of 4 stiff spines. Mugil L., grey mullets, stomach
muscular in part, like gizzard of fowl, feed on mud and sand, and have
long gill-rakers, along shores and in brackish lagoons, intestine much
convoluted and long, M. capita Cuv. grey mullet, and M. chelo Cuv.
lesser grey mullet, are British ; Chaenomugil, Querimana, Agonostomus,
Joturus.
Fam. 53. Sphyraenidae. Barracudas. Lateral line continuous, small
cycloid scales ; carnivorous pike-like fishes, often of large size, inhabiting
warm seas, many used as food ; Sphyraena Bl. and Schn.
Fam. 54. Polynemidae with Polynemus, Pentanemus, Galeoides, Poly-
dactylus ; flesh esteemed, air-bladder yields isinglass, humeral arch with
long filaments, sandy shores of trop. seas sometimes entering rivers.
Fam. 55. Chiasmodontidae. Deep-sea ; Chiasmodon Johnson or
Chiasmodus Gthr., Pseudoscopelus Lutken.
Fam. 56. Stromateidae, Pelagic or deep-sea fishes, with Nomeus,
Cubiceps, Psenes, Seriolella, Psenopsis, Centrolophus, Lirus, Stromateus,
Peprillus, Stromateoides.
Fam. 57. Tetragonuridae. Tetragonuriis, a rare fish from Mediter-
ranean, Atlantic and S. Pacific, poisonous as food.
Fam. 57a. Icosteidae. Icichthys, Icosteus, Acrotus, all deep-sea.
Fam. 58. Ophioeephalidae. Fresh-water fishes of the Indian region
232 SUB-CLASS (AND ORDER) TELEOSTEI.
and trop. Africa ; they are able to survive drought in semi-fluid or
beneath dry mud, and have an accessory branchial cavity for aerial res-
piration ; maxillae excluded from border of upper jaw ; head and body
covered with cycloid scales ; pectorals nearer ventral than dorsal line ;
pelvics if present near pectoral, with 6 rays ; dorsal and anal fins long,
without spines ; air-bladder long. Ophiocephalus, Channa.
Fam. 59. Anabantidae. Closely related to preceding, but differ in
part of the dorsal and anal fins, and the outer ray of the pelvic being
spinous. The accesory suprabranchial organ is more developed with thin
bony laminae which are more or less folded; f . w. fishes of India. Malay
'Pen. and Arch., and Africa. One genus, Anabas Cuv. ; A. scandens
Dald., climbing perch, Ind. region, can move on land, and has been taken
ascending a tree (five feet up) by means of its pre-opercular and anal
fin spines.
Sub-order 9. ANACANTHINI (GADIFORMES).
Median and pelvic fins without spinous rays ; the pelvics when
present are jugular or thoracic. Air-bladder, if present, with-
out duct. Parietals separated by the supraoccipital. Pectoral
arch suspended from the skull ; no mesocoracoid. Caudal fin,
if present, without expanded hypural, perfectly symmetrical
and supported by the neural and haemal spines of the posterior
vertebrae and by basal bones similar to those supporting the
dorsal and anal rays ; the ventral part of the caudal fin is not a
true caudal, but an anal shifted back to the end of the body ;
according to this view the condition in the Macruridae must be
more primitive than that in the Gadidae.
Fam. -> 60. Macruridae. Body ending in a long compressed tapering
tail without caudal fin ; covered with spiny, keeled or striated scales ;
one short anterior dorsal and a long posterior dorsal meeting the long
anal at the end of the tail ; deep-sea forms. Bathygadus, Macrurus,
Coryphaenoides, Macruronus, Malacocephalus, Moseleya, Lionurus,
Lyconus, Gadomus, Melanobranchus, Trachyrhynchus, Hymenocephalus,
Steindachneria.
Fam 61. Gadidae. Cod-fishes. More or less elongate, covered with
small smooth scales ; 1, 2 or 3 dorsal fins, 1 or 2 anals ; caudal distinct or
confluent with the dorsal and anal, symmetrical, the ventral part of it
having interspinous bones ; gill-opening wide ; gill-membrane usually
not attached to isthmus ; pseudobranch absent or glandular ; air-bladder
and pyloric caeca generally present ; gills 4, a slit behind the 4th ; genera
about 25 ; many highly valued as food, chiefly in the northern seas,
littoral, surface or abyssal ; one genus (Lota) is f . w. ; some marine mem-
bers of the family will live in f. w. lakes close to the sea. Gadus Art.
Arctic and temp, zones of the n. hemisphere. G. morrhua L. the cod, G.
aeglefinus L. the haddock, G. luscus L. bib or whiting pout, G. minutus L.
the power, G. merlangus L. whiting, G. pontassou Risso, G. pollachius L.
pollack ; Gadiculus, Mora, Strinsia ; Halargyreus and Melanorius are bathy-
ACANTHOPTERYGII. 233
bial. Merluccius Cuv. M. vulgaris Flem. hake ; PseudopTiycis, Lotella,
Physiculus, Uraleptus, Laemonema ;Phycisft\. Sch., Ph. blenntoides Bl.-Sch.;
Haloporphyrus (Lepidion) and Antimora abyssal ; Lota Cuv. f . w., L. vulgaris
Cuv., the burbot or eel pout, in some English rivers ; Molva Nilss. M.
vulgaris Flem. the ling ; Motella Cuv., rock-lings ; M. mustela Nilss., M.
cinibria Nilss., M. tricirrata Nilss., M. macro phthalma Gthr. ; Raniceps
Cuv., R. raninus ; Bregmaceros ; Brosmius Cuv., B. brosme the torsk ;
Theragra, Eleginus Fischer. Muraenolepis without separate caudal fin
may be placed here.
Sub-order 10. ACANTHOPTERYGII. Spiny-rayed fishes.
Anterior vertebrae unmodified : anterior rays of dorsal and
anal fins typically simple or spinous, but all the fin-rays are some-
times jointed. The lower pharyngeals are generally separate.
Air-bladder if present typically without pneumatic duct in
the adult. Border of upper jaw formed by premaxillary. Sup-
raoccipital in contact with frontals. Shoulder girdle attached
to skull by post-temporal. No mesocoracoid. Opercular appar-
atus complete ; gill-openings in front of the pectorals. Pelvic
fins more or less anterior, normally attached to the
shoulder-girdle, typically with 1 spine and 5 rays. The
great majority of marine fishes belong to this section. They
differ widely among themselves and some of them approach
closely to the sub-orders previously described. A certain number
of the tribes can be clearly defined, but many of them include
forms so diverse that they defy concise definition, and can only
be described as centres of relationship.
Tribe 1. PERCIFORMES, Perch-like fishes.
No bony stay for the preoperculum. Basis cranii double. Spinous
dorsal usually well developed. Pectoral arch with well-developed scapula
and coracoid, the former pierced by a foramen or fenestra ; somactids
longer than broad, more or less hour-glass shaped, four or five in number,
one or two of which are in contact with the coracoid. Pelvics thoracic.
Rays of the caudal fin not strongly forked at the base, hypural usually
with a basal spine or knob-like process on each side.
This group is incapable of concise definition. It includes fishes of
divers habits and forms. " The division into families, capable of rigid
definition is a task of considerable difficulty, and the necessities of a
linear arrangement result in the breaking up of some natural sequences." *
Fam. 62. Berycidae. Body compressed, covered with cycloid or
ctenoid scales ; head with large muciferous cavities covered by the skin ;
pelvics thoracic, with one spine and more than five soft rays ; with pseudo-
branch and numerous pyloric caeca ; air-bladder with pneumatic duct
in Beryx and Holocentrum ; mostly deep-sea fishes, many extinct species.
* Boulenger, in Cambridge Natural History.
OF THE
UNIVERSITY
or
234 SUB-CLASS (AND ORDER) TELEOSTEI.
Beryx Cuv., with large ctenoid scales, air-bladder with duct, deep-sea,
is found fossil in the chalk ; Polymixia, Aphredoderus, Plectromus, Scope-
logadus, Anoplogaster , Caulolepis, Trachichthys, Gephyroberyx, Myripristis,
Holocentrum.
Fam. 63. Monocentridae with Monocentris.
Fam. 64. Pempheridae, Pempheris, air-bladder divided into an
anterior and posterior portion ; Bathyclupea Alcock, with pneumatic
duct.
Fam. 65. Cyphosidae. Pacific and Indian Oceans. Cyphosus Lac.
(Pimelepterus Lac.), Hermosilla, Sectator.
Fam. 66. Lobotidae. Medialuna, Lobotes, very wide range.
Fam. 67. Centrarchidae. Sun-fishes, f. w. of N. Amer., most build
nests, valued as food. Pomoxis, Centrarchus, Acantharchus, Ambloplites,
Archoplites, Chaenobryttus, Enneacanthus, Mesogonistius, Apomotis,
Lepomis, Eupomotis, Micropterus Lac. (Euro C. and V.), black bass,
acclimatised in Eur., Elassoma, Kuhlia.
Fam. 68. Toxotidae. Toxotes Cuv., f . w. and coasts of E. Indies and
Australia, has the habit of throwing a drop of water at an insect near
the surface to make it fall in.
Fam. 69. Nandidae. Small carnivorous fresh-water fish from W. Afr.,
S.-E. Asia and S. Amer. Nandus.
Fam. 70. Percidae. No sub-ocular lamina of the suborbitals ; ento-
pterygoid present ; anterior vertebrae without transverse processes
all or most of the ribs inserted on to the transverse processes ; two nostrils
on each side ; gill membranes free from the isthmus ; 6-8 branchiostegals ;
gills 4, a slit behind the 4th ; pseudobranch variously developed, rarely
absent ; pharyngeal bones separate ; soft portion of dorsal fin not much
more developed than anal ; latter with 1 or 2 spines. F. w. fishes of
temp. N. hemisphere. Perca Art. Eur. C. and N. Asia, E.N. Amer. ;
P. fluviatilis Rond., the perch. Lucioperca Cuv., pike-perches ; Percina
(Pileoma) ; Etheostoma Raf., darters, N. Amer., E. of Rockies : also
from E. of N. Amer. are Boleosoma, Ulocentra, Diplesium, Ammocrypta,
Crystallaria ; Aspro C. and V. (Zingel), Cent. Eur. ; Percarina Nord.,
rivers discharging into Black Sea and Sea of Axov ; Acerina, Eur. and N.
Asia, A. ccrnua L., the pope.
Fam. 71. Cheilodipteridae. Cardinal-fishes ; small fishes of the tropics,
abundant in the E. Ind., some f. w., some mar. ; colour often bright
red. Ambassis Commers., the smallest Percoids, some not much more
than 1 in., trop. Indo-Pac. and f . w. of that area. Apogon Lac., coral-fishes,
on or near coral reefs, a few enter f. w. ; Apogonichthys, Chilodiptems,
Acropoma, Scorribrops, Glossamia, Epigonus, Amiichthys, Hypoclydonia ;
Pomatomus Risso, Med. and Atl. deep-water.
Fam. 72. Serranidae. Sea-bass. Second sub-orbital with an internal
lamina supporting the globe of the eye ; entopterygoid present. Anterior
vertebrae without transverse processes ; all or most of the ribs inserted
on the transverse processes where these are developed. Two nostrils on
each side ; 6 or 7 branchiostegals ; anterior vertebrae, ribs, gill mem-
branes, nostrils, gills, pseudobranch, pharyngeal bones (except
Centrogenys, in which they are united), dorsal fin as in Percidae. Carni-
vorous fish, chiefly mar., found in all warm seas and some in f. w.
One of the largest families of fishes, about 550 species ; Percichthys Gir.
f. w. of Chili, W. Argentina, Patagonia; Percilia Gir., f. w., Chili;
Lateolabrax Bleek, and Niphon C. and V., coasts China and Japan ;
ACANTHOPTERYGII. 235
Morone Mitch. (Labrax C. and V.), Atl., f. w. of N. Amer., Med. ; M . lupus,
bass ; Percolates Rani, and D.-O., f. w. and river mouths of S.-E. Aus-
tralia; Ctenolates Gthr., and Macquaria C. and V., rivers S.-E. Aus-
tralia ; Siniperca Gill., rivers of China, Manchuria and Jap. ; Acanihistius
Gill., S. Pac. and S. Atl. ; Pomodon Blgr., coasts Chili and Peru ;
Parascorpis Bleek, coasts S. Afr. ; Trachypoma Gthr., S. Pac., ; Cent-
rogenys Rich., Ind. and W.Pac. Oceans. Polyprion Cuv., Atl., and Pac.,
mostly at great depths, to 80 Ib. or more ; P. americanus Bl. Schn.
(cernium Val.), the stone-bass, excellent eating, has the habit of accom-
panying floating wood for the food on it ; P. (Oligorus) gigas, the
hapaku, coast of N. Zealand, also good eating ; Oligorus Gthr., 0. mac-
quariensis Othr., murray-cod, Australian rivers, good eating ; Stereolepis
Ayres, coasts Jap. and California ; Dinoperca Blgr., coasts of Baluchistan,
S. Afr., Sind ; Liopropoma Gill, coasts of Cuba, Jap. and Mascarene Islands ;
Aulacocephalus, Gonioplectrus, Plectropoma ; Epinephelus Bl. (Plectro-
poma}, a large number of species from temp, and trop. seas ; Anhyperodon,
Cromileptes, Paranthias. Serranus Cuv., sea-perches, coasts of Eur., Afr.
and Amer., a few enter brackish and fresh-water ; several of the specie
(S. cabrilla, scriba, hepatus) are normally hermaphrodite, distinction c f
species difficult, great variation with age, most are edible ; S. cabrilla L.
is Brit. Centropristis, Gilbertia, Colpognathus Klunz. (Plectropoma),
Caesioperca Casteln. (Anthias), Caprodon Temm. and Schleg. (Anihias),
Holanthias Gthr. (Anthias), Odontanthias, Anthias, Plectranthias, Dactylan-
thias, Callanthias, Plesiops, Trachinops, Pogonoperca, Grammistes, Rhypti-
cus, Priacanthus. Lates C. and V., L. niloticus, the perch of the Nile ; L.
calcarifer, the perch of the Ganges, cockup ; Centropomus, Psammoperca.
Fam. 73. Pseud ochro mi dae. Marine perches of small size in the
Atl., Ind. and Pac. Oceans. Opisthognathus, Pseudochromis, Cichlops,
Latilus, Caulalatilus, Lopholatilus, Malacanthus, Bathymaster, Rath-
bunella.
Fam. 74. Cepolidae. Band-fishes, marine. Cepola rubescens is
British.
Fam. 75. Hoplognathidae. Bones of the jaws with a sharp denti-
gerous edge : Australian, Japanese and Peruvian coasts. One genus
Hoplognathus.
Fam. 76. Sillaginidae. Small plain-coloured shore fishes common
in Indian Ocean to coasts of Australia. Sillago.
Fam. 77. Sciaenidae. Found on sandy shores in all warm seas, a few
species confined to f . w. ; many attain a large size, most are edible
and make a peculiar grunting or drumming noise ; air-bladder fre-
quently with numerous appendages. Pogonias Cuv. ; P. chromis L.,
the drum ; Micropogon, Umbrina, Sciaena, Pachyurus, Otolithus, Cyno-
scion, Ancylodon, Collechthys, Larimus, Eques, Nebris, Lonchurus,
Corvula, Bairdiella, Ophioscion, Stellifer, Menticirrus.
Fam. 78. Cirrhitidae. Carnivorous fishes of the warm seas, allied to
Serranidae and Scorpaenidae. Chilodactylus, Mendosoma. N emadactylus .
Latris Rich., Tasmania and N. Zealand, among the most important
food fishes of the S. hemisphere ; L. hecateia Rich., the trumpeter,
30 to 60 Ib., and L. ciliaris Forst. to 20 Ib. ; Chironemus, Cirrhites.
Fam. 79. Lutianidae. Edible, shores of warm regions. Hoplopagrus,
Evoplites, Neomaenis Gir., snappers ; Apsilus, Etelis, Verilus, Xenocys,
Nemipterus (Synagris).
Fam. 80. Haemulidae. Carnivorous fishes of the warm seas, mostly
236 SUB-CLASS (AND ORDER) TELEOSTEI.
edible. Haemulon, Anisotremus, Conodon, Pomadasis (Pristipoma), Ortho-
pristis, Diagramma.
Fam. 81. Sparidae. Sea-breams. Carnivorous shore-fishes of trop.
and temp, seas, mostly edible ; Sparnodus, Sargodon, Capitodus,
Soricidens, Asima are extinct forms from Eocene and Miocene.
Cantharina without molar or vomerine teeth. Caniharus Cuv. ;
C. lineatus Mont., black-sea bream, old-wife ; Box, Scatharus, Oblata
from Med. and adjacent Atl. ; Crenidens, Tripterodon, Ind. Oc. ;
Packymetopon, Dipterodon, Gymnocrotaphus from the Cape ; Girella,
Tepraeops from Chinese and Australian seas ; Doydixodon from
Coasts of Peru.
Haplodactylina, without molar with vomerine teeth. Haplo-
dactylus, from temp. S. Pac..
Sargina, with a single series of incisors, and several series of rounded
molars. Sargus Cuv. (Diplodus Raf., Archosargus Gill.); sargo,
sar, saragu ; several species in Med. and adjacent Atl. ; S. ovis Mitch.,
sheep's head, from coasts of U. S. ; Otrynter.
Pagrina, with single series of conical teeth in front, and molars
at the sides. Ltthrinus Cuv., trop. Indo-Pac., and one species on
W. coast Afr., Sphaerodon ; Pagrus Cuv. warmer temp, seas ; Steno-
tomus Gill., St. argyrops, scup, porgy ; Pagellus C. and V., P.
centrodontus De la R., sea-bream, chad ; Chrysophrys Cuv., trop.
and warm temp. seas. Ch. aurata L., gilt-head ; Calamus Swains.,
Amer. coasts.
Fam. 82. Maenidae. Carnivorous shore-fishes. Mavna, Smaris,
Caesio, Erythrichthys, Spicara, Emmelichthys.
Fam. 83. Gerridae. Trop. seas. Gerres, Eucinostomiis, Ulaema, Xystaema.
Fam. 84. Trichodontidae. Teeth slender and sharp, in bands on
jaws and on vomers, 4 holobranchs and large pseudobranch ; North
Pacific, living in sand near the shore. Trichodon Cuv., Arctoscopus
J. and E.
Fam. 85. Mullidae. Red mullets, slightly compressed, covered with
large thin scales which may be ctenoid ; two long erectile barbules on the
hyoid ; two short dorsals remote from each other ; pelvic s with 1
spine and 5 rays ; branchiostegals 4 ; mainly tropical. Mullus L.,
highly prized as food ; are skinned before death to produce expansion
of the red chromatophores ; M. barbattis L., Eur. species, M. sur-
muletus L., surmullet, is said to be the female of barbatus ; Mulloides,
Vpeneus.
Fam. 86. Caproidae. Boar-fishes. In rather deep water ; body
compressed ; mouth protractile ; minute teeth on jaws and vomer ; Medi-
terranean, Atlantic. Capros, Antigonia.
Fam. 87. Chaetodontidae. sometimes separated as a distinct tribe
and divided into families, may also be placed here ; the soft part of the
unpaired fins and sometimes the spinous part are covered with small
scales. The body is compressed and elevated and covered with scales
either ctenoid or smooth ; the limits of the group are uncertain ; it includes
forms showing analogies with the Carangidae on the one hand, and with
the Percoids on the other, and there are features of specialisation which
lead towards the Plectognathi. The majority are from tropical seas, and
abound chiefly in the neighbourhood of coral reefs. The beauty and
singularity of colouring of some of the genera, e.g. Chaetodon, Heniochus,
Holacanthus are remarkable.
ACANTHOPTERYGII. 237
Chaetodon Art., many species from trop. Atl. and Indo-Pac. ;
Chelmo Cuv., with long slender bill; Heniochus , Holacanthus, Po-
macanthus, Scatophagus, Ephippus, Drepane, Scorpis, Atypichthys.
Teitthis L. (Acanthurus Forsk., young form Acronurus), Naseus, Prio-
nurus, Xesurus J. and E., may be placed in the neighbourhood of the
Chaetodontidae.
Fam. 88. Osphromenidae. Second suborbital with a more or less
developed internal lamina ; entopterygoid present ; palate toothed.
Two nostrils on each side ; gills 4, a slit behind 4th ; pseudobranch
absent. Pel vies with not more than 5 soft rays. A super branchial
respiratory organ, placed in a cavity above the gills. F.w. fishes
resembling the Anabantidae, and confined to S.E. Asia and Africa ;
7 genera. Polyacanthus K. and v. H., E. Ind. Arch., beautiful
colours, some species domesticated and several varieties produced,
one called paradise-fish ; Osphromenus Commers., O. olfax Com-
mers., the gourami ; Betta Bleek, B. pugnax Cant., pla-kat or fighting
fish, very pugnacious ; they are kept by the Siamese for fighting ; when
two are brought together or a single one sees its reflection in a glass, they
become greatly excited and shine with a metallic lustre, and make repeated
darts at each other. Micracanthus, Trichogaster, Luciocephalus, Helostoma.
Fam. 89. Embiotocidae. Viviparous fishes (eggs developing in a
saccular enlargement of the oviduct), temp. N. Pacific. Ditrema,
Hysterocarpus, Cymaiogaster.
Fam. 90. Cichlidae (Chromides). No subocular shelf ; entopterygoid
present ; palate toothless ; lower pharyngeal bones more or less com-
pletely united. A single nostril on each side. Gill-membranes free from
the isthmus ; 5 or 6 branchiostegal rays ; gills 4, a slit behind the
4th ; no pseudobranch. Dorsal fin more or less elongate, with numerous
spines ; anal with 3 spines or more ; pelvics with 1 spine and 5
soft rays. F.w. or brackish water forms ; variable in form and
dentition. The eggs and young are cared for by the parents, male or
female, which shelter them in the mouth. About 45 genera, Afr., Mada-
gascar, Syria, India, C. and S.Amer. The fish-fauna of Lake Tanganyika
is largely made up of this family. Etroplus, Chromis, Acara. Heros,
Cichla, etc.
Fam. 91. Pomacentridae. Marine fishes living chiefly near coral reefs,
similar in mode of life to Chaetodon. Pomacentrus, Amphiprion, Parma,
etc.
Fam. 92. Labridae. Wrasses. No subocular shelf, entopterygoid
present, palate toothless ; anterior teeth usually strong and canine-
like ; posterior teeth often soldered at the base ; lower pharyngeals com-
pletely united into one bone with conical or tubercular teeth. Two nostrils
on each side. Body covered with cycloid scales ; one dorsal fin with the
spinous portion as well developed as, or more than the soft ; the soft
anal similar to the soft dorsal ; pelvics thoracic with 1 spine and 5
soft rays ; branchiostegals 5 or 6 ; gills 3i ; pseudobranch and
air-bladder present ; pyloric caeca and stomach caecum absent ; 60
genera, temp, and trop. seas, diminishing towards Arctic and Antarctic
circles, among rocks and kelp ; often brilliantly coloured and valued as
food fishes, are readily recognized by their thick lips. British genera are
Labrus Art., L. maculatus Bl. ballan wrasse, L. mixtus L. striped wrasse
or cook ; Crenilabrus Cuv., C, melops L. gold-sinny or cork- wing ;
Ctenolabrus C. and V., Ct. rupestris L. ; Acantholabrus C. and V. ;
238 SUB-CLASS (AND ORDER) TELEOSTEI.
Centrolabrua Gthr. ; C. exoletus L., rock-cook ; Coris Lac., C. Julia Gthr.,
rainbow wrasse. Other genera are
Tautoga Julis Duymaeria
Lachnolaemus Pseudodax Cirrhilabrus
Malacopterus Choerops Doratonotus
Cossyphus (Harpe) Xiphochilus Pseudochilinus
Chilinus Semicossyphus Hemigymnus
Epibulus Trochocopus Gomphosus
Anampses Decodon Cheilio
Platyglossus Pteragogus Cymolutes
Iridio Clepticus Chlorichthys
Halichoeres Labrichthys Xyrichthys
Novacula Labroides Miistius.
Odax ; Coridodax Gthr. ; C. pullux, butter or kelp-fish of N. Zealand ;
Olistherops, S'iphonognathus.
Fam. 93. Scaridae. Parrot-wrasses, close to preceding. Jaws form-
ing a sharp beak, the teeth being soldered together ; herbivorous fishes
especially abundant among coral reefs. Scarus Forsk., S. cretensis L.,
Med., much esteemed as food by the Ancients ; Scarichthys, Cryptotomus
(Callyodon), Pseudoscarus, Calotomus, Sparisoma.
Tribe 2. SCOMBRIFORMES, Mackerel-like fishes.
No bony stay for preoperculum. Spinous dorsal if distinct formed of
short or feeble slender spines. Pectoral arch similar to Perciformes, but
somactids more abbreviated. Pelvics thoracic ; caudal, if well developed,
with numerous rays deeply forked at the base. This tribe is not capable
of exact definition. It includes marine fishes, with few exceptions.
Fam. 94. Scombridae. Mackerels. Fusiform, naked or with small
scales, eyes lateral, dentition well developed, two dorsal fins, generally
finlets ; pel vies thoracic with 1 spine and 5 rays ; more than 10
abdominal, never more than 14 caudal vertebrae ; pseudobranch
large ; air-bladder small or absent ; most pelagic, valued as food, and
widespread ; their muscles receive a greater supply of blood and nerves
than in other fishes, and are of a red colour, and their temperature is several
degrees higher than in other fishes ; spawn in the open sea. Extinct
forms in the Eocene and Miocene. Scomber L., S. scomber L., the com-
mon mackerel without air-bladder ; S. pneumatophorus with air-bladder ;
Auxis C. et V. ; A. rochei Gthr. ; Thynmis Cuv. (Thunnus) (Orcynus
Liitken), Th. thynnus, the tunny, one of the largest fishes, to 10 ft. ;
Th. pelamys, the bonito, pursues flying fish ; some of the other species
(? separate genus Germo Jordan) are provided with very long pectoral
fins and are called by sailors " albacore." Pelamys C. et V. (Sarda
Cuv.), P. sarda C. and V. ; Cybium Cuv. (Scomberomorus Lac.). Acan-
thocybium Gill; Rhachicentron Kaup (Elacate C. et V.) may be placed
here.
Fam. 95. Gempylidae. Fishes of the high seas, widespread, descending
to considerable depths, usually breeding about rocky islands, most
used as food. Bipinnula J. and E., Ruvettus Cocco, Epinnula Poey,
Nealotus Johns., Gempylus C. et V.
Fam. 96. Lepidopidae. Transitional between muscular mackerel-
ACANTHOPTERYGII. 239
like fishes and band-shaped pelagic fishes with many vertebrae, Apha-
nopus Lowe, Euoxymetopon Poey, Lepidopus Gouan, Benthodesmus
G. and B.
Fam. 97. Trichiuridae, Surface-fishes of the tropics. Trichiurua L.
hairtails.
Fam. 98. Xiphiidae, Sword-fishes. The upper jaw is produced into
a long sword-like weapon ; pelagic fishes in all tropical and subtropical
seas, very strong and swift, change much with growth, some can
erect the dorsal fin above the water and use it as a sail ; attain to 12
or 15 ft.; attack Cetaceans and vessels and can pierce thick planks ;
sword formed by prolongation of premaxillaries and maxillaries, with
small villiform teeth on its lower surface, may be 3 ft. long and 3 in.
across at base, flesh esteemed. Histiophoms C. et V. (Istiophorus
Lac.), Ind. and Pac. with pelvics ; Tetrapturus Raf., Xiphias L.
sword-fish.
Fam. 99. Carangidae. Body more or less compressed oblong or
elevated, with small scales or naked ; teeth if present conical ; dorsal
spines few or slender or reduced ; a more or less developed spine adnate
to the soft portion of the anal, often preceded by a pair of spines separate
from the rest of the fin ; pelvics thoracic, sometimes small or absent ;
10 abdominal and 14 caudal vertebrae. Inhabitants of tropical
and temperate seas. First appear in cretaceous (Platax, Vomer, Aipich-
thys) ; extinct genera, Pseudovomcr, Amphistium, Archaeus, Dtictor,
Plionemus, Semiophorus. Living genera are : Caranx Cuv., horse mack-
erels, C. trachurus Lac. the British horse mackerel ; Argyriosus (Selene),
Micropteryx (Chloroscombrus) ; Seriola Cuv., yellow tails ; Serfolella,
Seriolickthys ; Naucrates Cuv., N. ductor C. and V., pilot-fish, to 12 in.,
precedes and accompanies sharks and vessels ; Chorinemus, Lichia, Tem-
nodon C. and V. (Pomatomus Lac.), T. saltator L., skip-jack, trop.
and sub-trop. seas ; Trachynotus, Pammelas Gthr. (Palinurichthys
Bleek), Psettus ; Platax C. and V., sea-bats, Ind. Oc. and W.
Pac. ; Anomalops, deep sea ; Diretmus, Equula, Gazza, Lactarius,
Paropsis, Platystethus, Citula, Alectis, Hynnis, Vomer. Zanclua C. and
V., rocky islands of Pacific.
Fam. 100. Coryphaenidae. Large pelagic fishes of brilliant colours
with Coryphaena, " dolphins," Brama, Taractes, Pteraclis, Diana Pvisso
(Luvarus Raf.), Ausonia, Mene.
Tribe 3. ZEORHOMBI.
Aberrant, strongly compressed Perciformes with very short pre-caudal
region, culminating in asymmetrical forms and characterised by the com-
bination of an increased number (6 to 8) of rays of pelvic fins with
absence of hypural spine (by which the Berycidae are excluded), or by
asymmetry of the skull in the forms in which the spine of the pelvic fin
has been lost.
Fam. 101. Zeidae. No subocular shelf, premaxillae strongly pro-
tractile. Gill-membranes free from the isthmus, 7 to 8 branchi-
ostegal rays ; gills 3J, pseudobranch well developed. Lower pharyngeal
bones separate. Hypural bone large, without the basal knob or spine
present in most Perciformes and in all Scombriformes. Dorsals and
anals elongate, the former with a distinct spinous portion, the latter with
1 to 4 spines detached from the soft portion. Pelvics with 1 spine
240 SUE-CLASS (AND ORDER) TELEOSTEI.
and 6 to 8 soft rays. Scales small or minute. Air-bladder present.
Marine fishes of temp. N. and S. hemispheres. Were it not
for the 3£ gills this family might be regarded as the originator of the
Pleuronectidae. Zeus Art., Z. faber L., John dory; Cyttus, Grammico-
lepis, Cyttopsis, Zenion, Oreosoma,
Fam. 102. Pleuronectidae. Flat-fishes. Cranium posteriorly normal,
anteriorly with twisted vertex to allow 2 orbits on the same side, or
one vertical and one lateral. The side on which the eyes are placed is
generally the same in the same species, but it may vary. In the young
fishes the two sides of the body are alike, and the eyes are one on each
side, with normal cranium. The body is compressed laterally and high ;
it lies on the left or right side, the lower side being colourless. Gills
4, a slit behind 4th, with pseudo branch, without air-bladder.
Abnormal specimens are found in which both sides are coloured (double
flat-fishes) ; in such, the eye which shifts, frequently does so incompletely
and remains on the top of the head ; in some cases a notch is left on the
anterior edge of the dorsal fin, suggesting the course along which the eye
has moved. Caudal fin, if well developed, supported by a large hypural,
generally without basal spine or knob. Dorsal and anal long, without
spines. Pel vies usually with 5 to 7 soft rays. The eggs float. Pset-
todes ; Hippoglossutt ouv., eyes on right side, dorsal fin commences above
the upper eye, scales cycloid ; H. vulgaris Flem., halibut, Hippoglos-
soides Gottsche, eyes right, dorsal fin commences above upper eye, scales
ctenoid ; H. limandoides Bl., rough dab. Rhombus Cuv., eyes left, dorsal
fin commences on snout, R. maximus L., turbot, R. laevis Rond.,
brill. Phrynorhombug Gthr. (Zeugopterus Gottsche), eyes left, dorsal fin
commences before the eye, scales ctenoid, Ph. unimaculatus Risso, top-
knot. Arnoglossus Bleek, eyes left, dorsal fin commences on snout, A.
megastoma Don., whiff, merry sole, A. laterna Walb., scald-fish ; Pseudo-
rhombus, Rhomboidichthys. Other genera with nearly symmetrical mouth,
in which the dorsal fin commences on the snout, are Citharus, Anti-
citharus, Brachypleura, Samaria, Psettichthys, Citharichthys, Hemirhombus,
Paralichthys, Liopsetta, Lophonectes, Lepidopsetta, Thysanopsetta. Pleuro-
nectes Art., eyes right, dorsal commences above the eye, PL platessa L.,
plaice ; PI. microcephalus Donov., smear-dab, lemon sole of fishmongers,
tasteless and wanting in firmness, occasionally passed off as the
sole by unscrupulous cooks ; PL cynoglossus L., craigfluke ; PL
limanda L., dab ; PL flesus L., flounder ; Rhombosolea. Solea
Cuv., eyes right, dorsal fin commences before the eye, and is not con-
fluent with caudal ; S. vulgaris Quensel, common sole, the most esteemed
of all food-fishes, young are called slips, nostril on the blind side not
dilated ; S. lascaris Risso (aurantiaca Gthr.), lemon-sole, one of the
nostrils on the blind side dilated and fringed ; S. variegata
Donov., banded sole, thick-back ; S. minuta Parn. (lutea Risso)
little sole ; Pardachirus, Liachirus, Synaptura, Aesopia, Cynoglossus,
Soleotalpa, Apionichthys with imperfect eyes, Ammopleurops, Aphoristia
(Symphurus), Plagusia, Achirus, Gymnachirus.
Tribe 4. KURTIFORMES.
No bony stay for the preoperculum. With one dorsal fin only, much
shorter than the anal, which is long and many-rayed. No supr abranchial
organ. Scapula absent, the coracoid supporting 4 small somactids ;
pelvics thoracic.
ACANTHOPTERYGII. 241
Fam. 103. Kurtidoe. Body compressed, deep in front, attenuated
behind. Snout short. Villiform teeth on the jaws, palatine and vomer
Indian and Pacific Oceans. One genus, Kurtus.
Tribe 5. GOBIIFORMES.
The sub-orbital ring is without a bony stay for the operculum. The
gill-membrane attached to isthmus ; gills 4, a slit behind the last ;
pseudobranch present. Pelvics inserted below pectorals with 1 spine
and 4 or 5 soft rays ; first dorsal of a few weak spines, sometimes
absent ; usually no air-bladder nor pyloric caeca. Carnivorous bottom
fishes, some marine, others f. w.
Fam. 104. Gobiidae, as above. Gobius Art., the gobies, temp,
and trop. coasts, 600 species, males of some species construct nests.
Several British species. Aphia Risso (Latrunculus Gthr.), A. pellucida*
laterally compressed, transparent fishes said to live only one year ;
Crystallogobius Gill, C. Nilssonii ; Etictenogobius, Lophiogobius , Doliich-
thys, Apocryptes, Evorthodus, Gobiodon, Triaenophorichthys. Sicydium
C. and V., small f. w. fishes in rivulets of islands of trop. Indo-
Pac. ; Lentipes ; Periophthalmus Schn., coasts of trop. Jndo-Pac.,
leave the water at low tide and hop over the wet ground by means of their
pectoral and pelvic fins and tail, the eyes are very movable and protrusible ;
Boleophthalmus very similar ; Eleotris, Trypauchen ; Callionymus L.
dragonets, the mature males have the fin-rays produced into filaments
C. draco, skulpin ; Mistichthys luzonensis from the Philippines measures-
only half an inch, and is the smallest known vertebrate. Vulsus, Bentho-
philus from the Caspian, Aniblyopus, Orthostomus, Platyptera, Lucio-
gobius, Oxymetopon, and a large number of tentative Amer. and Asiatic
genera.
Tribe C. DISCOCEPHALI (ECHENEIFORMES).
With characters of the family.
Fam. 105. Echeneididae : The Remoras. With a suctorial trans-
versely laminated oval disc on the upper surface of the head (the spinous
dorsal fin modified), thoracic pelvics. with external spines ; no air-bladder,
no pseudobranch, no finlets ; found in all seas ; attach themselves to
floating objects and other fishes. Echeneis Art. ; Phtheirichthys , Remi-
legia, Remora, Rhombochirus.
Tribe 7. SCLEROPAREI (TRIGLIIFORMES).
Acanthopterygians with the pectoral girdle normal. The third sub-
orbital bone extends across the cheek to or towards the preoperculum.
This group — the mail-cheeked fishes — is a heterogeneous one, and subject
to great variation.
Fam. 106. Scorpaenidae. Body oblong, more or less compressed ;
mouth large with villiform teeth, usually without canines ; gills 3^ or 4,
usually no slit behind the 4th gill ; pelvics thoracic, of the percoid
form with one spine and 5 soft rays ; sometimes small ; with air-
bladder (usually) and large pseudobranchs ; found in all seas as non-
migratory fishes living about rocks ; many with the skinny appendages
resembling the fronds of seaweeds ; many are viviparous. Sebastes
C. and V., S. norwegicus C. and V. ; Sebastodes Gill, shores of the N.
z — II R
242 SUB-CLASS (AND. ORDER) TELEOSTEI.
Pac. ; Helicolenus ; Scorpaena Art., scorpion-fishes, no air-bladder :
Pontinus, Glyptauchen, Lioscorpius, Setarches, Pterois, Apistus, Agriopus,
Synanceia, the dorsal spines possess poison glands and inflict serious
wounds ; Micropus, Chorismodactylus , Taenianotus, Centropogon, Penta-
roge, Tetraroge, Prosopodasys, Aploactis, Trichopleura, Hemitripterus,
Minous, Pelor.
Fam. 107. Heterolepidotidae (Hexagrammidae). Small shore fishes
of the N. Pac. ; the posterior nostril reduced to a minute pore. Chirus
Steller, with several lateral lines ; Ophiodon Gir., eultus cod, an important
food fish on the Pacific coast of N. Amer . ; Agrammus, Pleuro-
grammus, Hexagrammos, Zaniolepis, Oxylebius, Anoplopoma and Erilepis
with normal nostrils.
Fam. 108. Cottidae. Body oblong or subcylindrical ; teeth villiform
in bands ; gills 3£ to 4 ; 5th slit small or obsolete ; body naked or vari-
ously armed with scales, prickles or bony plates ; two dorsal fins (rarely
one), the spinous being less developed than the soft and than the anal ;
pseudobranch present ; air-bladder usually absent. Small fishes, mostly
of rock pools and shores of northern regions, some found in f.w. ;
of no value as food. Coitus Art., bull-heads and miller's thumbs, small
fishes from the shores and f.ws. of N. temp, zone ; C. gobio
L., common miller's thumb, f.w. ; C. scorpius and C. bubalis,
etc., common Eur. marine species ; Cantridermichihys, Icelus,
Platycephalus, Hoplichthys, Bembras, Bunocottus, Rhamphocotttis,
Triglops, Podabrus, Blepsias, Nautichthys, Scorpaenichthys, Hemilepi-
dotus, ArtediuA, Ptyonotus, Polycaulus Jordania, Paricelinus, Alcidea,
Chitonotus, Tarandichthys, Icelinus, Astrolytes, Archistes, Axyrias, Arte-
diellus, Ruscarius, Rastrinus, Radulinus, Prionistius, Elanura Melletes
Enophrys, Uranidea, Myoxocephalus, Megalocottus, Zesticelus, Gymnc-
canthus, Nautiscus, Ulca, Psychrolutes.
Fam. 109. Cyclopteridae (Discoboli). Lump-suckers. Short and
thick with a smooth, tubercular or spiny skin ; branchiostegals 6 ; gills
3| ; 2 dorsal fins ; pelvics thoracic, small, forming the bony centre of a
sucking disc, by which they attach themselves to stones, etc. ; air-bladder
absent ; northern seas. Cyclopterus Art., C. lumpus L. lump-sucker,
cock-and-hen-paddle, skin with tubercles ; Eumicrotremus, Lethotremus ,
Liparops ; Liparis Art. ; L. vulgaris Flem., sea-snail ; L. montagui Cuv.,
diminutive lump-sucker ; Neoliparis, Bathyphasma, Careproctus, Oyrin-
ichihys, Amitra, Paraliparis, Rhinoliparis.
Fam. 110. Agonidae. Fishes of the cold seas, living among rocks or
kelp ; most of small size and fantastic form, not valuable as food ; with
8 to 12 longitudinal rows of imbricated radially striated plates.
Percis Scop. (Hippocephaltis Swains.), Agonomalus, Hypsagonus, Stel-
lerina, Occa, Brachyopsis (Siphagonus), Pallasina, Leptogonus, Podothecus,
Agonus B. Schn., A. cataphractus L., sea poacher ; Stelgis, Agonopsis,
Averruncus, Sarritor, Xystes, Eaihyagonus, Xenochirus, Odontopyxis,
Bothragonus, Aspidophoroides.
Fam. 111. Triglidae. Gurnards. Elongate, more cr less fusiform,
covered with scales or bony plates ; gills 4, a large slit behind the 4th ;
pseudobranch and air-bladder present ; latter said to have an open pneu-
matic duct (Gunther) ; post-temporal forms an integral part of the cra-
nium ; pectoral large with broad base ; 3 lower rays detached and used
as feelers ; all warm seas ; grunt when taken out of water, caused either
by escape of air through open pneumatic duct, or by compression of air
ACANTHOPTERYGII. 243
bladder by muscles. Trigla Art., Gurnards, with British species, T. pini,
red gurnard ; T. lineata, streaked gurnard ; T. hirundo, sapphirine gur-
nard ; T. cuculus Bloch's gurnard ; T. lyra, the piper ; T. obscura, the
long-firmed. Prionotus Lac., all but one American.
Fam. 112. Peristediidae, Deep-sea gurnards. Peristedion Lac. (Peri-
stethus Kaup) ; Vulsiculus.
Fam. 113. Cephalacanthidae. Flying gurnards, with large pectorals,
are able to move in the air, but for a shorter distance than the flying fish.
Cephalacanthus Lac. (Dactylopterus Lac.).
Tribe 8. JUGULARES (BLENNIIFORMES).
Pelvics jugular ; gill-openings in front of the pectoral fin, the base of
which is vertical or subvertical.
Fam. 114. Trachinidae. Elongated, naked or covered with scales ;
teeth small ; one or two dorsals ; the spinous portion always shorter than
the soft ; the anal like the soft dorsal ; no finlets ; pelvics with 1 spine
and 5 rays ; carnivorous coast fishes of small size, world-wide, bottom
fishes in small depths, except Bathydraco.
FIG. 128. — Zoarces viviparus. A anus ; V urinogenital opening (from Claus).
Uranoscopina, Star-gazers. Eyes on upper surface of head
Uranoscopus, Leptoscopus, Agnus (Astroscopus), Kathetostoma, Anema.
Dactyloscopus, Gillellus, Dactylagnus, Myxodagnus.
Trachinina. Eyes more or less lateral. Trachinus Cuv., weevers ;
the mucus is poisonous, and they inflict poisonous wounds with
their spines, they lurk in the sands, and are a caution to bathers.
T. draco and T. vipera are British. Champsodon, Bovichthys, Bathy-
draco, Chaenichthys , Aphritis, Acanthaphritis, Eleginus C. and V.,
Bembrops, Chimarrhichthys, Cottoperca, Percophis.
Nototheniina. Lateral line interrupted ; dorsal fin of two por-
tions, Antarctic. Notothenia, Harpagifer.
Fam. 115. Trichonotidae. Trichonotus, Hemerocoetes.
Fam. 116. Gobiesocidae. Suckers. Body rather elongate, tadpole-
shaped, with smooth scaleless skin ; breast with a broad sucking disc
between the wide set pelvic fins ; no spinous dorsal ; no sub-orbital ring
or air-bladder ; gills 3£ ; marine fishes, living chiefly among loose stones
between tide-marks. Lepadogaster Gouan ; L. gouanii Lac. ; L. decan-
dolii Risso ; L. bitnaculatus Flem. ; Leptopterygius, Chorisochismus,
Cotylis, Gobiesox, Diplocrepis, Crepidogaster, Trachelochismus, Caularchus,
Bryssetaeres, Rimicola, Arbaciosa.
Fam. 117. Blenniidae, Blennies. Lateral line various, often want-
ing, often duplicated ; teeth various ; pelvics jugular or sub-thoracic,
•with 1 spine and 1 to 3 soft rays, often absent ; pseudobranch
244 SUB-CLASS (AND ORDER) TELEOSTEI.
present ; gills 4, a slit behind the 4th ; dorsal fin formed entirely
of spines. Littoral fishes of great generic variety in all temp, and
trop. seas ; some in f.w., e.g., in the Italian Lakes. Anarr-
hichas Art., sea- wolf, to 6 ft., strong tubercular teeth, N. Seas; A.
lupus L. , wo If -fish ( Fig. 117); Anarrhichthys ; Blennius Art. , littoral or attach
themselves to floating objects, readily accustom themselves to f.w.,
some acclimatised in inland lakes (B. vulgaris). British species are :
B. gattorugine Bloch., tompot : B. ocellaris L., butterfly blenny ; B,
galerita L. ; B. pholis L., shanny ; Chasmodes, Pelroscirtes trop.
Ind.-Pac. ; Salarias, Clinus, Cristiceps, Cremnobates, Tripterygium,
Slichaeus ; Blenniops Nils. (Carelophus Kroyer) ; B. ascanii Walb.
British ; Centronotus Bl. Schn. (Pholis Scop.) ; C. gunellus Bl. Sch.,
butter-fish, is British ; Apodichthys, Xiphidion, Cryptacanthodes, Pataecus.
Zoarces Cuv. ; Z. viviparus L., a viviparous form in British seas (Fig. 128),
Blennophis, Nemophis, Plagiotremus, Neoclinus, Cebidichthys, Myxodes,
Heterostichus, Dictyosoma, Lepidoblennius, Gunelichihys , Urocentrus,
Stichaeopsis, Sticharium, Notograptus, Pholidichthys, Pseudoblennius>
and a large number of other genera too numerous to mention.
Fam. 118. Batrachidae. With undivided post-temporal; gill-arches
reduced to 3 ; gills 3, with slit behind last ; no pseudobranch ;
head large, depressed ; 2 dorsals ; soft dorsal long ; anal similar,
but shorter ; tail homocercal ; carnivorous fishes of the warm seas ; some
ascending rivers. Batrachus Bl. Schn. (Batrachoides Lac.) ; Thallasso-
phryne Gthr., two dorsal and opercular spines with poison sacs; Pori-
chthys ; Opsanus Raf. (Batrachus Jord. and Gilb.), toad-fishes, O. tau L. ;
Daector.
Fam. 119. Ophidiidae. Body more or less elongate ; naked or scaly ;
median fins generally united, no separate anterior dorsal or anal ; pelvics
small or absent ; tail tapering ; without distinct caudal fin ; gill-openings
wide ; gill-membranes not attached to isthmus. Marine fishes, except
Lucifuga, partly littoral, partly bathybial.
Brotulina. Pelvic fins present, attached to the pectoral arch.
Brotula, Lucifuga, subterranean waters of Cuba, eye reduced or
absent ; bathybial are Bathynectes, Acanthonus, Typhlonus, Aphyonus,
Rhinonus ; surface forms are Brotulophis, Halidesmus, Dinema-
tichthys, Bythites ; Sirembo and Pteridium are from moderate depths ,.
and a considerable number of other genera (45 in all).
Ophidiina. Pelvic fins replaced by a pair of bifid filaments below
the glossohyal. Ophidium Art. ; Op. barbatum L. ; Genypterus.
Lepophidium, Rissola, Chilara, Otophidium.
Congrogadina. No pelvics, vent remote from head. Congro-
gadus, Haliophis.
Tribe 9. TAENIOSOMI (LOPHOTIFORMES).
Compressed, often ribbon-like fishes of doubtful affinities, probably
related to the earlier Acanthopterygians, the pelvics when well developed
having as many as 7 to 9 rays ; dorsal fin extending from the head
to the end of the tail ; anal fin short or absent. Pectoral fin with 3
short somactids. Scales minute or absent. Deep-sea or pelagic fishes
from the Atlantic, Mediterranean and Pacific.
Fam. 120. Trachypteridae., Ribbon-fishes. Deep-sea fishes often
found floating dead on the surface with their tissues loosened by the
OPISTHOMI. 245
gaseous expansion. Body riband-shaped ; dorsal fin as long as the body ;
anal absent ; caudal feeble, or not in the longitudinal axis of the fish.
In the young form some of the fin rays are enormously elongated. Tra-
chypterus Gouan ; Regakcus gksne, king of the herrings ; Stylophorns.
Fam. 121. Lophotidae.
Sub-order 11. OPISTHOMI.
Air-bladder without open duct. Operculum well developed,
hidden under the skin ; supraoccipital in contact with f rentals ;
pectoral arch suspended from the vertebral column far behind
the skull ; no mesocoracoid ; pelvics absent ; median fins with
spines.
Fam. 122. Mastacembelidae. F.w. fishes almost confined to
the Indian and Ethiopian regions ; Acanthopterygian eels. They con-
stitute part of the fish fauna of Lake Tanganyika. Mastacembelus*\
FIG. 129. — Lophius piscatorius (after Cuvier and Valenciennes, from Claus).
Sub-order 12. PEDICULATI (LOPHIIFORMES). Anglers.
Head and anterior part of body very large and without scales.
The spinous dorsal fin is advanced forwards, composed of a few
more or less isolated spines, often transformed into tentacles, or
entirely absent ; pelvic fins, jugular with 4 or 5 soft rays,
sometimes absent. Gill opening a small foramen in or near the
axil, posterior to the base of the pectoral ; pseudobranch usually
absent ; gills 2J, 3, or 3J ; air-bladder without duct. The som-
actids are elongated, forming a kind of arm which supports
the broad pectoral fins and by means of which they are able
to walk over moist ground, etc., in search of prey or to burrow
in the sand or clasp foreign objects. Marine fishes chiefly of
24G SUB-CLASS (AND ORDER) TELEOSTEI.
the tropics and abysses. Bad swimmers ; those found near the
coasts lurk in the mud or sand or among stones or sea-weed,
while the pelagic forms attach themselves to floating sea-weed.
Fam. 123. Lophiidae. Lophius Art., frog-fishes, anglers ; L. pisca-
torius L. (Fig. 129), with above-mentioned names ; also monk-fish, toad-
fish, sea-devil ; the anterior tentacle terminates in a lappet resembling
a worm or piece of meat ; is movable and is used as a bait ; the terminal
lappet can be rapidly regenerated ; their spawn has the form of floating
sheets of mucus, often of large size ; remarkable for their voracity.
Ceratias, Himantolophus, Melanocetus, Oneirodes, Mancalias, Cryptosaras,
Linophryne are abyssal ; Antennarius is pelagic ; Chaunax, Malthe (Ogco-
cephalus), Halieutaea, Dibranchus, Aegaeonichthys, Lophiomus, Ptero-
phryne.
Sub-order 13. PLECTOGNATHI.
With rough scales or with ossifications of the cutis in the form
Fio. 130.— Ostracion triqueter (Regn6 animal).
of scutes or spines ; skin sometimes entirely naked. Skeleton
incompletely ossified, with the vertebrae in small number. Gills
pectinate, a narrow gill-opening in front of the pectoral fins.
Mouth narrow ; the bones of the upper jaw generally firmly united.
A soft dorsal fin opposite to the anal ; sometimes elements of
spinous dorsal as well. Pel vies none or reduced to spines. Air-
bladder without duct. Scapula suspended to cranium by a post-
temporal. Inactive fishes, chiefly of the tropics.
Tribe 1. SCLERODERMI.
Supraclavicle vertical ; somactids not enlarged, movably attached
by ligament to the scapula and coracoid ; all the vertebrae with a single
neural spine ; dentary and articular co-ossified.
Fam. 124. Triaeanthidae. Covered with hard or spinous scales,
teeth separate, with spinous dorsal, pelvics paired. Indian and W.
Pacific Oceans. Triacanthus ; Triacanthodes ; Halimochirurgus, deep-sea.
PLECTOGNATHI. 247
Fam. 125. Triodontidae. Covered with small spiny bony laminae;
teeth fused into a beak ; without spinous dorsal and pelvics ; abdomen
with a dilatable sac ; Indian Ocean. Triodon.
Fam. 126. Balistidae. .Covered with juxtaposed movable scutes or
with minute rough scales ; teeth incisor-like ; spinous dorsal with one
to three spines ; pelvics, if present, as short rough spine ; flesh of many
species poisonous. Balistes Art., file-fishes, trigger -fishes, trop. or sub-
trop., feed on corals and molluscs, enemies of pearl-fisheries ; to 3 ft. ;
B. capriscus has been taken off Britain ; Monacanthus, Paraluteres, Pseuda-
luteres, Pseudomonacanthus, Alutera, Psilocephalus.
Fam. 127. Ostraciontidae. Trunk-fishes. Encased in a carapace
formed of large juxtaposed bony plates ; teeth incisor-like ; without
spinous dorsal and pelvics. Tropical seas, living near bottom ; about
20 species. Ostracion Art., coffer-fishes (Fig. 130) ; Aracana, Lactophrys.
Tribe 2. GYMNODONTES.
Supraclavicle oblique ; lower three somactids enlarged and immovably
united to the coraco-scapular cartilage, upper somactid small, suturally
united to the scapula. Anterior vertebrae with bifid divergent spines ;
suture between dentary and articular visible ; without spinous dorsal
and pelvics ; teeth fused to form beak ; trop. and sub- trop. seas,
a few in f.w. ; when taken they frequently produce sound by
expulsion of air from oesophagus ; flesh usually poisonous.
Fam. 128. Tetrodontidae. Globe-fishes. Beak with median suture;
skin naked or with movable spines ; caudal fin present ; can inflate the
oesophagus with air and so distend the body ; when dilated the spines
of the scaleless skin become erected, and when in this condition they turn
over and float at the surface belly upwards ; in some cases the spines
about the head can be erected by cutaneous muscles. Tetrodon L. ; T.
lagocephalua has been taken off Britain ; T. psittacus (Brazil), T. fahaka,
(Nile), and T. ftuviatilis (E. Ind.) are in large rivers. Ephippion,
Tropidichthys, Xenopterus, Chonerinus.
Fam, 129. Diodontidae. Porcupine-fishes. Beak without median
suture, belly inflatable ; trop. seas. Diodon Gthr. ; D. hystrix L. ;
Lyosphaera.
Fam. 130. Molidae. Body compressed, very short, dorsal and
anal fins confluent ; no air-bladder, tail short, without caudal fin ;
beak without median suture ; body non-inflatable ; skin rough or
tesselated ; an accessory opercular gill ; fishes of the open seas ; appar-
ently composed of a huge head to which small fins are attached ; bask
at the surface in calm weather ; young very different in form to adult
and described as a distinct genus, Molacanthus. Orihagoriscus Bloch,
(Mola Cuv.) ; 0. mola Bl. Schn., sun-fish, attains a large size ; Tanzania.
CHAPTER IX.
DIPNOI.*
Scaly fish with gills and lungs, external and internal nares,
cartilaginous autostylic skull covered with osseous dermal scutes,
persistent notochord with unsegmented sheath, and with an oper-
culum covering the gill apertures. Paired fins with long segmented
cartilaginous axes. Caudal fin diphycercal or heterocercal.
Branchiostegal rays absent. Heart with spirally twisted conus
arteriosus. Palatal and mandibular teeth few, tuberculated,
as though made up of fused denticles. The mid-brain roof is not
divided into optic lobes.
The important characters of the Dipnoi are the peculiar teeth,
the acutely lobate often fringed paired fins, the autostylic skull,
the internal opening of the nasal sac, the cartilaginous endo-
skeleton almost devoid of cartilage bone, the persistent uncon-
stricted notochord and absence of vertebral bodies, the conus
arteriosus, the incipient doubleness of the heart, and the
presence of a vein resembling the inferior vena-cava. In conse-
quence of the form of the skull, the vascular system and breathing
arrangements, the possession of an internal as well as of an
external opening of the nasal sac, the nature of the egg and the
* Owen, Lepidosiren, Trans. Lin. Soc. 17, 1840. Hyrtl, Lepidosiren
paradoxa, Prag, 1845. Giinther, Ceratodus, Phil. Trans, 161, 1872.
Huxley, Ceratodus, Proc. Zool. Soc., 1876, p. 24. Bridge, Skull of Lepi-
dosiren, Trans. Zool. Soc., 14, 1897; p. 325. Fritsch, Fauna der Gaskohle,
Bd. 2., 1888. Lankester, Hearts of Ceratodus, Protopterus, etc., Trans.
Zool. Soc. 10, 1879, p. 493. Boas, Herz u. Arterienbogen bei Ceratodus
u. Protopterus, Morph. Jahrb., 6, 1890, p. 321. W. N. Parker, Anatomy
of Protopterus, Trans. R. Irish Acad., 30, 1892, p. 109. Spencer, Blood-
vessels of Ceratodus, Maclay memorial volume, Lin. Soc. N.S.W., 1893.
Ehlers, Zur Kenntniss der Eingeweide v. Lepidosiren, Nach. K. Gesellsch.
d. W. zu Gottingen, 1895. R. Burckhardt, Das Centralnervensystem v.
Protopterus annectens, Berlin, 1892. Kerr, External Features in the
development of Lepidosiren, Phil. Trans., 192, 1900, p. 299. Semon,
Papers on Ceratodus by different authors in Zoologische Forschungsreisen
in Australien etc. Jena, 1898.
DIPNOI. 249
early development, the order has been said to^be intermediate
between the Fishes and Amphibia. By the form of the teeth
and the autostylic character of the skull, they resemble the
Holocephali ; while in the structure of the paired fins, the scales,
and, if we may judge by Polypterus, the form and function of
the air bladder, they approach the Crossopterygian Ganoids.
By their whole organisation they are essentially piscine, and in
many features of their structure, e.g. the nature of their endo-
skeleton and the structure of their vertebral column they
resemble the lowest fishes. In short they constitute an order
of fishes which, while showing affinity to most of the other
orders, are peculiar in possessing features which are not found
in other fishes but which are found in Amphibia. This
Amphibian tint, while not for one moment justifying an assign-
ment of the order to the Amphibia, or even to an intermediate
position between that class and Pisces, may by enlarging our
conception of the range of piscine structure be of service to us
in our speculative treatment of the numerous extinct forms
which, always imperfectly preserved, are in many cases most
difficult of interpretation.
The gill slits are covered by an opercular fold. There are no
eyelids. The nasal sacs possess as in Teleosteans and Ganoids
two openings, but one of these is into the mouth on each side of
the vomerine teeth, the other on the under side of the head
close to the mouth.
The tail is diphycercal, and the pelvic fins are inserted a little
in front of the anus. There are in Ceratodus two abdominal
pores leading into the body cavity, one on each side of, but a
little behind, the anus. In Lepidosiren abdominal pores are
not found ; in Protopterus it is said that there are two which
join to open by a single pore just in front of the anus within the
cloacal sphincter.
The scales lie in pockets of the dermis and resemble in structure
the cycloid scales of Teleosteans. The superficial layer is without
bone-cells, which however are found in the deeper fibrous layer.
There is no ganoin.
In the vertebral column the notochord persists and is uncon-
stricted, the sheath, which is invaded by cartilage, does not
segment or ossify ; there are dorsal and ventral arches which do
not meet laterally on the notochordal sheath (except sometimes
250 DIPXOI.
at the hind end of the tail and in the first two or three segments),
and intercalated pieces may occur. The ribs, arches, and fin-
supports show a tendency to ossification.
The chondrocranium consists almost entirely of cartilage. In
Ceratodus it is massive and completely developed, there being
no fontanelles in the roof or floor. In Lepidosiren the trabeculae
cranii have retained their primitive condition of rods of cartilage
bounding a large pituitary fontanelle, and have not extended
dorsally, so that the greater part of the side- walls and roof are
formed of membrane bone. The notochord is continued into
the base of the skull,with which the notochordal sheath of the
vertebral column is continuously and immovably united. In
Lepidosiren and Protopterus the first distinguishable neural arch is
ossified and placed behind the foramen for the second spinal
nerve, and the first rib (cranial rib) is articulated to the occipital
cartilage. In Ceratodus it would appear that the number of neural
arches which have been incorporated in the skull is greater.
The two exoccipital bones are the only cartilage bones found in
the chondrocranium.* The space containing the membranous
labyrinth is open to the cranial cavity as in Ganoids, Holocephali,
and Teleosteans. The skull is completely covered dorsally
(except over a part of the ethmoid cartilage) by dermal mem-
brane bones, on the floor there is a parasphenoid and a trace of
two vomers in the two chisel-shaped vomerine teeth in the front
of the roof of the mouth. There are two large palatopterygoid
bones, which meet in front beneath the ethmoid and carry two
large, tuberculated, palatal teeth. Maxillae and premaxillae
are absent. The suspensorium has the form of a triangular
shelf, continuous with and projecting from the skull, and sup-
ported by the stout pterygo-palatine bone in front and by the
squamosal behind. The quadrate region of this suspensorium
is unossified. Meckel's cartilage is persistent and ensheathed
by two, sometimes three, membrane bones, of which the splenials
are of unusual size and carry the two large tuberculated teeth.
The teeth consist of fenestrated bony tissue continuous with
that of the jaws, and of dentine covered by enamel on the exposed
tubercles. The hyoid is attached to the hinder upper part of
the suspensorium where it passes into the auditory cartilage,
* Fiirbringer (Anat. Anzeiger, 24) finds that these do not belong to
the chondrocranium, but are the neural arch of an incorporated vertebra.
SKELETON. GILL-CLEFTS. 251
and consists in Ceratodus of a small dorsal piece, identified by
Huxley as the hyomandibular, and of a stout ossified ventral
piece which joins its fellow of the opposite side. A post -temporal
is present in Protopterus and Ceratodus but not in Lepidosiren.
There are two opercular bones, the operculum and inter-
operculum, each of which carries on its inner side a small band
of cartilage (cartilaginous opercular rays). The branchial
arches are five in number, slender, and often unsegmented.
The pectoral girdle is placed just behind the head and consists
of a cartilaginous coraco-scapular arch, continuous with its
fellow ventrally. It is overlaid by a closely applied clavicle and
supraclavicle (cleithrum). The skeleton of the pectoral fin is
unibasal, rachiostichous and mesorachic. It consists in
Ceratodus (Fig. 138) of a segmented cartilaginous axis (axial
somactids) which tapers distally and proximally is attached to
a stout basal somactid. The latter is articulated to the shoulder
girdle. Attached to the pieces of the axis are on each side a
number of small segmented somactids which carry a fringe of
dermotrichia. The fin is therefore fringed on the crossopterygian
type and its skeleton constitutes what has been called the
" archipteryyium" The pelvic girdle is a single piece of cartilage
in the middle line, with a forwardly directed process. The
pelvic fin skeleton is very similar to the pectoral. In Lepidosiren
the paired fins are filamentous and the skeleton consists of the
axis of Ceratodus only, without the lateral somactids and dermo-
trichia. In Protopterus somactids and dermotrichia are present,
though in a reduced form.
Gill-Clefts. There is no spiracle ; the hyoid arch bears a
gill which in Ceratodus is a pseudobranch supplied by arterial
blood, but in Protopterus is a gill supplied by a branch from the
afferent vessel to the first branchial arch. In Ceratodus and
Protopterus there are five gill- clefts, the last being behind the
4th branchial arch. In Lepidosiren the hyobranchial cleft is
closed in the adult though open in the larva. The partitions
between the gill-clefts are membranous septa to which the
branchial lamellae are attached, thus approximating to the
condition found in Selachians. In Ceratodus the four anterior
branchial arches bear a double row of lamellae ; in Protopterus
and Lepidosiren* the 1st and 2nd branchials are without gills,
* There is considerable individual variation in the respiratory
lamellae of Lepidosiren.
252 DIPNOI.
the 3rd and 4th have a double series ; while in Protopterus the 5th
arch bears one row of gills which are probably an extension of
the hindermost row of the 4th branchial.
In Protopterus there may be three external gill-filaments just
above the opsrculum. They are not present in all specimens.
They are not found in the adults of the other two genera, though
external gills are found in the larva of Lepidosiren (Fig. 134).
The stomach is a dilatation of the hind end of the oesophagus
and the pylorus is at its hind end. The intestine is straight
with a spiral valve, and is supported by a ventral as well as by
a dorsal mesentery. The hind end of it is a cloaca and receives
the urinary and generative ducts.
The spleen appears to be embedded in the wall of the stomach
and there is a pancreas concealed round the bile duct and in
the wall of the intestine. There are no pyloric caeca.
The lung of Ceratodus is single ; it lies on the dorsal side of
the alimentary canal, but opens into the ventral wall of the
oesophagus, round the right side of which it turns. It contains
a central cavity communicating with air-cells in the thickness
of its walls. The lungs of Protopterus and of Lepidosiren are
very similar, but they are double except in front where they
open into the oesophagus.
The heart shows a tendency to be divided into two lateral
halves. This is most completely carried out in Lepidosiren,
least so in Ceratodus. The conus arteriosus is well developed
and twisted into a spiral (Fig. 131). It contains several longi-
tudinal rows of valves ; most of these valves are small, but
those of one row are enlarged (Fig. 131, B) and to a certain
extent united so as to form a longitudinal valve which in the
contraction of the heart divides the conus into two halves, in
such a way that the venous blood is directed into the two
posterior afferent branchial arteries of each side, while the
arterial and the mixed blood is sent into the branchial arteries
to the 1st and 2nd branchial arches. The ventral aorta is
extremely short as in Amphibia, the branchial arteries arising
close together immediately in front of the conus (Fig. 131 A).
In Ceratodus the sinus venosus is divided into a narrow left portion into
which the pulmonary veins open and a larger right portion receiving the
systemic veins (Fig. 131, svp, sv). Both of these open into the single auricle,
which is partially divided by a septum arising from its dorsal wall (w).
VASCULAR SYSTEM.
253
This incomplete septum is continued into the ventricle. The conus pre-
sents traces of eight transverse rows of valves. The number in each row
varies in different parts of the conus (posteriorly about eight, anteriorly
four or even one). The valves of the first two rows and those of one
longitudinal row are larger than the others. The longitudinal row referred
to lies in the ventral middle line in the posterior part of the conus and to
the right side in the anterior region (in consequence of the spiral twi.«t
which the anterior part of the conus has undergone). These valves are
so enlarged and united with one another by fibres that they form the
longitudinal valve above referred to.
In the heart of Protopterus the arrangements are very similar, .except
7iG 131. A. ventral
view of heart of
Ceratodus (after
Boas), at, auri-
cle ; ve, ventricle *
c, conus; la to 4a,
arteries to the four
branchial arches
springing close to-
gether from the
ventral aorta va.
B. — Median section through the contracted
heart of Ceratodus slightly diagrammatic
(after Boas) ; the posterior part of the
conus only is shown, at, auricle ; co,
conus ; ve, wall of ventricle ; svp, left
(pulmonary) division of sinus venosus ;
sv, larger right (systemic) division of
sinus ; w, imperfect auricular septum, the
cavity of the auricle can be seen in the
section passing on the ventral side of the
free edge of this ; 1s, I6, the 5tb and 6th
valves of the row constituting the longi-
tudinal fold.
that (1) the valves of the longitudinal row are more completely united to
form the longitudinal fold ; (2) there is in the anterior part a second
longitudinal fold formed from two valves of the two first transverse rows ;
and (3) the other smaller valves of the conus are much less numerous than
in Ceratodus.
In Lepidosiren the two longitudinal valves of the conus completely
divide it into two parts, and the ventricular septum indicated in the other
two genera is complete except for a small pore between it and the conus
septum. The auricular septum is also well developed, though the meshes
in the ventricular end of it may admit of some intercommunication
through it.
The ventral aorta gives off three arteries on each side. The
254 DIPNOI.
posterior of these divides to form the afferent arteries to the
3rd and 4th branchial arches, on which a double row of gill-
filaments are always present ; it arises somewhat more dorsally
than the two anterior vessels which go to the 1st and 2nd
branchial arches, which are without gills in Proloplerus. The
anterior of these, viz. that to the first branchial arch sends a
branch to the hyoid gill in Protopterus. The efferent vessels of
each side unite to form one vessel (root of dorsal aorta), which
joins its fellow to form the dorsal aorta. The carotid arteries
pass off from the efferent vessel of the hyoid gill which joins the
aortic root, and the pulmonary arteries arise from the roots of
the aorta.
In Ceratodus the hyoid gill is a pseudobranch and is supplied by a vessel
from the ventral end of the efferent vessel of the first branchial arch ; its
blood is returned into an artery called the anterior carotid, which goes to
the head. The pulmonary artery also arises from the efferent vessel of
the fourth branchial arch.
The anterior part of the venous system is constructed on the
usual piscine type. In the posterior part there are some remark-
able peculiarities which recall Amphibia. On the left side there
is a posterior cardinal which arises in the left kidney and empties
into the left ductus cuvieri ; on the right side there is a vein
which may be the right posterior cardinal, but which is called
the inferior vena cava, which indeed it closely resembles ; it
arises in the right kidney, passes anteriorly through the liver,
receives in Protopterus the hepatic veins, and opens directly
into the sinus venosus. The kidney is supplied by the dorsal
aorta and by the caudal vein. .
In Ceratodus the hepatic veins fall into the sinus venosus, and there is
an anterior abdominal vein formed by the union of a branch from each
iliac vein (from the pelvic limb). It empties directly into the sinus
venosus. Moreover in Ceratodus the left posterior cardinal and inferior
vena cava are direct continuations of the two branches into which the
caudal vein bifurcates ; they receive from, but do not give blood to, the
kidney. The venous blood to the kidney is partly derived from
veins of the posterior body wall and partly from a branch of the iliac vein.
In Ceratodus and possibly in all Dipnoi there is, as in Elasmobranchii, a
sub-intestinal vein which lies along the spiral valve and joins the portal
vein.
The brain* presents the following features (Fig. 132). The
* Burckhardt, Das Centralnervensystem von Protopterus annectens, Berlin
1892. Kerr, Q.J.M.8., vol. 46, 1903, p. 428.
NERVOUS SYSTEM.
255
-10
cerebrum is double and gives off the olfactory lobes from the
dorsal surface anteriorly ; each half con-
tains a lateral ventricle, which is con-
tinued into the olfactory lobe. There
is no thin pallium, but each lateral
ventricle contains the usual choroid
plexus which projects into it from its
hind end, where its wall is continuous
with the thin roof of the thalamencepha-
lon (see below). Behind this the roof
dips inwards as a fold, the velum
transversum ; then follows a protrusion
of the roof with thin walls, behind
which is the superior commissure, the
attachment of the pineal stalk, and
the posterior commissure. The pineal
stalk is inclined forwards and ends in
the pineal body which lies on this
complex of structures. The roof of
the mid-brain is not bilobed externally,
and the cerebellum is small. On the
dorsal side of the 4th ventricle, there
is on each side a diverticulum of the
membranous labyrinth called the sac-
cus endolymphaticus, which gives off
diverticula. The infundibulum pre-
sents lobi inferiores and a succus
vasculosus.
Just in front of the velum transversum
(Fig. 133) the roof of the brain is thin and
folded, and swollen up. In Lepidosiren
the velum is a paired structure, not ex-
tending across the middle line (Kerr).
The first spinal nerve is the hypo-
glossal ; it perforates or notches the
" exoccipital." The second spinal nerve
either perforates the exoccipital (Pro-
topterus) or emerges between the ex-
occipital and the first distinct neural
arch.
: —7
-if— - 4.
\ 3
FIG. 132. — Dorsal view of the
brain of Protopterus (after
Burckhardt). 1 spinal cord ;
2 dorsal root of first spinal
nerve ; 3 diverticula of 4
the saccus endolymphaticus ; 5
medulla oblongata ; fi fourth
ventricle ; 7 cerebellum ; 8
mesencephalon ; 9 stalk of
pineal body ; 10 thalamen-
cephalon ; 11 velum trans-
versum ; 12 pineal body ; 13
lobus hippocampi ; 14 choroid
plexus ; lf> cerebrum ; 16
olfactory lobe.
DIPNOI.
Urinogenital Organs. The kidneys* are without nephro-
stornata in the adult ; they are elongated glands not differentiated
into meso- and meta-nephros. Each of them has a ureter which
either joins its fellow before opening into the cloaca (Ceratodus}
or the ureters open separately into a cloacal caecum
derived in development from the fused hind ends of
the longitudinal ducts. The larva possesses a pro-
nephros on the Amphibian type with two funnels and an
elongated glomerulus contained in an incompletely separated off
portion of the body-cavity. The ovaries and testes are elongated
bodies. The oviducts are convoluted tubes opening anteriorly
and far forward into the body cavity and joining behind to open
into the cloaca just in front of the ureters. The testis has a
FIG. 133.— Longitudinal vertical section through the brain of Protopterus (after Burckhardt).
1 choroid plexus of 4th ventricle ; 2 cerebellum ; 3 mesencephalon ; 4 posterior com-
missure ; fi pineal stalk ; 6 superior commissure ; 7 velum transversum ; 8 pineal body ;
.9 choroid plexus ; 10 corpus callosum ; 11 anterior commissure ; 12 optic chiasma ; 13
saccus vasculosus ; 14 pituitary body ; 15 spinal cord.
longitudinal duct extending along its whole course. This duct
communicates with the tubuli seminiferi on the one hand and by
a number of transverse tubes with the hinder part of the kidney.
It ends blindly in front and behind, and has been fully made out
in Lepidosiren ; it probably exists in Ceratodus. A similar duct
is described by Parker in Protopterus, where it is said to open
into the cloaca and not to communicate by transverse tubes
with the kidney. This is however denied by Kerr. The male
possesses a well-marked vestige of the oviduct.
The egg is of considerable size and undergoes complete unequal
cleavage. The early development is very like that of Amphibia
* Kerr, Proc. Zool. Soc. 1901, p. 484. .
HABITS. 257
and the blastopore persists as the anus. In Ceratodus the central
nervous system arises by the closing in of a groove as in most
vertebrates. In Lepidosiren the medullary canal has at first
the form of a solid keel-like thickening of the ectoderm, as in
Lepidosteus and Teleosteans. The young are hatched as larvae
which possess external gills in Lepidosiren, but not in Ceratodus.
Growth probably lasts for some time if not throughout life, and
a length of three feet may be attained. It is quite probable
that during this long period of growth the structure of the
animal may change considerably, and that contradictory
anatomical results may be explained in this way. It is probable
that the fins can be regenerated.
In Protopterus there does not appear to be any marked external
difference between the sexes, but in Lepidosiren the male
FIG. 134. — A larva of Lepidosiren 25 days after hatching, -showing the external gills,[ the
rudiments of the fore and hind limbs, and the cloacal aperture c.l.o (after Kerr).j
acquires during the breeding season a large tuft of long highly
vascular papillae on its pelvic fins. Both these genera breathe
air when living in water, bub the respiratory movements are
less frequent than in the cocoon form.
Ceratodus is not a mud-fish. It never leaves the water. It
is found in the dry season in the deep pools of the rivers hi which
it lives. These pools become very foul when the river shrinks
in the hot season, and no doubt under these conditions the
branchial respiration is largely supplemented by pulmonary.
Lepidosiren and Protopterus are true mud-fish. They bury
themselves at the beginning of the dry season in the mud of the
swamps in which they live. As the drying mud stiffens they
retire deeper into the burrow, an opening always remaining at
the upper end for respiration. In this burrow the Protopterus
Z II. s
DIPNOI.
etrth.t
-earth
lies with the body bent and the tail folded over the face, and
surrounded by a cutaneous secretion of mucus containing earthy
particles. The outer layer of this mucus which is in contact
with the earth of the burrow hardens and constitutes the cocoon
or capsule. The upper end of the capsule is closed by a kind
of lid, on the surface of which is an aperture leading into a pipe
of dried mucus which passes between the lips of the animal
(Fig. 135). As the water diminishes the animal ceases its
branchial respiration and the
lung respiration alone con-
tinues. Lepidosiren lies at
the bottom of its burrow sur-
rounded by mucus, but there
does not appear to be a
special cocoon with lid and
pipe as in Protopterus.
Breeding takes place shortly
after the return of the water
and the liberation of the animal
from the mud. This varies
considerably in accordance with
the season. Lepidosiren lays
its eggs in underground bur-
rows, which after descending
vertically about one foot run
horizontally for two to five
feet. The male remains in the
nest with the eggs in a curled
up position.
All three genera take
both vegetable and animal
food.
The Dipnoi may be divided into two sub-orders or families.
One of these — the Sirenoidei — includes the living genera and
numerous fossil teeth, which are found only in the Jurassic and
Triassic formations and on which the genus Cemtodus was
originally founded. The bulk of the Dipnoi are, however,
exclusively Palaeozoic forms. It is a noteworthy fact that the
genus Cemtodus which existed in Triassic and Jurassic times
has persisted to the present day, though no remains of it or of
FIG. 135. — Diagram of the torpid Protoptenis
in situ (after W. N. Parker). The tube is
open above, and the cocoon lies in the
bottom of it. The pipe is shown leading
into the mouth, coc cocoon ; earth earthy
mass round cocoon ; earth, t burrow through
earth ; Id lid of cocoon : Id. p pipe from lid
of cocoon ; pc.l pectoral fln ; pl.l pelvic
fin ; tl tail.
DIPNOI.
259
any other Dipnoan are found between the Jurassic and the
present time.
The other sub-order includes Palaeozoic forms only. Some
of these present, in the heterocercality of the tail and in the
differentiation of the unpaired fin, features which are regarded
by some anatomists as more primitive than the diphycercality
and continuous unpaired fin of living forms. We however are
not inclined to attribute so much importance to these facts of
FlG.£36. — Dipterus'valenciennessii. Ag. Old red sandstone, \ nat. size, restored (from Wood-
wardfafter Traquair).
structure. We think on the contrary that they show merely
that there was considerable variability in the fins in the Palaeo-
zoic forms\nd the particular combination of characters possessed
by these organs in living Dipnoi is merely one which might
quite well have been found — indeed is found — in the Palaeozoic
Dipnoi.
1. Ctenodipterini. Skull with numerous small scutes, with jugular
plates ; vomerine teeth have not been observed. Devonian, Carboniferous,
Permian. Dipterus Sedgwick and Murchison (Fig. 136). Scaumenacia,
with heterocercal tails and two dorsal fins and an anal ; Phaneropleuron
Huxley, with diphycercal tail and distinct anal fin ; Ctenodus Ag., Sageno-
dus Owen, Uronemus Ag., Conchopoma Kner, with diphycercal tail and
continuous dorsal fin.
FIG. 137. — Protopterus annectens (from Claus).
2. Sirenoidei. Skull covered with few large scutes ; with long, single
dorsal fin and anal fin continuous with diphycercal tail-fin. Two vomerine
teeth present. Ceratodus (Epiceratodus) Ag., with one lung, rivers of
Queensland. Teeth of this or a closely allied genus are found in the
Trias and Jurassic. The Dipnoan type is then lost until it appears in the
three genera of the present day. C. forsteri Krefft, barramunda, rivers of
Queensland. Prolopterus Owen, with two lungs, swamps of tropical
Africa. Pr. annectens Owen. Lepidosiren Fitz., with two lungs, trop.
Amer. L. paradoxa Nat.
260
DIPNOI.
FIG. 138. — a, Ceratodus forsteri ; b, its pectoral fin (after Gunther). c, lower jaw with dental
plates (after Krefft).
Arthrodira.
The Arthrodira is a group of Devonian fishes showing some resem-
blance to and sometimes grouped with the Dipnoi. The vertebral column
appears to have been unossified, but the dorsal and ventral arches and
the fin-supports are weakly ossified. The head and anterior part of
the body are covered with large bony plates ; of which the head
plates are movably articulated with the anterior body plates. The
posterior part of the body appears to have been sometimes without
armour, sometimes with large dorsal and ventral plates ; the tail is hetero-
cercal, without scales. They were probably autostylic ; at any rate, no
trace of a hyomandibular has been observed. The chondro cranium was
probably unossified, but it is possible that in some genera there were
exoccipitals and ossified parachordals. The pectoral girdle and fin
have never been found, unless the slender hollow spines of Brachydeirus
are related to them. Teeth are absent, or confined to the pterygo -palatine
region, vomers, and lower jaw. Dorsal and anal fins are differentiated.
These fishes are very unlike anything now living, and must have had a
remarkable organisation. Coccosteus Ag., Diuichthys Newberry, including
forms of very large size (head-shield sometimes a metre across), Homosteus
Asmuss, Brachydeirus Koenen.
\
FIG. 139. — Coccosteus decipiens, restored, i, showing pelvic fins, the heterocercal caudal fin
hypothetical (after Smith Woodward).
hypothetical (after Smith Woodward).
Ostraeodermi.*
The fossils which are grouped together under this heading have been
* Claypole, Pteraspidian fishes in the upper silurian rocks of N. America,
OSTRAOODERMI.
261
referred to various classes of animals, including Crustacea and Arachmda.
They were first recognized as fishes by L. Agassiz, but their systematic
position within that group is still quite uncertain, and it may well be that
they are not fishes at all. They are confined to the upper Silurian and
to the Devonian. Their internal skeleton is very little known. They are
without any trace of jaws, visceral arches, paired fins and their girdles,
and a segmented axial skeleton. The head and anterior part of the
trunk are always invested by a powerful dermal armour, consisting of
large plates, of which one covers the whole dorsal aspect of the head.
The orbits are small and frequently placed near together on the dorsal
surface of the cephalic shield as in L-imulus. They are divided into three
groups.
FIG. 140. — Pteraspis rostrata, restored, £, side view (from Smith Woodward).
Heterostraci. Head and anterior part of the body covered Lby a
dorsal shield, rarely simple, usually composed of several pieces. The
orbits are small and^placed far apart on the outer edge of the dorsal shield.
Hinder part of body covered by rhombic plates. The cephalic plates are
without bone cells. Pteraspis Kner (Fig. 140), dorsal shield narrow in
front and prolonged into a rostrum, with a median spine behind ;
Palaeaspis Claypole, Cyathaspis Lank.
2. Osteostraei. Head
covered by a large
dorsal shield on which
«./. _ // \\ ^ the two orbits lie near
together (Fig. 141) and
which contains bone
cells ; body covered
with rhombic scales.
Cephalaspis Ag. (Fig.
141), the posterolateral
angles of the shield are
produced and there is a
median spine, dorsal
and anal fins with well-
developed rays, upper
$.c. , — f / / \. j \ \ „ c Silurian and Devonian.
Tremataspis Schxidt,
upper Silurian.
f. a.
FIG." 141. — Cephalic shield of Cephalaspis Agassizi (after
Lankester, from Woodward), x J, L. Old Red Sandstone.
«/, antorbital fossae ; ap antorbital prominences ; ig inter-
orbital ridge ; me, marginal cells ; or orbital rim ; va
posterior angle ; pc posterior cornu ; pov postorbital
depression ; pr posterior ridge ; ps. posterior : spine ; r rim.
3. Antiarcha. Head
and body covered by
an armour of symme-
trically arranged bony
plates. ) Orbits close
Quart. J. of Geol. Soc., 1857, 13, p. 48. Huxley, Cephalaspis and Pteraspis,
Ibid, 12, 1856, p. 100 ; 1858, 14, p. 267 ; 1861, 17, p. 163. Lankester and
Powrie, Cephalaspidae, Palaeont. Soc., 1868.
262
ICHTHYODORULITES. COXODONTS
together on the dorsal surface of the head. Head and lateral plates'with
grooves for the sensory canals. An appendage, covered with plates and
supposed to be the pectoral fin, is attached on each side in front. A
short dorsal fin, with fulcra in front. Tail covered with scales. Devonian.
Pterichthys Ag. (Fig. 142), Asterolepis Eichw., Botkriolepis'lSLchw.
orSi
FIG. 142. — Pterichthys milleri, restored after Traquair x $. ap lateral appendages (? pec-
toral) ; j joint in appendage ; m supposed upper jaw with notches for narial opening ;
op operculum ; orb orbits ; double dotted lines indicate grooves for sensory canals.
Ichthyodorulites. Fin spines consisting of dentin or vasodentin
and probably Selachian are indicated by this term. Some of them have
been assigned to genera of which nothing is known but these spines.
They are found in Palaeozoic rocks. Of such genera may be mentioned
Ctenacanthus Ag., Onchus Ag., Homacanihus Ag., Psammosleus Ag.
Conodonts are minute denticles met with from the Lower Silurian
to the Carboniferous Limestone ; they are sometimes compared with the
teeth of lampreys. They consist of a single cusp or of a series of cusps on
one ba?;e, and appear to be formed of structureless concentric lamellae.
They might be teeth of Molluscs or Annelids.
CHAPTER X.
CLASS AMPHIBIA.*
Cold-blooded Vertebrata with naked scaleless skin (except in
Gymnophiona], with 'pulmonary and usually with transitory or
permanent branchial respiration, with two occipital condyles and
without amnion or allantois. The limbs when present are on the
pentadactyle type and the heart is provided with two auricles, one
ventricle and a conus arteriosus.
The Amphibia stand in an intermediate position between
fishes and reptiles. Whereas in the general form of their body
and in certain anatomical features they are more reptilian, in
the young state they are markedly piscine and in their full-
grown condition they exhibit many important piscine characters.
They differ from fishes and resemble the higher Vertebrata in
five important respects : (1) they are without fin-rays (dermo-
trichia), (2) they possess a limb constructed on the pentadactyle
type, (3) the periotic capsule possesses a fenestra ovalis and a
stapes, (4) paired posterior cardinal veins are absent in the
adult, (5) a cloacal bladder is present. On the other hand they
present the following features in which they resemble fishes and
differ from the higher forms : (1) the presence of functional
* Lacepede, " Histoire naturelle des quadripedes ovipares et des serpents,"
Paris, 1788-9. Merrem, " Beitrdge zur Geschichte der Amphibien," 3 vols.
Leipzig, 1790-1821. Daudin, " Histoire Generate et particuliere des
Reptiles," 8 vols, Paris, 1802-1803. J. G. Schneider, " Historia amphi-
biorum naturalis et litter aria" Jena, 1799-1801. J. Wagner, " Naturliches
System der Amphibien, Stuttgart, 1828-33. Dumeril et Bibron, " Erpeto-
logie generate, 9 vols. Paris, 1834-55. E. Schreiber, " Herpetologica
europaea," Braunschweig, 1875. G. A. Boulenger, " Catalogue of the
Batrachia Gradientia and Salientia in the British Museum" 2 vols, London,
1882. H. Gadow, " Amphibia and Reptiles" Cambridge Natural History,
London, 1901. A. Davison. A contribution on the anatomy etc. of
Amphiuma means, Journal of Morphology, xi, 1985. Ecker's Anatomic
des Frosches, 2nd Ed. by E. Gaupp, 1897.
264
CLASS AMPHIBIA.
FIG. 142. — Skeleton ? of Menopoma
alleghaniensis (from Claus). Et orb-
itosphenoid ; F frontal ; Jl pelvic
girdle ; Jmx premaxilla ; MX maxilla ;
N nasal ; Od exoccipital : P parietal ;
Pe prootic ; Pt pterygoid ; R ribs ;
S sacral vertebra ; Sc scapula ; Ty
squamosal ; Vo vomer. 5 Hyoid appa-
ratus; Zb hyoid ; Kb branchial arches.
gill-slits and gills, (2) a single
artery — the ventral aorta — alone
leaves the heart, (3) there are
only ten pairs of cranial nerves,
(4) the presence of a functional
pronephros in the larva, (5) the
sexual part of the kidney is
distinct from the testis and not
incorporated into it as an epidi-
dymis, (6) the character of the
ovum and the early develop-
ment, (7) the absence of an
amnion and allantois, (8) the
presence of functional lateral
line sense-organs.
On the whole it will be gene-
rally admitted that they stand
nearer to fishes than they do
to the higher forms, and that
Huxley's inclusion of them with
Pisces in a group which he
called Ichthyopsida has a solid
basis of fact. Nevertheless it
must not be forgotten that the
higher Amphibia present certain
subtle features of approach to
the Reptiles which are not shared
by the lower members of the
group. We refer especially to the
asymmetry of the systemic aortic
arches in the Anura (p. 284),
and to the apparent abortion of
the sexual part of the kidney in
the male Alytes (p. 293).
In the main the Amphibia are
aquatic in their habits : the
majority live in or near water,
and in almost all the congress of
the sexee takes place and the
eggs are laid in water. But
VERTEBRAL COLUMN.
265
burrowing (Gymnophiona), arboreal (tree frogs) and purely
terrestrial forms are found.
The vertebral column consists of separate, ossified vertebrae,
which vary in number from over 250 in large specimens of some
Gymnophiona, a variable but considerable number in the Urodela
(Fig. 142), to nine in the Anura.* The first vertebra, sometimes
called the cervical, has two concave surfaces for articulation
with the paired occipital condyles.
In the Urodela it has a forwardly
directed process of its centrum which
has been identified as the odontoid
process ; in this case it must be re-
garded as the axis vertebra, the atlas
having fused with the skull. It is
without ribs and usually without
transverse processes. The remaining
vertebrae may be divided into trunk
vertebrae, one sacral vertebra (two in
Pelobates, Pipa, Hymenochirus, absent
in Siren and Proteus) and, except in
Anura, caudal vertebrae. Most or all
the trunk vertebrae carry short ribs
(Fig. 143, It) which are two-headed in
Gymnophiona and most Urodeles. The
sacral vertebra is without ribs in the
Anura, but has them in the Urodela.
In the Anura, in which there are
almost always eight presacral verte-
brae, the sacral vertebra is followed FIG. 143.— vertebral column of
by an unsegmented bony rod, the
os coccygis or urostyle, which is with-
out spinal cord or any trace of
notochord in the adult. Indications
of segmentation may sometimes be
discerned in the front end of this
(Fig. 143, Pte). The caudal vertebrae of the Urodela ^are
provided with complete haemal arches enclosing the tail
blood vessels. The vertebrae are amphicoelous in the
Gymnophiona and lower Urodela, the notochord being persistent
* Hymenochirus has only seven vertebrae.
Off
Discoglossus pictus (after Wie-
dersheim) • Ob neural arch ;
Oc urostyle ; Pdzygapophysis;
Po supposed odontoid process ;
Ps neural spine ; Pt transverse
process ; Pte transverse pro-
cesses of caudal vertebrae
(urostylar) ; R ribs ; Sy arti-
cular concavities for occipital
condyles ; SW sacral vertebra.
266
CLASS AMPHIBIA.
and continuous. In the higher Urodela (most Salamandridae)
the vertebrae are opisthocoelous. In the Anura they are usually
procoelous, though occasionally opisthocoelous and the noto-
chord is for the most part obliterated.
-R
FIG. 144. — Longitudinal sections through the vertebral columns of some Urodeles (after
Wiedersheim) . A Ranidens, B Amblystoma, C Spelerpes, D Salamandrina. I, II, III, the
three anterior vertebrae ; Ch notochord ; Ck intravertebral cartilage ; Gp, Gk articulating
cup and ball ; Jvk intervertebral cartilage ; K bone of centrum ; Ligt intervertebral
ligament ; Mh marrow cavity ; R transverse process ; (S vertebral constriction of ihe
notochord ; ** the intervertebral cartilage.
SKULL. 267
In the lower Urodela the notochord is constricted first vertebrally, but
later owing to the great development of the unossined intervertebral
connecting cartilage (Fig. 1-14, A and B, Jvh) it also becomes encroached
upon intervertebrally. This great development of intervertebral carti-
lage is the marked feature of the amphibian vertebra. In some forms
(Fig. 144 C) the intervertebral encroachment is very considerable, so
great indeed that in most Salamandrines the notochord is entirely sup-
pressed and the intervertebral cartilage is segmented into a cup and ball
joint, one part uniting with the centrum of the anterior and the other
with that of the posterior vertebra (Fig. 144 D). The bony tissue of the
vertebral body would appear to make its appearance, in some cases at
least, before the perichordal tissue has developed into cartilage. In the
centre of the vertebral bodies of certain forms some cartilaginous tissue
appears (Fig.|l44 A and C, CK}, which is doubtless derived from the peri-
chordal cartilage, though it has been supposed by some anatomists to be
notochordal and therefore hypoblastic in origin.* In the Anura the
notochord persists in a few forms vertebrally throughout life (Rana).
The skull f of the Amphibia presents the following character-
istics. The cartilage is largely persistent, there being but few
cartilage bones ; the occipital region rarely has more than the
two exoccipitals which furnish the two occipital condyles ;
basioccipital, supraoccipital, basisphenoid, alisphenoid and
presphenoid bones are always or almost always absent ; there
is no interorbital septum ; well-developed paired frontal, parietal
and nasal membrane bones are found in the roof and an unpaired
parasphenoid and paired vomers in the floor ; the jaw suspension
is autostylic, the palato-quadrate bar being united at each end
with the skull ; the auditory region presents, for the first time,
a fenestra ovalis which is filled up by a cartilaginous plate, the
stapes (see p. 276). The quadrate, which in some cases remains
cartilaginous, is covered by a membrane bone, the squamosal
(paraquadrate). The visceral arches are in the larva five in
number (hyoid and four branchial). These become variously
reduced in the adult according to the condition of the breathing
organs, but the hyoid and traces at least of two branchials
generally persist together with a median ventral copula, of which
* For a fuller account of the morphology of the vertebral column and
ribs of Amphibia see F. M. Balfour, Comparative Embryology vol. 2, London,
1885. H. Gadow. Phil. Trans. 1896, vol. 187, p. 1-57. E. Goppert
Morph. Jahrb., 22, 1895.
f In addition to the textbooks already cited (Reynolds, Marshall,
etc.) see Stohr, Z. f. w. Z., 33 and 36 for the development of the
skull ; Gaup, Primordial cranium etc. of Rana fusca, Morph. Arbeiten,
2 : and W. K. Parker's various memoirs in the Phil. Trans, of 1871
(FrozV 1877 (Urodeles), 1881 (Batrachia) ; A. Davison op. cit.
268
CLASS AMPHIBIA.
they are processes. The hyoid is attached dorsally, directly or
by ligament, to the auditory capsule or to the quadrate.
In the Urodela the cartilaginous cranium is much reduced. Cartilage
is found in the roof and floor of the skull in the occipital region only. In
front the trabeculae remain separate both dorsally and ventrally, so that
there are large supracranial and basicranial fontanelles filled in by the
overlying membrane bones (parietals, frontals, and parasphenoid). In
some of the lower forms (Proteus, Necturus) the trabeculae retain through-
out life the form of narrow cartilaginous bars. The auditory capsules
possess a prootic and one or more other periotic bones, and in the anterior
FIG. 145. — A dorsal, B ventral, C side view of the skull of the newt (Triton cristatus) x 2£
(after Parker, from Reynolds). The cartilage is dotted, the cartilage bones are marked
with dots and dashes, the membrane bones are white. 1 premaxilla ; 2 anterior nares ;
3 internal nares ; 4 nasal ; 5 frontal ; 6 parietal ; 7 prelronto-lacrymal ; 8 maxilla ;
#vomero-palatine ; 10 parasphenoid ; 11 orbitosphenoid ; 12 pterygoid ; 13 squamosal ;
14 prootic region of exoccipito-periotic bone ; 15 quadrate ; 16 quadrate cartilage ; 17
exoccipital region of exoccipito-periotic ; 18 articular ; 19 articular cartilage ; 20 dentary ;
21 splenial ; 22 middle narial passage ; II, V, VII, IX, X. foramina for'exitloi corresponding
cranial;, nerves.
part of the sphenoid region there is a cartilage bone, the'orbitosphencid
(Fig. 145, 11) The ethmoid region (nasal capsules) is unossified. The
parietals and frontals are separate bones and the parasphenoid is not
dagger -shaped. The vomer is double and usually fused with the palatine
(Fig. 145, 9). There is a prefrontal in front of the orbit, with which a
lacrymal element is supposed to be fused (7). There is a palato-pterygoid
bar in the larva, but in the adult the pterygoid and palatine bones are
usually not connected. The quadrato-jugal is represented by ligament
only. In the lower forms the quadrate is directed forwards as in the larva
of all Amphibia, but in the higher forms it stands out at right angles or
SKULL.
269
may even be inclined backwards. The lower jaw presents articular,
dentary, and splenial elements. Teeth may be present on the premaxillae,
maxillae, vomeropalatines, and parasphenoid, and on the lower jaw.
The visceral arches are generally reduced to the hyoid and two branchials
in the adult, but sometimes four (Siren, Amphiuma, etc.) or three (Nec-
turus, Proteus] pairs of branchials persist in the adult (Fig. 145 bis, A].
There is no tympanic cavity in Urodeles.
In the Anura (Fig. 146) the cartilage of the cranium is much more
developed, there being a complete cartilaginous floor and roof, which
latter however contains some fontanelles. The two orbitosphenoids are
replaced by a single "girdle" bone which extends into the hinder*part]of
the ethmoid region
and is called the
sphenethmoid (El).
The parietal and
frontal (Fp) are
fused and the
parasphenoid i s
dagger-shaped (Ps).
The suspensorium
slopes backwards
and the palatopte-
rygoid arch persists
as a bar extending
from the ethmoid
to the suspensorum.
Quadrato-jugals.(^ )
are present, reach-
ing from the max-
illa to the quadrate.
The lower jaw con-
tains a mento-
meckeliaii cartilage
bone at the sym-
physis (o s s i fi e d
mento - meckelian
cartilage of the
larva). A tym-
panic cavity, com-
municating with the pharynx by a eustachian tube is present, and'the
stapedial plate is connected by a cartilaginous, partly ossified, rod, the
columella auris, with the tympanic membrane, which is supported by a
cartilaginous ring. Teeth are found on the premaxillae, maxillae, vomer?,
and the lower jaw, though the latter is frequently edentulous. The
visceral arches (Fig. 145 bis, B) of the adult are represented by a large
basilingual plate in the floor of the mouth which is connected with the
otic region of the skull by the curved hyoid arches. All the four
branchial arches and part of the copula of the larva completely disappear,
the processes (including the bony thyrohyals) on the basilingual plate of
the adult being new formations.*
As has already been stated, short two-headed ribs are often
* Ridewood P.Z.S., 1897, -p. 577.
o
FlQ. 145 bis. — Visceral arches of, A Triton cristatus ; B Rana tem-
poraria ; C tadpole of Rana ; D Siredon pisdformis {from Reynolds).
The bone is shaded and the cartilage left white. 1, basilingual
plate ; 2, hyoid arch ; 3, first, 4, second, 5, third, 6, fourth bran-
chial arch ; 7, thyrohyal ; 8, copula.
270
CLASS AMPHIBIA.
Jms:
Jmx
jfe
Et
Flo/146. — Skull of Rana esculenta (from Claus). a dorsal, b ventral view. The membrane
bones of one side are removed. The cartilage is shaded dark. Et girdle-bone (spheneth-
moid) ; Fp frontoparietal ; J quadrato-jugal ; Jmx premaxilla ; MX maxilla ;. N nasal ;
Ocl exoccipital ; Pe prootic ; PI palatine ; Ps parasphenoid (right half cut away) ; Pt
pterygoid ; Ty squamosal (paraquadrate) ; V vomer.
present on many of the
trunk vertebrae of the
Urodeles. In the Anura
they are generally absent,
but in a few forms (e.g.
Discoglossus , Xenopus) they
are present on the anterior
vertebrae. In no Amphi-
bian do the ribs reach the
, sternum.
The sternum in the Uro-
deles is a cartilaginous
plate lying behind and
interposed between
coracoids (Fig. 147, #).
Anura the sternum
partly in front of and partly
behind the ventral union of
the coracoids (Fig. 148).
The part in front is called
the omosternum (episternum,
presternum), the part be-
hind is the sternum proper,
Pro. 147.-A, ventral, B, lateral view of the which expands behind into
shoulder girdle and sternum of Triton cristatus +1^ porfilacrinniKs
(from Reynolds, after Parker). 1 scapula;
2 suprascapula ; 3 coracoid ; 4 glenoid cavity ; rmm
S precoracoid 6 sternum. *
the
In
lies
PECTORAL GIRDLE.
271
In the Urodela the pectoral girdle is mainly cartilaginous
being ossified only in the neighbourhood of the glenoid cavity
(Fig. 147). The coracoids overlap one another ventrally and
are articulated with the anterior end of the sternum. They are
without a fenestra, but possess a, well marked precoracoid.,
There is no clavicle. The radius and ulna are separate and there
are usually four and never more than four digits in the manus
(3 or 4 in Siren, 3 in Proteus, 2 or 3 in Amphiuma), the pollex
probably being absent. The carpus is cartilaginous in the
lower and ossified in the higher Urodeles. When four digits
are present, it typically consists of a proximal row of three
FIG. 148. — Pectoral girdle and sternum of A, an old male frog (firmisternal), B, an adult
female Docidophryne gigantea (arciferous). From Reynolds. In both, the left supra
scapula is removed. The unshaded parts are ossified \ the parts marked with small dots
are hyaline cartilage, those with large dots calcified cartilage. 1, calcified cartilage of
suprascapula ; 2, ossified part of same ; 3, scapula ; 4, coracord ; 5, epicoracoid ; 6, pre-
coracoid ; 7, clavicle ; 8, glenoid cavity ; 9, coracoid fenestra ; 10, 11, episternum (omoster-
num) ; 12, sternum ; 13, xiphisternum.
pieces, a distal row of four, and a centrale ; but there is often
a certain amount of fusion and suppression of the carpalia
and sometimes there is more than one centrale (Megalobatra-
chus).
In the Anura (Fig. 148) the scapular portion of the pectoral
girdle is divided into an incompletely ossified suprascapula and
an ossified scapula, and the coracoid portion possesses a fenestra
dividing it into a cartilaginous, usually slender, precoracoid
and a stouter ossified postcoracoid (often called coracoid). The
epicoracoid (cartilaginous) is the ventral portion of the coracoid
which meets (firmisternal) or overlaps (arciferous, Fig. 148. B)
its fellow in the middle line. In the fore-limb the Radius and
ulna are fused, the carpus is usually reduced, and there are four
272
CLASS AMPHIBIA.
D
FIG. 149.— Ventral view of pelvic girdle of Sola-
mandra (after Wiedersheim). Ac acetabulum ;
; Ep epipubis ; Fo foramen for obturator nerve ;
J', J ilium ; JP pubis ; Sy symphysis ; * *
ischium.
complete digits and a much
reduced pollex which is re-
presented only by a short
metacarpal.
In the Urodela the ilium
of the pelvic girdle (Fig. 149)
is vertically directed and the
ischio-pubis is a flat plate
which meets its fellow ; the
ilium and the ischial part
of the ischio - pubis are
ossified. There is often an
* 1_ * 1 1 1*T
epipubis, developed mde-
, , , „ , , , .
pendently of the pubis and
corresponding to the pre-
sternum of the pectoral girdle. The tibia and fibula are not
fused and there are usually five digits. The tarsal elements are
often complete, but there may be some fusion and more than
one centrale.
In the Anura the ilium (Fig. 150) is elongated and directed
backwards and the ischiopubis is fused with its fellow to form
a disc. The ilium and ischium are ossified, but the pubic portion
consists of cartilage which may become calcified. In Xenopus
there is a small epipubis. The tibia and fibula are fused and
there are usually five digits with trace of a prehallux. The
tibiale and fibulare (intermedium absent) are much elongated
and partially fused and the distal tarsals are reduced.
The skin of the Amphibia is usually soft and moist owing to
the secretion of cutaneous glands. In the young larva it is
ciliated. In some ft
forms it is covered
with warts, and in
toads it is dry.
Epidermal scales
and except in the
Gymnophiona der-
mal scales are
never present in
living forms. In FIG. ISO.— Side view of pelvic girdle of Raw esculenta (after
, c,, Wiedersheim). Ac acetabulum ; /. P1 ilium ; P mibis, Is
the extinct Stegoce- ischium.
LATERAL LINE. BRAIN. 273-
phali there is a well developed dermal skeleton, and in
some Anura bony plates, which are sometimes united to the
subjacent vertebrae, are present beneath the dorsal integument
(Ceratophrys, etc.).
Horny thickenings of the epidermis are sometimes found on
the ends of the digits giving rise to claws (e.g. Onychodactylus ,
Xenopus), and in other places (e.g. on cutaneous excrescences,
hand of male frog, etc.). In all Amphibians the stratum corneum
periodically peels off and the animal is said to cast its skin.
Lateral line sense-organs are present in the larvae and in
aquatic forms on the head and in longitudinal rows (usually
three) on the body (Fig. 151). The latter are innervated by the
lateral line branch of the vagus. The skua is almost always
pigmented and the colours are often brilliant. The pigment is
FIG. 151. — Larva of Salamandra maculata (after Malbranc from Claus). Ms, Us rows of
lateral line sense-pits.
found in the epidermis (brown or yellow), and in branched cells
in the cut is, where it may be black, brown, yellow or red. Colour
change * is a widespread phenomenon in Amphibians and is
under the control, though not necessarily the voluntary control,
of the nervous system. The secretion t of the cutaneous glands
is very generally poisonous, especially in those with bright
yellow markings, e.g. Salamandra maculosa, Bombinator,
Dendrobates.
The lateral muscles are divided into myomeres after the
piscine manner in the lower Urodeles, but in the higher forms
this segmentation is lost.
The brain ± is small and distinguished by the small size of
the cerebellum. The cerebral hemispheres are separate and
* Biedermann, W., Pfluger's Arch. Physiologic, 51, p. 455.
f Boulenger, in Natural Science, 1, 1892. Paratoids are aggregations-
of cutaneous glands forming swellings on the sides of the head of some
forms.
{ Burckhardt, R., " Him. u. Geruchsorgan von Triton u. Ichthyophis"
Z. /. w. Z., 152, 1891, p. 369.
Z — II T
•274
CLASS AMPHIBIA.
contain lateral ventricles. In the Anura the olfactory lobes are
united across the middle line, in the Urodela they are separate.
The pineal body is disconnected from its stalk and lies outside
the skull in Anura. There does not appear to be any parietal
organ or pineal eye.
There are ten pairs * of cranial nerves arranged very similarly
to those of fishes, excepting that in
l—JI II the abranchiate forms the sense-organ
branches (ophthalmicus superficialis,
mandibularis externus, buccalis of the
7th, and lateral line branch of the
vagus) have disappeared.
In the frog, as an example of the abraiichi
ate forms, the roots of the fifth and seventh
are separate though their ganglia are united
into a ganglion which may be called the
ganglion prooticum (Gasserian and geniculate
ganglia fused). The ophthalmic nerve (a
purely sensory nerve except for glandular and
vascular branches) passes below the rcctus
superior muscle. The superior maxillary nerve
contains motor fibres and supplies the depres-
sor muscle of the lower eyelid and the levator
bulbi. The sixth nerve joins the ganglion
prooticum and passes out in the ophthalmic
nerve ; it supplies the retractor bulbi as well
as 'the external rectus. The seventh nerve
divides in the ganglion prooticum into its two
branches, the palatine and the hyomandibular.
The palatine except for vascular and glandular
branches is purely sensory; the hyomandi-
bular is a mixed nerve, and is connected by
an anastomosing branch with the glossopharyn-
geal. The vagus group of nerves arises from
the medulla by four roots, which contain the
elements of the glossopharyngeal and vagus.
They pass out of the skull by the foramen jugulare and unite into a single
ganglion, the ganglion jugulare, from which pass out the glosso pharyngeal
and the vagus. The glossopharyngeal immediately dilates into a ganglion. It
is a mixed nerve, supplying the anterior slip of the petrohyoid muscle and
the mucous membrane of the pharynx and tongue, and, as stated above,
it is connected by an anastomosing branch with the hyomandibular of
the seventh. The vagus usually leaves the ganglion jugulare in two
* von Plessen u. Rabinovicz, Die Kopfnerven v. Salamandra maculata
im vorgeruckten Embryonalstadium, Miinchen, 1891. Strong, The cranial
nerves of Amphibia, Journal Morphology, 10, 1895, p. 101.
J. 152. — Dorsal view of the
brain of Triton cristatus (after
Burckhardt). 1, olfactory
nerve ; 2, olfactory lobe ; 3,
cerebral hemisphere ; 4, me-
dulla oblongata ' 5, cerebel-
lum; 6, optic lobes]; /"/pineal
body ; 8, thalamencephalon ;
9, choroid plexus.
CRANIAL NERVES.
275
branches, the auricular
and the main stem.
The auricular is a
sensory nerve to the
skin. The main stein
is a mixed nerve which
contains the elements
of the spinal accessory
or llth nerve of higher
types (branch to the m.
cucullaris}. Its motor
fibres supply the three
posterior slips of the
petrohyoid muscle, the
laryngeal muscles a.nd
one of the shoulder-
girdle muscles (inter-
scapularis). There are
no occipital andspino-
occipital nerves (ven-
tral vagus roots) in
Amphibia.
In the Anura (Fig.
153) there are only ten
pairs of spinal nerves
and the spinal cord is
shorter than the ver-
tebral column, ending
in the filurn terminate
(Fig. 153). In the
Urodela the spinal
nerves are more nume-
rous and the' spinal
cord extends along
the caudal region. In
adult Urodeles * and
aglossal Anura the first
spinal nerve is without
a dorsal root ; in the
phaneroglossal Anura
it is absent in the
adult and the first
spinal nerve, which
leaves the spinal canal
between the first and
second vertebrae, is
really the second.
Thid esppnnH «r»irml
nerve joins the bra-
chial plexus but it
* This nerve is present with both roots in the embryo, but the dorsal
root disappears in development. It resembles in this respect the occipito-
spinal nerves of fishes.
FIG. 153. — Nervous system of the frog (after Ecker). Br,
brachial nerve ; Js, ischial nerve ; 0, eye ; Ol, olfactory
nerves ; Op, optic nerve ; Spn 1, first spinal nerve ; Sg. 1-10,
276 CLASS AMPHIBIA.
gives off a strong branch to the tongue which constitutes the
hypoglossal. In the frog the ganglion of the posterior root extends on to
the common stem, and the dorsal and ventral rami of the spinal nerves
both arise from it.
The sympathetic is distinct and connected with the ventral rami of
the spinal nerves by rami communic antes. In the Urodeles it extends
along the whole length of the body into the caudal canal. In the Anura
it commences anteriorly in the skull as a cord leaving the ganglion
prooticum, receives a branch from the ganglion jugulare, and dilates in
the neck into the first ganglion of the sympathetic chain, which is con
nected by a ramus communicans with the first (second) spinal nerve
(Fig. 153). This is followed by nine ganglia, each of which is connected
with its spinal nerve by one, or in the case of the posterior ganglia by
more than one, ramus communicans. The tenth ganglion is small and
not always distinguishable.
Sense organs. The nasal sacs are always provided with
internal nares. The eyes are reduced and covered by the skin
in the subterranean and cave-forms (Gymnophiona, Proteus,
Pipa). Eyelids, both upper and lower, are present in the
Salamandridae. but absent in other Urodeles. In the Anura
there is an upper eyelid and a movable nictitating membrane
which is sometimes called the lower eyelid. In Bufo there is in
addition a small lower lid. In the Anura there is a retractor
bulbi muscle by means of which the large bulb of the eye can be
drawn back. Lacrymal glands are absent, but there is an
Harderian gland in the inner angle of the orbit of the Anura
which opens within the nictitating membrane. There is a
fenestra ovalis (vestibuli) in all Amphibia, and in many Anura
a fenestra rotunda (cochleae) as well. There are three semi-
circular canals, and a small cochlea was discovered by
Deiters in the frog, and is probably present in other Amphibia.
The tympanic cavity and membrane are absent in Gymnophiona
and Urodela, and in some Anura they are much reduced or even
absent (Pelobatidae, Bombinator. Phryniscus, Batrachophrynus,
etc.). In most Anura they are present, though the membrana
tympani is not always visible on the exterior. In the Aglossa
the eustachian tubes join and have a single opening into the
pharynx ; in other forms they remain separate. The columella
auris extends from the fenestra ovalis to the tympanic membrane,
It lies outside the tympanic cavity, but projects into it. Its
internal end, called the stapes or operculum, fits into and fills-
the fenestra ovalis ; its outer end is connected with the membrana
tympani. In the Aglossa the outer end expands into a cartila-
ALIMENTARY CANAL. BODY-CAVITY. 277
ginous plate which is coextensive with the membrana tympani.
The shaft of the columella is frequently ossified, its two ends
remaining cartilaginous. In the Urodela, in which it exists
embedded in the muscles, its stapedial portion may be ossified
and it is connected to the quadrate by ligament. It is probably
homologous with the hyomandibular of fishes, though in the
Amphibia it is never connected with the hyoid arch. The
membrana tympani is attached to a cartilaginous ring.
The cup-like sense organs of the lateral line found in the
aquatic forms and in the larvae of land forms have already been
referred to (p. 273).
Alimentary canal. The mouth opening is a wide slit.
Teeth, which are ankylosed to the bones, are present upon the
premaxillae, maxillae, andvomers, soijaifcimes on the dentaries,
palatines, and parasphenoid. They^are absent in Pipa and
some toads. The tongue is immovable in Urodeles, absent in
Aglossa, movable and free behind in other Anura, in which it is
used as a prehensile organ. The posterior n res and eustachian
tubes have already been referred to. Salivary glands are not
present. In many male Anura the lining of the buccal cavity
is produced into sacs, the vocal sacs, which act as resonators.
In Rhinoderma they are used as nurseries for the young. Oeso-
phagus, stomach, small intestine and rectum are present. The
hind end of the rectum is called the cloaca and possesses a median
ventral appendage, the bladder.* The urinary and generative
ducts open into the cloaca. The cloaca opens to the exterior
by the anus. Liver and pancreas are present, and the former
has a gall bladder.
The thyroid, unpaired in its origin, but becoming paired
later, is present ; and an organ representing the thymus and
derived as epithelial buds from some of the branchial pouches
is present close to the angle of the lower jaw (in the Anura behind
the tympanic cavity and beneath the depressor mandibulae
muscle).
The body-cavity is completely divided into the pericardial
and peritoneal cavities. The peritoneal cavity extends forwards
on each side of the pericardial. Abdominal pores are absent.
* So-called alla^toic bladder, though the Amphibia have no allantois
in the embryo.
278 CLASS AMPHIBIA.
Nephrostomes are very generally present and will be dealt with
under the urinogenital organs.
Respiratory organs. The skin is an important organ of
respiration in all Amphibia, and in some abranchiate Urodeles
it is the sole * respiratory organ, lungs being entirely absent
(Desmognathinae, Plethodontinae, Amblystoma opacum, Sala-
mandra perspicillata) . In such forms there is no pulmonary
vein and the auricular septum is perforated by a large aperture.
In all other members of the group lungs are present, and in some
of the Urodeles gills and gill-slits as well. With very few
exceptions the larvae are provided with gills. It is this com-
bination of branchial and pulmonary respiration which is found
in the adults of some forms and at some period in the life-history
of nearly all, which confers a special interest on the breathing
and vascular mechanisms t of the Amphibia and necessitates
their being treated at some length.
With a few exceptions (for which see the systematic part and
p. 296), all Amphibia are hatched as larvae, and possess while in
that condition gill-slits and external gills. In all cases which
have been fully investigated the rudiments of six visceral arches
and of five pharyngeal pouches (Fig. 154) are laid down in
development : the arches are the mandibular, the hyoid, and
four branchial ; the pouches are the mandibulo -hyoid, the
hyobranchial, and the pouches between the successive branchial
arches, there being no pouch behind the fourth branchial arch.
Of these pouches the first (Fig. 154, HM) rarely I acquires an
external opening ; in the frog it gradually fades away and the
tympanic cavity is formed later in its neighbourhood. The
others (Fig 154) become perforate and give rise to the four
gill-clefts, which are found in the larvae of Urodela and Anura.
The external gills, which are formed before the gill-clefts become
perforate, are three in number on each side ; they are branched
structures and are attached to the dorsal ends of the three
anterior branchial arches. These are the only gills found in
* It has been suggested that the lining of portions of the alimentary
canal may cooperate, vide Wilder, Anat. Anzeiger, 9, 1894, p. 216 and 12,
1896, p. 182 ; Lonnberg, Zool. Anzeiger, 19, 1896, p. 33.
f Boas J. E. V., Morph. Jahrb., 1, 1882, p. 488 ; and 13, p. 115. Maurer
F., Ibid., 14, 1888, p. 175.
j It appears to do so in the Coecilian Hypogeophis and a small dorsally
placed cleft (spiracle) is formed, but it is doubtful if this cleft becomes
perforate in any other Amphibians.
BREATHING ORGANS.
279
the Urodela ; but in the Anura in which the gill-openings become
covered by a membranous operculum (fold of skin growing back
from the hyoid arch), the external gills atrophy and are replaced
OF
BF
OS
3 R.I
BR.2
KA
KA
FIG. 154.— Horizontal section of the head of a tadpole at the time of hatching x 40 (after
Marshall). AF afferent vessel of first branchial arch ; BF fore brain; BR\ first, BR2
second, BRB third branchial arch ; C body-cavity ; EF efferent vessel of first bran-
chial arch; HM hyomandibular pouch; HY hyoid arch; IN infundibulum ; KA
archinephric duct of right side, KA' of left side ; KP pronephros ; KS third opening of
right pronephros, KS' ditto of left pronephros ; OF olfactory pit; OS optic stalk; TP
" pharynx ; TI intestinal region of enteron ; Y yolk cells.
by a series of very similar but smaller structures developed
along the more ventral portions of all four branchial arches.
These are the internal gills, so called from their position beneath
the operculum and not from any essential difference between
280 CLASS AMPHIBIA.
them and the external gills. Like the latter they are branched
cutaneous structures covered by ectoderm. There is a double
row of these gills on each of the first three branchial arches and
one row on the fourth. In all the Anura and in most of the
Urodela the gill-clefts close and the gills atrophy when the adult
state is reached, but in a few of the Urodela, the so-called
Perennibranchiates (Proteus, Necturus, Siren, etc.), some of them
persist throughout life (for details, see systematic part). In
the Amphiumidae the gills disappear but the last cleft usually
persists, and in the genus Amblystoma the animal sometimes
becomes sexually mature in the larval condition and 'does not
metamorphose (Siredon, the axolotl). This phenomenon of the
retention of larval characters in the sexually mature state has
been called neoteny, or paedogenesis ; it is not confined to
Amblystoma but is found occasionally in the genus Triton (Molge).
An analogous phenomenon is presented by many tadpoles and
by some Urodeles, in which the metamorphosis is occasionally
considerably retarded, but the larvae do not acquire sexual
organs.
Gill-rakers, analogous to the gill-rakers of fishes, are found on the
branchial arches of many forms. They consist of processes containing
-a peculiar form of connective tissue. In the larva of the salamander and
in the tadpole of the frog there is one row of them on the first and fourth
arch and two on the second and third. In the tadpole they are especially
well developed and form a filtering apparatus which detains even the
smallest particle.
In the Urodela the gills are not covered by an operculum,
but a slight cutaneous fold from the hyoid arch represents this
structure. All Amphibia with the exception of the lungless
forms referred to on p. 278 possess lungs. These are simple
sacs with more or less sacculated walls ; in the Anura they open
either directly or by short bronchi (Aglossa) into a laryngo-
tracheal chamber which communicates by the slit-like glottis
with the pharynx. The laryngo-tracheal chamber is supported
by cartilages which can be identified with some of those found
in the larynx of the higher forms, and in the Anura contains
vocal chords. In the Gymnophiona and some of the more
elongated Urodeles (Siren, Amphiuma, Cryptobranchus) there is
a median tracheal tube supported by cartilages. Respiration
is effected by a swallowing movement, the air being drawn into
the mouth through the nares with the mouth closed. The
VASCULAR SYSTEM 281
Urodela can only make a slight noise, but the Anura have a
considerable voice, which is much intensified by the vocal sacs
of the mouth and larynx.
Vascular system. There is always a special anterior section
of the ventricle, the conus arteriosus, which is rhythmically
contractile and guarded by semilunar valves at its two ends.
Moreover there is a further resemblance to fishes in the fact
that the ventricle (conus division of it) gives off only one artery,
the ventral aorta or truncus arteriosus. It is true that this
vessel is always very short and that in the Anura it is actually
divided into two by a horizontal septum, but its homology with
the ventral aorta of fishes and embryos cannot be disputed.
In possessing this structure the Amphibia present a piscine
feature, and one in which they markedly differ from the Reptilia
and higher Vertebrata. In other features of the vascular system
they approach the higher forms and depart from fishes, e.g. in
the presence of an auricular septum, of an inferior vena cava, of
a branch of a posterior vascular arch to the lung sacs, in the fact
that in the adults of the higher forms branchial structures are
not present on the vascular arches, that the vascular arches
tend not to be connected with each other dorsally, and in the
differentiation in the higher forms of the right systemic arch
from the left. But with regard to these features it must be
noted that the first three are already found in Dipnoi, and that
the others are only characteristic of the higher members of
the Amphibia. §,
The heart is contained in the pericardial sac and is typically
five-chambered, consisting of sinus venosus, two auricles, a single
ventricle and a conus arteriosus (bulbus cordis). The chambers
are more compacted together than in fishes, the sinus venosus
being placed more forward on the dorsal side of the auricle.
The left auricle is smaller than the right and the interauricular
septum is incomplete in Urodeles and Gymnophiona, complete
in Anura. The sinus venosus opens into the right auricle, and
the pulmonary veins into the left. All the chambers of the
heart are rhythmically contractile. Except at its base the cavity
of the ventricle is broken up by muscular strands, so as to present
a spongy character and its wall is without blood vessels. The
conus arteriosus is spirally twisted and usually possesses a longi-
tudinal valve, the attachment of which lies along the axis of the
282
CLASS AMPHIBIA.
spiral. There are two valves at the junction of the sinus and
right auricle, and two considerable valves at the margin of the
combined auric ulo- ventricular apertures (Fig. 158). The latter
are held to the ventricular wall by cords, and there may be two
smaller additional valves. The auricles open into the left side,
and the conus arises from the right side of the ventricle, and
from that portion of it which is free from muscular strands
(Fig. 158). There is a row of three, sometimes four, semilunar
valves at each end of the conus (Fig. 157). The conus arteriosus
leads into a short ventral aorta (truncus arteriosus) which in
A B
FIG. 155. — A ventral, B dorsal view of the heart of a frog (after Gaupp). 1 linejf marking
the anterior limit of the pericardium ; 2 right auricle ; 3 conus artertosus (bulbus cordis) ;
4 ventricle ; 5 sulcus coronarius marking the junction of the auricles and ventricle ; 6 truncus
arteriosus ; 7 left auricle ; 8 pulmono-cutaneous artery ; 9 aorta ; 10 common carotid ;
11 pulmonary vein; 12 sinus venosus ; 13 inferior vena cava ; 14 right superior^ vena
cava ; 15 left auricle.
the Anura is divided into a dorsal and ventral chamber by a
horizontal partition. The branches of the ventral aorta are
bound together for a short distance in a common sheath.
In the Gymnophiona the conus is short, not spirally twisted, is without
a longitudinal valve, and in some species has only one row of valves. In
other Amphibia there is a row of valves at each end. In Proteus and
Menobranchus it is straight and without the longitudinal valve. The
longitudinal valve presents considerable variations, e.g. in the genus
Triton it may be present, or absent, or made up of a row of small processes.
a condition which suggests that it is really composed, as it is in Dipnoi, of
a row of small semilunar valves. It begins posteriorly close to one of the
VASCULAR SYSTEM.
283
FlQ. 156. — The conus of Salamandra 'macidosci laid
open (after Boas), showing the four rather ;long
semilunar valves of the anterior row, of which that
marked 1 is continued backwards as the longi-
tudinal valve (Sp). When only three valves j are
present, the valve marked 4 is absent.
valves which guard the ventricular end of the conus and is continuous
with the convex posterior side of the right hand valve of the three (or
four) valves which guard its anterior end (Fig. 156). It is attached in the
main to the dorsal wall of the
conus and projects freely
into it, reaching half or two-
thirds of the way across it.
Its line of attachment lies in
the axis of the spiral into
which the conus is twisted.
In Salamandra (Fig. 157) the
branches of the ventral aorta,
which are continued as the
arterial arches, are connected
by a common sheath and are
given off as explained in the
following description. The
ventral aorta is undivided
posteriorly (Fig. 157), but in
front it is divided by a hori-
zontal septum into two com-
partments of which the ventral is again divided by three vertical partitions,
which do not however reach the hind end of the horizontal septum, into
four canals. Of these the two median are continued into the anterior
(carotid) arches (/). and the lateral into the second (aortic) arches (//).
The dorsal division is divided by a vertical septum into two, each of which
is continued as the
at first >, conj oined
third and fourth
arches (IV).
In Rana and [its
allies the conus has
three semilunar
valves at each end.
The -j -, longitudinal
valve " (Fig. 158)
begins on the ven-
tral side of the ven-
tricular ope n i n g
near the right
semilunar valve ;
its line of attach-
ment, running
across the ventral
side of the conus,
passes on to : its
left wall and then
on to the dorsal
wall, ending in front
in the right hand
valve (No. 1 ; of the anterior row as described for Salamandra. It § incom-
pletely divides the conus into two chambers, of which the right hand
one is called the cavum aorticum (Fig. 159), the other the cavum
FIG. 157. — Conus and ventral aorta of Salamandra maculosa ; a
piece of the ventral wall has been removed (after Boas). The
ventral aorta is slightly diagrammatic. I, II, IV. divisions of
the ventral aorta or roots of the arterial arches, I, the carotid,
//, the systemic, IV, the conjoined third and fourth (pul-
monary), pp, a bristle inserted into IV ; ct, limit between the
conus and ventral aotra (points a little too high up) ; 2, 3, 4,
three valves of the distal row corresponding to those similarly
numbered in Fig. 156 ; sp, longitudinal valve ; vd, vd", vd' valves
of posterior row.
284
CLASS AMPHIBIA.
, 12
pulmo-cutaneum. The position of these is reversed at the ventricular
opening (where the valve is attached ventrally), the cavum pulnio-
cutaneum being on the right and the cavum aorticum on the left. Inas-
much as the longitudinal valve runs to the right valve on the right side
of the ventricular opening, it is clear that the cavum pulmo-cutaneum,
which at this point is, as above described, on the right side of the conus,
does not lead into the ventricular opening but is cut off from it by the
longitudinal valve (Fig. 158). The cavum aorticum on the other hand
leads behind right into the ventricle. The result of this arrangement is
that when the conus becomes functionally divided into two chambers,
as it does when it contracts, and the free edge of the longitudinal valve
meets the opposite wall, the cavum pulmo-cutaneum is completely cut off
from the ventricle and ends blindly.
Anteriorly the longitudinal valve
is connected (Fig. 159) -with valve
No. 1 (the valve on the right side
of the anterior end of the conus),
which is very large and extends
right across the conus, so that the
middle point of its free edge is at-
tached to the opposite wall (left)
of the conus between the other two
valves (2 and 3) (Fig. 160, A, a).
Turning now to the ventral aorta,
wo find that the horizontal sep-
tum, which in Salamandra divides it
anteriorly into a ventral portion con-
tinupus with the carotid and aortic
arches, and a dorsal portion con-
tinued into the pulmonary arches
(Fig. 157), here reaches back to the
hind end of the ventral aorta (Fig.
159), and is attached posteriorly to
the inner (concave) surface of the
valve No. 1 (trs, Fig. 100). The
left hand side of the hind end of
this septum is attached to the
valve at the point where the latter
is fused with the left hand
wall of the conus between valves
2 and 3^ (Fig. 160, A, a). The result of this arrangement is that the
ventral aorta is completely divided into two passages of which the dorsal
(pr.lmonnry) opens behind into the cavum pulmo-cutaneum of the conus
(left), the opening being guarded by valve No. 2 and one half (16, dorsal)
of the divided valve No. 1, while the ventral passage (carotid and aortic)
leads into the cavum aorticum with valve No. 3 and the other half (1 a)
of valve No. 1. It is further to be noted, and this is a highly interesting
point, that the two carotid arches open by a common opening into the
right aortic arch (Fig. 159), thus foreshadowing the arrangement found
in Reptiles.
The object of these elaborate arrangements in the conus and ventral
aorta of tho higher Amphibia is to ensure a proper distribution of the
pulmonary and venous blood along the outgoing arteries. Tn the Urodeles
••"17
FlG. 158. — Heart of Rana opened by a longi-
tudinal horizontal section, ventra'l view of
the dorsal half (after Gaupp). 1 right
auricle ; 2 dorsal, 5 right of the three
proximal valves of the conus ; 3 longi-
tudinal valve of the conus ; 4 conus arterio-
sus ; 8 see above ; 6 right auriculo-ventri-
cular valve ; 7 spongy part of ventricle ;
8 clear central space of ventricle ;
9 dorsal auriculo- ventricular valve ; 10
interauricular septum; It left auricle;
12 ostium venae pulmonalis ; 13 ostium
sinus venosi.
VASCULAR SYSTEM.
285
in which the longitudinal valve of the conus and the horizontal septum
of the ventral aorta are less developed, no separation of the arterial (pul-
monary) blood from the systemic venous blood is possible ; the two must
undergo complete admixture in passing through the ventricle, conus
and ventral aorta. In the Anvra however this is not the case. In these
animals the anatomical arrangements are of a nature to ensure that the
pulmonary arteries receive purely venous blood, the mixed and purely
arterial blood being directed into the aortae and the carotids. It is further
said that the carotids receive more purely arterial blood than the systemic
M+IV-1.
FIG. 159.— Conus and ventral aorta of Eana plaiyrrhina, opened along the ventral side
ventral aorta slightly diagrammatic (after Boas). 7, 77, III— IV roots of the aortic
arches, carotid, aortic, and pulmonary (777— 7 V] ; p p bristle inserted from the conus
into orifice of the pulmonary, it passes dorsal to the horizontal septum of the ventral aorta
through the opening guarded by valve So. 2 and Ib ; 2 valve No. 2 of anterior row ; 3 valve
No. 3 of anterior row ; la ventral half of valve No. 1 which with 3 guards the entrance into
the ventral division of the ventral aorta which has been laid open ; the other half of this
valve 16 is not shown : the attachment of la to the left hand wall of the conus is between
valve 2 and 3 ; this is not clearly shown in the figure ; co conus ; sp longitudinal (spiral)
valve of conus ; tr ventral aorta (points a little too far up). The hind end of the conu*
where the attachment of the longitudinal valve becomes ventral is not shown.
aortae ; this may be true, but it is not quite so clear from the arrangements
how it is effected.
The ventricular cavity is, except at its base where the auricles and
conus open, broken up by muscular bands so as to assume a spongy
character. This prevents the mixture of venous and arterial blood which
is poured in from the auricles. The blood which enters from the right
auricle is venous, and this is discharged into the right side of the ventricle
from which the conus arises ; consequently the blood which flows into
the conus during the first phases of the ventricular systole will be venous.
This will distend the conus and fill both chambers into which it is im-
perfectly divided by the longitudinal valve, and passing forward along the
cavum pulmo-cutaneum will also fill the pulmonary arteries which are-
286
CLASS AMPHIBIA.
empty and interpose much less resistance to the entry of blood than do
the aortic and carotid arteries (as will be explained in a moment). In
the second phase of the ventricular systole, the conus itself contracts and
the free edge of the longitudinal valve becomes applied to its ventral
wall, whereby its cavity becomes converted into two separate chambers.
Of. these the cavum pulmo-cutaneurn is closed behind so that no more
blood can enter it from the ventricle ; but it remains open in front to the
dorsal division of the ventral aorta and so to the pulmonary arteries.
The result of the contraction of the conus upon the cavum pulmo
cutaneum will be to empty it and to drive the blood through the pul-
monary arteries, thus rendering easy the entrance of blood into these
stractures at the next ventricular systole The cavum aorticum on the
other hand remains open to the ventricle during the second phase of the
ventricular systole. It contains probably a certain amount of venous
blood already driven
into it and receives
now all the rest of the
veiitricul a r b lo o d,
namely, that from the
left side. This must
be largely arterial, for
most of it must have
entered the ventricle
from the left (p*ulmo-
nary) auricle. This
blood, together with
the venous blood al-
ready in the cavum
aorticum, must be en-
tirely delivered throTigh
the cavum aorticum
into the ventral divi-
sion of the ventral
aorta, and so into the
carotid and systemic
arteries. The question
now arises whether
there is any arrange-
ment whereby this blood is sifted and the most arterial of it sent into
the carotid arteries. It is said that observation has shown that the carotids
receive more purely arterial blood than the systemic aortae. The following
structural features have been alleged as contributing to this, from a
physiological point of view desirable, result. The three arches of the left
side lie in n line with the conus and ventral aorta, the arches of the right
side passing off at an angle (Fig. 159). The effect of this will be that the
blood in order to enter the right aortic arch and the two carotids, which
as we have seen come off from this arch, will have to pass round a corner.
It? will be easier therefore for it to flow straight on into the left systemic
arch. In this way it is possible that the first blood from the cavum
aorticum, i.e. mixed venous and arterial, will pass into the left arch, leaving
only the last blood which enters the conus, i.e. as we have shown the most
purely arterial, to enter the right arch and the carotids. It has further
been alleged that the carotid glands (described below) interpose ad
FIG. 160. — Two transverse sections through the conus of Rana
platyrrhina. A at the junction of the conus and ventral
L aorta ; B a little further back (after Boas) ; a the point
where valve No. 1 is fused with the left wall of conus ; Ib
dorsal part, la ventral part of valve No. 1 ; 2 dorsal,
3 ventral of the three valves of the anterior row ; trs, hori-
zontal septum of the ventral aorta. The sections are viewed
from the front side. The longitudinal valve of the conus
is not shown, but if posterior sections were represented, it
would appear as a continuation of valve Ib and la, the
pocket of this valve with the horizontal septum trs dis-
appearing.
VASCULAR SYSTEM. 287
ditional resistance to the entrance of blood into the carotid arteries, so
that no -blood enters them until the systemic arteries are full. Lastly,
we "must mention the fact that there is in each systemic aorta, at the
point where it diverges from the carotid and pulmonary, a small semi-
lunar valve, so arranged as to interpose resistance to the flow of blood
into- the aorta. It is difficult to see how this paradoxical valve (valvula
paradoxa as it has been called by Gaupp) assists in sifting the blood of the
cavum aorticum, but it may be of use, as probably the carotid gland is
of use, in preventing the venous blood which enters the conus in the first
phase of the ventricular systole from passing into the systemic aortae.
To summarize the wholo matter : the first blood which enters the conus
purely venous and passes mainly into the pulmonary arteries in which
the resistance is less than in the systemic and carotids, partly because
the pulmonary arteries are empty and ready to receive it and partly
because of the resistance of the valvtila paradoxa and carotid f glands ;
FIG. 161. — The arterial arches of a larval salamander slightly diagrammatic (after Boas).
la-3a the three branchial arteries (afferent branchial vessels) ; lv-3v the corresponding
branchial veins (efferent vessels) ; 4 the fourth arterial arch ; ao dorsal aorta ; aw root of
dorsal aorta ; ce external carotid ; ci internal carotid ; p pulmonary artery : tr ventral
aorta ; x anastomosing vessels between external carotid and first afferent branchial vessel ;
y, z, anastomosing vessel between the afferent and efferent vessels of the second and third
branchial arches.
the last blood which enters the conus is unable to pass into the pulmonary
because the cavurn pulmo-cutaneum is entirely cut off from the ventri-
cular orifice by the longitudinal valve. The first of this blood together
with the previously-arrived venous blood, i.e. mixed blood, enters the
left systemic arch because this is easiest of access, being in a straight line
with the conus and ventral aorta. This blood is distributed mainly to
the visceral arteries (see below). The last blood, i.e. the most purely
arterial, will enter the right arch and the carotid arteries which leave
the right arch. This blood is distributed to the head and the posterior
part of the body (exclusive of the viscera). The valvula paradoxa being
a small single valve will cease to act as a serious obstruction as soon as
the artery becomes sufficiently distended to allow of the blood passing it.
If this account is correct it is clear that the systemic arches are differen-
tiated functionally in the Anura as they are in the Reptilia. The left arch
receives mixed blood which is mainly sent to the viscera, the right arch
receives purely arterial blood which is sent to the head and posterior
288
CLASS AMPHIBIA.
part of the body ; the principal functional difference being that in
Amphibia the left subclavian is in connection with the left systemic arch,
whereas in Reptilia it conies off from the system of^the rightjarch.
Four arterial arches are developed in the Amphibia, the first,
second, third and fourth branchial. In addition to the seethe
ventral aorta of the larva sends a branch to the hyoid which
however is usually incomplete, not reaching the dorsal system ;
in all cases it eventually atrophies. The vascular arches of the
larval salamander are shown in Fig. 161. The ventral aorta
gives off four branches on each side. Of these the first three
pass to the first three branchial arches and supply their gills.
They may consequently be described as consisting of an afferent
(branchial artery) and an efferent (branchial vein) portion united
Fro. 162. — Arterial arches of an adult Salamandra maculosa (after Boas). 1, 2, 3, 4 the four
branches of the ventral aorta (vascular arches) ; ao dorsal aorta ; aw root of dorsal aorta ;
cd carotid gland ; ce external carotid ; ci internal carotid ; co conus arteriosus ; cu ductus-
Botalli of pulmonary arch ; p pulmonary artery ; oe oesophageal branches of p ; S sub-
clavian artery ; tr ventral aorta.
by the vessels in the gills. In addition to these connections
the afferent and efferent vessels of the second and third branchial
arches are directly connected by anastomosing vessels (y, z).
The first afferent vessel is not so connected with its branchial
vein, but fine anastomosing vessels (x) pass between it and the
external carotid (ce, lingual) which is a branch of the first efferent
vessel. Further dorsally the first efferent vessel gives off the
internal carotid (ci). All the efferent vessels fall into the dorsal
aorta. The fourth vascular arch is not connected with a gill ;
it is a slender vessel running in the fourth branchial arch. Dor-
sally it gives off the pulmonary artery and joins the efferent
vessel of the third arch ; of which indeed the pulmonary artery
has the appearance of being a branch.
VASCULAR SYSTEM. 289
In the adult salamander the arrangement is shown in Fig. 162.
The ventral aorta has four branches (for the exact way in which
they come off see below). The gills have disappeared and the
afferent and efferent limbs of the vessels are continuous. The
first arch has become the carotid and has lost its dorsal connec-
tion with the second. The second arch has become the arch
of the aorta (systemic arch) ; the third remains as a small vessel
joining the second dorsally, but in some individuals it appears
to' be absent ; the fourth is continued as the pulmonary artery,
but retains its dorsal connection (ductus arteriosus or Botalli)
with the preceding arches
In Triton the third arch has disappeared in the adult, and the first arch*
(carotid) retains its dorsal connection with the second. In Proteus and
Menobranchus the fourth vascular arch is not present in the adult, and-
the pulmonary is a branch of the third, the ventral end of which is con-
joined with that of the second.
In Siren four arches are present and the arrangement is similar to that
in the larval salamander. In all the Perennibranchiates the relation of
the gills to the arches is similar to that found in the salamander larva.
In the Anura * the third arch is completely absent in the adult, though^
present in the larva. The pulmonary artery is a branch of the fourth,,
and the first and fourth arches are not usually connected with the dorsaH
system. The Carotid Gland is a plexus of small vessels inserted in the
course of the carotid artery. It is not derived from a gill as was formerly
supposed, but from the vessel which directly connects the efferent and
afferent limbs of the first branchial arch in the older larva. This vessel
becomes plexiform and together with some epithelial tissue derived from
the first branchial cleft gives rise to the carotid gland.
Of the rest of the arterial system there is not much to be said.
The frog may be taken as typical, with one exception, viz. that
the visceral arteries are all gathered up into one, the coeliaco-
mesenteric, which leaves the left aortic arch close to its union
with the right. Almost all the blood of the left aortic arch of
the Anura goes into this vessel, the continuation of it to the
dorsal aorta being very small. In the Urodeles the visceral
arteries come off as many branches from the dorsal aorta. There
are two superior venae cavae (ductus Cuvieri) made up by the
junction of the jugulars (anterior cardinals) and the subclavians,
and an inferior vena cava which arises in the kidneys. The
venous blood of the hind end of the body is all sent either through
* For an account of the development of the vascular arches of the frog,
see A. M. Marshall, " Vertebrate Embryology," London, 1893.
z — n. u
290 CLASS AMPHIBIA.
the kidney to which it is taken by the renal-portal veins or
through the liver by the anterior abdominal vein. Vertebral
(azygos) veins are very generally present, opening into the
superior venae cavae.
The question of the homology of the inferior vena cava with the piscine
veins is difficult to settle. From its relations to the kidneys and from
the condition in Dipnoi, it would appear to be one or both of the posterior
cardinals. The difficulty in the way of this view is that it does not, so far
as is known, develop from the posterior cardinals which are always present
in the embryo.
In Proteus and Siren some of the pulmonary blood is returned into the
vena cava inferior (Hyrtl).
The red blood corpuscles are nucleated. They are oval in
shape and of considerable size, reaching in Amphiuma in their
greatest diameter yVtii mm.
The lymphatic system consists of vessels 'and sinuses. There
is a large subcutaneous lymph sinus, especially well developed
in the Anura, and a large subvertebral sinus enveloping the
aorta, kidneys, etc. The lymphatic vessels open into the great
veins, and near the point of opening are often dilated into mus-
cular contractile chambers, the lymph-hearts. In the frog there
are two pairs of these ; a posterior pair placed near the hind end
of the urostyle and opening into the femoral veins, and an
anterior beneath the suprascapulae and opening into the sub-
scapular veins. In the Urodeles the posterior pair alone is
present. There are no lymphatic glands along the course of
the vessels as in birds and mammals, but patches of lymphatic
tissue, in which amoeboid cells are set free, are present in different
parts of the body.
A spleen, usually placed in the mesentery near the stomach,
is present.
The Urinogenital Organs * are constructed on the same
type as those of Elasmobranchs. The kidney is an elongated
gland (except in Anura) with persistent nephrostomes and with
a duct to which the collecting tubules pass. In the male there
is a testicular network, through which the sperm passes from
the testis to some of the kidney tubules. The kidney duct
serves therefore as vas deferens as well as ureter. It opens
* Spengel, J. W. Arbeiten a.d. Zool. Inst. Wiirzburg, 3, 1876, p. 1.
Brauer, A. " Entwick. der excretionsorgane der Gymnophionen," Zool.
Jahrb. (Anat.), 1902, 16, p. 1.)
URINOGENITAL ORGANS.
291
posteriorly into the side of the cloaca. In the female the
mullerian duct forms the oviduct ; its abdominal opening is far
a
Fio. 163. — Urinogenital organs oi the left side of a a male, and b a female salamander, partly
diagrammatic (from Claus). Dr prostate glands ; HI longitudinal (mesonephric) duct of
the kidney ; Kl cloaca ; Mg oviduct ; N kidney with collecting tubules passing to the longi-
tudinal duct ; or ovary ; T testis ; ve vasa efferentia ; Wy longitudinal (mesonephric) duct
of the male.
forward, and posteriorly it opens laterally into the cloaca. It
generally persists as a vestige in the male. The cloaca possesses
a vesicular ventral appendage — the cloacal or allantoic bladder
292 CLASS AMPHIBIA.
which is not found in fishes and into which the urinary ducts
do not open as they do in mammals. There is no copulatory
organ (though in the Gymnophiona the cloaca can be extruded
and used as such). There is a lobed fat-body frequently connected
to the front end of the generative gland. There is always a
functional pronephros in the larva which atrophies in the adult.
In the salamander or newt, which may be taken as type, the
kidney is much narrower in front than it is behind (Fig. 163).
The narrower, anterior portion may be called the sexual part,
because in the male the testis is connected with it by the testi-
cular network. It is also sometimes called the mesonephros
because it corresponds roughly to the mesonephros (Wolffian
body) of the embryos of the Sauropsida and Mammalia. In
this case the posterior thicker portion might be called the
metanephros, on the view that it corresponds to the permanent
kidney of the higher types. The duct runs by the side of the
gland and receives the collecting tubes. In the male the col-
lecting tubes of the metanephros are inclined backwards and all
join to open at one point into the longitudinal duct close to the
cloaca (Fig. 163 a). An incipient ureter is thus formed. In
this case the longitudinal duct is mainly associated with the
anterior sexual part of the kidney or mesonephros and is for that
reason frequently spoken of as the mesonephric duct (Leydig's
duct).
The renal tubules (nephridia) consist of four parts, (1) the collecting
tubule, which is continuous in the kidney with (2) the contorted tubule
which is the especially glandular part, and passes into (3) the malpighian
body, from which passes (4) the peritoneal canal to the body-cavity
opening (nephrostome) placed on the ventral surface of the kidney (Fig.
164). The contorted tubule and peritoneal canal usually join before
opening into the malpighian body (Fig. 164 mk'). Such a tubule is called
a primary or simple tubule. The anterior part of the kidney (mesonephros )
of Urodeles consists entirely of such primary tubules. In the metanephros
however we find compound tubules. These consist of primary tubules
each with its nephrostome, and of a number of dorsally placed secondary
tubules (also with nephrostomes) which open into the collecting part of
the primary tubule. The primary tubules are not arranged segmentally
in any Amphibian, except the Gymnophiona. The number of primary
tubules in a segment is greater in the posterior than in the anterior part
of the kidney. The testicular network or connection between the testis
and mesonephros is constructed as follows (Fig. 163). There is a longi-
tudinal duct, called the longitudinal duct of the testis (not shown in fig.)>
running along the base of the testis and receiving the testicular tubules.
This gives off an irregular number of canals — the vasa efferentia — which
URINOGENITAL ORGANS.
293
tr
pass into a second longitudinal canal (Fig. 163) placed near the meso-
nephros.and called the longitudinal canal of the mesonephros (absent in
Spelerpes, Batrachoseps, etc.). This sends off transverse canals, which
correspond in number with the primary rt>nal tubules in the part of the
kidney involved in the testicular connection and open into the malpighian
bodies of these tubules. So that the sperm passes through the renal tubules
of the mesonephros into the mesonephric duct. The nephrostomes of
these sexual tubules atrophy in the adult of all male Urodeles except
Spelerpes ; but are present in this region in the young form and in the
female. The sexual part of the kidney varies much in length. In Siredon
as many as 32 primary tubules are connected with the testis. It is much
reduced in Spelerpes. A vestige of the miillerian duct is generally present
in male Amphibia ; and rudiments of the testicular network can fre-
quently be detected in the female (Fig. 163 b). The collecting tubules
of the metanephros are directed backward and join into one or more short
ducts (ureter) before opening into the mesonephric duct. In Batrachoszpv
the first collecting tube is specially
developed and receives all the other
collecting tubes of the metane-
phros. In the female of all Urodeles
and in the males of Proteus, Meno-
branchus and Siren the collecting
tubes retain their transverse course
and open direct into the mesone-
phric duct. In rare cases the
ureter opens direct into the cloaca.
In the Gymnophiona the kidney
is narrow and elongated, extending
almost the whole length of the
body cavity. The primary tubules
are segmentally arranged, but many
of them become compound in the
adult. There is but little indication
of differentiation into meso- and
metanephros, and the testicular
network is joined to the kidney
some little distance behind its
front end (Fig. 165). The nephrostomes both of the sexual and non-
sexual part of the kidney persist in the adult.
In the Anura the kidney is compact, and the sexual part is not marked
off from the rest. There is a testicular network which in Bufo, etc., is
connected with some of the malpighian bodies (Fig. 166). In Rana the
transverse canals which leave the longitudinal canal of the mesonephros,
pass through the kidney and open into the collecting tubes of the renal
tubules. In Bombinator the longitudinal canal runs through the kidney
and opens into the anterior end of the kidney duct which curves round
the front end of the kidney ; the transverse canals end blindly in the
substance of the kidney. In Discoglossus a canal arises from the front
end of the testis and passes round the front end of the kidney to be con-
tinued into the anterior end of the ureter. This canal appears to be the
only representative of the testicular network. In Alytes the arrangement
is very peculiar and differs from that of all other Anura (Fig. 167). There
is a ureter (fused metanephric collecting tubes) passing out from the hind
FIG 164. — Malpighian body and nephrostome
of a kidney tubule of Proteus (after Spengel).
tr, Nephrostome ; trg, peritoneal canal ; mk
malpighian body, and 2 beginning of con-
torted tubule of the sexual part of the kidney ;
mk' stalk of malpighian body.
294
CLASS AMPHIBIA,
my.-—]
Ot
<P
fi
—mr.ct
\~c.
FIG. 165.— Urinogenital organs of Epicrium glutinomm. A male ; B female (after Spenge
from Wiedersheim). a anus ; B bladder ; B' appendage of bladder ; ct, d cloaca ; / fat body ;
Ho testis ; Ig, kidney duct ; mg, mg' miillerian duct in male ; od miillerian duct (oviduct) in
female ; mr, ct retractor muscle of cloaca ; N kidnej ; Ot abdominal opening of oviduct ;
ov ovary ; r rectum.
URINOGENITAL ORGANS.
295
FIG. 166.— Urinogenital system of male
Bufo (after Spengel)./ fat body; m
malpighian body; ov Bidder's organ
(ovary) ; t testis ; ug duct of kidney.
end of the kidney and joining the mesonephric duct (Leydig's duct). The
latter is continued forwards beyond
the kidney ending blindly in front ;
and receiving a small testicular net-
work which passes from the testis
round the front end of the kidney
and is entirely disconnected from the
kidney. This would appear to be
an extreme modification of the con-
dition characteristic of Urodeles, the
sexual part of the kidney having been
entirely aborted.
In the Anura nephrostomes are
present, but it is doubtful whether they
open into the kidney tubules in the
adult. It has been asserted * that
they open into the renal veins. This
statement must be accepted with
caution. It appears more probable
that they have lost their connection
with the renal tubules and persist as
ciliated cups on the surface of the
kidney.
Bidder's organ is found in Bufo as a structure attached to the front end
of the generative gland. In both sexes it consists of an aggregation of
immature ova.
The fat-body consists of lymphatic tissue with fat in the meshes. It
appears to be a reserve of nutriment which is drawn upon when the sexual
glands are becoming mature.
The Suprarenal bodies are small yellow
structures on the ventral surface of the
kidneys in the Anura, on their median
side in Urodela.
The oviducts open separately into the
cloaca, except in Hyla, Bufo and Alytes,
in which the opening is median. They
receive through their abdominal opening
the eggs, which are dehisced into the
body-cavity. They are usually more or
less convoluted, possess glandular walls
which secrete an albuminous covering
for the eggs, and they are frequently
dilated into a receptacle in which the
eggs are collected, close to their cloacai
opening.
FIG. 167.— Urinogenital system
of Aljftes obstetricans (from
Gegenbaur, after Spengel).
t testis ; ng longitudinal
duct of kidney (meso-
nephric) ; sb seminal vesicle ;
t testis ; u ureter (after
Spengel, from Gegenbaur).
* E. J. Bles, Proc. Cambridge Phil. Soc., 9, 1898.
296 CLASS AMPHIBIA.
Males and females are often distinguished by their size and
colour, and also by other peculiarities (vocal sacs, dorsal crests,
<etc.) which are specially prominent at the breeding season. In
spite of the absence of organs of copulation, sexual intercourse
takes place, but it usually consists merely of an external
approximation of the two sexes (Anura in which the male em-
braces the female from the back), and results in the fertilisation
of the eggs outside the body of the mother. In cases in which the
spermatozoa are introduced into the female generative tracts,
spermatophores are formed, probably by the cloacal glands,
and introduced into the female cloaca by the application of the
swollen lip of the male cloaca to the anus of the female (Sala-
mandrines). In such cases the eggs may
undergo their development within the
oviduct, and the young be born at a
more or less advanced stage of devel-
opment (Salamandra maculosa, S. atra,
Spelerpes fuscus, etc.). It is only excep-
tionally that the parents have an instinct
to watch over the further fate of their
brood, as for example in Alytes (Fig. 168)
and the Surinam toad (Pipa dorsigera).
The male of Alytes winds the strings of
eggs round its hind legs and burrows into
FIG. 168.— Alytes obfstetricans.
Male, with the string of the damp earth, and only gets rid of its
eggs, (from Claus). i i i ji -11
load when the embryonic development is
(Completed. In Pipa the eggs are placed on the back of the female,
which then develops a cell-like pouch round each egg. In this
^ase the whole development takes place in the egg. In Noto-
irema the eggs are conveyed into a spacious brood pouch beneath
the dorsal integument, in which the eggs undergo their embryonic
•or their whole development. In Rhinoderma the eggs are placed
in the enlarged vocal sacs of the male, where they undergo the
whole of their development. In these cases the eggs are large
so that the young can undergo the whole or part of their later
development in the egg. This is the case also in some forms in
which the eggs are deposited in damp situations and the young
are not hatched until after the loss of the gills (Arthroleptis
seychellensis , Rana opisthodon, Hylodes martinicensis, etc.).
When the eggs are relatively small, they are usually laid in
DEVELOPMENT.
297
water, either singly and attached to water plants (e.g. newt),
in clumps (e.g. frog), or in strings (e.g. toads) ; but in some cases
they are deposited out of the water, in situations in which the
larvae can easily reach it.
Development.* The eggs, which possess a considerable
'amount of food yolk, are relatively small, and undergo (except in
the Gymnophiona) a total, but unequal segmentation (Fig. 169). A
gastrula is formed by a modification of the process of invagina-
tion, and the blastopore in some cases (e.g. newt) persists as the
anus and in some cases (e.g. frog) closes up, the anus being a
later perforation on its site. A neurenteric canal is very generally
present. An amnion and allantois are not formed, though a
cloacal bladder, an organ homologous with the allantois, arises
as a median ventral diverticulum of the cloaca. The embryos
FIG. 163. — Unequal segmentation of the frog's egg in ten successive stages (after Ecker).
are also without any external yolk-sac constricted off from the
body, the yolk being enclosed at an early period by the side-
walls of the body. With a few exceptions, which have already
been referred to and are mentioned again in the systematic part,
the young leave the egg in an immature condition and undergo
the later part of their development as free-swimming larvae. f
In the Anura these larvae are generally known as tadpoles.
The larvae are always aquatic and breathe by gills (see p. 278)
and possess other larval organs, e.g. a pronephros, and lateral
line sense organs. Their vascular system is on the piscine type
which gradually gives place to that characteristic of air-breathing
* Balfour, Comparative Embryology, vol 2, 1883. Marshall, Vertebrate
Embryology, 1893, Brauer, op. cit.
f The resemblance in certain cranial characters between the anuran
larva and the marsipobranchii has already been referred to (p. 96).
298
CLASS AMPHIBIA.
forms (p. 289) as the lungs develop. In the so-called perenni-
branchiate forms the gills and lateral line persist, either partly
or throughout life, but the pronephros always gives place to
the kidney. In some cases the larvae actually become sexually
mature (paedogenesis, p. 280). In the Anura the larval organs
are more conspicuous and the final change by which the aquatic
tadpole becomes a terrestrial animal is so striking as to be called a
metamorphosis. The tadpole possesses two suckers (Fig. 170. 8)
on the ventral surface behind the mouth, which however disappear
quite early in larval
life (similar suckers
are present on the
throat of Triton larvae,
where however they
are stalked). It also
possesses a horny beak
(Hz) on each lip which
is lost at the metamor-
phosis. Moreover the
caudal region of the
body is represented
by a well developed
laterally compressed
tail, which is gradually
absorbed after the
animal has become
terrestrial, and the
limbs functional. The
limbs develop during
larval life : the anterior limbs are formed beneath the opercular
fold and only appear at the metamorphosis, when that membrane
is shed ; the posterior limbs develop at the side of the anus and
are visible from their first appearance as buds. The operculum
develops early in larval life as a cutaneous fold from the hyoid
arch which gradually grows back over the gills and gill-slits,
causing the atrophy of the external gills (Fig. 170). A branchial
chamber is thus formed between the fold and the body, into
which the gill-slits open. These chambers at first open widely
behind, but very soon the openings narrow. In the Aglossa both
openings persist and are lateral in position. In the Disco-
FIQ. 170. — Larval stages of the frog (after Ecker). a,
embryo some time before hatching, with wart-like gill
papillae on the branchial arches, b, larva some time
after hatching with external gills, c, older larva with
horny beak and small branchial clefts beneath the
integumentary operculum, with internal gills. N nasal
pit ; S sucker ; K external gills ; A eye ; Hz horny
tooth.
DEVELOPMENT.
299
glossidae the openings converge and combine into one median
ventral opening. In other Anura the right opening passes on
to the left side and combines with the left, so that there is only
one spiracle, as these openings are called, on the left side of the
body.
The intestine of the tadpole is long and spirally coiled. At
the metamorphosis the animal undergoes an ecdysis, with which
is connected the appearance of the anterior limbs, the closure
FIG. 171.— Later stages in the development of Pelobates fuscus. a, larva without limbs, with
well -developed tail, b, older larva with hind limbs, c, larva with two pairs of limbs.
d, young frog with caudal stump, e, young frog after complete atrophy of tail.
of the gill-slits and the absorption of the internal gills. The
horny beak is cast off, and the eyes which have hitherto been
concealed beneath the skin appear on the surface and are of
considerable size. The larva has now become an exclusively
air-breathing four-legged adult, which has only to lose its
swimming tail in order to acquire its definitive form (Fig. 171).
The duration of tadpole life is usually considerable (some
months) and during the later stages the larva breathes by its
300 CLASS AMPHIBIA.
lungs as well as by its gills. At the metamorphosis the gill
slits close and the animal becomes wholly air-breathing.
The Amphibia frequently live in water only during larval
life. As terrestrial animals in the adult state they usually
choose damp shady places near water, since the cutaneous
respiration necessitates a moist atmosphere. The food almost
always consists of insects and worms, but in larval life vegetable
matters form a considerable part of it. The Amphibia can live
for months without food, and many of them hibernate buried
in the mud, and in hot countries aestivate. They are cold-
blooded ; and resist a considerable amount of cold, even frost ; but
if the whole body is frozen they do not recover. The power of
regenerating lost parts is considerable, e.g. lost or mutilated
limbs. This power is greater in young than in old individuals.
Distribution. The Anura are almost cosmopolitan. They
are represented by one species only (Liopelma) in New Zealand
and are absent in most Oceanic islands ; the latter fact being
due to the fatal effect of salt water, especially upon the larvae.
The Urodela are mainly Nearctic and Palaearctic, and the
Gymnophiona are confined to the Neotropical, Ethiopian and
Oriental regions.
Urodela and Anura are not found fossil until the Eocene,
Gymnophiona are unknown in the fossil state.
Order 1. GYMNOPHIONA.* APODA.
Vermiform Amphibia without limbs or limb-girdles, with
biconcave vertebrae, and usually with numerous small scales em-
bedded in the skin. The tail is short or absent, the /rentals are
distinct from the parietals and the palatines are fused with the
maxillaries.
The body is covered with a smooth, slimy, transversely ringed
skin, which contains in the cutis numerous small calcified scales
* J. Miiller, Ueb. d. Kiemenlocher der jungen Coecilia, Mutter's
Arch. 1835. R. Wiedersheim, Die Anatomie der Gymnophiona, Jena,
1879. G. A. Boulenger, op. cit. and P.Z.S. 1895, p. 401. P. and F.
Sarasin, " Zur Entwick. u. Anat. der Ichthyophis glutinosus" Ergeb.
naturwiss. Forsch. auf Ceylon, 1887. R. Burckhardt, " Him u. Geruchs-
organ von Triton and Ichthyophis" Z. /. w. Z. 52, 1891 p. 370. J. W.
Spengel, " Urogenitalsystem der Amphibien" Semper' 8 Arbeiten, 3, 1876,
p. 1. A. Brauer, Entwick u. Anat. der Gymnophionen, Zool. Jahrb.,Anat.t
10, 1897, p. 389, and 12, 1899, p. 477.
G YMNOPHION A . 301
arranged in transverse rows. The eyes are small, functionless
and covered by the skin ; though reduced in size, all the usual
parts are present. There is on each side of the head behind the
external narial opening a small pit which penetrates the maxillary
bone and contains a protrusible tentacle-like structure (Fig. 173,
T). A well developed harderian gland pours its secretion into
this pit. There is no tympanum or tympanic cavity. The
anus is close to the hind end of the body, the caudal region being
very small or absent. The notochord is persistent (except in
the centre of the vertebrae), and the vertebrae are biconcave and
numerous, mostly with ribs, which do not meet to form a sternum.
The skull (Fig. 173) is compact and has a complete bony roof.
The parietals and frontals are separated and there is sometimes
a small bone called the turbinal or lateral nasal just external
to the outer nostrils (shown, but not marked in Fig. 173). The
jugal arch is well developed and joins the parietal and frontal,
thus roofing over the temporal fossa ; it reaches back to the
FlQ. 172. — Siphonops mexicana (Regne animal) from Claus.
suspensorium, which appears to consist of fused squamosal and
quadrate. The vomer is double and bears teeth. The palatine
also bears teeth and extends back on the inner side of the maxilla
with which it is continuous. There is a prefrontal, and some-
times a postorbital (postfrontal) which nearly encircles the
orbit. The stapes is perforated and is connected with the
suspensorium (quadrate). The orbit is small, and the maxilla
is perforated by a pit for the tentacular organ. The mandible
in some forms has two rows of teeth. The remains of the hyoid
and three branchial arches are found in the adult, the hyoid
and 1st branchial being connected to the same median piece.
The lungs are asymmetrical as in the snakes, the right being
much larger than the left which is more or less atrophied.
The conus arteriosus possesses two rows (Ichthyophis) or one
row (Siphonops} of valves, and is without a spiral valve. The
ventral aorta is long. There are only two pairs of aortic arches.
Of these the first is the systemic (2nd branchial) which gives off
the carotid, and the second is the pulmonary. They are joined
302
CLASS AMPHIBIA.
bj> a ductus Botalli. In the larva there is a slender anterior
arrh (1st branchial), which disappears.
The urinogenital organs are on the usual type (p. 293).
Gymnophiona are found in Central and South America,
Equatorial Africa, India and the Malay Archipelago. They are
not found in the West Indian islands or in Madagascar. They
burrow in the surface soil in damp places and near streams.
Their eyes which may usually be discerned through the skin are
of lise only in enabling them to avoid the light. In the male
FIG. 173.— Skull of IcJithyophis qiutinosa (from Gadow. after Sarasin). A from the side ; B from
below ; C from above. A posterior process of the os articulate ; Ca carotid foramen ;
Ch internal narial opening ; F frontal ; J jugal ; Lo exoccipital ; MX maxilla ; N nasal ;
No external narial opening ; 0 orbit ; P parietal ; Pa palatine ; Pm premaxilla ; Pof post
frontal ; Prf prefrontal ; Pt pterygoid ; Q quadrate ; 5 squamosal ; St stapes (columella
auris) ; T tentacular groove ; Vo vomer ; X foramen for vagus nerve.
the cloacal walls are eversible and when protruded form an
intromittent organ by which sperm can be transferred to the
cloaca of the female. Fertilisation therefore is internal. Some
species, e.g. Typhlonectes compressicauda, Dermophis thomensis,
are viviparous ; others are oviparous. The eggs are of con-
siderable size (in Ichthyophis qlutinosa 9x6 mm.) and are
meroblastic. In the viviparous forms, so far as is known, the
young are born fully developed and there is no larval stage.
In the oviparous forms there seems to be some difference in this
GYMNOPHIONA. 303
respect : in Ichthyophis glutinosa (Ceylon) the just hatched
young take to the water and lead a larval life of some duration,
whereas in Hypogeophis (Seychelles) they are hatched ready for
a terrestrial life and there is no larval stage.
The development has been examined in two oviparous forms, viz.
Ichthyophis and Hypogeophis, but has not been fully worked out in any
species. The eggs are always laid in holes in the ground and the mother
remains coiled round them during their development. The segmentation
Is confined to one pole of the egg, but the layers appear to be formed on the
ordinary amphibian type. In Hypogeophis, at least, the blastopore
persists as the anus. Three external gills of considerable size are developed,
but they vanish before hatching. The eggs increase in size and weight
considerably during the developmental period owing either to absorption
of water or to the supply of nutriment from the cutaneous glands of the
mother.
In Ichthyophis, in which the breeding season is after the spring monsoon,
the eggs become surrounded in the oviduct by a considerable coat of
albumen, which becomes twisted in a chalaza-like manner at opposite
poles ; the embryo moreover acquires a number of cutaneous sense-organs
on the head and a lateral line row of similar organs along the body. It
also develops a small vertical tail fin and retains a gill-aperture on each
side which leads internally to two gill-clefts. The just-hatched larva
which is without gills of any kind, either internal or external, makes its
way to the nearest water and there lives for a considerable time as an
aquatic larva with gill apertures and a tail fin. Eventually these dis-
appear, and the animal takes to its terrestrial burrowing life. The so-
called gill apertures being without gills, the larva has to depend entirely
upon its lungs for respiration ; it frequently rises to the surface to breathe.
In Hypogeophis, which appears to breed all the year round, neither
lateral line sense-organs nor tail fin are developed, and the gill-clefts are
entirely closed at hatching. In this form it has been definitely ascer-
tained that five visceral clefts are formed in the embryo on each side, viz.,
a small one (spiracle) between the mandibular and hyoid arch, only
developed dorsally, and four others, the last being between the third and
fourth branchial arches.
The Gymnophiona possess a large pronephros which may extend over
as many as 12 segments in the larval and embryonic states.
In the present state of our knowledge there can be no question
that the Gymnophiona must be placed with the Amphibia. This
is shown by the form of the heart, the presence of a conus
arteriosus, the form of the brain and of the urinogenital organs.
But they differ from other living Amphibia in the form of the
skull, the presence of scales in the dermis, the possession of a
large meroblastic egg, the absence of a larva breathing by gills,
and the absence in the adult of the carotid arch.
There are about 40 living species. The group is not known
in the fossil state.
304
CLASS AMPHIBIA.
Fam. Coeciliidae, with the characters of the order. The genera may
be grouped as follows : —
I. Cycloid scales imbedded in the skin.
A. Eyes distinct or concealed under the skin.
1. Two series of teeth in the lower jaw.
a. Jugal (squamosal) and parietal in contact. Ichthyophis
Fitz., India, Ceylon and Malay Arch. ; Dermophis Peters,
Amer. and Afr. ; Hypogeophis Peters, E. Afr. and Seychelles ;
Coecilia L., Amer.
6. Jugal separated from parietal. Rhinatrema Dam. and
Bibr., Amer. ; Geotry petes Peters, W. Afr. ; Uraeotyphlus
Peters, W. Afr. and India.
2. One series of teeth in lower jaw, Cryplopsophis Boul., Sey-
chelles.
B. Eyes below the cranial bones, jugal in contact with parietal.
Herpele Peters, Panama and Gaboon ; Gymnopis Peters, S. Amer.
II. Scales absent.
A. Eyes distinct or concealed beneath the skin.
1. Two series of teeth in the lower jaw. Typhlonectes Peters,
Amer. ; Chthonerpeton Peters, Amer.
2. One row of teeth in lower jaw. Siphonops Wagl., Amer ;
Bdellophis Boul., E. Afr.
B. Eyes below the cranial bones.
1. Two rows of teeth in lower jaw, Gegenophis Peters, India.
2. One series of teeth in lower jaw, Scolecomorphus, E. Afr.
Order 2. UBODELA.* CAUDATA.
Scaleless Amphibia with a well developed tail, usually with two
pairs of limbs, with or without external gills and gill-slits in the
adult.
The vertebrae are opisthocoelous or amphicoelous even in
closely allied forms. The eyes are small, sometimes functionless,
and without lids except in the Salamandridae. A tympanic
membrane and tympanic cavity are not developed. They are
usually oviparous, rarely viviparous. Fertilisation is generally
internal, sperm transference being effected by application of the
swollen lips of the cloacas, or a spermatophore is deposited in
the water and sucked up by the cloaca of the female. The
sperm is often stored in the seminal receptacles of the female
* Laurenti, Synopsis Eeptilium emendata Wien, 1768. Daudin, Hist-
nat. gen. et part, des Reptiles, Paris 1802-4. Tschudi "Class, der Batra-
chier," Mem. Soc. Scien. nat. Neuchdtel, 2, 1839. Dumeril, " Obs. sur la
reproduction dans la Menagerie des Reptiles du Mus. d'hist. nat. des
Axolotls," Nouvelles Arch, du Mus. d'hist. nat. de Paris, 1860. Boulenger,
Gadow, op. cit. A. Strauch, " Revision d. Salamandridengattungen,"
Petersburg, 1870. Vaillant, Mem. pour servir a 1'hist. anat. de la Sirene
lacertine, Ann. Sc. Nat. (4), 19, 1863.
URODELA. 305
for a considerable time. The development is almost always
partly embryonic and partly larval, but in a few viviparous
forms the young are born fully developed. The larva has gills
and gill -slits which may or may not persist in the adult. They
are mostly aquatic animals, but a few leave the water and are
purely terrestrial in the adult state, merely returning to' the
water to lay their eggs or deposit their larvae. They are car-
nivorous and live on insects and worms and such like. In a
few cases the larvae have the power of developing sexual organs
and of reproducing (paedogenesis, neoteny). This frequently
happens in the genus Amblystoma and occasionally in other
genera (Triton}. They are found all over the temperate parts
of the northern hemisphere but do not (Spelerpes excepted)
extend into the southern. There are about 100 species.
Farn. 1. Amphiumidae. Without gills in the adult ; gill-clefts absent
or one pair only (between the third and fourth branchial arches) ; with
maxillary bones ; both jaws with teeth ; vertebrae amphicoelous ; two
pairs of small limbs ; without eyelids ; United States, E. Asia. Crypto-
bronchus* Leuck., limbs functional with 4 fingers and 5 toes, gill-cleft on
both sides or on left side only. C. (Menopoma) alleghaniensis Daud., the
hellbender, about 18 in., entirely aquatic, E. United States ; C. japonicus
v.d. Hoev., without gill-openings, in China and Japan 600 to 4500 ft. above
sea-level in small streams, may attain to 5 ft., eggs laid in Aug. and Sept.
in strings. Amphiuma Gard., N. America, gill-opening present, 4 branchial
arches, limbs very small, digits 2 or 3 ; .4. means Gard. to 3 ft., swampa
or muddy waters, eggs laid in Aug. and Sept., female coils round them.
Fam. 2. Salamandridae.t Without gills or gill slits in the adult,,
maxillary bones present, both jaws with teeth, with movable eyelid*
except in Typhlotriton, two pairs of limbs.
Sub-fam. 1. Desmognathinae. Series of palatal teeth trans-
verse, restricted to posterior portion of vomers, parasphenoid with
dentigerous plates, vertebrae opisthocoelous, 5 toes, N. America ;.
Desmognathus Baird, D. fuscus Raf., to 5 inches, lungless, eggs in
strings wrapped round the body of the female, said to be meroblastic ;
Thorius Cope, Th. pennatulus Cope, under two inches ; Typhlotriton^
blind, Rock House Cave in Missouri.
Sub-fam. 2. Plethodontinae. Like the last except vertebrae
amphicoelous and 4 or 5 toes, confined to America except Spelerpes
fuscus, found in Eur. (mountains near Gulf of Genoa and Sardinia) ;
Spelerpes Raf., " tongue attached by its central pedicle only, is free
all round, ends in a soft knob, and can be shot out to a considerable
* Hyrtl, Cryptobranchus japonicus, Wien, 1865.
f Rusconi, Amours des Salamandres aquatiques, Milan, 1821. Id,
Hist, nat., development, et metamorphose de la Salamandre terrestre,
Paris, 1854. v. Siebold, Observationes quaedam de Salamandris et Tritoni-
bus, Berolini 1828. Id. Ueb. d. receptaculum seminis d. weiblichen
Urodelen, Z. /. w. Z. 1858.
Z— n x
306 CLASS AMPHIBIA.
distance," the young of many species with balancers, 4 fingers, 5 toes
free or webbed, limbs well developed except in the worm-like Sp.
parvipes (Orizaba) and uniformis (Costa Rica), several species are
lungless, 20 species, N. and C. Amer., N.W. South Amer. (3 species),
Hayti (1 species), Eur. (1 species). Manculus Cope, N. Amer., with
4 toes, tongue as in preceding ; Anaides Baird (Autodax), tongue
cannot be protruded, 5 toes, N. Amer., A. lugubris Hallow.,
entirely terrestrial, lungless, eggs laid in ground and whole develop-
ment passed through in the egg, embryo with external gills ;
Plethodon Tschudi, N. Amer., tongue as in last, 5 toes ; Batrachoseps
Bonap., tongue as in last, 4 toes, N. Amer.
Sub-fam. 3. Amblystomatinae. Series of palatal teeth transverse
or posteriorly converging, on posterior portion of vomers ; parasphe-
noid toothless ; vertebrae amphicoelous, toes 4 or 5, N. Amer., N.
Asia. Hynobius Tschudi, 5 toes, Japan ; Salamandrella Dyb., 4 toes,
E. Siberia. Onychodactylus Tschudi, fingers (4) and toes (5) with
black claws, Japan ; Banidens Kessler, 5 toes, E. temp. Asia ;
Batrachyperus Boul., 4 toes, China ; Dicamptodon Strauch, California ;
Amblystoma Tschudi, palatal teeth in a nearly straight transverse
line or an angle, not separated in the middle by a wide interspace,
5 toes, N. and C. Amer., and 1 species (A. persimile) in Siam ; A.
talpoideum Holbr. runs in light soils like a mole, S.E. Un. States ;
A tigrinum, Green, Un. States and Mexico, the larva is the axolotl,
which was formerly thought to be an adult form and called Siredon
(S. axolotl, or S. pisciformis) ; the axolotl has a tail fin, 3 pairs of
external gills and 4 pairs of open gill clefts, develops sexual organs
and lays eggs, it breeds several times a year. The axolotl is found
in a state of nature in various parts of Mexico and of the United
States. The causes of this retention of the larval characters and
the absence of a metamorphosis from an aquatic to a land animal
appear to be abundance of food and other favourable conditions of
life.* Larvae bred from axolotls in captivity will in some members
of the same brood develop into the Amblystoma, in others remain as
axolotls. An axolotl, which does not undergo the metamorphosis
naturally, may be made f to undergo it by gradually accustoming
it to a terrestrial life, but this becomes increasingly difficult as the
animal grows older. Axolotls of six months are comparatively
easily induced to metamorphose. Further an animal which has
become accustomed to a terrestrial life and has partly undergone
the metamorphosis may be induced to go back to the larval stage.
The axolotl becomes sexually mature at about six months.
Sub-fam. 4. Salamandrinae. Palatal teeth in two longitudinal
series, diverging behind, inserted on the inner margin of the two
palatine processes, parasphenoid toothless, vertebrae opisthocoelous ;
fingers 4, toes 5 except in Salamandrina ; mainly Eur., but found in
Algeria, E. Asia, Asia Minor, America. Salamandra Laur., land-
salamanders, tail subcylindrical, Eur., W. Asia ; S. maculosa Laur.,
the spotted salamander, eject from the skin glands a poisonous white
fluid, viviparous, young are born as larvae from April to June, the eggs
then pass into the oviducts and are fertilised before copulation by sper-
* Gadow, Nature, 67, 1903, p. 330.
t V. Chauvin, Z. /. w. Z., 27, 1876, and 41, 1885, p. 365. Velasco,
Biol. Centralblatt 2, 1882.
URODELA. 307
rnatozoa which have been introduced in the previous July and stored
•until the young of the previous year are born ; S. atra Laur. alpine
salamander, black, viviparous, produces only two young at a birth,*
which are born fully developed, the uterine yoiing have external
gills which absorb nutriment and oxygen, they nourish themselves
on other embryos which break down, they are able to live in water
if removed before development is completed f ; S. caucasica Waja,
Chioglossa Bocage, Spain, Portugal. Triton Laur. (Molge Merrem),
aquatic salamanders, newts, with laterally compressed tail, Eur.,
Asia, N. Amer., pair in water, in the pairing the males of some species
develop a crest, oviparous, eggs glued singly to stones or water plants,
may attain sexual maturity if prevented from metamorphosing
•(v. Siebold, Z. /. w. Z. 28, 1877) ; T. cristatus Laur., the crested newt,
Gt. Britain, Eur., said to be in rare cases viviparous (Balfour, Comp.
Embryology, vol. 2), T. vulgaris L. (taeniatus], Gt. Britain, Eur.
Salamandrina Fit z. with 4 toes, Italy; Tylototriton Anders., Yunnan,
Himalayas ; Pachytriton Blgr. China.
Fam. 3. Proteidae. Three pairs of external gills and two gill-open-
ings (hyobranchial and last branchial closed) persist throughout life ;
maxillaries absent ; premaxillaries, vomer, and mandible toothed, amphi-
coelous vertebrae, no eyelids, fore and hind limbs present. Necturus
FIG. 174. — Necturus maculatus (Regne animal) from Claus.
Raf. (Menobranchus] 4 fingers, 4 toes, eyes exposed, N. Amer. ; N.
tnaculatus (M. lateralis) (Fig. 174), 1 foot, spawn Apr. and May; Proteus
Laur., the olm, 3 fingers, 2 toes, eyes hidden, Carniola subterranean
waters, white turning black if exposed to light, spawn Apr., eggs fastened
singly to stones ; Typhlomolge, waters of an artesian well in Texas.
Fam. 4. Sirenidae. External gills (3 pairs) and gill openings (3
pairs, hyobranchial being closed) through life, maxillaries absent, pre-
maxillaries and mandibles toothless but with horny beaks, amphicoelous
vertebrae, no eyelids, hind limbs absent, fore limbs 3 or 4 toes, S.E. Un.
States, young larvae unknown, in the youngest known the gills are small
and covered by the skin and the respiration is said to be aerial (Cope,
Amer. Nat. 19, 1885, p. 1226), later the gills increase in size. Siren L.
3 gill clefts on each side, 4 fingers, S. lacertina Gray, mud-eel, Pseudo-
branchus Gray, 1 gill cleft on each side, 3 fingers.
Order 3. ANURA.J BATRACHIA.
Scaleless Amphibia without tail, external gills or gill-slits in the
•adult state ; with four limbs.
* Schwalbe, Zeitsch. Biol., (2), 16, 1897, p. 340.
t v. Chauvin Z. /. w. Z, 27, 1876.
J Roesel v. Rosenhof " Historic, naturalis ranarum nostratium" Niirn-
308 CLASS AMPHIBIA.
The body is without a tail, and the vertebral column is short,
consisting only of nine vertebrae and a urostyle. On the head
are the wide mouth and the large eyes, the iris of which has
usually a golden lustre. The eyelids are well developed and
the lower, which is transparent, can be drawn as a nictitating
membrane completely over the eye. The nasal apertures are
placed far forward on the extremity of the snout, and can be
closed by membranous valves. In the auditory organ there is
generally a tympanic cavity, which communicates with the
buccal cavity by a short wide eustachian tube and is bounded
externally by a large tympanic membrane, which is sometimes
free and sometimes concealed beneath the skin. The tongue
is absent in the Aglossa ; it is usually attached between the
rami of the lower jaw in such a way that its posterior part is
completely free, and can be protruded as a prehensile organ.
Ribs are as a rule absent, but the transverse processes of the
vertebrae may attain a considerable length. Pectoral and
pelvic girdles and limbs are always present. The pelvic girdle
is distinguished by the styliform elongation of the ilium. In
the skin, which is scaleless, glands with an acrid milky secretion
are often aggregated in many places, especially in the region of
the ear, where they form large projections (parotoids). Glandu-
lar aggregations occur also on the middle divisions of the hind
legs (Bufo calamita) and on the sides of the body. Reproduction
usually takes place in the spring, but Australian frogs spawn
when external conditions of moisture allow of it. Sexual con-
gress is confined to an external approximation of the two sexes
and almost always takes place in the water. The male, which
sometimes has a wart-like elevation on the hand (Rana) or
gland on the arm (Pelobates), embraces the female from the
back, usually with the front limbs, and pours out the seminal
fluid over the spawn as it issues in strings or in clumps. The
individual eggs are surrounded by a viscous layer of albumen
which swells up in the water. The larvae have the form of
tadpoles.
Some Batrachia are purely land animals (toads and tree-frogs),
berg, 1758. Daudin, " Histoire naturelle des Eainettes, des Qrenouilles^
et des Crapauds" Paris 1802. Rusconi, " Developpement de la grenouille
commune," Milan, 1826. C. Bruch, " Beitrage zur Naturgeschichte u.
Classification der nackten Amphibien," Wurzburger naturg. Zeitschrift*
.1862 and 1863. Boulenger, Ecker, Gadow, loc. cit.
ANURA. 309
which especially love dark and damp hiding places ; others live
indifferently on land or in water. In the first case the five toes
of the hind feet are entirely without a connecting membrane,
or they have an incomplete one ; exceptionally however they
are completely webbed (Pelobates). In the second case, on the
contrary, the hind feet are, as a rule, completely webbed. The
land-frogs usually seek the water only at spawning time ; they
crawl, run and hop on the land, or dig passages and holes in the
earth (Pelobates, Alytes), or they are able to climb up shrubs
and trees by means of discs on the ends of their digits (Dendro-
bates, Hyla}. About 900 species are known.
Sub-order 1. AGLOSSA. There is no tongue and the eus-
tachian tubes are united to
open by a median opening
into the pharynx. The tym-
panic membrane is not
distinct from the rest of the
skin. The vertebrae are opis-
thocoelous and the 2nd, 3rd
and 4th carry ribs which tend
to fuse with the transverse
processes. The transverse
processes of the sacrum are
dilated and confluent with the
urostyle. The epicoracoids do
not overlap. The lungs are
complex with restricted free
lumen. The first spinal nerve
FIG. 175. — Zenopus (Dactylethra) laems.
is present. They are entirely
aquatic in habit. The tadpoles of Xenopus have a pair of spira-
cles (branchial openings), and according to Bles have the normal
form but they are without " internal " gills or horny jaws. They
feed on micro-organisms and use the gill slits simply for
filtering. They possess a sucker, and the external gills are
present in the just-hatched form, but soon disappear, the
larval respiration being entirely by lungs.
Fam. 1. Aglossidae with the characters of the suborder. Xenopus
Wagl. (Dactylethra], upper jaw toothed, ilia to 9th vertebra, pupil round,
phalanges pointed, fingers free, toes broadly webbed and the first three
have horny nails, trop. and S. Africa : X. laevis the clawed-toad, plathander.
310 CLASS AMPHIBIA.
Hymenochirus, trop. Afr. Pipa Laur., the Surinam toad, tropical Amer.,.
without teeth, fingers free, end in 4 appendages, skin papillated, the
eggs which are laid after the rains appear to be fertilised internally and
placed by the protruded cloaca upon the back of the female where they
sink into the skin (Bartlett, P.Z.S. 1896, p. 595), each egg- containing
pouch in the skin so formed is covered by a lid the origin of which is un-
known ; the young leave these skin cells in a condition closely resembling
the adult, the tail formed in the embryo being absorbed before hatching.
Sub-order 2. PHANEROGLOSSA. A tongue is present and
the eustachian tubes are separate. The tadpoles have one spira-
culum only, on the left side except in the Discoglossidae in which
it is median.
Series A. ARCIFERA. The epicoracoids of the two sides overlap.
Fam. 2. Discoglossidae. Upper jaw toothed, transverse processes
of sacral vertebra dilated, short ribs to anterior transverse processes,
vertebrae opisthocoelous, tongue a round non-protrusible disc, males
without vocal sacs, tadpoles with median spiracle. Discoglossus Otth,
S. Eur., N.W. Afr., tympanum indistinct. Bombinator Merr.,Eur., Asia,
no tympanum ; B. igneus Giinth, unke, fire-bellied toad. Alytes Wagl.,
tympanum distinct, the male attaches the eggs to its hind limbs, where
they remain until hatching, Eur. ; A. obstetricans Laur. Liopelma Stein-
dachn., New Zealand, no tympanum or eustachian tubes, the only New
Zealand Amphibian.
Fam. 2. Pelobatidae. Upper jaw toothed, transverse processes of
sacral vertebra dilated, no ribs ; tongue protrusible, vertebrae procoelous
except in Asterophrys and Megalophrys where they are opisthocoelous ;
tympanum hidden or indistinct, absent in Pelobates. Scaphiopus, spade-
foot, N. Amer., Mexico. Pelobates Wagl. spade-footed toad, Eur., inner
tarsal tubercle shovel-shaped ; P. ftiscus Laur., Central Eur., 3 inches,
tadpole larger than adult. Pelodyles Fitz., S.W. Eur., Batrachopsis
Blgr., New Guinea; Leptobrachium Tschudi, E. Ind. ; Xenophrys Giinth,
mountains of India ; Megalophrys Kuhl, E. Ind. ; Asterophrys Tschudi,
New Guinea ; Ranaster Mackay, N. Guinea.
Fam. 3. Bufonidae. Toads. Teeth absent, except in Notaden which
has them on the vomers ; transverse processes of sacral vertebra
dilated ; tympanum usually distinct, but variable ; vertebrae procoe-
lous, without ribs ; includes terrestrial, burrowing, aquatic (Nectes) and
probably arboreal (Nectophryne) forms ; nearly cosmopolitan, absent from
Madagascar, Papuasia and Pacific Islands, and New Zealand. Engystomops
Espada, trop. Amer. ; Pseudophryne Fitz, Australia ; Nectophryne Buchh.
and Peters, W. Afr., E. Ind. ; Bufo Laur., pupil horizontal, metastermun
cartilaginous, sometimes ossified along the middle ; fingers free ; toes
more or less webbed, tips simple or dilated into small discs, more
than 100 species, cosmopolitan except Australian region and Mada-
gascar ; B. vulgaris Laur., common toad of the palaearctic region, is
absent from Ireland, male without vocal sacs, in S. Eur. may attain to
6 inches, devour insects, worms, snails, and have been known to eat mice ;
skin is dry but can exude a white poison, harmless and useful creatures ;
B. calamita Laur., the natterjack, W. Eur., England, Wales and S.W.
Ireland. Nectes Cope, Java ; Notaden Giinth., Australia ; Myobatrachus
ANURA. 311
Schleg., Aust. ; Rhinophrynus Diini. and Bibr., Mexico. Codophryne,
Himalayas.
Fam. 4. Hylidae. Tree-frogs. Upper jaw toothed (Amphignathodon
Blgr. of Ecuador possesses teeth in the lower jaw also), transverse processes
of sacral vertebra dilated, terminal phalanges claw-shaped and swollen
at the base and carry an adhesive cushion ; vertebrae procoelous, no ribs ;
tympanum free or hidden ; with the exception of Hyla arbor ea and two
other species found in N. India and S. China are exclusively American or
Australian (absent from Madagascar and Africa). Thoropa Cope, Brazil ;
Chlorophilus Baird, N. Amer., Peru, includes the smallest frogs, less than
f- in. ; Acris Dum. and Bibr. N. Amer. ; Hyla Laur., pupil horizontal,
tympanum distinct or hidden, fingers and toes with adhesive discs, more
than 150 species, cosmopolitan except ethiopian region ; H. arbor ea L. the
tree-frog of Europe ; H. faber Wied., the ferreiro or smith, the female
makes pools with mud walls for the eggs (P.Z.S. 1895, p. 89), Brazil ; H,
goeldii, eggs carried on back of female, Brazil. Nototrema Giinth. (Noto-
delphys Weinl.), female has a pouch on the back opening behind for recep-
tion of eggs, some at least emit tadpoles, trop. Amer. Hylella Reirih. and
Liitk. trop. Amer. and Australia. Nyctimantis Blgr., Ecuador. Agalych-
nis Blgr., C. Amer. Phyllomedusa Wagl., lays its eggs on leaves of plants
overhanging water into which the tadpole falls at hatching (Budgett,
Q.J.M.S. 42, 1899, p. 313), trop. Amer. Triprion Cope, Yucatan ;
Diaglena, Corythomantis, Pternohyla.
Fam. 5. Cystignathidae. Upper jaw toothed, transverse processes
of sacral vertebra not or but slightly dilated, terminal phalanges never
claw-shaped ; auditory organ variable ; a large family exhibiting great
variety of habit (aquatic, terrestrial, arboreal, burrowing) and presenting
alliances to other families, mostly neotropical, but found also in. trop.
C. Amer., and in Australia and Tasmania.
Sub-fam. 1. Hemiphraetinae. Teeth in both jaws, vertebrae
opisthocoelous, tympanum distinct, S. Amer. Hemiphractus Wagl.,
Ecuador and Colombia ; Ceratohyla Espada, Ecuador ; Amphodus
Ptrs., Brazil.
Sub-fam. 2. Cystignathinae. Teeth in upper jaw only, vertebrae
procoelous. Pseudis Laur., with teeth in upper jaw only, fingers
free, toes webbed, pupil horizontal, first finger opposite the others,
S. Amer. ; Ps. paradoxa, L. 2£ inches, with enormous tadpole to 10
inches, Gui&nas ; Hylodes Fitz., trop. Arner. ; H. martinicensis Tschudi,
large eggs, embryo without gills or clefts hatched as perfect frog,
W. Indies ; Calyptocephalus Bibr., dermal ossification of cranium,
large tadpoles, Chili, Panama ; Ceratophrys Boie, horned toads, toad-
like, some species with a bony dorsal shield in the cutis, eyelid often
as an upright triangular appendage, S. Amer. ; Lepidobatrachus
Budgett, Paraguay ; Leptodactylu^ Fitz., fingers and toes not webbed,
trop. Amer. ; Paludicola Wagl., trop. and S. Amer. ; Centrolene Espada,
Ecuador ; Cyclorhamphus Tschudi, Brazil ; Telmatobius Wiegm.,
W. S. Amer. ; Elosia Tschudi, Brazil ; Edalorhina Esp., Ecuador and
Peru ; Plcctromantis Ptrs., W. S. Amer. ; Limnomedusa Cope,
Uruguay ; Hylorhina Bell, Chili ; Borborocoetes Bell, W. S. Amer. ;
Zachaenus Cope, Brazil; Hylopsis, S. Amer. ; Chiroleptes Gthr., first
finger opposed to the others, Australia ; Heleioporus Gray, Australia ;
Limnodynasles Fitz., Australia ; Crinia Tschudi, Australia ; Mixophyes
Gthr., Australia ; Cryptolis Gthr., Australia ; Hyperolia Cope, Aus-
tralia.
312 CLASS AMPHIBIA.
Sub-fam. 3. Dendrophry nisei nae. Without teeth. Batracho-
phrynus Ptrs., an aquatic genus without tympanum and eustachian
tubes, Peru ; Dendrophryniscus Esp., Brazil.
Series B. FIRMISTERNTA. The epicoracoids do not overlap but are
firmly united with one another.
Fam. 6. Engystomatidae. Transverse processes of sacral vertebra
dilated, vertebrae procoelous and without ribs ; the preeoracoid may be
weak or absent.
Sub-fam. 1. Engystomatinae. Without teeth in the upper
jaw ; neotropical and palaeotropical ; many genera live on ants ;
the mouth is often small and the snout projecting ; in some genera
the digits have adhesive discs supported by T-shaped phalanges.
The sub-family includes terrestrial, aquatic and burrowing forms but
none are arboreal. Rhinoderma Duin. and Bibr., Chili, Eh. darwinii
D. and B., total length 3 cm., male with a subgular vocal sac to which
the eggs are transferred and in which they develop, the tadpoles are
without gills and the whole development appears to take place in
the pouch ; Phryniscus Wieg., trop. Amer. ; Brachycephalus Fitz.,
with broad dorsal osseous shield, S. Amer. ; Stereocyclops Cope, Brazil ;
Engystoma Fitz., Amer. ; Oreophrynella ; Hypopachus Kef erst., trop.
Amer. ; Melanobatrachus Beddome, India ; Sphenophryne Ptrs. and
Doria, New Guinea ; Liophryne, New Guinea ; Calophrynus Tschudi,
E. Indies, S. China ; Microhyla Tschudi, China, E. Indies ; Callula
Gthr., E. Indies ; Xenobatrackus Ptrs. and D., New Guinea ; Phryno-
mantis Ptrs., Africa and Amboina ; Cacopus Gthr., India ; Glypho-
glossusGthr., India ; Brevicep* Merr., Africa ; Hemisus Gthr., Africa ;
Rhombophryne Boettg., Madagascar ; Kcaphiophryne Blgr., Mada-
gascar ; Xenorhina, Ptrs., New Guinea ; Phrynella, Malacca ;
Mantophryne, New Guinea ; Cacosternum, Africa.
Sub-fain. 2. Dyseophinae.* With teeth in the upper jaw;
those with disced digits are climbers. Calluella, Burmah, all the
other genera from Madagascar, viz. Dyscophus, Plcihodontohyla,
Mantipus, Platykyla, Phrynocara, Platypelis, Cophyla, Anodontohyla.
Sub-fain. 3. Genyophryninae. With very small teeth on the
anterior portion of the lower jaw. Genyophrynet Sudest Island between
N. Guinea and the Louisiade Archipelago.
Fam. 7. Ranidae. Transverse processes of sacral vertebra cylindri-
cal ; the precoracoids are always present ; vertebrae procoelous.
Sub-fam. 1. Ceratobatrachinae. Teeth in both jaws ; tongue
notched and free behind ; pupil horizontal ; tympanum distinct ;
fingers and toes free, with swollen tips ; male with two internal vocal
sacs. Ceratobatrachus, Solomon Islands.
Sub-fam. 2. Raninae. With teeth in the upper but none in the
lower jaw ; tympanum variable ; adhesive discs present or absent ;
tongue free behind, sometimes notched ; terrestrial, arboreal and
aquatic forms are known ; mainly arctogaean, 3 species in Papuan
region and 4 genera in the tropical andesian. Phyllobates D. and B.,
trop. Amer. ; Oyyglossus Tsch., E. Indies ; Rana L., frogs, pupil
horizontal, vomers with teeth, fingers free, toes webbed, 4th and 5th
metatarsals diverging and webbed together, cosmopolitan except the
S. parts of S. Amer. and New Zealand, one species in N. Australia ;
R. temporaria L., the common European brown or grass-frog, spawn
* Boulenger, Ann. and Mag. Nat. Hist. (6), 4, 1889, p. 247."
ANURA. STEGOCEPHALI. 313
end of Febr. or beginning of March, hatch in about 5 days, leave the
water in about 3 months, Eur., N. and temp. Asia ; R. esculenta L.,
the common water-frog of Europe, also in W. Asia and N.W. Africa,
is found locally in England at Foulmire Fen and Thetford etc.,
probably introduced ; R. silvatica Leconte, N. Amer. ; R. catcsbiana
Shaw (mugiens), bull-frog, E. N. Amer., to 7 in., will take ducklings ;
R. opisthodon, Solomon Islands, the whole metamorphosis takes
place in the egg. Rhacophorus Kuhl, E. Indies, Japan, Madagascar,
many species have dermal appendages, in Rh. pardalis (Borneo,
Phillipines) the webbed hands and feet are much enlarged and act
as parachutes ; the female of Rh. reticulatus of Ceylon attaches the
eggs to the surface of her belly, in other species the eggs are laid out
of water in a foamy mass. Chiromantis Ptrs., trop. Afr. Ixalus
D. and B., E. Indies. Micrixalus, India. Chirixalus, Karin Hills.
Cornufer Tsch., Polynesia, Austro-Malayasia, Phillipines. Phryno-
batrachus Gthr., Africa. Nyctibatrachus Blgr., India. Nannobatra-
chus Blgr., Ind. and Ceylon. Nannophrys Gthr., Ceylon. Arthro-
leptis Smith, Africa, Madagascar, islands of Indian Ocean, in A.
seychellensift the tadpoles are sometimes found adherent to the back
of the adult. Rappia Gthr., trop. Afr. and Madagascar. Megalixalus
Gthr., trop. Afr. and Madagascar. Cassina Gir., trop. Afr. Hylam-
bates A. Dum., trop. Afr. Hylixalus Esp., Ecuador. Prostherapis
Cope, S. Amer. Phyllodromus Esp., Ecuador. Colosteihus Cope,
Colombia. TrichobatrachtisJ$lgr., Congo ; Gampsosteonyx Blgr. Congo ;
Phrynopsis, Mozambique ; Batrachylodes, Solomon Islands ; Phry-
noderma, Karin Hills ; Oreobatrachus, Borneo.
Sub-fam. 3. Dendrobatinae. Teeth absent. Mantella Blgr.,
Madagascar ; Dendrobales Wagl., trop. Amer., D. tinctorius strongly
poisonous cutaneous secretion, D. braccatus of Brazil carries its tad
poles on its back. Cardioglossa, the Gaboon.
Order 4. STEGOCEPHALI.*
The Stegocephali are extinct salamander-like or lizard-like
Amphibia in which the dorsal surface of the skull is completely
covered by dermal bones. There is also usually a greater or
less development of bony dermal plates on other parts of the
body, and a parietal foramen is present between the parietal bones.
They make their appearance in the Lower Carboniferous and
extend through the Permian into the Upper Trias in which
they disappear. They are the earliest known pentadactyle
animals.
The vertebral column varies considerably in structure. In some forms
the notochord appears to have been persistent and almost unconstricted,
while at the other extreme of modification solid slightly amphicoelous
vertebrae are present (Labyrinthodonts). The ribs, which are one- or
* Sometimes termed Phractamphibia. For literature and fuller account
see Zittel, Grundzuge der Palaeontologie, 1895 (English edition, Macmillan
& Co., 1902); and Woodward, Vertebrate Palaeontology, 1898.
314
CLASS AMPHIBIA.
two-headed are short and never completely encircle the thorax so as to
reach any sternal elements. The skull is in many respects amphibian-
like but in some features it recalls the Reptilia. It is always covered by
a number of bony plates which appear to have been dermal in position
and recall in many respects the condition found in ganoid fishes and in
crocodiles. In many forms the occipital region of the cartilaginous
cranium appears to have been unossified, and there is a ring of small
sclerotic plates round the eye. In some of the palaeozoic genera
(Branchiosaurus etc.) unmistakable remains of bony branchial arches are
present. The teeth are conical ; they are usually present on the jaws
and sometimes on the palatines and vomers. In the Labyrinthodonts
the pulp-cavity gives off branching diverticula into the dentine and the
surface of the dentine is folded in a complicated manner as in certain
extinct crossopterygian fishes. The shoulder girdle, though imperfectly
known appears to have
had scapula (cleith-
rum), clavicle, coracoid
and interclavicles. The
limbs are on the normal
pentadactyle type and
present no approxima-
tion to those of fishes.
The hand when known
presents 4 digits, the
foot 5.
FIG. 176. — Branchiosaurus amblystomus Credner.
A skeleton of adult (nat. size). B restoration
of a larva with branchial arches (after Credner,
from Zittel).
The Stegocephali
appear to have been
fresh-water or ter-
restrial animals.
Although generally
referred to the
Amphibia, • their
systematic position
cannot be regarded
as fixed. The reason
for regarding them as Amphibia is the presence of gill- arches in
some genera, the fact that the ribs never so far as is known
reach a sternum and that traces of the lateral line system of
sense-organs are suggested by grooves on some of the cephalic
scales. But it must be remembered that these and other features
often asserted as characteristic of the Stegocephali have only
been found in some forms ; and that some members of the group
possess features which suggest reptilian affinities. We shall
probably not be far wrong in assuming that the order as at
present constituted is a composite one, containing genera some-
STEGOCEPHALI. 315
of which are amphibian and others reptilian. But whatever
view be taken on this point, it is clear that none of them can be
regarded as bridging the gulf between the piscine and terrestrial
type, for not only do they all present fairly specialised skeletal
features, but in all in which the extremities are known the
pentadactyle type of skeleton is fully developed.
Sub-order 1. BRANCHIOSAURI. Small salamander-like animals, with
well developed gill arches in what are supposed to be immature specimens.
Occipital region of skull unossified. Carpus and tarsus cartilaginous.
Ventral scales thin and in rows. Upper Carboniferous and Permian.
Branchiosaurus Fritsch (Protriton, Pleiironura), Lower Permian of Saxony,
Bohemia and France (Fig. 176) ; Pelosaurus Credner ; Melanerpeton
Fritsch ; Dawsonia Fritsch ; Amphibamus Cope ; Pelion Wyman ;
Urocordylus Huxley and Wright.
Sub-order 2. AISTOPODA. Body long, snake-like without limbs or
pectoral girdle ; vertebrae amphicoelous. Upper Carboniferous, Lower
Permian. Dolichosoma Huxley, Ophiderpeton Huxley.
Sub-order 3. LABYRINTHODONTIA. The dentine of the teeth is much
folded, ventral armour is usually present. From the Lower Carboniferous
to the Trias. Archegosaurus H. v. Meyer, with ventral armour, 4 fingers,
5 toes, Lower Permian ; Sparagmites Fritsch ; Chelidosaurus Fritsch ;
Actinodon Gaudry, etc. Mastodonsaurus Jaeger, the largest Labyrintho-
dont, the skull may attain a length of 1.25 m., Trias ; Trimatosaurus
Braun ; Labyrinlhodon Owen, Keuper. Labyrinthodonts are described
from the Trias of S. Africa and of New South Wales. Footprints which
are supposed to have been made by Labyrinthodonts are found in the
Lower and New Red Sandstone of Europe, Africa and America.
Such footprints usually show five fingers and five toes, which is incon-
sistent with this view as no Labyrinthodont is known to have 5 fingers.
The MICROSATJRIA from the Upper Carboniferous and Lower Permian
with Hyloplesion, Petr abates, Keraterpeton, Lepterpeton, Seeleya etc.,
are usually placed with the Stegocephali.
CHAPTER XI.
CLASS REPTILIA.*
Cold-blooded, usually scaly Vertebrala, with a right and a left
aortic arch, a single occipital condyle, and pulmonary respiration.
The ovum is large and meroblastic, and the embryo has an amnion
and allantois.
The class Reptilia is represented at the present day by lizards,
snakes, turtles, tortoises, crocodiles, and the New-Zealand
lizard, Sphenodon. These however are but a very small pro-
portion of the whole class. The extinct groups, which are almost
confined to the secondary period of geological history, form by
far the most important part of the class both in variety of struc-
ture and habit, and in strangeness of form. Of the living groups
the lizards and snakes are almost entirely terrestrial, and not
found fossil earlier than the tertiary period and then only in
small numbers ; the Chelonia and Crocodilia, which are partly
aquatic, date from the beginning of the secondary period, while
Sphenodon is the representative of a sub -order which made its
appearance in the Permian and has persisted to the present day.
Among the extinct forms we find the whale-like marine
Ichthyosauria, the bird-like flying Pterosaur 'ia, the huge bipedal
Dinosauria, and the mammal-like Anomodontia. It is a signi-
ficant fact that some of the most highly specialized and ancient
of the Reptilia, such as the Chelonia and Pterosauria, make their
first appearance with all their special characters fully developed ;
and in none of the eight sub- classes can it be said that the earliest
forms are definitely annectant to other sub-classes.
* For literature of living forms see the subclasses. For extinct forms
see Zittel, Orundzuge der Palaeontologie, Leipzig, 1895, and the same trans-
lated into English, 1902, Macmiilan & Co., London. A. S. Woodward,
Vertebrate Palaeontology, Cambridge, 1898. For general account of Rep-
tiles see H. Gadow, Amphibia and Reptiles (Cambridge Natural History),
Macmiilan & Co., 1901 ; and C. K. Hoffmann, Reptilian, in Broim's Klassen
u. Ordnungen des Thierreichs.
CLASS REPTILIA. 317
The Eeptilia are essentially scaly tetrapodous, pentadactyle
animals, but great modification in form and habit are met with
in the group. Functional gills are not developed at any time of
life, and they usually lay large yolked eggs which develop outside
the body of the mother.
The integument is scaly in all living reptiles. The scales are
horny epidermal structures usually placed on dermal papillae.
In some cases (Chelonia, some Crocodilia, and Lacertilia),
osteoderms may be present in the cutis in some parts of the body.
It is possible that in some of the extinct forms e.g. Ichthyosauria,
scales may have been absent.
An upper and lower eyelid is generally present, and frequently
a third eyelid, the nictitating membrane. A tympanic mem-
brane is also usually present. But in snakes there is no tym-
panic membrane, and the eyelids are transparent and fused over
the eye, so that they appear to be absent.* There is a cloaca
which receives the openings of the urinogenital ducts, and opens
to the exterior by the anus. The tail is usually of considerable
length, and the limbs are sometimes capable of supporting the
weight of the body ; but more often they serve merely to push
on the body which glides along the ground on its belly. In snakes
and some lizards limbs are absent. -
Cutaneous glands are confined to certain places and are not
generally distributed. The skin is usually diversely coloured,
owing to the presence of pigment in the dermis and sometimes
in the deeper layers of the epidermis.
The phenomenon of colour-change is met with in lizards and
some snakes : it is particularly developed in the chameleons.
The endoskeleton is well ossified, and the membrane bones
are so closely incorporated with the skeleton that they cannot be
peeled off.
The vertebral column is usually divided into cervical, thoracic,
sacral and caudal regions. The faces of the centra vary con-
siderably : they are frequently hollow in front and convex be-
hind (procoelous), but they may be flat, or hollow at both ends
(amphicoelous), or even hollow behind (opisthocoelous). The
amphicoelous condition is found in some extinct forms and in
Sphenodon and the Geckonidce among the living. In this case
* It is possible that they are absent and that the transparent membrane
stretched across the eye is the nictitating membrane.'
318 CLASS REPTILIA.
remains of the notochord occupy the intercentral spaces. The
neuro-central suture persists in many forms and it is common
to find separate cervical ribs. The cervical ribs are usually
double-headed, but the ribs of the thorax may be single or
double-headed. A lumbar region in which the ribs are indis-
tinguishable in the adult is usually present. In Sphenodon and
crocodiles the vertebral part of the ribs carry a posteriorly-
directed process, the uncinate process. The sacrum in living
forms, if present, nearly always consists of two vertebrae, but
is often more extensive in the extinct groups. It is absent in
Ophidia, Mosasauria and Ichihyosauria. Chevron bones (haemal
arches) are frequently present in the caudal region, and are
usually attached between the centra. Wedge-shaped inter-
central bones are sometimes found between the vertebrae of the
cervical and caudal regions.
A sternum is very generally present (absent in Ophidia and
Chelonia}. It is rhomboidal, and may be cartilaginous. The
ribs which reach it belong to the anterior part of the thoracic
region of the vertebral column, and the hindermost of them are
generally attached to a single or double backward prolongation
of it. Abdominal ribs are splint-like membrane bones placed in
the ventral abdominal wall of Sphenodon, crocodiles, and some
extinct groups. They are of the nature of osteoderms and have
nothing to do with true ribs.
In the skull there is a single occipital condyle (Monocondylea),
to which the exoccipitals usually contribute. In the auditory
region three bones are developed, the epiotic, opisthotic and
prootic. Of these it is characteristic that the epiotic unites
with the supra-occipital, and the opisthotic with the exoccipital,
before either of them unites with the prootic or with each
other. The prootic usually remains distinct.
The basisphenoid bone is always present, and sometimes the
alisphenoid, but the presphenoid and orbito- sphenoid are usually
absent. The presphenoid is frequently replaced by a splint
(basisphenoidal rostrum) formed of membrane bone and pro-
jecting forwards from the basisphenoid. This splint represents
the anterior part of the parasphenoid of the Ichthyopsida, and
remnants of the posterior part of the same bone are sometimes
present on the ventral side of and fused to the basisphenoid.
The alisphenoid and orbito -sphenoids are likewise sometimes
SKULL. 319
replaced by downwardly projecting processes of the parietals
and f rentals, or by a bone known as the epipterygoid (columella
cranii). The parietals and f rentals are paired or unpaired and
there is a squamosal which is usually attached to the parietals.
The quadrates which are always present and give articulation to
the lower jaw are moveably (Streptostylica) or immoveably
(Monimostylica) attached to the skull. They are usually carried
by outwardly projecting processes ('parotic processes) of the
auditory region into which the prootic, opisthotic and exocci-
pital bones enter ; but they are also attached to the squamosals,
which may in some extinct forms overlap them externally so
much as almost to conceal them. This condition is an approxi-
mation to that of mammals in which the quadrate must be
regarded as being indistinguishably fused with the squamosal.
The nasal capsules remain largely cartilaginous and are covered
dorsally by the premaxillae, nasals and prefrontals. There is
always a prefrontal and a postfrontal, and usually a lacrymal.
The orbit is generally completed behind by the union of the post-
frontal with the jugals, between which a separate bone, the
postorbital, may be intercalated. The temporal fossa, which is
thus cut off from the orbit, is frequently divided into two by a
bridge of bone formed by the postfrontal sending backwards a
process to unite with an anteriorly directed process of the squa-
mosal. This bridge is called the supratemporal arcade and the
cavity between it and the skull the supratemporal fossa *or
vacuity. Moreover the jugal is in many forms connected with
the lower end of the quadrate by a quadrato-jugal, which con-
stitutes the infratemporal arcade and forms the lower boundary
of what may be called the lateral temporal fossa or vacuity. In
Rhynchocaphalia, Dinosauria, Crocodilia and Pterosauria, both
these arcades and both fossae are present ; in Ichihyosauria,
Plesiosauria, and Anomodontia, both arcades appear to be pre-
sent, but they are continuous and the lateral temporal fossa is
absent or very small (in some Anomodontia), so that there is only
one broad temporal arcade and one fossa (the supratemporal).
In Chelonia there is, as a rule, only one arcade, but it consists of
jugal and quadrato-jugal only and is the lower one, the supratem-
poral arcade not being developed (this is the mammalian arrange-
ment, save for the presence of a quadrato-jugal). IntheLocer-
320 CLASS -REPTILIA.
tilia the supratemporal arcade alone is present and in Ophidia
both arcades are absent.
In many reptiles, e.g. Rhynchocephalia, Crocodilia, Lacertilia
and some Chelonia the parietal sends out a process which reaches
the squamosal : this is the parieto-squamosal or posterior
temporal arcade, which forms the superior boundary of a pos-
terior temporal fossa, the lower boundary of which is formed
by the parotic process of the exoccipital and periotic bones.
The palate varies considerably in structure in the different
groups, but the pterygoids tend to converge rapidly towards the
middle line, instead of being parallel or even divergent as in
the Amphibia.* The palatal vacuities may be extensive as in
Lacertilia and Ophidia, or there may be a continuous bony
palate with secondary palatal plates, as in Chelonia and
Crocodilia. A transpalatine (ectopterygoid) connecting the
pterygoid and maxilla is present in many forms.
The lower jaw is composed of five membrane bones, the den-
tary, splenial, angular, surangular and coronoid, and of a cartilage
bone the articular. Meckel's cartilage often persists through life.
In the shoulder girdle there is a scapula arid a coracoid which
reaches the sternum, when that structure is present ; and
clavicles and interclavicles are frequently found. The humerus
is provided with one or two condylar foramina in Sphenodon and
some extinct forms, and the number of digits varies from two
to five, or in Ichthyosauria to even a larger number.
The pelvis exhibits great variations which are described later
under the orders : it may even be mammal-like (some Anomo-
dontia) or bird- like (Dinosauria) . The ankle-joint is intertarsal
and the number and form of the toes vary considerably.
Central nervous system. — The spinal cord possesses
except in snakes cervical and lumbar enlargements and in some
extinct forms the lumbar swelling seems to have been larger
than the brain.
The cerebro-spinal axis is bent at the junction of spinal cord
and brain. The cerebral hemispheres (Fig. 177) are small and
smooth ; they are largest in the Crocodilia. There are two
optic lobes. The cerebellum is a mere strip in snakes and lizards :
it is rather larger in Chelonia, and in Crocodilia it consists of a
* Mr. Lister has called my attention to this character, which has not,
so far as I know, been noticed before.
nix- A ix.
321
central vermis and two small lateral lobes. There is a parietal
organ in Sphenodon (Fig. 178) and Lacertilia, which is described
below under Lacertilia. There are twelve pairs of cranial
nerves except in snakes in which the spinal accessory is absent.
The facial is not united with the trigeminal, and the glosso-
pharyngeal is an independent nerve though it has several con-
nections with the vagus. The
hypoglossal or twelfth cranial nerve
passes out through a foramen or
sometimes more than one foramen
in the exoccipital bone. The 9th
10th, and llth nerves leave the
skull together.
The 3rd nerve gives off a twig to the
muscle of the upper eyelid. The Cth
supplies the muscles of the nictitating
membrane and the retractor bulbi. The
5th nerve has two roots, a smaller motor
and a larger sensory. The ophthalmic
nerve which sometimes has a special
ganglion corresponds to the R. ophthal-
micus superficialis portio trigemini of
fishes. The 7th has become mainly a
motor nerve ; it gives off a palatine nerve,
which may anastomose with the superior
maxillary, and a mandibular branch which
enters into similar relations with the
inferior maxillary. The main nerve
passes back dorsal to the columella auris
and supplies the muscles of the hyoid, the
cutaneous muscles of the neck, and the
mylohyoid. The 7th nerve sends off
anastomosing branches to the 9th (Jacob-
son's anastomosis). The 10th nerve
possesses a ganglion of the trunk as well
as of the root.
The spinal accessory is a part of the
vagus which becomes distinct in Sauro-
psida and Mammalia. It arises by several
roots from the spinal cord between
the dorsal and ventral spinal nerve-roots as far back as the third
spinal nerve, and passes forwards through the foramen magnum into the
skull which it leaves in association with the vagus. It supplies the
trapezius and other muscles. Part of its fibres enter the vagus.
The hypoglossal may be regarded as being generally homologous with
the spino-occipital nerves (ventral vagus roots) of fishes. It represents
a variable number of anterior spinal nerves which have lost their dorsal
roots and become associated to form an additional cranial nerve.
z.— ii. Y
FIG. 177.— Brain of the Alligator,
dorsal view (after Eabl Riickhard),
Cb cerebellum ; M h optic lobes
(corpora bigomina) ; Mo medulla
oblongata ; I olfactory lobes ; II
optic, IV trochlear, V trigeminal,
VIII auditory, IX glossopharyn-
geal, X vagus, XI spinal accessory
nerves ; 1C, 2C first and second
spinal nerves ; Vh cerebrum.
322
CLASS REPTILIA.
The sympathetic system consists typically of a chain of
ganglia on each side commencing at the upper end of the neck
and extending the whole length of the trunk and possibly into
the tail (caudal canal). Its anterior end enters the skull and
connects with some of the cranial nerves. In crocodiles the
cervical sympathetic is double as in salamanders : a deep portion'
lies in the vertebral- arterial canal of the ribs, and a superficial
in the usual position ; both are connected with the spinal nerves
and with each other by rami communicantes.
The eyes are always present though they vary considerably
in size. The sclerotic is provided with a circle of bony plates
in Chelonia and .Lacertilia. A vascular pigmented fold very
Pa-'
Bol
a-MirVUP
Fio. 178. — Brain of Sphenodon. Side view (after Wiedersheim). Bo? swollen termination of
olfactory lobe ; Ch optic chiasma ; GHS pedunculi cerebri ; Op pineal body ; HII cerebellum ;
Hyp pituitary body ; h small prominence in front of the cerebellum ; Jni infundibulum :
Lp lateral projection of cerebrum ; MH optic lobes : NH medulla oblonprata ; Pa parietal
organ ; Tr tractus nervi optici ; VH cerebrum ; I-XII the twelve cranial nerves.
similar to the pec ten of birds projects into the vitreous humour
in most Lacertilia and in Crocodilia. A retractor bulbi is present
except in Ophidia. There is usually an upper and lower eyelid
and a nictitating membrane, but in Ophidia, Amphisba enidae
and geckos eyelids appear to be absent (p. 317). There are two
lacrymal glands, — the harderian (gland of the nictitating mem-
brane) on the inner (anterior) side of the eyeball, and the lacry-
mal on the outer (posterior) side.
Auditory organ. The membranous labyrinth as in most
Pisces and Amphibia is divided into a" pars superior or utricle
with its three semicircular canals, and a pars inferior or saccule
which gives off posteriorly and ventrally a cochlear process
(sometimes called lagena). The cochlear process is tubular in
SENSE ORGANS. 323
crocodiles and Sphenodon, and slightly bent, thus resembling
that in birds and foreshadowing the spiral cochlea of mammals.
In many reptiles the ductus endolymphaticus (aqueductus
vestibuli) ends in the cranial cavity just beneath the skull roof,
and in the Ascalabota it extends from the skull cavity into the
neck, swelling into a large lobed sack in the neighbourhood of
the shoulder girdle. It is rilled with a soft otolithic mass.
The patches of sensory epithelium in the membranous labyrinth, where
the branches of the auditory nerves end, are as follows : (1) in each ampulla
there is a projection of sensory epithelium known as the crista acustica ;
(2) there is a patch in the saccule and utricle known as the macula
acustica of the saccule and utricle respectively ; (3) on the floor of the
utricle there is an additional patch, the macula acustica neglecta ; (4) in the
cochlear there are two patches, the papilla acustica basilaris and the
papilla acustica lagenae. In the Chelonia and Ophidia the cochlear process
is hardly differentiated into a pars basilaris next the utricle and a peripheral
lagena, but in the Crocodilia the pars basilaris is well developed and forms
the main part of the ductus cochlearis, the lagena being merely a terminal
end-sac. The papilla acustica basilaris which is contained in the pars
basilaris is not differentiated into the organ of Corti, but in crocodiles the
membrane on which it is placed is called the membrana basilaris and there
is an indication of the scala vestibuli, scala tympani and membrane of
Reissner. *
A tympanic cavity, membrane and eustachian tube are present
except in snakes and apodal lizards. There is a fenestra rotunda
as well as a fenestra ovalis, and the columella auris passes from
the latter to the tympanic membrane (for details see account of
orders). A cutaneous fold above the tympanic membrane of
crocodiles represents the first trace of an external ear.
The olfactory organ presents, particularly in the Chelonia
and Crocodilia, a considerable augmentation of the surface of
the mucous membrane, the folds of which are supported by the
single cartilaginous turbinal. The lacrymal duct usually opens
beneath the turbinal, but it may open into the posterior nares
(Ophidia) or into the pharynx (Ascalabota).
Jacobson's organs are absent in Crocodilia and Chelonia.
In Lacertilia and Ophidia they are present between the nasal
sacs and the roof of the mouth (between the turbinals and
vomer) as a pair of sacs 'lined by olfactory epithelium and open-
ing into the mouth just in front of the choanae. They develop
as outgrowths of the nasal sacs, are innervated by the olfactory
* G. Retzius. Das Gehorogan d. Wirbelthiere, vols. 1 and 2, Stockholm,
1881 and 1884.
324 CLASS REPTILIA.
and trigeminal nerves, and are to be regarded as a second
olfactory organ especially developed in connection with the
mouth. The tongue is always well developed. In snakes and
many lizards this organ serves for feeling and in other cases, e.g.
the chameleon, for the prehension of food.
Alimentary canal. Teeth are usually present on the
premaxillae, maxillae, and dentary, and frequently on the pala-
tine and pterygoid. They are continually replaced, and are
pleurodont, acrodont, or thecodont (p. 343). They are conical
or hooked, and are adapted for prehension not for mastication
(except in some extinct forms). In Chelonia teeth are absent,
being replaced by the horny epidermal beak-like covering of
the jaws.
True salivary glands are usually absent. There is a sublingual
in Chelonia. Labial glands, both upper and lower, and palatal
and lingual glands are frequently present. The poison glands
of snakes are upper labial.
The alimentary canal presents no remarkable features. The
large intestine is short and often has a small caecum. It leads
into the cloaca which receives the urinogenital ducts and in
Lacertilia and Chelonia an allantoic bladder. The anus is a
transverse slit in lizards and snakes, a longitudinal slit or a
roundish opening in chelonians and crocodiles.
The Reptilia breathe exclusively by lungs, which have the
form of spacious sacs with alveoli in the walls (snakes, lizards),
or the cavity is much broken up and the lungs are spongy
(Chelonia, Crocodilia). The trachea is long and differentiated"
in front into a larynx which opens into the pharynx by a slit-
like glottis. An epiglottis is found in many tortoises, snakes
and lizards. Vocal chords are present only in chameleons,
geckos and crocodiles.
In lizards and crocodiles peculiar adhesions may be formed
between the lungs and the liver. In crocodiles * these are exten-
sive and complicated and constitute a diaphragmatic mem-
brane separating the pleural cavities from the general body-
cavity.
Vascular system.t In all reptiles the heart consists of a
* Butler, P.Z.S. 1889, p. 452.
f Sabatier, Le Coeur, Montpellier, 1873. Rose, Morph. Jahrb., 16, 1890,
p. 27. G. Fritsch. Arch. f. Anat. and Physiologic, 1869, p! 654.
VASCULAR SYSTEM.
325
sinus venosus, two auricles and, except in crocodiles, of a single
ventricle. It therefore resembles the amphibian heart, but it
differs from this in the absence of a conus arteriosus and in the
fact that the division of the ventral aorta which has commenced
in the Amphibia (particularly in the Anura) is completed and
the ventricle gives off three separate arteries, the right and left
systemic aortae and the pulmonary.
Both right and left systemic aortic arches persist, but the right
is the most important and alone gives off the carotids and sub-
clavians. The left arch either gives
off no vessels, or at most only the
coeliac artery (Chelonia, Crocodilia,
Fig. 179) close to its union with the
right arch. In the Crocodilia the
ventricular septum is complete and
there are two separate ventricles.
Of these the right gives off the
pulmonary artery and the left sys-
temic aorta, while the right aorta
arises from the left ventricle. But
the separation of the two sides is not
complete, for the two sytemic aortae
communicate by a small aperture,
the foramen Panizzae, where they
cross one another, just beyond the
semilunar valves The venous sys-
tem * is very similar to that of
Amphibia. There are two superior
venae cavae (ductus Cuvieri), an
inferior vena cava which arises in the
kidney, and a renal-portal system, which however is reduced
in Chelonia, the greater part of the blood of the iliac veins
passing to the liver. There is a single or double anterior
abdominal vein which joins the portal system. All the venous
blood of the hind end of the body passes through the kidneys or
the liver.
Fio. 179.— Heart and Arteries of a
Chelonian (Chelydra). d right,
s left auricle ; c carotid ; alright,
as left aortic arch ; pd right,
ps left pulmonary artery ; c1
coeliac artery ; sd right, s s left
subclavian artery (from Cegen-
baur).
In the snake? and lizirJb the anterior abdominal vein is single, and
does not anastomose with the cauial and iliac veins, which are distributed
* Rathke, Bau u. Entwick. des Venensystem der Wirbelthiere. Konisberg,
1838. Hochstetter, Morph. Jahrb., 13, 17, and 19.
326
CLASS REPTILIA.
entirely to the kidney. In crocodiles and cheloniaiis the caudal veins
bifurcate in front and are continued as the two anterior abdominal veins,
which receive the iliac veins. In the crocodile the renal-portal veins start
from a transverse vessel which connects the two branches of the caudal.
There is an imperfect septum in the sinus venosus. The inter-auricular
septumTis always complete. The ventricular cavity is largely broken
up by muscular trabeculae, the central clear space being not very large.
The interauricular septum reaches right down to and divides the auriculo-
ventricular opening into a right and left division (Fig. 180). To the
posterior free edge of this septum are attached two valves (r, v'), one
guarding the right auriculo-ventricular aperture and the other the left ;
these are the only auriculo-ventricular valves, except in crocodiles (see
below). The dorsal and ventral ends of these valves are attached to the
dorsal and ventral wall of the ventricle by muscular bands, which consti-
tute together with the valves an incipient septum dividing the ventricle
KAo,
FIG. 180.— The heart of a turtle (Chelone midas). A, a diagram explanatory of the
arrangement of the cavities and vessels. B, a drawing from nature, the ventral face
of the ventricle being laid open (after Huxley), a muscular flap projecting from the
ventral wall and forming an incomplete septum dividing the cavum venosum C.v ; Cp
part of the cavum venosum from which the pulmonary artery rises ; L.A left, R.A
right auricle ; L.Ao left, R.Ao right aorta ; P. A pulmonary artery ; s arrow showing
course of blood in left aorta, t in right, z in pulmonary artery and y behind the
incomplete septum ; v, v' the right and left auricnlo- ventricular valves ; w, x arrows
in auriculo-ventricular openings.
into a right and left portion. Of these the right, which is the larger and
receives the opening of the right auricle, is called the cavum venosum (C.v],
while the smaller left receives the left auricle and is called the cavum
arteriosum. The cavum arteriosum gives off no vessels ; whereas the
cavum venosum gives off three — a dorsally arising pulmonary artery, and
a right and left systemic aorta. The left systemic aorta, arises to the right
of the other and crosses to the left side (Fig. 180), passing ventrally to it.
The cavum venosum is imperfectly divided into two by a muscular
projection of its ventral wall (a). From the right side of this projection,
from the cavum pulmonale as it may be called, arises the pulmonary
artery, from the left the two systemic arches. When the ventricle con-
tracts the free edge of the imperfect septum so constituted meets the dorsal
wall of the ventricle and the heart becomes functionally divided for the
VASCULAR SYSTEM.
327
moment into two chambers. Of these the right being nearer to the opening
of the venous auricle is charged with venous blood which it delivers into
the pulmonary artery, whereas the left contains mixed blood near the sep-
tum and arterial blood in the cavum arteriosum. The former will pass
mainly into the left aortic arch, the latter into the right, from which the
carotids and subclaviaris spring. A proper distribution of blood is thus
assured, the carotids receiving arterial blood only. In the crocodile the
ventricle is double and its cavity much clearer of muscular trabeculae
than in the other orders. Further the auriculo-ventricular openings are
guarded not only by the mesially attached pocket-valve, alone found in
other reptiles, but also by a muscular flap of the ventricular wall (like
that in the right ventricle of birds).
The vascular arches which persist in reptiles are the 3rd, 4th,
and 5th postoral.* The vessel of the third arch (first branchial
of fishes) becomes the carotid : in Lacertilia it usually retains
its connection dor-
saliy with the next
arch (Fig. 181) by
a vessel which is
called a ductus
Botalli. In Chelonia
(Fig. 179) the fifth
or pulmonary arch
retains its connec-
tion with the pre-
ceding (fourth or
systemic), so that
the duct as Botalli
is between the
fourth and fifth
arches.
The lymphatic system is similar to that of Amphibia. There
are some wide lymphatic spaces, and posterior lymph hearts
opening into the ischiadic veins are present. Lymphatic glands
are absent, except in crocodiles in which there is one in the
mesentery.
Spleen, paired thymus, thyroid, and suprarenal bodies are
always persent.
The kidneys are usually lobed structures placed posteriorly.
* It is maintained by some anatomists that the persisting arches are
the third, fourth, and sixth, the fifth early undergoing atrophy. In this
case the pulmonary artery of reptiles will be derived from the vessel of the
sixth postoral arch as in Amphibia (see Boas, Morph. Jahrbuch, 13, 1887,
p. 115).
FIG. 181. — Diagrams illustrating the metamorphosis of the
vascular arches in a lizard A, and snake B (from Balfour).
a internal, 6 external, c common carotid ; d in A, ductus
Botalli between third and fourth arches, in B, right aortic
trunk ; e in A, right aortic trunk, in B vertebral artery ;
/ subclavian in A, left aorta in B ; g dorsal aorta ; h in A
left aorta, in B pulmonary artery ; i pulmonary artery in
A, ductus Botalli in B ; k connection, lost in the adult
between pulmonary and systemic arch.
328 CLASS REPTILIA.
They correspond to the posterior thick part of the amphibian
kidney. The ureter, which is to be regarded as the united
collecting tubes of the metanephros of Amphibia, opens into the
cloaca, and the urine is often a whitish mass of firm consistency
containing a considerable quantity of uric acid. There is a
bladder in Lacertilia and Chelonia.
In the reproductive organs the mesonephros of Amphibia
and its duct have become entirely taken over into the service of
the testis. The mesonephros (wolfFian body) has lost its kidney
structure and become incorporated into the testis as a portion
of the epididymis, while the mesonephric duct (pronephric,
primitive longitudinal duct) forms the rest of the epididymis
and vas deferens. In the female the mesonephros and its duct
atrophy or persist as a small vestige (Rosenmiiller's organ, canal
of Gaertner), and the duct of Miiller persists as the oviduct.
The oviducts begin with a wide abdominal ostium, have a
sinuous course and glandular walls, and open into the cloaca.
The eggs are large and much distended with yolk as in birds.
They are fertilized in the oviduct and receive a coating of
albumen and a shell (membranous or calcareous) in their passage
down the latter. They are usually laid as soon as the shell is
formed and undergo the greater part of their development out-
side the mother, who as a rule takes no further trouble about
their fate, but in a few forms they are retained for a considerable
time in the oviduct, sometimes till the embryonic development
is completed.
The males always possess organs of copulation, to which
similarly arranged but smaller structures (clitoris] correspond in
the female. In snakes and lizards these organs are paired and
consist of protrusible hollow pockets of the cloaca. When pro-
truded their surface is traversed by a groove which conveys the
sperm from the genital openings in the cloaca. In Chelonia and
Crocodilia, a median erectile penis, consisting of two corpora
cavernosa and a terminal glans and supported by fibrous bands,
is attached to the ventral wall of the cloaca.
The developmental history * of reptiles is very similar to that of
* C. E. v. Baer, Entwickelungsgeschichte der Thiere, II. Konigsberg,
1837. H. Rathke, Entwickelungsgeschichte der Natter, Konigsberg, 1839.
Id., Die Entwick. der Schildkroten, Braunschweig, 1848. Id., Unters.
ub. d. Entwick. u. d. Korperbau der Crocodile, Braunschweig, 1866. L.
Agassiz. Embryology of the Turtle, Contributions to the Natural History
of the United States, II, Boston, 1857.
RHYNCHOCEPHALIA. 329
birds. The cleavage is meroblastic, and the embryo is provided
with an amnion and allantois. The amnion is a purely em-
bryonic structure, but the allantois is the cloaca! bladder which is
precociously developed and enormously enlarged as the embry-
onic respiratory organ.
Reptiles are cold-blooded. In the cold and temperate regions
they fall into a kind of winter sleep, and in hot climates there is
a summer sleep which comes to an end with the beginning of the
rainy season. Most of them are very tenacious of life and can
exist a long time without food and with limited respiration.
The power of reproducing lost parts exists (e.g. the tail in lizards),
but is less than in Amphibia.
They first make their appearance in the Lower Permian
(Protorosaurus). In the Secondary Period they obtained an enor-
mous development both in variety of form and in size. In the
Tertiary Period they declined. There are about 3,500 living
species at present known. They are divided into nine sub-
classes, the interconnections of which are somewhat compli-
cated. They may be arranged as follows :—
Sub-class 1. Rhynchocephalia. Permian to present day.
,, 2, Lepidosauria.
Order 1. Dolichosauria, Cretaceous.
,, 2. Mosasauria, Cretaceous.
,, 3. Lacertilia, Jurassic to present day.
,, 4. Ophidia. Cretaceous or Eocene to
present day.
Sub-class 3. Crocodilia. Triassic to present day.
„ 4. Dinosauria. Triassic to Cretaceous.
,. 5. Plerosauria. L. Jurassic to Cretaceous.
6. Ichthyosauria. Triassic to Cretaceous.
7. Plesiosauria. Triassic to Cretaceous.
„ 8. Anomodontia. Permian and Triassic.
„ 9. Chelonia. Triassic to present da}-.
Sub-class 1. RHYNCHOCEPHALIA.*
Lizard-like creatures with biconcave vertebrae, immoveable quad-
* A. Giinther, " Anatomy of Hatteria,'' Phil. Trans. 167, 1867, p. 595.
G. Osawa, a series of papers on the anatomy of Hatteria in Arch. f. mic.
Anat., vols. 47, 1896, p. 570 ; 49, 1897, p. 113 ; 51, 1898, p. 481 ; 52, 1898,
p. 268. F. Siebenrock, Zur Osteologie des Hatteria-Kopfes, Sitzb. Akad.
330 CLASS REPTILIA.
rate, upper and lower temporal arcades, acrodont teeth, 5-toed
limbs, and a parietal organ. The premaxillae are paired, the
mandibular symphysis usually ligamentous, the skin has horny
scales, and the vertebrae frequently contain persistent remains of
the notochord. Anal opening transverse.
The living genus Sphenodon may be taken as the type of the
group. The body is lizard-like in appearance, possessing a
scaly skin, a long tail and four pentadactyle limbs adapted for
walking. The vertebrae are amphicoelous, the cavities between
the centra containing persistent vestiges of the notochord, as
in the geckos. Intercentra in the form of subvertebral wedge-
bones or chevrons are present on all the vertebrae. The atlas
and axis are as in other living reptiles and there is a so-called
proatlas as in crocodiles (p. 373). The- caudal vertebrae are
divided by a septum as in lizards, and the tail when lost is re-
produced. The ribs are single-headed, and some of them
possess cartilaginous uncinate processes. There is a median
sternum to the anterior end of which are attached the coracoids
and the interclavicle. Abdominal ribs are present in the form
of numerous transverse rows of small splint-bones (three in each
row), between the sternum arid the pelvis. In the skull (Fig.
182) there are paired f rentals, parietals and premaxillaries, and
a pineal (parietal) foramen. The upper temporal arcade is
formed by the postorbital and squamosal, the lower by the jugal
and quadrato-jugal which reaches back to the quadrate. The
posterior border of the orbit is formed by the postfrontal, post-
orbital and jugal. There is an epipterygoid extending from
the parietal to the pterygoid and quadrate. The palate is almost
entirely bony ; the internal nares are narrow and elongated,
immediately external to the vomers, and there is a vacuity
between the median parts of the pterygoids. The pterygoids
reach back to and are suturally united with the quadrates which
are fixed. The bottom of the orbit is almost completely
osseous. The dentary pieces of the mandible are united by
ligament and not suturally.
Wien, 102, 1893, p. 250 (and in Ann. Mag. Nat. Hist. (6), 13, p. 297).
G. B. Howes and H. Swinnerton, " Development of the skeleton of Sphen-
odon," etc., Trans. Zool. Soc., 16, 1901 (contains a bibliography). H. S.
Harrison " Development and succession of teeth in Hatteria," Q.J.M.S.,
44, 1901, p. 161. A. Dendy, Outlines of the Development of the Tuatara,
Q.J.M.S. 42, 1899, p. 1. For extinct forms see Woodward, Zittel, op. cit.
RHYNCHOCEPHALIA.
381
The dentition is acrodont, and the teeth are fused with the
subjacent bone. The premaxillary teeth, and the downwardly
carved premaxillae with which they are fused, have the appear-
ance, especially when worn down, of a pair of rodent-like incisors.
There is a row of small triangular teeth on the maxilla and
another on the palatine. The single row of mandibular teeth
Prf Fr
I>tf Por Pa
FIG. 182. — Sphenidon punctatus, skull A from the side B from above, C from below, D from
behind (after Giinther, from Zittel). A orbit ; Any angular ; art articular : Bo basi-
occipital ; Ch internal nares ; d dentary ; Exo exoccipital ; Fr frontal ; Ju jugal ; K sur-
angular ; MJC maxilla ; JV external nares ; Na nasal ; Opo opisthotic ; Pa parietal : PI
palatine ; Pmx premaxilla ; Por postorbital ; Pr, prefrontal : Pt pterygoid : F if postfrontal ;
Qu quadrate ; Qu Ju quadrato-jugal ; S superior temporal fossa ; Sq squamosal ; So supra-
occipital ; Vo vomer.
upper jaw. In
teeth on the
some young
vomers. The
bite between these two rows in the
specimens there are a few small
pterygoids are edentulous.
There is a T-shaped interclavicle and a clavicle, and the cora-
coid is without fenestrae. The humerus has an entepicondylar
as well as an ectepicondylar foramen. The carpus has ten
separate bones. The pelvis is somewhat lacertilian though the
332 CLASS REPTILIA.
ilium is more erect than in that group. There are five digits on
each limb.
The tympanic membrane is not visible externally, but on
removing the skin in the aural region there is found a strong
aponeurotic expansion which represents it. The tympanic
cavity is represented by a large pharyngeal recess. The hyoid
arch is continuous with the outer cartilaginous end (extra-
stapedial) of the columella,* which is in contact with the parotic
process of the skull. It would thus appear that the extra-
stapedial cartilage in Sphenodon is the proximal end of the
hyoid arch. In their internal anatomy generally they resemble
lizards, the most important difference being the absence of
co.pulatory organs. The anus is a transverse cleft as in snakes
and lizards. The parietal organ is well developed (Figs. 178,
189, and p. 344).
Sphenodon was formerly common on the main islands of New
Zealand, but is now restricted to some small islets in the Bay
of Plenty. It appears to be on the verge of extinction. The
animals inhabit burrows and are nocturnal in habit. They are
carnivorous and as a rule slow in their movements. They can
however run fast and can defend themselves with some vigour.
They lay eggs from November to February. Though the young
appear to be almost fully developed in August, they do not
hatch out until thirteen months after oviposition.
There can be little doubt that the Rhynchocephalia are more closely allied
to the Lacertilia than to other living reptiles. This is shown by the general
form of the body, the presence of a parietal organ, the structure of the
respiratory organs, of the vascular system, and by the internal anatomy
generally ; and on the whole by the skeletal system. There are however
importa,nt points of difference. The most noteworthy of these are the
form of the palate (particularly the apposition of the pterygoids), the
immoveability of the quadrats, the presence of a lower temporal arcade
in the skull ; the erect ilium and the presence of uncinate processes and
abdominal ribs. In these features they may be said to approach the
Crocodilia, and in some of them the Dinosauria. and Chelonia. The
amphicoelous character of the vertebrae is found again in the Geckos, but
the absence of copulatory organs is a unique feature a,mong reptiles : on
the whole it seems advisable in the present state of knowledge to associate
them as was done by Giinther and Huxley with the Laccrlilia and Ophidia,
but it must not be forgotten that they do present certain skeletal features
which are not present in lacertilians, but which are found in othe^ reptilian
groups, particularly in crocodiles.
* Huxley, P.Z.S., 1869, p. 391.
RHYXCJKK KPHALIA. 333
They make their appearance in the Permian and they are therefore
the oldest known reptiles. For this reason and also on account of the
above-mentioned resemblances to other reptilian groups they have been
regarded by some authors as an ancestral group or at least as being closely
allied to the ancestors of reptiles generally and possibly of birds. We do
not share this view. The Rhynchocephalia are essentially reptilian, i.e.
they present so far as we know them all the typical features of reptilian
organisation in full development. This is hardly what we should expect
if they were an ancestral group. It is true that the earlier forms from the
Permian are very imperfectly known, but this fact can hardly be alleged
as an argument in favour of the view that they are ancestral. Doubtless
the view would not have been put forward had it not been for the earliness
of their appearance as fossils. But arguments based on this fact lose
much of their weight when wre consider the necessary imperfection of the
geological record. The fact that fossil remains of any particular animal
are not found in any particular strata cannot be regarded as evidence of
the non-existence of the animal. If it could we should have to regard the
living genus Splienodon as being totally disconnected with the other eenera
of its family, for the family Sphe-nodoniidae is not found fossil after the
Jurassic period. Again the Chelonia make their appearance in the Triassic
strata with all the specialities of the order. When we consider the small
change which has taken place in the organisation of the Chelonia or indeed
of the Crocodilia since the Triassic age, is it reasonable to suppose that they
were evolved from sphenodon-like forms in the interval comparatively
short which elapsed between the laying down of the Permian and Triassic
strata ? The Chelonia of the Trias must have had predecessors. It can
hardly be regarded as an unreasonable view to hold that their remains per-
haps in a less specialised form will some day be found in the Permian or
perhaps even earlier ; and even if they are never found in those earlier
strata, it is hardly open to us to argue that they did not exist before the
Triassic age, unless indeed we give up the evolution hypothesis altogether and
assume that they came into existence suddenly and without predecessors.
And if they existed before the Triassic age the argument that the
Rhynchocephalia are ancestral to them, in so far as it is based on their
antiquity, is much weakened, if it does not completely fall to the ground.
As already stated the Rhynchocephalia are represented at the present
time by the genus Sphenodon which lives in New Zealand, and so far as we
know has not been found in the fossil state.
The group may be classified as follows : —
Protorosauridae. Premaxillae, maxillae and mandibles with conical
teeth either implanted in shallow pits or fused with the jaws. Vomer
covered with small teeth. Interclavicle rhombic in front, prolonged
behind. Permian and Trias. Palaeohatteria Credner, long-tailed small
lizards 45 cm. in length, vertebrae amphicoelous with continuous notochord,
abdominal ribs as numerous small oat-shaped scutes, Lower Permian, near
Dresden. Protorosaurus H. v. Meyer, the Thuringian lizard, to (j or 7
feet ; with long neck ; skull and limb girdles imperfectly known, intercentra
in the neck only, vertebrae amphicoelous, neurocentral suture obliterated,
limbs well developed, Upper Permian of Thuringia ; Telerpeton Man tell,
Elgin Sandstone (Trias).
Fragments from the Permian of Texas and the Lower Permian of
Bohemia known as Clepsydrops, Dimeirodon, Naosaurus, etc. seem to be
allied here. They have been classed as Pelycosauria and many of the
genera have enormous neural spines with lateral branches.
334 CLASS REPTILIA.
The remaining families are sometimes classed as Rhynchocephalia vera.
Mesosauridae. With numerous fine, brush-like teeth in the jaws ; neck
long, with short hatchet-shaped ribs ; tarsus with two bones in the proximal
row. Permian and Trias. Mesosaurus Gervais, Lower Trias of S. Africa.
Stereosternum Cope, Permian of Brazil.
Ghampsosauridae. Large aquatic reptiles with gavial-like head from
the Cretaceous and Lower Eocene of N. Amer. and the Lower Eocene
of Europe. Champsosaurus Cope.
Rhynchosauridae. Skull massive with edentulous bent down beak-like
premaxillae ; upper jaw and palate with 3 or more rows of pyramidal
teeth ; Trias. Rhynchosaurus Owen, Upper Trias, Warwickshire ;
Hyperodapedon Huxley, 6 feet in length, no parietal foramen, Elgin Sand-
stones and Indian Trias.
Sauranodontidae. Upper Jura of France.
Sphenodontidae- Upper Jura and present time. It is interesting to note
the long period (Cretaceous and Tertiary) in which these reptiles have not
been found. Homaeosaurus v. Meyer, very like Sphenodon, but ribs
without uncinates, without intercentra in the dorsal region, without
entepicondylar foramen in the humerus, Upper Jurassic ; Ardeosaurus,
Acrosaurus v. Meyer ; Euposaurus Jourdan ; Pleurosaurus v. Meyer ;
phenodon Gray (Hatteria Gray), living, N. Zealand.
Sub-class 2. LEPIDOSAURIA (SQUAMATA).
With procoelous, rarely amphicoelous vertebrae, and with horny
scales ; sacrum of two vertebrae or absent ; ribs single-headed ;
abdominal ribs absent. Quadrate moveable, attached to the skull
by its proximal end only ; lower temporal arcade absent, palate
with many vacuities ; ptery golds not reaching to the vomers.
The Lepidosauria comprise the orders Lacertilia and Ophidia
and the extinct groups of aquatic forms, the Dolichosauria and
the Mosasauria.
Order 1. DOLICHOSAURIA.
Small aquatic snake-like forms with well developed limbs and limb-girdles ;
vertebrae with zygantra and zygosphenes ; teeth pleurodont ; lower jaw with
sutural symphysis.
This order includes the long-necked Cretaceous form Dolichosaurus Owen
with 17 cervical vertebrae ; and the genera Aigialosaurus, Pontosaurus,
etc. probably belong to it.
Order 2. MOSASAURIA.*
Large extinct marine reptiles, with two pairs of clawless five-toed limbs.
Skull varanus-like with a pineal foramen ; lower jaw with ligamentous sym-
physis. Sacrum absent, the ilia not reaching the vertebral column.
The vertebral column always contains more than 100 vertebrae, dis-
tinguishable into cervical, thoracic, lumbar and caudal. Zygosphenes
and zygantra are occasionally, but rarely, present. The skull has a superior
* Sometimes called Pythonomorpha.
LACERTILIA. 335
temporal arcade and resembles that of Varanus. It has an epipterygoid,
but resembles snakes and Rhynchocephalia in having a ligamentcus
symphysis to the lower jaw. Further there is a joint in each ramus just
behind its middle joint. Teeth are present on both jaws and on the ptery-
goids. The limbs a^e paddle-shaped ; they and their girdles are fairly
normal, but the long bones are much shortened and the digits often have
an increased number of phalanges and are without claws. There is no
clavicle, and the ilia are loosely, if at all, attached to the vertebral column.
They usually reach a considerable size (to 25 feet or more) and in their
general appearance recall that of the toothed whales. They are found
in the Upper Cretaceous of Europe, N. and S. America, and N. Zealand.
Mosasaurus Conyb. (Leiodon Owen), Upper Cretaceous of Maestricht
(Holland), of Belgium, France, X. Germany and N. America. Platecarpus
Cope, N. Amer. ; Clidastes Cope (Edestosaurus Marsh), N. Amer. ; Tylo-
saurus Marsh (Leiodon Cope), N. Amer. ; Hainosaurus Dollo, Belgium ;
Taniivhasaurus Hector, N. Zealand.
Order 3. LACERTILIA * (AuTOSAuni).
Reptiles with horny epidermal scales, moveable quadrate bones,
transverse anal opening, paired copulatory organs, a cloacal bladder,
and two sacral vertebrae. The skull is without a bony quadrato-
jugal arcade.
The lizards always have an elongated and sometimes a snake-
like body. As a rule there are four limbs, which however scarcely
carry the body raised from the ground. In locomotion they are
used principally for pushing the body forward, but they may
also be used for clinging (Chamaeleon], climbing (geckos), and
digging. They usually end with five clawed digits. They are
sometimes so short and reduced, that they have the appearance
of stumps applied to a serpent-like body, and are without separate
digits (Chamaesaura}. In other cases vestiges of the posterior
limbs alone exist (Pseudopus, Pygopus, Fig. 183), or anterior
limbs alone are present (Chirotes], or finally external limbs may
be entirely absent (Anguis, Anelytropidae, Amphisbaena}. The
pectoral and pelvic girdles are however present, and in all lizards
except Amphisbaena there is at least a trace of the sternum,
* Tiedemann, " Anatomic und Naturgeschichte der Drachen," Nurn-
berg, 1811. Wiegmann, " Herpetologica mexicana, Pars I, Saurorum
species amplectens," Berlin, 1834. Fischer, " Die Gehirnnerven der
Sauriern " Abh. a. d. Geb. der Naturw. Hamburg, vol. 2, 1852. Rathke
" Untersuchungen ueber die Aortenwurzeln u. die von ihnen ausgehenden
Arterien der Saurier," Denkschr. der Wiener Akad., 15, 1857. E. Schreiber,
" Herpetologica europaea," Braunschweig, 1875. G. A. Boulenger,
" Catalogue of the Lizards in the British Museum," London 1885, 3 vols.
E. D. Cope, " The Crocodilians, Lizards and Snakes of N. America,"
Report of the U. S. National Museum, 1898, pp. 153-1,270, 1900. Huxley,
Zittel, Gadow, op. cit.
336 CLASS KEPTILIA.
which increases in size as the anterior limbs become more
developed, and then serves for the attachment of a correspondingly
greater number of ribs. Except in the Amphisbaenidae and a
few other lizards the tail is long. The limbless forms and those
with reduced limbs are by no means specially related to one
another. They turn up in many of the families and the loss or
reduction of the limbs seems to be associated with some special
habit of life, such as burrowing or living among stones and thick
vegetation.
Most lizards have an upper and lower eyelid and a nictitating
membrane, but in the Amphisbaenidae and Geckonidae and some
jScincidae the eyelids are fused over the eye as in snakes
and there is a cavity lined by conjunctiva between them
FIG. 183. — Pygopus lepidopus (R6gne animal).
and the cornea. In some Scincidae the centre of the
lower eyelid is transparent and can be raised over the eye
without hindering the sight. In chameleons the single eyelid
is circular, consisting of a muscular ring of skin with circular
opening. An exposed tympanic membrane is usually present,
but in Amphisbaenidae both it and the tympanic cavity are
absent, and in many lizards (Anguis, Anelytropidae, Chamae-
leontidae etc.) the tympanic membrane is covered by the skin or
absent.
The integument of lizards resembles in its general features
that of snakes, but presents much greater variety. As a general
rule it is scaly. The scales consist of horny epidermal
plates placed on dermal papillae and frequently overlap.
LACERTILIA. 337
The latter may in some forms (Scincidae, Anguidae, on the
head only in Lacertidae) develop bony plates (osteoderms),
which on the head may coalesce with the subjacent bones. The
scales on the head are arranged much as in snakes and the same
nomenclature is used in describing them. The scales may have
the form of chagrin-like granules or of variously formed tubercles.
In the Amphisbaenidae the skin is soft and scaleless. The
horny layer of the epidermis periodically peels oil in flakes, or
as in Anguis etc. in one piece. Cutaneous lobes on the throat
and sides of the trunk, and crests on the back and top of the head
are often present. Cutaneous glands are present on the inner
sides of the thighs (femoral glands, Fig. 191a, SP) and in front
of the anus, otherwise they appear to be absent. They are
tubular structures filled either with a slimy mass or with a short
wart-like body of a horny consistency which in the breeding
season may project on the surface. They are present in both
sexes or only in the males, and are absent in some genera.
Most lizards are capable of changing colour. This is
especially seen in the chameleons.
The vertebrae are procoelous except in the Geckonidae in
which they are aniphicoelous. In this family the notochord
persists, except in the middle of the vertebrae, throughout the
vertebral column. All the vertebrae in front of that carrying
the first sternal rib are cervical. There are one or two lumbar,
two sacral, and a large number of caudal. The atlas consists
of three pieces, one ventral and two dorso-lateral. The odontoid
is closely attached to the axis. The two sacral vertebrae are not
ankylosed, but they are united by strong ligaments. The anterior
caudal vertebrae have chevron bones attached to the centra and
not to the intervals between ; and subvertebral wedge-bones,
consisting of small separate ossifications found on the ventral
surface at the junction of two vertebrae, are often present on
Other parts of the vertebral column.
Til the Iguanidae the vertebrae are articulated by zygantra and zygo-
sphenes as in snakes, in addition to the ordinary articulating processes.
In many lizards the caudal vertebrae are composed of two halves, an
anterior shorter to which the transverse process is attached, and a longer
posterior portion. This phenomenon is due to the presence of a thin
unossined transverse septum traversing the vertebrae. As is well known,
many lizards when seized by the tail have a habit, of breaking off the part
seized and so escaping. Such breaks always take place at one of the weak
z.— ii. z
338
CLASS REPTILIA.
Mst.
spots caused by these unossified septa. The lost tail is replaced by
regeneration, but the new tail (which may be double) has an imperfect
skeleton and its scaling may differ from that of the lost part.*
The ribs are single headed and are attached to the vertebrae
between the centrum and the arch ; a ligament, however, often
passes from the neck of the rib to the neural arch. In the
anterior and posterior vertebrae they are often attached to
transverse processes. Ribs are found on all the precaudal
vertebrae except the atlas and sometimes the
next two, and on one or two of the presacral ver-
tebrae (lumbar). The proximal part alone ossifies,
the distal part remaining cartilaginous or be-
coming calcified.
The posterior ribs present a peculiar modification
in Draco, being extremely long and serving to support
lateral expansions of the skin, by which the animal is
able to perform its nights. In the geckos and chamaeleons
the posterior ribs meet each other in the ventral middle
line forming complete hoops.
Except in the Amphisbaenidae and some other
lizards in which the fore-limbs are absent, a variable
number of the anterior thoracic ribs are connected
by a cartilaginous sternal portion with the ster-
num.
In all lizards except some of the Amphisbaeni-
dae there is at least a trace of a sternum (though
as we have seen it is not always connected with the
ribs), which increases in size in forms in which
the anterior limbs are more developed. The
sternum typically consists of a rhomboidal plate
of cartilage, from the posterior part of which a
single or double prolongation is continued back-
wards into the wall of the abdomen. A few (two
to four) sternal ribs are attached to the rhomboidal plate and
the remainder (one to four) to the posterior continuations (Fig.
185).
In the skull (Fig. 186) there is a cartilaginous interorbital sep-
tum (except in the Amphisbaenidae). The temporal region (exoc-
* Boulenger, P.Z.S., 1888, p. 351.
Fm. 184.— Ster-
num and ster-
nal ribs of
Chamaeleo
(from Gegen-
baur). St
sternum ; Mst
posterior part
of sternum,
(metast e r n-
u m) ; Co
coracoid ; c,c'
ribs.
LACERTILIA.
339
cipital, prootic and opisthotic) is prolonged outwards into
parotic processes (as in the Chelonia), to the outer end of which
the quadrate is articulated (usually moveably). There is a small
bone at the outer ends of these processes, called the supra-
temporal (14). There are no alisphenoids, orbitospheiioids,
or presphenoids ; this part of the skull wall being mainly mem-
branous with tracts of cartilage. There is in all, except the
Amphisbaenidae and Chamaekonidae and the genus Anniella, a
rod-shaped bone — the epipterygoid — extending from the parietal
St
FIG. 185. — Sternum with ribs and shoulder girdle of A, Iguana ; B, Lophiunis ; C, Platydacty-
L_ lus. St sternum ; ep interclavicle (episternum) ; Mst posterior prolongation of sternum
i carrying sternal ribs ; Co coracoid ; Cl clavicle ; Cr sternal crest ; X posterior continuation
£ of sternum without ribs (xiphisternum) (from Gegenbaur).
to the pterygoid on each side, in close contact with the mem-
branous or cartilaginous wall of the skull (23)- This bone is some-
times called the columella cranii which is a bad name because
it leads to confusion between it and the columella auris. Those
lizards which possess it have been called the Kionocrania. There
is a small ossification in some Chelonia between the descending
process of the parietal and the pterygoid which seems to corre-
spond to it. The occipital condyle is mainly formed by the
basioccipital but the exoccipitals participate. It is double in
the Amphisbaenidae. The opisthotic is fused with the exoccipital
and the epiotic with the supraoccipital. the prootic remaining
separate. The parietals are not joined suturally to the
340 CLASS REPTILIA,
supraoccipital (except in the Amphisbaenidae and chameleons),
but by fibrous tissue, so that the fronto-parietal part of the skull
is usually slightly moveable upon the occipito-sphenoidal part.
There is a pineal foramen either in the course of the sagittal
suture or between the parietals and f rentals. The parietals
are usually fused in the adult but remain separate in the geckos.
The frontals are usually paired, bat may fuse in the adult. A
thin splint of bone projects forwards from the basisphenoid be-
neath the interorbital septum (%8) ; this is a membrane bone fused
with the basisphenoid and representing the anterior part of
the parasphenoid of Ichthyopsida. The posterior part of the
parasphenoid is represented in the embryo by two membrane
bones which fuse with the basisphenoid in the adult (basi-
temporals). The praemaxillae are fused and there is a small
bone on each side just above the vomer, in the anterior part of
the nasal region called the septomaxillary (29). A perforated
lacrymal is generally present in the anterior part of the orbit.
The squamosal (,9) is attached to the parotic process and extends
forward to the postfrontal (except in the geckos) forming the
supratemporal arcade and bounding the outer side of the supra-
temporal fossa (15}. The parietal sends out a postero lateral pro-
cess to the squamosal thus forming the posterior boundary of this
fossa. In most lizards the postfrontal (16) is joined to the
jugal (6), completing the orbit and closing the supratemporal fossa
in front, but in the geckos and Amphisbaenidae these bones are
separate and the orbit is open behind. The infratemporal arcade
is not developed, there being no bony connection between the
jugal and quadrate. The bones of the maxillopalatine apparatus
are firmly connected with one another and with the anterior
part of the skull, but the pterygoids (7) are moveably articulated
with the basisphenoid and quadrate. There are two vomers
(19) forming the inner wall of the posterior nares. The pala-
tines (4) pass back from these and the maxillaries to the
pterygoids, which diverging from one another extend back to
the quadrate (except in the chameleons) articulating on the way
with lateral (basipterygoid) processes of the basisphenoid.
There is a transpalatine (5) passing from the palatine and
pterygoid to the maxilla and jugal. In the chamaeleons the
supratemporals (pterotic) are much elongated and send
backwards and dorsalwards a process which unites with a
LACERTILIA.
341
FIG. 186. — Skull of Vromastix (after original drawings by J. J. Lister). A dorsal, B ventral,
C posterior, D side view, E and F lower jaw. 1 premaxilla ; 2 maxilla ; 3 prefrontal ;
4 palatine ; 5 transpalatine ; 6 jugal ; 7 pterygoid ; 8 quadrate ; 9 squamosal ; 10
exoccipital and opisthotic ; 11 basioccipital ; 12 supraoccipital ; 13 posttemporal fossa ;
14 supratemporal bone ; 15 supratemporal fossa ; 16 postfrontal ; 17 pineal foramen ; 18
olfactory capsule ; 19 yomer ; 20 parietal ; 21 frontal ; 22 nasal ; 23 columella cranii
(epipterygoid) ; 24 basisphenoid with which a basitemporal ossification has united ; 25
columella'auris ; 26 prootic ; 27 alisphenoid cartilage ; 28 parasphenoid ; 29 septomaxillary ;
3(> Meckel's cartilage ; 31 articular ; 32 coronoid ; 33 supraangular ; 34 dentary ; 35
angular ; .%• splenial.
median backward process of the parietals, thus forming the
casque of these skulls.
The lower jaw contains the usual six bones (Fig. 186), and the
distal end of Meckel's cartilage persists. The two rami are
usually firmly connected at the symphysis. The hyoid consists
of an elongated body, and two long cornua on each side. It is
mainly cartilaginous the posterior cornua being partly ossified.
In the geckos the anterior cornua are connected to the skull.
342 CLASS REPTILIA.
The pectoral girdle is always present, even when the fore-
limbs are absent, though it may be much reduced and not reach
the sternum.* Typically (Figs. 187 and 188) it consists of a
suprascapula, scapula, and coracoid which articulates with the
sternum ; and of a clavicle, and interclavicle. The scapula and
coracoid are partly ossified and fenestrated. Clavicles and
interclavicle are absent in the chameleons, and in some of the
limbless forms.
The manus usually possesses five digits, in which case the
carpus consists of eight bones, — an ulnare, radiale, centrale,
and five distal bones.
The pelvic girdle consists of ilia which articulate with the
two sacral ribs, and pubes and ischia which meet in a ventral
/i.cr
FIG. 187. — Side view of the pectoral girdle and sternum of Iguana tuberculata (from Huxley).
cl clavicle ; cr coracoid ; e.cr epicoracoid ; gl genoid cavity ; i.cl interclavicle ; m.cr ineso-
coracoid ; m.sc mesoscapula ; p.cr precoracoid ; s.sc suprascapula ; st sternum : x.st xiphi-
sternum.
symphysis. The pubo-ischiadic foramen is only divided by
ligament. There is usually a cartilaginous (or calcified) epipubis,
and a cartilaginous continuation of the ischiadic symphysis
backward, to support the cloaca (hypo-iscMum or os cloacae}. In
the limbless forms the pelvic girdle may undergo great reduc-
tions, but no part appears to vanish entirely ; and the sacral
connection is preserved, except in the Amphisbaenidae.
The pes usually possesses five digits. In the tarsus there is a
tendency to an intertarsal joint. The proximal row consists
of two large bones more or less closely united, and articulated
* M. Fiirbringer, " Die Knochen u. Muskeln der Extremitdten bei den
Schlangendhnlichen Saurien," Leipzig, 1870.
LACERTILIA.
343
with the tibia and fibula in a way which allows of very little
motion. The distal row contains a cuboid carrying the meta-
tarsals of the fourth and fifth digits, that of the fifth being bent
as in Chelonia. Other distal tarsals may be present or they
may be fused with the metatarsals.
The phalangeal formula of the maiius is usually 2. 3. 4. 5. 3,
of the pes 2. 3. 4. 5. 4.
Alimentary canal. Teeth are present on the premaxillae,
maxillae, and dentary, and often on the palate. They may be
conical, blade-like, or crushing (Cyclodus). They usually become
ankylosed to the bone, either by
their bases to the edge of the jaw
(acrodont), or by their sides just
inside the edge (pleurodont). They
are never lodged in alveoli (the-
codont). The tongue varies con-
siderably. It is generally notched
anteriorly and posteriorly drawn
out into two processes which may
unite behind the glottis, so that
the glottis lies in the back of the
tongue. In the geckos, Iguanidae,
Agamidae, etc., it is short ; in
the Amphisbaenidae, it is forked.
In some forms (Varanidae, etc.)
it is long, narrow and forked,
and provided with a sheath at
its base into which it can be
retracted. In the chameleons
it is very long and clubbed at its
end.
Salivary glands are absent, but labial glands opening on the
lips are present. There is a gall-bladder, usually a short caecum
on the anterior end of the rectum, and the cloaca has a bladder.
The larynx consists of a cricothyroid cartilage and of arytenoid
cartilages. The cricothyroid frequently has fontanelles and in
Amphisbaenidae is represented by two lateral bands of cartilage
united by cross bands (as in snakes). An epiglottis is some-
times present. Vocal chords are absent except in geckos and
chameleons. The tracheal rings are usually complete. The
Fm. 188.— Ventral view of the pectoral
girdle and sternum of Iguana. Letters
as in Fig. 187 (from Huxley).
344
CLASS REPTILIA.
bronchi are short and open into the lungs, which are sacs with
honeycombed walls. In the chameleons and some geckos
the posterior part of the lungs is produced into narrow
diverticula which lie among che viscera and foreshadow the
air-sacs of birds. In the snake-like forms the lungs are often of
unequal size.
The brain has a small cerebellum. Almost all lizards appear
FIG. 189. — Longitudinal section through the connective tissue capsule and the parietal organ
of Hatteria punctata (after Spencer from Wiedersheim) . g bloodvessels ; h cavity of parietal
organ ; k connective tissue capsule ; I lens-like thickening of the dorsal wall ; r retina-like
part of the parietal organ ; m molecular layer ; st cord connecting the organ to the pineal
body ; x cells in st.
to possess a parietal organ * (Fig. 178) tying in the parietal
(pineal) foramen or just below it, and often in close relation
with the skin. This organ is a vesicle the walls of which may
* H. W. de Graaf, Bijdrage tot de ken. van d. Bouw en de Ontivickkeling
der Epiphyse bij Amphibien en Reptilien, Leyden 1886. Spencer, Q.J.M.S.
27, 1886. Beraneck, Jen. Zeitschr.,1881, 21. ~Leydig,Biol. CentralbL, 8,
1889, p. 707 and 10, 1890 p. 278 ; and Abh. Senckenb. Nat. Ges., 16, 1890,
p. 441-551.
I.ACERTILIA. 345
be a simple epithelium, but more often they present peculiar
modifications which recall the structure of an eye. In such cases
the dorsal wall is thickened in a manner which suggests a lens-
like structure (Fig. 189) ; while the rest of the wall is pigmented,
contains several layers of nuclei and generally presents an aspect
which recalls that of a retina. The parietal organ is sometimes
quite separate from the brain (Calotes, Seps, etc., Fig. 190) but
more usually perhaps it is connected with the pineal body by
a cord of tissue. In Cydodus its cavity is continuous with that
of the pineal stalk and so with that of the 3rd ventricle. On
account of the eye-like structure and also because it is often
attached by a cord of tissue to the pineal body or to the roof of
the thalamencephalon just in front of and in close connection
with that body, the parietal organ is sometimes spoken of as the
" pineal eye." The hypothesis as to its nature suggested by this
name must be received with caution, as will be explained later on.
It is usually placed close to the skin of the top of the head and
the skin over it is frequently without pigment. In such cases a
portion of the scale immediately overlying it may have a cornea-
like appearance. There is however no relation between this
external indication and the degree of eye-like development of
the parietal organ ; e.g. in Hatteria in which it has a more eye-
like structure than in any other form, there is no external indi-
cation of it on the top of the head, while in Ceratophora, in which
the modified scale is present, there is no parietal organ.
The eye-like character is not always discernible, e.g. in Cydodus in which
though it lies in the parietal foramen and has a modified scale -over it, it
appears to be nothing more than the distended end of the pineal stalk
(pineal body), in Chamaeleon and others there is no pigment and the walls
of the vesicle show no retinal or lens-like differentiations, though the
vesicle is connected to the pineal body (or stalk ?) by a solid cord. In others
again in which the eye-like features can be detected there is considerable
variety as to the extent to which they are differentiated, and also as to the
presence or absence of a connection (always solid when eye-like structure
is present) with the pineal body (Fig. 190). Lastly in forms in which the
parietal foramen is closed (e.g. Gecko, Ameiva, Ccratophora) the parietal
organ is absent, and the pineal body ends just within the skull- wall.
Developmentally the parietal organ appears to ariso as a diverticulum
from the anterior side of the pineal body or directly from the cerebral
roof immediately in front of this organ (see p. 70).
So far as can be ascertained from experiment the parietal organ has no
trace of a visual function, and the interpretation of it as the vestige of a
once functional median eye rests entirety upon the evidence of histology.
But the histological evidence is by no means conclusive. The nervous
346
CLASS REPTILIA.
nature of the cord which connects it with tho epiphysis has been expressly-
denied by Leydig, and the fact that pigment may bo found in the
dorsal (lens-like) part of the wall as well as in the retinal part of the
vesicle is not in favour of its optical nature.
Moreover the absence of a nerve connecting it with the brain at least
in some if not in all cases, is against the optical interpretation, if we may
judge from what we know of the degeneration of the paired eye. Neither
can the frequent presence of the so-called cornea above the parietal foramen
be regarded as a strong support of the view, for no such cornea! area is left
in cases of extreme degeneration of the paired eyes. While not attaching
any importance to the extreme variability of the organ itself, especially
in relation to the " corneal " patch on the skin, the case of Cyclodus is
difficult to explain on the median-eye hypothesis. For here there is
apparently an ordinary pineal body without any eye-liko structure and
placed in tho parietal
foramen, and over it
a " corneal " modifica-
tion of the skin. From
these and other con-
siderations it is clear
that the interpretation
of the parietal organ as
an aborted visual or-
gan, though it cannot
by any means be dis-
missed as a baseless
hypothesis, must bo
received with more
caution t h an has
hitherto been accord-
ed it.
FIG. 190.— Diagrams showing the relation of the parietal The eyelids have
organ and pineal body of Lacertilia A, in Cyclodus ; B, in * oon\ u
Chamaeleon; C, in most Lacertilia ; D, in many Lacertilia alreadv (p.OoO) been
(Calotes, Seps, Leiodera, etc.). 2 parietal organ ; 3 pineal M j mi
body ; st cord connecting parietal organ and pineal body ; described. lliere
1 parietal bone (after Snencer). . „ ,
is a ring of bony
plates in the sclerotic and a vascular projection of the
choroid (pecten) into the vitreous humour. Lacrymal and
harderian glands are present.
A tympanic cavity is present except in the Amphisbaenidae
and communicates by wide openings with the pharynx. The
columella auris is a bony rod which passes from the fenestra
ovalis to the extracolumellar cartilage. The latter is attached
to the tympanic membrane. The hyoid arch is far removed
from the skull except in the Geckonidae in which it is attached
to the epiotic, close to an attachment of the extracolumellar
cartilage to the same bone. In the chameleons in which there
LACERTILIA. 347
is no tympanum the extracolumellar cartilage is attached to the
inner side of the quadrate.
In the vascular system there are a sinus venosus, a single
ventricle with an incomplete septum, and three pairs of arterial
arches with a ductus Botalli between the carotid and systemic
arches (except in the Varanidae). The subclavians are given
off separately or together by the right arch. The visceral arteries
arise from the dorsal aorta. The anterior abdominal vein is
unpaired and does not anastomose with the iliac and caudal
veins.
Fat bodies between the skin and ventral abdominal muscles
are often present. They are largest in the spring at the time of
propagation.
The kidneys are placed hi the posterior part of the body-
cavity, and are covered on the ventral side only by peritoneum.
They are more or less lobed, are sometimes united with one
another and may extend into the caudal region. A cloacal
bladder is present.
The testes are oval bodies placed further forwards than the
kidneys (Fig. 191). The ureter usually joins the vas deferens
of its side and the two open by one opening into the lateral part
of the cloaca. The oviducts have the usual arrangement.
There are two penes. They have the form of eversible hollow
sacs opening into the posterior wall of the cloaca, and attached
by a retractor muscle, passing from their hinder end, to some
of the caudal vertebrae. A groove runs to them from the open-
ing of the vas deferens for the conveyance of sperm. Erectile
tissue is found in their walls. These organs can be everted
through the anus and used as copulatory organs. They are
present in both sexes, though less developed in the female than hi
the male.
Most lizards lay eggs, but a few are viviparous (Lacerta vivi-
para, Anguis fragilis, Seps, Chamaeleon). In some cases the eggs
are retained for a part of the development and the young are
hatched at a greater or less period after laying. The shell is
usually leathery, but may be hard. Most of them are harmless,
and are useful by destroying insects. Larger species, as the
Iguana, are hunted for the sake of their flesh. By far the greater
number and all the larger and more beautifully coloured species
inhabit the warmer and hot countries.
348
CLASS REPTILIA.
Comparatively few fossil forms are known, and these but
imperfectly. The oldest, but incompletely known, form is
Macellodon from the Upper Jurassic (Purbeck Beds). In the
Lower Eocene they are more numerous, belonging to the
Varanidae (Thinosaurus), Anguidae (Glyptosaurus, etc.),
Fid. 191. — Urinogenital organs of Lacerta agilis (after C. Heider). a, of the male, b of the
female. Cl cloaca ; H testis ; Hb urinary bladder ; Md rectum (cut). N kidney ;
Nh epididymis ; Ov ovary ; P vestige of wolffian body ; Pe penes ; Sd femoral glands ;
SP pores of femoral glands ; T oviduct (mullerian) or its vestige in the male ; Vd vas
deferens.
Iguanidae (Iguanavus) and Chamaeleontidae. The lacertilian
fossils of the Miocene belong largely to existing genera. There
are about 1800 living species.
Sub-order 1. LACTERTILIA VERA. The nasal bones enter
the border of the nasal apertures, and the pterygoid is in contact
LACERTILIA. 349
with the quadrate. Clavicles are present when the limbs are
developed. The tongue is flattened.
Fam. 1. Geckonidae (Ascalabota). With amphicoelous vertebrae, with
persistent notochord, and a cartilaginous septum, without bony temporal
arches ; parietals separate ; clavicles dilated, loop-shaped proximally ;
eyelids as small folds not moveable (except Aelurosaurus and Ptenopus),
but the eye is covered with a transparent membrane (possibly the
nictitating membrane) behind which the eyeball moves ; pleurodont ;
tongue protrusible ; in some genera the vestibule of the membranous laby-
rinth is much enlarged and, perforating the bone, projects as a bag behind
the ear or at the side of the neck ; many have adhesive (by production
of numerous vacuums) digits, by which they can climb smooth vertical
surfaces ; they are oviparous (Naultinus is said to be viviparous), with
hard-shelled eggs ; they are quite harmless, mostly nocturnal, found
in the hotter parts of all regions ; about 50 genera, 270 species, no extinct
forms known. Ptychozoon Kuhl, of the Malay Islands and Peninsula
has cutaneous expansions of the head, body, limbs and tail, which pro-
bably act as a parachute ; the digits are webbed. Alphabetical list of
genera :—
Aeluronyx, Seychelles, Madagascar ; Aelurosaurus, E. Indies, ? Aus-
tralia ; Agamura, Persia ; Alsophylax, Turkestan, Persia ; Aristeliiger, W.
Indies, C. Amer. ; Calodactylus, S. India ; Ceramodactylus, Persia, Arabia ;
Colopus, S. Afr. ; Chondrodactylus, S. Afr. ; Dactychilikion, S. Afr. ;
Diplodactylus, Australia ; Ebenavia, Madagascar ; Eurydactylus, New
Caledonia ; Gecko, Japan, China, E. Indies, New Guinea and neighbour-
ing islands ; Geckolepis, Madagascar ; Gehyra, E. Indies, Australia,
Mexico, islands of Indian and S. Pacific oceans ; Gonatodes, trop. Amer.,
E. Indies ; Gymnodactylus, borders of Mediterranean S. Asia, Aust., Pac.
Islands, Trop. Amer. ; Hemidactylus, S. Eur., S. Asia, Afr., trop. Arner.,
Polynesia ; Heteronota, Australia ; Homonota, S. Amer. ; Homopholis, S.
Afr. ; Hoplodactylus, S. Pacific Islands, S. India ; Lepidodactylus, E. In-
dies, Polynesia, S.W. Australia ; Luperosaurus, Phillipines ; Lygodactylus,
Africa, Madagascar ; Microscalabotes, Madagascar ; Naultinus, New
Zealand ; Nephrurus, Australia ; Oedura, Australia ; Pachydactylus, Africa ;
Perochirus, Phillipines, Carolines, New Hebrides ; Phelsuma, Madagascar,
Mauritius etc. ; Phyllodactylus, trop. Amer., Australia, Afr., islands of
Mediterranean: Phyllopezus, Brazil; Pristurus, N.E. Afr., S.W. Asia ;
Ptenopus, S. Afr. ; Ptychozoon, E. Indies ; Ptyodactylus, N. Afr., S.W.
Asia, Sind ; Rhacodactylus, New Caledonia ; Rhoptropus, S.W. Afr. ;
Rhynchoedura, Australia ; Spathoscalabotes, E. Indian Archipelago ;
Sphaerodactylus, W. Indies, C. Amer., Colombia ; Stenodactylus, N. Afr.,
S.W. Asia, Sind ; Tarentola (Platydactylus) (Fig. 192), W. Afr., borders of
Mediterranean, W, Indies ; Teratolepis, India ; Teratoscincus, Persia,
Turkestan ; Thecadactylus, trop. Amer., islands of Torres Straits.
Fam. 2. Eublepharidae. Similar to foregoing except that the vertebrae
are procoelous, the parietals fused, and there are functional eyelids.
Psilodactylus Gray, W. Afr. ; Eublepharis Gr., S. Asia, Cent. Amer., S.
North- Amer. ; Coleonyx Gr., C. Amer.
Fam. 3. Uroplatidae. Resembling the Geckonidae except that the
nasal bones are fused, the interclavicle is small, and the clavicles are not
dilated. Uro plates Gr., Madagascar.
Fam. 4. Pygopodidae. Snake-like, with scales ; fore-limbs absent,
350 CLASS REPTILIA.
hind-limbs as scaly flaps (Fig. 183) with 5 concealed ossified toes ; sternum
feeble ; pleurodont ; eyes without lids, unprotected ; tail long ; Australia
Tasmania and New Guinea. Pygopus Merr. (Fig. 183) ; Cryptodelma
Fisch. ; Delma Gr. ; Pletholax Cope ; Aprasia Gr. ; Lialis Gr.
Fam. 5. Agamidae. Acrodont, teeth usually divided into incisors,
canines, molars ; tongue short and thick ; orbit closed and temporal fossa
bridgad ; in Lyriocephalus a process of the pre-and-post-frontals unite to
form an arch ; osteoderms are absent ; premaxilla single, nasals double,
frontal arid parietal single ; eyes with lids ; Old World ; about 30 genera,
200 species.
Acanthosaura Gr., S.E. Asia ; Agama Daud., Afr., S. Asia, S.E. Eur. ;
Amphibolurus Wagl., Australia ; Aphaniotis, Ptrs., Malayasia ; Aporo-
scelis, Blgr., E. Afr. ; Calotcs Cuv., crest on neck and back, remarkable
for changes of colour, India and the Malay Islands ; Ceratophora Gr.,
Coylon ; Charasia Gr., India ; Chelosania Gr., Australia ; Chlamydosaurus
Gr., large frill-like dermal expansion on either side of the neck, runs
upon its hind limbs in a semierect position, Australia ; Cophotis Ptrs.,
Ceylon, Sumatra; Diporophora Gr., Australia; Draco L., flying dragon,
ribs much prolonged supporting a wing-like dermal expansion, E. Indies ;
Gonyocephalus Kaup,
E. Indies, Papuasia,
Polynesia, X.E. Aus-
tralia ; Harpesaurus
Blgr., Java ; Japa-
lura Gr., E. Indies,
S. China ; Liolepis
Cuv., S.E. Asia ;
Lophocalotes Gthr.,
E. Indian Arch. ;
Lophura Gr., E.
Indies ; Lyriocepha-
lus Merr. , chameleon-
FIG. 192.— Tarentola maurUanica (Rggne Animal). jike Ceylon ; Mo-
loch Gr., mouth
small, teeth in upper jaw horizontal, directed inwards, body
covered with large spines, W. and S. Australia ; Otocryptis Wieg., Cey-
lon, S. India ; Phoxophrys Hubr., Sumatra ; Phrynocephalus Kaup, S.E.
Eur., C. Asia ; Physignathus Cuv., Australia, Papuasia, Siam ; Ptycto-
laemus Ptrs., N. India ; Salea Gr., S. India ; Sitana Cuv., 4 toes, India,
Ceylon ; Tympanocryptis Ptrs., Australia ; Uromastix Merr., spiny-tailed
lizards, arid tracts of N. Afr. and S. Asia.
Fam. 6. Iguanidae. Closely resemble the Agamidae, but with pleuro-
dont, rarely heterodont (and then but slightly) dentition ; Chamaeleolis
has teeth on the palatines ; osteoderms are absent on the body, but may be
present on the head as in the horn-like tubercles of Phrynosoma ; about
50 genera and 300 species ; arboreal, terrestrial, burrowing, semi-aquatic ;
some genera have abdominal ribs ; almost entirely American, except
Hoplurus and Chalarodon in Madagascar, and Brachylophus in Fiji ;
species of Sceloporus and Phrynosoma are viviparous. Anisolepis
Blgr., S. Brazil; Anolis Daud., abdominal ribs, digits dilated, with
transverse lamellae inferiorly, expert climbers, more than 100 species,
trop. and sub-trop. Amer. ; Amblyrhynchus Bell, herbivorous, semi-
marine, living on algae, Galapagos ; Basiliscus Luur., high and erectile
LACERTILIA. 351
crests on the male, C. Anier., B americanus to 3 ft. ; Brachylophus
Wag!., Fiji and Friendly Islands ; Cachryx Cope, Yucatan ; Callisaurus
Blainv., S.W. N.-Amer. ; Chalarodon Ptrs., Madagascar ; Chamaeleolis
Coct., Cuba ; Conolophus Fitz., herbivorous, edible, Galapagos ; Cory-
thophanes Boie, C. Amer. ; Crotaphytus Holbr., S. N.-Amer. ; Ctenoble-
pharis Tsch., Peru ; Ctenosaura Wiegm., C. Amer. ; Cyclura Harl.,
W. Indies ; Diplolaemus Bell, Patagonia ; Dipsosaurus Hall, S.W. N.-
Amer. ; Enyalioides Blgr., Veragua to Peru ; Enyalius Wagl., S. Amer. ;
Helocephalus Phil., Atacama and N.W. la Plata ; Holbrookia Gir., S. N.-
Amer. ; Hoplocercus Fitz., S. Amer.; Hoplurus Cuv., Madagascar ; Iguana
Laur., attain to 5-6 ft., herbivorous, esteemed as food, they live in trees,
trop. Amer. and W. Indies ; Laemanctus Wiegm., C. Amer. ; Liocephalus
Gr., digits with keeled lamellae, W. Indies and S. Amer. ; Liolaemus
Wiegm., Amer. S. of equator, about 25 species ; Liosaurus D. and B.,
S. Amer. ; Metopoceros Wagl., W. Indies ; Norops Wagl., trop. Amer. ;
Ophryoessa Fitz., S. Amer. ; Petrosaurus Blgr., Lower California ; Phry-
nosoma Wiegm., horned toads, N. Amer., and Mexico ; Phyniaturus
Gravh., Chili ; Pueustes Merr., Paraguay ; Polychrus Cuv., abdominal
ribs, colour very changeable, digits with carinated lamellae ; trop.
Amer. ; Pristidactylus Fitz., Patagonia; Saccodeira Gr., S. Amer. : Sauro-
malus A. Dum., S.W. N.-Amer. ; Scartiscus Cope, Paraguay ; Sceloporus
Wiegm., N. and C. Amer. ; Stenocercus D. and B., W.S. Amer. ; Strobiiurus
Wiegm., Brazil ; Tropidodactylus Blgr., Venezuela and W. Indies ; Tro-
pidurus Wied., S. Amer., digits with keeled lamellae ; Uma Baird,
Arizona ; Uraniscodon Kaup, S. Amer. ; Urocentron Kaup, S. Amer. ;
Urostrophus D. and B., S. Amer. ; Uta B. and G., N.-Amer. and Mexico ;
Xiphocercus Fitz., trop. Amer.
Fam. 7. Xenosauridae. Pleurodont, teeth numerous, small, with long
cylindrical shafts not hollowed out at the base ; anterior part of tongue
retractile ; palatines widely separate ; T-shaped interclavicle ; osteodermal
plates absent from the body. Xenosaurus Ptrs., with one species, S.
Mexico.
Fam. 8. Zonuridae. Pleurodont, teeth as in preceding, but hollowed
out at the base ; tongue short not retractile ; supratemporal fossa roofed
over by dermal ossifications ; palatines and pterygoids widely separated,
interclavicle cruciform ; no abdominal ribs. Zonurus Merr., dermal
ossifications on the trunk and tail, S. Afr. and Madagascar ; Pseudo-
cordylus Smith, S. Afr. ; Platysaurus Smith, S. Afr. ; Chamaesaura
Schn., snake-like body and reduced limbs. S. Afr.
Fam. 9. Anguidae. Pleurodont, teeth solid at the base, new teeth
originate between the old ones ; teeth may be present on the pterygoids,
palatines and vomers (Ophisaurus) ; anterior part of tongue emarginate,
retractile into the posterior part ; osteodermal plates on head and body ;
palatines and pterygoids well separated ; limbs variously developed, may
be absent, but limb-girdles always present; terrestrial ; Angnis is viviparous ;
Amer., Eur., India. Gerrhonotus Wieg., 4 well-developed pentadactyle
limbs, W. and S. N.-Amer., C. Amer. ; Ophisaurus Daud. (Pseudopus
Merr.), limbs absent, or reduced to vestiges of the hind pair, S.E. Eur.,
N. Afr., S.W. Asia, S. N.-Amer., Mexico ; 0. apus Pall., the glass-snake,
Balkan Peninsula etc. Diploglossns Wieg., limbs pentadactyle, well
developed, trop. Amer. ; Sauresia Gr.. limbs tetradactyle, W. Indies ;
Panolopus Cope, 4 limbs, anterior without digits, posterior with a rudi-
mentary digit on the inner border, W. Indies ; Ophiodes Wagl., no forelimbs
352 CLASS REPTILIA.
styliform vestige of hind limbs, S. Amer. ; Anguia L., teeth fang-like, no
limbs, palate toothless, Eur., W. Asia, Algeria ; A. fragilis L., slow-worm,
blind-worm, eyes well developed with moveable lids, ear- opening minute,
tail as long as body, to more than one ft.
Fam. 10. Anniellidae. Vermiform, limbs absent, eyes and ears con-
cealed ; tongue bifid ; teeth large, few, fang-like, skull ophidian-like, no
columella cranii, no squamosal, post-orbital arch ligamentous. Anniella
Cope, California.
Fam. 11. Helodermatidae. Pleurodont, teeth fang-like and grooved
with labial poison-glands ; limbs well developed ; tongue bifid ; post-
fronto -squamosal arch absent ; osteoderms present. Heloderma Wieg.,
the poisonous lizard (Gila monster), Mexico ; Lanthanotus Steind., Borneo
is ailed here.
Fain. 12. Varanidae. Pleurodont, old-world lizards with a long,
bifid and protractile smooth tongue ; osteoderms absent ; postorbital
arch incomplete ; tail long ; teeth large, dilated at the base. Varanus
(Hydrosaurus) Merr., Monitor, with 30 species, Afr., S. Asia, Australia ;
in some species they attain to 7 feet.
Fam. 13. Xantusiidae. Pleurodont with short tongue, and supra-
temporal fossa roofed by the cranial bones ; no osteoderms ; no moveable
eyelids ; C. Amer., and Cuba. Lepidophyma A. Dum., C. Amer. ;
Xantusia Baird, California ; Cricosaura G. and P., Cuba.
Fam. 14. Teiidae. Dentition intermediate between pleurodont and
acrodont, teeth not hollow at the base ; tongue long and bifid, with scale -
like papillae ; palatines in contact anteriorly ; no osteoderms ; limbs
various, they may be normal, or shortened (Proctoporus), or more reduced
with incomplete number of digits (Scolecosaurus), or digits absent arid as
bud-like rudiments (Cophias, Ophiognornon, in one species of the latter the
pelvic limbs are absent) ; confined to the New World, 40 genera, more
than 100 species.
Alopoglossus Blgr., Ecuador. Peru ; Ameiva Cuv., trop. Amer. ; Anadia
Gr., Costa Rica to Ecuador ; Argalia Gr., Venezuela and Colombia ;
Arthrosaura Blgr., Ecuador ; Callopistes Gravh., Peru, Chili ; Centropyx
Spix, S. Amer.; Cercosaura Wagl., Brazil; Cnemidophorus Wagl., Amer. ;
Cophias Fitz., S. Amer. ; Crocodilnrus Spix, Guianas, Brazil ; Dicrodon D.
and B., Peru ; Dracaena Daud., Guianas and Amazon ; Ecpleopus P. and
B., S. Amer. ; Euspondylus Tsch., Venezuela to Peru ; Gymnophthalmus
Merr., trop. Amer. ; Heterodactylus Spix, Brazil ; Iphisa Gr., Brazil,
Guianas ; Leposoma Spix, S. Amer. ; Loxopholis Cope, Colombia ;
Micrablepharus Boettg., Brazil, Paraguay ; Monoplocus Gthr., trop. Amer. ;
Neusticurus D. and B., S. Amer. ; Ophiognomon Cope, Upper Amazons ;
Oreosaurus Ptrs., Colombia, Ecuador, Brazil ; Pantodactylus D. and B.,
S.E. S. Amer. ; Perodactyliis R. and L. Brazil ; Pholidobolus Ptrs., Ecua-
dor ; Placosoma Tsch., Brazil; Prionodactylus O'Sh., S. Amer. ; Procto-
porus Tsch., Andes of Ecuador and Peru; Scolecosaurus Blgr., S. Amer. ;
Teius Merr., S.E. S.-Amer. ; Tupinambis Daud., teju, to 3 ft., S. Amer. ;
Tretioscincus Cope, Colombia, C. Amer.
Fam. 15. Amphisbaenidae. Vermiform, teeth acrodont or pleurodont,
scales of body reduced, skin soft divided into squarish segments forming
regular annuli ; eyes and ears concealed ; limbs absent, except in Chirotes,
which has 4-clawed forelimbs ; girdles much reduced ; sternum absent
except in Chirotes in which it is not connected with the ribs ; tail short ;
skull without interorbital septum, epipterygoid, postorbital and fronto-
LACERTILIA.
353
squamosal arches ; aritero-lateral walls of skull completely closed by bone
as in Ophidia ; burro we rs, may live in ant's nests and manure heaps, can
progress backwards, and forwards in their burrows by slight vertical
undulations ; Amer., W. Indies, Africa and round Mediterranean.
Chirotes Cuv., Mexico, California, Platte River ; Blanus Wagl., borders of
Mediterranean ; Amphisbaena L. (Fig. 193), trop. Amer. and Afr. ; Anops
Bell, S.E. S.-Amer., W. Afr. ; Geoccdamus E. Afr. ; Monopeltis Smith, Afr.;
Rhineura Cope, Florida ; Lepidosternon Wagl., S. Amer. ; Trogonophis
Kaup, X.-W. Afr. Pachycalamus Gthr., Socotra ;
Agamodon Ptrs., E. Afr.
Fam. 16. Lacertidae. Pleurodont ; tongue long,
bifid, with papillae or folds ; pterygoid often with
teeth ; pterygoids and palatines separate mesially ;
postorbital and postfronto-temporal arches complete,
temporal fossa roofed over by large postfrontals and
by osteoderms ; no osteoderms on body ; limbs well
developed, pentadactyle ; tail long, brittle ; some
genera have a transparent patch in the lower eyelid,
so that they can see when the eye is shut (Eremias,
Cabrita etc.), and in Ophiops the lower eyelid is fused
with the upper ; about 20 genera and 100 species,
Old World, but not in Madagascar or Australia.
Acanthodaclylus Wieg., S. Spain and Portugal, Afr.
n. of eq., S.W. Asia ; Algiroides Bibr., E. coast of
Adriatic, Greece, Sardinia, Corsica ; Aporosaura
Blgr., W. Afr. ; Cabrita, Gr., India ; Eremias Wiegm.,
Afr., Asia ; Gastropholis Fisch., E. Afr. ; Holaspis
Gr., W. Afr. ; Ichnotropis Ptrs., Afr. s. of eq.
Lacerta L., Eur., X. and W. Asia, Afr. north of
equator, L. vivipara Jacq. the common English Liz-
ard, the only reptile found in Ireland ; the young
are hatched in the uterus or directly after the eggs
are laid ; L. agilis L. sand lizard, also found in S.
of England ; L. viridis Laur., found in Jersey ; L.
oo°llata Daud. the eyed-Lizard, S. France, X.W. of
Italy, Spain, Portugal ; L. muralis Laur., S. Eur., X.
Afr., Asia Minor, Latastia Bedr., E. Afr., Arabia;
Nucras Gr., trop. and S. Afr. ; Ophiops Men., Turkey,
X.-Afr., Asia ; Poromera Blgr., W. Afr. ; Psammo-
dromus Fitz., S.W. Eur., X. Afr. ; Scapteira Wieg., C.
Asia, S. Afr. ; Tachydromus Daud., E. Asia, Japan,
Ind. Archipelago ; Tropidosaura Fitz., S. Afr.
Fam. 17. Gerrhosauridae. Pleurodont, with
osteoderms on head and body ; limbs sometimes
reduced ; Africa S. of Sahara, and Madagascar. Ger-
rhosaurus Wieg., Tetradaclylus Merr., Cordylosaurus
Gr., Zonosaurus Blgr., Madagascar ; Tracheloptychus Ptrs., Madagascar.
Fam. 18. Scincidae. Pleurodont, with strongly developed osteoderms
on head and body ; tongue scaly, feebly nicked ; premaxillaries sometimes
separated ; cranial arches complete ; limbs may be reduced or absent, but
this feature is not an indication of affinity within the family , there may be
a transparent disc on the lower eyelid ; all are viviparous ; nearly 30
genera, and 400 species, cosmopolitan including Pacific Islands.
m 193 _Amphi8baena
fuliffinosa (K6gne
animal).
354 LACEKTILIA.
Ablepharus Fitz., lower eyelid fused with upper, Australia, S.W. Asia,
S.E. Eur., trop. and S. Afr. ; Acontias Cuv., S. Afr., Madagascar, Ceylon ;
Brachymeles D. and B., Philippines ; Chalcides Laur. (Seps), S. Eur., N.
Afr., S.W. Asia ; Chalcidoseps Blgr., Ceylon ; Corucia Gr., Solomon
Islands ; Egernia Gr., Australia ; Eumeces Wieg., N. and C. Amer., E. and
S.W. -Asia, N. Afr. ; Hemisphaeriodon Ptrs., Queensland ; Herpetoseps
Blgr., S. Afr. ; Lygosoma Gr., 160 species, Australasia, E. Indies, China,
N. and C. Amer. , trop. and S. Afr. ; Mabuia Fitz., semiaquatic, 70 species,
Afr., Madagascar, S. Asia, C. and S. Amer., W. Indies ; Macroscincus
Bocage, Cape Verde Islands ; Melanoseps Blgr., E. Afr. ; Ophiomorus D.
and B., Greece, Asia Minor to Syria ; Pygomeles Grand.. Madagascar ;
Ristella Gr., India; Scelotes Fitz., trop. and S. Afr. Madagascar; Scincus
Laur., (Fig. 194) N. Afr., Arabia, Persia, Scind ; Sepophis Bedd., S. India ;
Sepsina Boc., S. Afr., Madagascar ; Tiliqua Gr. (Cyclodus), stout lateral
teeth with spherical crowns, Australia, Austo-Malay and Indo-Malay ;
Trachysaurus Gr., Australia ; Tribolonotus D. and B., New Guinea ;
Tropidophorus D. and B., S. China, Indo-China, Philippines, Borneo ;
Typhlacontias Boc., S.W. Afr.
FlG. 194. — Scincus officinalis (R£gne animal).
Fam. 19. Anelytropidae. Degraded Scincoids, burrowing, limbless,
with osteoderms ; without bony postorbital and postfrontosquamosal
arches ; mterorbital septum and columella cranii well developed, with
abdominal ribs ; eyes concealed, no ear opening ; trop. and S. Afr., Mexico.
Anelytropsis Cope, Mexico ; Feylinia Gr., W. Afr. ; Typhlosaurus Wieg.,
S. Afr.
Fam. 20. Dibamidae. Body vermiform ; tongue pointed, undivided
in front ; no interorbital septum or columella cranii ; no cranial arches ;
limbs absent, no sternum, eyes concealed, no ear opening. Dibamus
D. and B., New Guinea, Moluccas, Nicobars.
Ophiopsisepa Blgr., Australia is probably the type of a distinct family ;
snake-like ; eyes without lids, scaly tongue ; Australia.
Sub-order 2. Rhiptoglossa. Nasal bones not bounding
nasal apertures ; pterygoid not reaching quadrate ; clavicles and
interclavicle absent, limbs well developed ; tongue vermiform,
projectile.
Fam. 21. Chamaeleontidae. Acrodont, teeth on the maxillaries and
mandible, premaxillaries and palate without teeth ; tongue projectile to
OPHIDIA. 355
a length equal to that of the body, club-shaped and viscose at the end ;
digits arranged in two bundles of two and three respectively ; eyes large
covered with a thick granular lid pierced by a small central opening for
the pupil ; they act independently of one another. Tympanum and
tympanic cavity absent ; skin with great power of changing colour ; *
skull with interorbital septum, without columella cranii (epipterygoid) ;
parietal single forming a crest and meeting posteriorly the supra-temporals
which connect it on each side with the squamosals ; parietal not moveable
upon occipital ; nasals narrow, not entering nasal apertures ; pterygoids
do not reach quadrate ; quadrate not moveable ; vertebrae procoelous ;
abdominal ribs present ; the tail is prehensile, coiling ventralwards, not
renewable ; the lungs end in several diverticula which extend far back
into the body cavity ; a few species are viviparous ; about 50 species, most
in Afr., Madagascar, a species in Socotra, another in S. Arabia, and a third
in India and Ceylon. Chamaeleon Laur., Afr., Madagascar, S. of Spain,
Arabia, India, Ceylon ; Ch. vulgaris, Daud., N. Afr., Syria., Asia Minor,
Andalusia, to one ft. ; Ch. pumilus Daud., to 5 or 6 in., S. Afr. : Ch. parsoni
Cuv., to two ft., Madagascar ; Brookesm Gr., Madagascar ; Rhampholeon
Gthr., trop. Afr.
Order 4. OPHIDIA. t
Elongated Reptiles without limbs, with horny epidermal scales
without osteoderms, with moveable quadrate bones, transverse anal
opening, and paired copulatory organs. Without eyelids, tympanic
cavity, urinary bladder and sacrum. The rami of the mandible
are united at the symphysis by an elastic ligament.
Snakes are chiefly characterised by the absence of extremities,
and by the distensibility, which is sometimes extraordinary, of
the mouth and pharynx. They cannot however be sharply
separated from lizards. Formerly the limitations of this class
rested entirely upon the absence of limbs, and thus not only were
the Gymnophiona among the Amphibia, but also the blind worms
and other genera of apodal lizards included in it. Moreover
some snakes have traces of posterior limbs which are placed at
the root of the tail and carry a conical claw projecting at the
sides of the anus.
* Thilenius, Morphol. Arbeiien, 7, 1897, p. 515; Keller, Arch. Physiol.,
61, 1895, p. 123.
f J. Miiller, " Ueb. eine eigenthiimliche Bewafmung des Zwischen
kiefers der reifen Embryonen der Schlangen u. Eidechsen," Mutter's
Arch., 1841 Dumeril et Bibron, " Erpetologie generale," Paris, 1854,
A. Giinther, " On the geographical distribution of Snakes," Proc. ZooL
Soc., 1858. Id. " The Reptiles of British India" London, Ray Society,
1864. ^G. Jan, " Iconographie generate des Ophidiens" Paris, 1860-82.
Lenz, " Schlangerikunde" ed. 2, Gotha, 1870. G. L. Boulenger, " Cata-
logue of Snakes in the British Museum,'" London, 1893-6. Huxley, Cope,
Zittel, Gadow, op. cit.
356
OPHIDIA.
The skin is scaly, but the scales are purely epidermal struc-
tures placed on thickenings of the cutis ; osteoderms are absent.
The scales vary much in form, number and arrangement. When
they are small and overlap they are called scales, but when they
are .large and only touch by their edges the term shield is applied
to them.
The scales of the head are dis-
tinguished according to their
position (Fig. 195). The mental
shields (q), i.e. the scales in the
mental groove on the ventral
surface between the rami of the
lower jaw, may be mentioned
as peculiar to snakes ; in front
of these two accessory labial
shields on either side form with
the median labial shield (o) the
anterior boundary of the mental
groove. The scales 011 the
ventral surface are for the most
part broad and invest the body
like transverse bands (Fig. 195
b, t), but small scales may also
be present here. The ventral
surface of the tail, on the other
hand, is as a rule, covered by a
double, or rarely by a single,
row of shields.
Snakes moult several
times in the course of the
year. They strip off the
whole of the scaly epidermis.
The vertebrae are very
numerous and are divided
into caudal and precaudal
only. All the precaudal vertebrae, except the atlas, carry
ribs, and the caudal vertebrae have long transverse
processes. The vertebrae are procoelous, the posterior surfaces
being hemispherical. The zygapophyses are flat and look dor-
sally and ventrally and in addition to them the anterior side of
the neural arch carries above the neural canal a wedge-like
process — the zygosphene (Fig. 196) which fits into a correspond-
ing depression — the zygantrum — on the posterior surface of the
FIG. 195. — Head of Calopeltis aesculapii. a
dorsal, b ventral view, c side view of head of
Tropidonotus viperinus (from Claus, after
E. Schreiber). a frontal shield ; b super-
ciliary shields ; c posterior snout, d anterior
snout, e parietal, / rostral shield ; g upper
labial shields ; h nasal shield ; i preorbital
shield ; k loreal, I postorbital, m temporal,
o median labial shield ; p lower labial shields ;
q mental shields ; r jugular shields, s jugular
scales ; t ventral shields.
SKULL. 357
neural arch of the preceding vertebra. The neural arches are
completely fused with the centra. The transverse processes in
the trunk are short and carry the ribs. Some of the anterior
trunk vertebrae have hypapophyses. In Dasypeltis the an-
terior of these are tipped with an enamel-like substance (p. 368).
There are no chevron bones, but the transverse processes of the
caudal vertebrae have strong descending processes which have
the same relation to the caudal vessels. The atlas and axis are
similar to those of lizards. The vertebral column is capable
of a considerable amount of lateral flexion, but of very little,
if any, dorso- ventral flexion.
The ribs are articulated to the transverse processes of the trunk
FIG. 196.— Anterior and posterior view of a trunk vertebra of a Python (from Huxley), zs
zygosphene ; z a zygantrum ; p z prezygapophysis ; pt z postzygapophysis ; t p transverse
process.
vertebrae. They have capitula only, and are very moveable in
an antero-posterior direction. They are usually hollow and end
ventrally in a cartilage which is attached to the connective tissue
underlying the ventral shields. The movements of the ribs in
combination with the flexion of the vertebral column are of great
use in locomotion. Snakes run, in a sense, on the extreme
points of their ribs which are moved forwards, carrying with
them the ventral shields to which they are attached. There is
no trace of a sternum in any snake.
The skull presents a number of peculiarities in which it differs
from the ordinary lacertilian type ; but it is interesting to notice
that some of these crop up in different families of lizards. The
most important points of difference are the following. (1) The
cranial cavity is long and extends, but little diminished in depth,
into the interorbital region, there being no interorbital septum.
358
OPHIDIA.
The anterior and middle parts of its walls are formed by descend-
ing processes of the parietal and frontal bones (Fig. 197 B), and
there is no epipterygoid (columella). The bones of the cranium
are firmly and suturally connected and there are no membranous
fontanelles ; in these points it resembles the Amphisbaenidae.
(2) There are no parotic processes. (3) The basisphenoid is con-
tinued forwards as an ossified rostrum (Fig. 197 B}, which pro-
bably represents a parasphenoid element, into the ethmoidal
region. (4) The nasal region is but slightly ossified, and the
Etfi
lo
Jrt-
B
FIG 197 —Skull of Tropidonotus natrix ~~< A dorsal, B ventral view (from Wiedersheim) Ag
angular, Art articular ; Bp basioccip ital ; Bs basisphenoid ; Ch choanae ; Cocc occipital
condyle ; Dl dentary ; Eth ethmoid ; F frontal ; F' postorbital ; Fov fenestra ovaiis
foramen for optic nerve ; M maxilla ; N nasal : 01 exoccipital ; Osp supraoccipital ; P pari
tal ; Pe periotic ; Pf prefrontal ; PI palatine ; Pmx premaxilla ; Pt pterygoid ; Qu qua<
SA suranguar ; Squ squamosal ; Ts transpalatine ; Vo vomer.
premaxilla is small, unpaired, and only connected with the
maxilla by ligament. (5) The temporal arcades are absent : the
postfrontal is not directly connected with the squamosal, and
there is no jugal or quadrato-jugal ; the geckos and amphis-
baenids among lizards present approximations in these respects.
(6) The palatines do not unite directly with the vomers or with
the base of the skull. They are joined behind to the pterygoids,
which are connected with the maxillae by long fcranspalatine
SKULL. 359
bones and posteriorly with the highly mobile quadrates. (7)
There is no parietal foramen. (8) The rami of the lower jaw are
not united at the symphysis but connected only by an elastic
ligament.
The supraoccipital does not enter into the foramen magnum
(Fig. 197 A, Osp). The parietal is unpaired and sends down
lateral processes which articulate with the basisphenoid. The
frontals are paired and send down lateral processes which unite
with one another on the floor of the skull dorsal to the basi-
sphenoidal rostrum. This is a unique arrangement.
Whether these downward processes contain elements of the orbito-
sphenoid and alisphenoid is not clear. According to Rathke * the parietals
and frontals arise from paired centres of ossification in patches of cartilage
in the dorso-lateral part of the skull. That there is something unusual
in this part of the skull is further rendered probable by the fact that the
trabeculae cranii persist in many adult snakes as two separate cartilaginous
rods placed in grooves on the dorsal side of the basisphenoidal rostrum
and ventral to the union of the frontals.
There are postfrontals behind the orbit, and prefrontals lying
upon the ethmoid cartilage in front of the orbit (Fig. 197 A, F' , Pf).
The prefrontals have descending processes for articulation with
the maxillae and palatines. There are two nasals and two
vomers (vo) close together and in front of the choanae (Ch).
The quadrates are very moveably articulated to the posterior
end of the squamosals, which are elongated and project back
from the parietal region of the skull (Fig. 197, Qu).
The lower jaw contains the usual bones but the coronoid is
sometimes absent. The hyoid is much reduced, consisting of a
pair of cartilaginous rods lying ventral to the trachea and
united in front.
In the Typhlopidae the palatines are placed transversely and meet in
the middle line. The pterygoids are not joined to the quadrates and there
is no transpalatine. In Xenopeltis, which like Python has teeth in the
premaxilla, the squamosal is applied to the side wall of the skull, so that the
short quadrate appears to articulate directly with the skull. In most
non-poisonous snakes a row of recurved teeth is present on the maxillae,
palatines and pterygoids, the palatine and pterygoid are arranged longi-
tudinally and are firmly connected, and the squamosals are slightly move-
able. In the Viperidae. the maxillae are short and moveably articulated
with the pref rental. The squamosal, and quadrate are very moveable
and the pterygoid is moveably attached to the palatine. The maxillae
each possess only one large tooth — the poison fang — which contains a
* Ueb. d. Entwickelungsgesch. der Natter, Konisberg, 1839.
360
OPHIDIA.
canal open at each end. The poison gland opens at the base of the fang
and its secretion passes into the canal. When the mouth is shut, the
fangs are directed backwards and lie along the roof of the mouth. When
the mouth opens (Fig. 198) the ventral end of the quadrate, which when
at rest is inclined backwards, is brought forward. The pterygoid is thus
thrust forward and the ptery go-palatine joint bent. This forward move-
ment of the pterygoid is conveyed by the transpalatine bone to the maxilla
and causes it to rotate through about 90° upon its prefrontal articulation,
in such a way that the surface to which the fang is attached is carried
forwards and ventralwards, and the fang is erected, i.e. is made to project
downwards at the front end of the mouth (Fig. 198).
There is no trace of anterior limbs or of shoulder girdle in any
snake, and in most
Ccs
Fig 198.— Skull of Crotalus horridus (from. Claus). Art
articular ; Bs basisphenoid ; D dentary ; Lt ethmoid ; F
frontal ; Jmx premaxilla ; MX maxillary ; N nasal ; Ocb
basioccipital ; Ocl exoccipital ; Ocs supraoccipital ; P
parietal ; Pf postfrontal ; Pr prootic ; PI palatine ; Prf
prefrontal ; Pt pterygoid ; Qu quadrate ; Sq squamosal ;
Tr transpalatine.
the pelvis and
hind limbs are also
absent. But traces
of the pelvis and
sometimes even of
the hind limbs are
present in a few
forms (Typhlopidae,
Boidae, Xenopeltis).
The vestige of the
pelvis seems to be
restricted to a single
bone on each side,
longitudinally dis-
posed and embedded
in the muscle near
the anus ; it is
probably the ischium. To these, very short vestiges of hind
limbs carrying claws are frequently attached.
Alimentary Canal. The teeth are acrodont and ankylosed
to the jaws. They are sharp-pointed and curved backwards.
They are usually absent from the premaxillae, but are present
on the maxillae, palatines, and pterygoids (occasionally absent
from the pterygoids) and on the dentaries. They chiefly serve
to hold the prey while it is being swallowed. In most of the
non-poisonous snakes the teeth are conical, but in the others
and in all the poisonous forms some of the maxillary teeth are
grooved in front. This groove is in the most poisonous forms
ALIMKXTARY CAXAL. S<>1
( Viperidae) converted into a canal open at both ends. The teeth
appear to be continually replaced.
Labial glands are present in a row in the upper and lower jaw.
The posterior labial gland of the upper jaw is in the poisonous
snakes modified as the poison gland. It is larger than the rest
and different in structure, and its duct opens into the mouth,
sometimes at the base of the poison fang ( Viperidae). Sublin-
gual glands in the floor of the mouth are also present.
The tongue is long, narrow and forked, and retractile into a
basal sheath. It is well provided with sense organs and is
exceedingly protractile. It is used as a tactile organ, and can be
protruded through an indentation at the extremity of the snout
even when the mouth is closed ; eustachian tubes and tym-
panic cavities are absent. The glottis is placed far forwards,
close behind or even perforating the tongue-sheath, and can be
projected into the mouth during the act of swallowing. The
oesophagus is long and leads into the tubular stomach, the anterior
part of which is dilated, the posterior (pyloric) narrow and
intestine-like. The windings of the small intestine are con-
nected together by connective tissue and enclosed in a common
sheath of peritoneum. The rectum varies in length and
there may be a caecum on the anterior part of it. The liver is
elongated and not divided into lobes : it extends from the
pericardium to the cardiac region of the stomach. The gall-
bladder is placed at some distance from it, on the right side of
the duodenum. The pancreas lies on the right side of the
duodenum, into which it opens by one or more ducts close to
or in common with the bileduct. The spleen is usually distin-
guished by its light colour and is placed near the pancreas.
The cloaca is without a urinary bladder. The anus is placed
at the junction of the body and tail, which varies in length in the
different families.
Fat-bodies are present in the form of lobed structures on each
side of the intestine in the hinder part of the body-cavity.
Thymus and thyroid are present, and the suprarenal bodies
have the form of narrow elongated bodies of a yellow colour
placed on the renal veins or on the vena cava inferior.
The glottis is a longitudinal slit and is without distinct epi-
glottis, though there may be a trace of the latter. The larynx
consists of two lateral longitudinal cartilages connected ventral ly
362 OPHIDIA.
and sometimes dorsally by transverse pieces. There are no
vocal cords. The trachea is long and the tracheal rings are com-
plete in front, incomplete behind. The lungs are saccular and
provided with air-cells in their walls. They are never sym-
metrical. As a rule the left is the smaller, and in some cases,
e.g. most poisonous snakes, one lung is completely suppressed.
In such cases the posterior end of the trachea may possess,
usually on its dorsal side, air-cells in its walls and take^on the
structure of a lurig. In many snakes the alveolar structure is
less marked and may be entirely absent in the hind end of the
lung. It thus happens that in these snakes, as in some lizards
(Chamaeleo), the hind end of the lung has a smooth wall without
lung structure and is supplied with blood vessels from the sys-
temic circulation. Inspiration is effected by swallowing move-
ments as in Amphibia and lizards.
The brain is very similar to that of lizards, but there is no
parietal organ. The spinal accessory cranial nerve is not pre-
sent, and the sympathetic system is but feebly developed, the
viscera in the greater part of the trunk being supplied by the
ventral rami of the spinal nerves.
The eyelids are always fused over the eye, so that the conjunc-
tival space is closed and there appear to be no eyelids (see p. 317).
The lacrymal gland opens into this space, which also communi-
cates with the nose by a lacrymal canal. There is no retractor
bulbi muscle.
Tympanic membrane, tympanic cavity and eustachian tube
are absent. In spite of this snakes appear to have a good sense
of hearing. The columella auris extends from the stapedial
plate to the quadrate, against which it abuts by a cartilaginous
epiphysis. In some snakes the stapes is a bony plate closing
the fenestra ovalis and without a shaft-like columella.
The nasal openings are usually placed at the front end of the
snout.
The heart is placed far back at some distance from the head.
It is constructed as in lizards and chelonians. There are a sinus
venosus, two auricles, and a single ventricle imperfectly divided
by a septum. Three arteries leave the ventricle, the pulmonary
artery and two systemic arches. The right systemic arch
gives off the single or double carotid artery. In many snakes
(Python, Boa, Tropidonotus, Xenopeltis, etc.) there are two
HABITS. ' 363
carotids.* These may arise from the arch by a common stem,
and the right is usually smaller than the left. In other snakes
only one carotid and that the left is present. In such cases it
often happens that there is an artery in place of the right carotid,
which goes to the blood-glands in front of the pericardium
(a. thyroidea). There are, of course, no subclavians. The left
arch gives off no vessels. The anterior abdominal vein is single
and arranged as in Lacertilia, i.e. it conveys blood from the
ventral body wall and bladder to the liver. The caudal vein is
continued as the renal portal.
The kidneys are elongated, slightly lobed bodies placed at
some little distance in front of the cloaca. They are not quite
symmetrical the right extending a little further forward than the
left. The ureters leave their hind ends and are of some length ;
they open through the side-walls of the cloaca on a papilla which
in the males contains also the opening of the vas deferens. There
is no urinary bladder.
The genital glands are like the kidneys slightly asym-
metrical ; those of the right side reaching a little further forward
than the left. The testes are usually rather elongated bodies
and lie in front of the kidneys. The coiled vasa deferentia lie
along their inner sides and open behind, as stated, into the cloaca
close to the ureters. The ovaries are elongated and consist
of two lamellae with a lymph space between them. The oviducts
have the usual arrangement. The penes are paired evagin-
able cloacal pouches and closely resemble those of lizards.
Accessory glands in the neighbourhood of the anus are found
in both sexes of many snakes.
Most snakes are oviparous, but in a few (many sea-snakes and
vipers) the development takes place in the oviduct and the young
are born fully developed. The eggs have soft shells and are laid
in comparatively small numbers, it may be at an advanced stage
of development. The embryo possesses a tooth-like process on
its premaxilla for breaking the shell.
Snakes feed exclusively on living animals, both warm and
cold-blooded, which they attack suddenly, and swallow without
mastication. Swallowing is effected thus : the teeth on the
lower jaw are alternately hooked further and further forwards
into the body of the prey (the two halves of the mandible
* Rathke, Denkschriften Wiener Akad. xi, 1856, Abt. 2, p. 1.
364 OPHIDIA.
moving forwards alternately), as a result of which the mouth
and pharynx of the snake are gradually drawn over the animal,
the surface of which is at the same time made slippery by the
secretion of the buccal glands. During this process the larynx
is projected forwards between the rami of the jaws, so that respir-
ation can be maintained. After the completion of the laborious
process of swallowing, the animal appears to be entirely pros-
trated and passes a long period in inactivity, during which the
slow digestion takes place.
Some snakes kill their prey by crushing, e.g. Python ; some
by poison ; and others, the majority, swallow their prey directly.
The poisonous snakes belong to different families and cannot
easily be distinguished by any external mark from the non-
poisonous. The poison is secreted by some of the upper labial
glands, and is introduced into the subcutaneous tissue of the
victim by a groove (in the Viperidae converted into a canal) on
the anterior side of some of the maxillary teeth
The actual poison of the venom appears to consist of albuminous
substances in solution, and is different, judging by its action, in different
snakes.* The best treatment is to inject the serum of animals which
have been rendered partially immune by repeated doses of the venom.
Failing this, the best plan is to apply a ligature above the wound, twisting
the string with a stick, and then to make a free incision of the wound.
" Then bandage the limb downwards towards the wound, repeating this
several times. Direct application into the widened wound of bleaching
powder (calcium hypochlorite) or of a 1 per cent, solution of Condy's
fluid is good. Amputation is of course the best remedy, if a very deadly
snake has bitten the part." Alcohol and injection of ammonia are use-
less, and sucking the wound is dangerous. Many mammals are said to
be immune to snake -venom, e.g. the mongoose, the hedgehog and the pig.
Most of the species distinguished by size or beauty of colour
belong to the warmer zones, only the smaller forms extend
into northern temperate climates. Many snakes are fond of
the water and are truly amphibious. Others live for the most
part on trees or shrubs, or on sandy ground ; others exclusively
in the sea. In temperate climates they fall into a kind of winter
sleep ; in hot countries they may undergo a summer sleep in the
dry season.
About 400 genera and 1,800 species are known. Very few
fossil forms are known. It is claimed that they make their first
* See Martin in Allbutt's System of Medicine, 2, London, 1896.
OPHIDIA.
365
appearance in the Cretaceous, but this is doubtful. Fragments
are however found in the Eocene (Palaeophis, etc.), and J the
remains become more extensive as the present time irf ap-
proached.
Fam. 1. Typhlopidae. Burrowing snakes with reduced eyes covered by
the scales, and without teeth in the lower jaw ; maxilla transversely placed
and toothed, palate toothless. The cranial bones are solidly united ; there
are no ectopterygoids or squamosals (supratemporal) and the pterygoids
are not united to the quadrates ; vestiges of the
pelvis as a single bone on each side ; widely dis-
tributed, absent from New Zealand. Helminth o-
phis Ptrs., trop. Amer.; Typhlops Schn. (Fig. 199),
S. Eur., S. Asia, Afr., trop. Amer., Australia, about
110 species ; Typhlophis Ptrs., Brazil and Guiana.
Fam. 2. Glauconiidae. Like the former, but
maxillaries normal and toothless, lower jaw
toothed. The pelvic girdle and hind limbs show
the least reduction in any snake ; the ilium, pubis
and ischium can be distinguished, the latter form-
ing a symphysis, and there is a vestige of a femur.
Anomalepis Jan, Mexico ; Glauconia Gr., Africa,
S.W. Asia., Amer., 30 species.
Fam. 3. Boidae. Usually large snakes with
vestiges of the hind limbs appearing as spurs on
each side of the anus ; the ventral scales are trans-
versely enlarged and the eyes are functional and
free. Teeth are present on the mandibles, ptery-
goids, palatines, maxillaries and in some genera
on the premaxillaries. Maxilla, palatine, ptery-
goid moveable ; ectopterygoid present and
pterygoid extending to quadrate ; squamosal
present, suspending quadrate : prefrontal in con-
tact with nnsal ; vestiges of pelvis and hind limbs
present ; worldwide except New Zealand . prefer
wooded districts, climbing trees ; crush their prey
in the coils of the body ; oviparous ; 20 genera.
Aspidites Ptrs., N. Australia ; Boa L., trop.
Amer., Madagascar ; B. constrictor L., S. Amer.,
to 11 ft. ; Bolieria Gr.. Round Island near
Mauritius ; Caldbaria Gr., W. Afr. ; Casarea
Gr., Round Island near Mauritius ; Charina Gr.,
W. N.-Amer. ; Chondropython Meyer, New
Guinea ; Corallus Daud., trop. Amer., Mada-
gascar ; Enygrus Wagl., Moluccas, Papuasia,
Polynesia ; Epicrates Wagl., trop. Amer. ; Eryx
Daud., N. and E. Afr., S. and C. Asia ; Eunectes Wagl., the anaconda,
aquatic and arboreal in habit, S. Amer. ; Liasis Gr., Flores, Timor,
Papuasia, N. Australia : Lichanura Cope, California ; Loxocemus Cope,
Mexico ; Nardoa Gr., New Zealand ; Python Daud., trop. and S. Afr.,
S.E. Asia, Papuasia, Australia ; P. spilotes Lacep., the carpet-snake,
N. Guinea, Australia ; P. reticulatus Schn., Indo-China, Malay Isl.. to
FIG. 199. — Typhlops
lumbricoides (R6gne
Animal).
366 OPHIDIA.
30 ft. ; P. molurus L., India and Ceylon, to 30 ft. ; Trachyboa Ptrs.,
S. Amer. ; Ungalia Gr., W. Indies, Guatemala, Ecuador, Peru ; Ungaliophis
F. Mull., Guatemala.
Fam. 4. I'ysiidae. Cranial bones are more or less solidly united ;
ventral scales hardly enlarged ; teeth and pelvis as in the last. Ilysia
Hemp., S. Amer. ; Anomalochilus Jeude, Sumatra ; Cylindrophis Wagl.,
Ceylon and S.-E. Asia.
:'-*yFam. 5. Uropeltidae. Burrowing snakes of small size, restricted to
Ceylon and S. India. Cranial bones solidly united, pterygoid not reaching
quadrate, with ectopterygoid, without squamosal ; eye small ; tail short
ending in a large shield. Uropeltis Cuv., Ceylon; Rhinophis Hemp.,
Ceylon and S. India ; Silybura Ptrs., India, Ceylon ; Pseudoplectrurus
Blgr., S. India ; Plectrurus S. India ; Melanophidium Gthr., S. India ;
Platyplectrurus Gthr., S. India.
Fam. 6. Xenopeltidae. Cranial bones more or less solidly united ;
ectopterygoid present, pterygoid reaching quadrate, squamosal present,
pref rental in contact with nasal ; teeth in jaws, palate and premaxillary ;
mandible without coronoid ; dentary moveably articulated to the articular ;
tail short ; a single genus and species Xenopeltis (Tortrix) unicolor
Reinw., in S.-E. Asia.
Fam. 7. Colubridae. Facial bones moveable, prefrontal not in contact
with nasal, ectopterygoid present, pterygoid extending to mandible or
quadrate, squamosal present, maxillaries horizontal, mandible without
coronoid, both jaws and palate toothed ; 242 genera, cosmopolitan, with
terrestrial, arboreal and aquatic forms. The family is divided into 3 series.
Series A. AGLYPHA — All the teeth solid, not grooved. Series B.
OPISTHOGLYPHA. — One or more of the posterior maxillary teeth grooved.
Series C. PROTEROGLYPHA. — Anterior maxillary teeth grooved or perforated.
Series A. AGLYPHA.
The Aglypha are harmless non-poisonous snakes and are divided into
3 subfamilies.
Sub-fam. 1. Acrochordinae. The postfrontal bone produced over
the supraorbital region ; scales not or but slightly imbricate ; S.-E.
Asia and C. Amer. ; many spscies are aquatic in rivers and estuaries.
Acrochordus Hornst., Malay P. and Arch., N. Guinea ; Xenodermus
Reinh., Java, Sumatra, Penang; Chersydrus Cuv., mouths of rivers
and coasts of S.-E. Asia and Papuasia ; Stoliczkaia Jerd., Khasi
Hills, N.-E. India ; Nothopsis Cope, C. Amer.
Sub-fam. 2. Colubrinae. Postfrontal bones not produced over
the supraorbital region ; scales usually imbricate ; teeth on the entire
length of the maxillary and dentary bones ; cosmopolitan, but scarce
in Australia. The sub-family contains about 1 ,000 species, and the
genera may be arranged in two groups according to the presence or
absence of hypapophyses on the posterior dorsal vertebrae.
I. Genera which have the hypapophysis on all the vertebrae,
arranged alphabetically.
Ablabophis Blgr., S. Afr. ; Achalinus Ptrs., China, Japan ;
Amphiardis Cope, Texas ; Aspidura Wagl., Ceylon ; Blythia Theo.,
Khasi Hills ; Boodon Gthr., trop. and S. Afr. ; Bothrolycus Gthr.,
W. Afr. ; Boihrophihalmus Ptrs., trop. Afr. ; Brachyorrhus Boie,
Malay Arch., N. Guinea ; Chersodromus Reinh., Mexico and Guate-
mala ; Cyclocorus D. and B., Philippines; Compsophis Mocq., Mad.;
OPHIDIA. 367
Dromicordryas Blgr., Mad. ; Elapoides Boie, Malay Arch. ; Glypholycus
Gthr., C. Afr. ; Gonionotophis Blgr., Congo ; Haldea B. and G., N.
Am. ; Haplocercus Gthr., Ceylon ; Helicops, Wagl., C. and S. Amer.,
S.-E. As., trop. Afr. ; Hormonotus Hallow, W. Afr. ; Hydraethiops
Gthr., trop. Afr. • Hydrablabes Blgr., Borneo ; Ischognathus D. ana
B., X. and C. Am. ; Lamprophis Smith, S. Afr. ; Lioheterodon D.
and B., Mad.; Liophidium Blgr., Madagascar; Lycognathophis Blgr. ,
Seychelles ; Lycophidium D. and B., trop. and S. Afr. ; Macropisthodon
Blgr., E. Indies ; Micropisthodon Mocq., Mad. ; Opisthotropis. Gthr.,
W. Afr., s. China, Malay Arch. ; Oxyrhabdium Blgr., Philippines ;
Plagiopholis Blgr., mountains of Burma ; Polyodontophis Blgr.,
Mad., Comoros, S.-E. As., C. Am. ; Prymnomiodon Cope, Siam ;
Pseudoxenodon Blgr., E. Indies, S. China ; Pseudoxyrhopus Gthr.,
Mad. ; Rhabdops Blgr., India, S. China ; Simocephalus Gthr., trop.
and S. Afr. ; Sirepiophorus D. and B., C. Am., N.-W. S. Am.
Tetralepis Boet., Java ; Trachischium Gthr., E. Himalayas, Khasi
Hills; Tretanorhinus D. and B., C. Am., Cuba; Trirhinopholis Blgr.,
Burma ; Tropidonotus Kuhl, Eur., As., Af., N. Aust., N. and C.
Am., 74 species ; T. natrix, grass-snake, of this country, is widely
distributed, but absent from Scotland and Ireland, can climb trees
and swim, oviparous ; pair in May, June ; lay in July, August in
rich vegetable soil ; to 6 ft., average 3 ft. ; Xenochrophis Gthr., S.E.
As. ; Xylophis Beddome, S. India.
II. Genera in which the hypapophyses are absent on the posterior
dorsal vertebrae, arranged alphabetically.
Abastor Gr., N. Am. ; Ablabes D. and B., S.-E. Asia, Japan ;
Aporophis Cope, S. Amer. ; Arrhyton Gthr., Cuba ; Atractus Wagl.,
C. and S. Am., about 25 species ; Calamaria Boie, from Assam,
Burmah and S. China to Malay Arch., about 35 species ; Carphophis
Gerv., N. Am. ; Cemophora Cope, N. Am. ; Chilomeniscus Cope,
Lower California; Chlorophis Hallow, trop. and S. Afr. ; Coluber L.,
Eur., As., N. and trop. Amer., about 50 species. C. qiiatuorlineatits
Lacep. to 6 ft., Italy, S.E. Eur., S. Tyrol ; C. leopardinus Bp., S.
Italy, S.E. Eur., As. Min. ; C. longissimus Laur., aesculap Snake, S.
France, Italy. S.E. Eur. ; Contia B. and G., S.-W. Asia and Sind,
Am., about 20 species ; Coronella Laur., Eur., S.-W. As., India, N.
Amer., about 20 species ; C. laevis Lac. (austriaca], the smooth
snake, found in England, superficially resembles the viper but with
round pupils, to 2 ft. ; Cyclagras Cope, S. Am. ; Dendrelaphis Blgr.,
India, Ceylon, Burma, Malay Pen. and Arch. ; Dendrophis Wagl.,
S.-E. As., Aust., tree-snakes ; DimadesGr., S. Am. ; Dinodon D. and
B., China, Japan ; Dirosema Blgr., C. Am. ; Drepanodon Per., S.
Am. ; Dromicus Bibr., W. Indies, Chili, Peru ; Drymobius Cope,
Am., Texas to Peru ; Dryocalamus Gthr., S.-E. As. ; Farancia Gr.,
X. Am. ; Ficimia Gr., Arizona, Texas, Mexico ; Gastropyxis Cope,
W. Afr. ; Geagras Cope, Mexico ; Geophis Wagl., C. and S. Am. ;
Gonyophis Blgr., Malay Pen., Borneo ; Grayia Gthr., trop. Afr. ;
Hapsidophrys Fisch., W. Afr. ; Herpetodryas Wagl. ; Heterodon Latr.,
N. Am. ; Homalosoma Wagl., Afr. ; Hydromorphus Ptrs., C. Am. ;
Hydrops Wagl., S. Am. ; Hypsiglena Cope, S. N.-Am., C. Am.,
Venezuela ; Hypsirhynchus Gthr., S. Domingo ; Idiopholis Mocq.,
Borneo ; Leptocalamus Gthr., trop. Amer. ; Leptophis Bell, C. and S.
Am., tree snakes ; Liophis Wagl., Am., W. Indies, about 20 species ;
368 OPHIDIA.
Lycodon Boie, S. As. ; Lystrophis Cope, S. S.-Am. ; Lytorhynchua
Ptrs., N. Afr., As., Arizona, California ; Macrocalamus Gthr. .
Oligodon Boie, S. As., Lower Egypt, about 20 species ; P ztalognathus
D. and B. trop. Am. ; Philothamnus Smith, trop. and S. Afr. ;
Phrynonax Cope, trop. Am. ; Prosymna Gr. trop. and S. Afr. ;
Pseudaspis Cope, S. Afr. ; Pseudorhabdium Jan, Malay Pen. and
Arch. ; Rhabdophidium Blgr., Celebes ; Rhadinaea Cope, C. and S.
Am., 26 species ; Rhamnophis Gthr., trop. Afr. ; Rhinochilus B. and
G., N. Am., Mexico, Venezuela ; Scaphiophis Ptrs., trop. Afr. ;
Simophis Ptrs., Brazil ; Simotes D. and B., S. China, E. Indian
continent and Arch., about 25 species ; Spilotes Wagl., S. Am. ;
Stegonotus D. and B., Philippines, Moluccas, Papuasia, Queensland ;
Stilosoma Brown, Florida ; Symphimus Cope, Mexico ; Sympholis
Cope, Mexico ; Synchalinus Cope, C. Am. ; Thrasops Hallow, W. Afr. ;
Trimetopon Cope, C. Am. ; Tropidodipsas Gthr., C. Am. ; Typhlo-
geophis Gthr., Philippines ; Uromacer D. and B., Santo Domingo ;
Urotheca Bibr., Cuba, C. and S. Am. ; Virginia D. and B., N. Am. ;
Xenelaphis Gthr., Burma, Malay Pen. and Arch. ; Xenodon Boie,
trop. Am. ; Xenurophis Gthr., W. Afr. ; Zamenis Wagl., Eur., As.,
N. Afr., Senegambia, N. and C. Am., 31 species ; Z. mucosus,
rat-snake of India, to 7 ft. ; Z. constrictor, the black-snake of
America, to 6 ft. an expert climber ; Zaocys Cope, S.-E. As. The
position of Amastridium Cope, Colombia, and Anoplophallus Cope,
Tahiti is doubtful.
Sub-fam. 3. Rhachiodontinae. Only a few teeth on the posterior
part of the maxilliary and dentary bones and on the palatines. Some
of the anterior thoracic vertebrae with the hypapophysis much
developed, directed forwards and capped with enamel ; one genus and
species. Dasypeltis scabra L., to 2£ ft., trop. and S. Afr. ; they eat birds'
eggs which they break in transit [along the oesophagus with the
hypapophyses above mentioned.
Series B. OPISTHOGLYPHA.
One or more of the posterior maxillary teeth grooved in front ; more or
less poisonous but not seriously harmful to man, the poison being weak
or the poison teeth too far back ; about 300 species, cosmopolitan except
New Zealand, terrestrial, arboreal, and aquatic.
Sub-fam. 4. Homalopsinae. Nostrils valvular on the upper sur-
face of the snout ; viviparous, aquatic in the rivers and estuaries of
the E. Indies from Bengal to N. Australia. Hypsirhina Wagl. ;
Homalopsis Kuhl ; Cerberus Cuv. ; Eurostus D. and B. ; Myron Gr. ;
Gerardia Gr. ; Fordonia Gr. ; Cantoria Gir. ; Hipistes Gr. : Herpeton
Wagl.
Sub-fam. 5. Dipsadomorphinae. Nostrils lateral, dentition well
developed; long-tailed, terrestrial, arboreal, and subaquatic ; about
70 genera, cosmopolitan except the, northern parts of the N. Hemi-
sphere.
Amblyodipsas Ptrs., Mozambique ; Alluandina, Mocq., Mad. ;
Amplorkinus Smith, trop. and S. Afr. ; Aparallactus Smith, trop.
and S. Afr. ; Apostolepis Cope, S. Am. ; Brachyophis Mocq., Somali -
land ; Calamelaps Gthr., trop. Afr. ; Chamaetortus Gthr., E. and C1
Air. • Chrysopelea Boie, S.-E. As. ; Coelopeltis Wagl., S. Eur., S.-V.
OPHIDIA. 369
As., N. Afr. ; Conophis Ptrs., Mexico, C. Am., S. Brazil ; Dipsadoboa
Gthr., W. Afr. ; Dipsadomorphus Fitz., trop. Afr., S. As., Papuasia,
Aust., about 22 species; Ditypophis Gthr., Socotra ; Dispholidus
Duv., trop. and S. Afr. ; Dromophis Ptrs., trop. Afr. ; Dryophiops
Jan, S.-E. As. ; Dryophis Dalman, S.-E. As. ; Elapomoius Jan,
Brazil ; Elapomorphus Wieg., S. Am. ; Elapops, Gthr., W. Afr. ;
Elapotinus Jan ; Erythrolamprus Wagl., trop. Am., Texas ; Eteiro-
dipsas Jan, Mad. ; Qeodipsas Blgr., Mad. ; H emir hag err his Boettg.,
E. Afr. ; Himantodes Cope, Mexico to trop. S. Am. ; Hologerrhum
Gthr., Philippines ; Homalocranium D. and B., trop. Amer., about
25 species ; Hydrocalamus Cope, C. Am. ; laltris Cope, S. Domingo ;
Ithycyphits Gthr., Mad., Comoros ; Langaha Brug., Mad. ; Leptodira
Gthr., trop. and S.-Afr., trop. Am. to Texas ; Lycodryas Gthr.,
Comoros; Lycognathus D. and B., trop. S.-Am. ; Macrelaps, Blgr., S.
Afr. ; Macroprotodon Guichen., Spain and N. Afr. ; Manolepis Cope,
Mexico ; Micrelaps Boettg., Palestine, Somaliland ; Mimophis Gthr.,
Mad. ; Miodon Dum., W. Afr. ; Ogmius Cope, Mexico ; Oxybelis
Wagl., trop. Am. ; Oxyrhopus Wagl., C. and S. Am., about 20 species ;
Philodryas Wagl., S. Am., about 13 species ; Polemon Jan, W. Afr. ;
Psammodynastes Gthr., S.-E. As. ; Psammophis Wagl., Afr. and S.
As., 17 species ; Pseudablabes Blgr., S. Brazil, Uruguay ; Pythona-
dipsas Gthr., trop. Afr. ; Rhamphiophis Ptrs., trop. Afr. ; Rhino-
bothryum Wagl., trop. S. Am. ; Rhinocalamus Gthr., E. Afr. ;
RhinostomaFitz., S. Am. ; ScolecophwCope, C. Am. ; Stenophis Blgr.,
Mad., Comoros ; Stenorhina D. and B., Mexico, C. Amer., Colombia,
Ecuador ; Tachymenis Wieg., Bolivia, Peru, Chili ; Taphrometopon
Brandt, C. As., and Persia ; Tarbophis Fleischm., S.-E. Eur., S.-W.
As., trop. and N. E. Afr. ; ThamnodynastesWagl., S. Am. ; Thelotornis
Smith, trop. and S. Afr. ; Tomodon D. and B., S. Am. ; Trimero-
rhinus, Afr. S. of Eq., E. Afr. ; Trimorphodon Cope, California to C.
Am. ; Trypanurgos Fitz., trop. S. Am. ; Xenocalamus Gthr., trop.
Afr. ; Xenopholis Ptrs., S. Am.
Sub-fam. 6. Elachistodontinae. Only a few teeth on the pos-
terior part of the maxillary and dentary bones and on the palatines and
pterygoids ; some of the anterior thoracic vertebrae with the hypa-
pophysis much developed and capped with enamel one genus and
species. Elachistodon westermanni Reinh., Bengal.
Series C. PROTEROGLYPHA.
Anterior maxillary teeth grooved or perforated ; behind these poison
fangs a series of smaller solid teeth ; all extremely poisonous and most
are viviparous.
Sub-fam. 7. Hydrophinae. Sea-snakes. Tail strongly compres-
sed laterally, with the neural spines and hypapophyses very much
developed. Body more or less compressed ; eyes small with round
pupil ; marine (except one species of Distira confined to a fresh-water
lake at Luzon in Philippines), entering tidal streams ; except
Platurus specimens of which have been found at some distance from
water, exclusively aquatic ; all are viviparous ; as a rule they are not
found in mid-ocean, and some of them at least visit the shores of
low islands to give birth to their young ; Indian and Pacific Oceans ;
about 10 genera and 50 species. Hydrus Schn., Indian and Pacific
z — II. B B
370
OPHIDIA.
Oceans ; Thalassophis Schm., coast Java of ; Acalyptophis Brgl.,
W.-trop. trop. Pacific ; Hydrelaps Blgr., N. coast of Australia ;
Hydrophis Daud. (Fig. 200), Indian and Pacific Oceans, 22 species ;
Distira Lac., Indian and Pacific oceans, about 20 species ; Enhydria
Merr., coast of India to Chinese sea and New Guinea ; Enhydrino,
Gr., Persian Gulf to New Guinea ; Aipysurus Lac., Malay Arch., and
W.-trop. Pacific ; Platurus Daud., E. parts of the Indian and W.
Pacific Oceans.
Sub-fam. 8. Elapinae. Tail cylindrical ; hypapophyses more or
less developed throughout the vertebral column ; about 29 genera
and 150 species ; Africa, S. Asia, S. N.- America, Central and S.
America, and Australia in which
they constitute the bulk of the
ophidian fauna ; absent from Mada-
gascar and New Zealand.
Acanthophis Daud., Moluccas,
Papuasia, Austr. ; A. antarcticus,
the death-adder of Australia ; As-
pidelaps Smith, S. Afr., Mozam-
bique ; Boulengerina Dollo, C. Afr.;
Brachyaspis Blgr., Aust. ; Bungarus
Daud., S.-E. As. ; B. candidus L.,
the krait, Indian sub-region ; Cal-
lophis Ptrs., S.-E. As. ; Dendraspis
Schleg., trop. and S. Afr. ; Deni-
sonia Krefft, Aust., Tasmania, Solo-
mons, 21 species ; Diemenia Gthr.,
Aust., N. Guinea ; Doliophis Gir.,
Burma, Cochin China, Malay Pen.
and Arch. ; Elapechis Blgr., trop.
and S. Afr. ; Elapognathus Blgr.,
Aust.; Elaps Schn. (Fig. 201),
America, about 30 species ; Furina
D. and B., Aust. ; Qlyphodon Gthr.,
N. Guinea and N. Aust. ; Hemi-
bungarus Ptrs., S.-E. As. ; Homo-
relaps Jan, S. Afr. ; Hoplocephalus
Gthr., Aust. ; Micropechis Blgr., N.
Guinea, Solomons ; Naia Laur., Afr.,
S.-Asia, the neck region can be
expanded into a hood by the spread-
ing and moving forwards of the
ribs ; N. tripudians, Merr., cobra, from Transcaspia to China and
the Malay Islands, to 6 ft. ; N. haje L., the aspis or spy-slange of
Africa ; N. bungarus Schleg., the hamadryad, King- Cobra, Snake-
eating Cobra, to 12 ft., India to S. China and the Philippines ;
Notechis Blgr., Aust., Tasmania ; N. scutatus, tiger snake ; Ogmodon
Ptrs., Fiji ; Pseudechis Wagl., Aust., N. Guinea ; Ps. porphyriacus,
the black-snake (females " bro wn- adders ") of Australia; Pseudelaps
D. and B., Aust., Moluccas, Papuasia ; Ehinhoplocephalus F. Mull.,
Aust. ; Rhynchelaps Jan, Aust. : Sepedon Merr., S. Afr. ; S. haema-
chates, the ringhals, S. Afr. ; Tropidechis Gthr., Aust. ; Walterinnesia
Lataste, Egypt.
JFlG. 200. — Hydrophis bicolor (R6gne
Animal).
OPHIDIA.
371
Fam. 8. Amblycephalidae. Facial bones slightly moveable, prefrontals
not in contact with nasals, ectopterygoid present, these characters, as
in Colubridae ; differ from Colubridae in fact that pterygoids do not reach
quadrate ; externally distinguishable from Colubridae by absence of longi-
tudinal median mental groove ; they resemble in their head and neck
poisonous snakes, but are harmless ; S.-E. Asia, C. and S. America. Haplo-
peltura Blgr., Pinang, Malay Arch. ; Amblycephalus Kuhl., S.-E. As.
Leptognathus D. and B., C. and S. Am. ; Dipsas Laur., S. Am. ; Pseudo-
par eas Blgr., S. Am.
Fam. 9. Viperidae. Facial bones moveable, prefrontal not in contact
with nasal, ectopterygoid present ; squamosal present, loosely attached
and suspending quadrate ; maxillary short, erectile perpendicularly to
ectopterygoid and carrying a
pair of large perforated fangs
without external groove,
without other teeth ; teeth
on palatine and pterygoid ;
mandible without coronoid
bone; hypapophyses through-
out vertebral column; poison-
ous ; all excep ting Atractaspis
viviparous ; includes terres-
trial, semiaquatic, arboreal,
and burrowing types ; Eu-
rope, Asia, Africa (absent
from Madagascar), America.
Sub-fam. 1. Viperinae.
Without sensory pit on
the side of the snout,
maxillary not hollowed
out above ; Old World,
except Madagascar.
Causus Wagl., trop. and
S. Afr. ; AzemiopsHlgr.,
Upper Burma ; Vipera
Laur., Eur., Asia, N. and
trop. Afr. ; V. berus L.,
the common European
viper, to 28 inches, bite
as a rule not fatal, V.
russellii Shaw, the daboia, to 5 ft., India, Ceylon, Burma, Siam
Bitis Gr., Africa, B. arietans Wagl., puff-adder, to 5 ft., very poisonous,
Afr., S. Arabia. Pseudocerastes~B\gr., Persia ; Cerastes Wagl., N. Afr.,
Arabia, Palestine, C. cornutus L., horned viper ; Echis Merr., Afr. n.
of equator, S. Asia. Atheris Cope, trop. Afr. ; Atractaspis Smith,
trop. and S. Afr.
Sub-fam. 2. Crotalinae. Pit-vipers. With a deep pit on each
side of the snout between the nostril and the eye ; maxillary hollowed
out above ; America, S. Asia ; includes rattle-snakes which are con-
fined to America. Without rattle are, Ancistrodon Baird, Caspian,
As., N. and C. Am., about 10 species ; A. pisc.ivorus Lac., water-
viper, E. N.-Am. ; A. conturtrix L., the copper-head, N. Am. Lachesis
Daud., S.-E. As., N. and S. Am., about 40 species. With rattle are,
FIG. 201. — Elaps corallinus (R6gne Animal).
372 CROCODILIA.
Sistrurus Garni., N. Am. E. of Rockies, Mexico ; and Crotalus L.,
Am. (not in the W. Indies), about 11 species ; C. horridus L., common
rattle-snake of U.S. ; C. durissus L., to 8 ft., S.-E. U.S. ; C. terrificus
Laur., S. Amer.
Sub-class 3. CROCODILIA.*
Lizard-like long-tailed Reptiles, usually of considerable or
moderate size, with immoveable quadrates, a hard palate, and a
quadrato-jugal arch, and with teeth implanted in alveoli of the jaws
to which they are confined ; with loose abdominal ribs, sternum
and inter clavicle, a sacrum composed of two vertebrae. The ven-
tricle is divided by a complete septum. Anal opening longitudinal.
Crocodiles are scaly animals, the scales consisting of cornifi-
cations of the epidermis. They have two pairs of limbs of which
the anterior have five digits, the posterior four. The three
preaxial digits in each limb possess nails. The hind feet are
more or less webbed. The nostrils are placed at the end of the
long snout and can be closed. The tympanic membranes are
exposed, but can be covered over by a cutaneous fold. The
eyes have vertical pupils, two lids and a nictitating membrane.
There is a bony plate in the upper eyelid. They all possess on
the back, and sometimes (Caiman, Teleosaurus, Stagonolepis} on
the belly, a dermal skeleton of bony plates, which are arranged
in transverse rows and correspond in form to the overlying epi-
dermal scales. The bony plates of the back are pitted and
sculptured and frequently keeled ; the ventral plates are less
sculptured, not keeled, and are sometimes composed of two
suturally united pieces, a small anterior and a large posterior.
On the tail these plates form a dentated dorsal crest, paired in
front, but single behind.
The vertebral column is marked out into cervical, dorsal,
* Cuvier, " Sur les differentes especes de Crocodiles vivants et leur
caracteres distinctifs." Ann. du Mus. d'hist. Nat., 10, 1807. R. Owen,
" Palaeontology ," London 1860. Huxley, " On the dermal armour of
Jacare and Caiman, etc." Journ. Proc. Lin. Soc., 4, 1860. Rathke,
" Untersuch. ub. d. Entwick, u. d. Korperbau der Crocodile," Braunschweig,
1866. Huxley, " On Stagonolepis robertsoni and on the evolution of the
Crocodilia," Quart. J. Geol. Soc. 31, 1875, p. 423. Id. ' Crocodilian remains
in the Elgin Sandstone,' Memoirs of the Geological Survey of the United
Kingdom, monograph hi., 1877. Cope, " Crocodilians, Lizards and Snakes
of N. America," Rep. U. S. Nat. Mus., 1898. Boulenger. " Catalogue
of Chelonians and Crocodiles in the British Museum," 1889. Hoffman,
Gadow. Zittel, op: cit.
SKELETON.
373
lumbar, sacral, and caudal regions^Fig.
202). There are 24 or 25 presacral
vertebrae, 35 or more caudal and two
sacral. The presacral vertebrae are
usually distributed as follows : nine
cervical, eleven or twelve dorsal, and
three or four lumbar. In living croco-
diles and in extinct species from the
Cretaceous onwards, all the vertebrae
except the atlas and axis (epistropheus),
the second sacral, and the first cau-
dal, are procoelous. The second sacral
is flat in front and concave behind,
and the first caudal is biconvex. In
precretaceous forms the centra are
feebly amphicoelous. The centra are
united by discs of fibro-cartilage and
the neurocentral suture persists.
All the cervical vertebrae have ribs. Tho
atlas consists of four pieces, an unpaired ven-
tral, two lateral, and a dorsal. The ventral
piece carries a pair of backwardly project-
ing single-headed ribs ; the dorsa1 piece is
developed in membrane and has oeen inter-
preted as the remnant of the neural arch of
a vanished proatlas vertebra. The axis has c
an odontoid process, which is suturally joined
to it. A two-headed rib is attached to the
odontoid process. The other cervical ver-
tebrae all possess two-headed overlapping
ribs, of which the capitulum articulates with
a facet or small tubercle on the centrum,
and the tuberculum with a short transverse
process projecting from the neural arch
above the neuro-central suture. In the
first and second dorsal vertebrae the capi-
tular tubercle is on the neurocentral suture,
and in the third dorsal it has risen above
this and is on the transverse process. In
the succeeding vertebrae the point of at-
tachment of the capitulum gradually moves
outwards until it becomes joined to the tuber-
cular attachment, and there is only one at- p
tachment for the rib, at the end of the
transverse process. The lumbar vertebrae
are without ribs and have long transverse L lumbar
o. 202. — Skeleton of Crocodile. C
first caudal vertebra ; D dorsal
(thoracic) region ; F flbula ; Fe
femur ; H humerus ; J ischium ;
„ i ; R radius ; Ri
ribs ; Sa sacral region ; Sc scapula;
Sta abdominal ribs ; T tibia ; U
ulna.
374
CROCODILIA.
Pmx
processes arising from the neural arch. In the sacral vertebrae the
ribs are attached to the centrum and neural arch. The anterior cau-
dal vertebrae bear ribs ankylosed to the centrum and neural arch.
Chevron bones are present, attached to the posterior part of the centra
of the caudal vertebrae, except on the first and the posterior vertebrae.
The sternum consists anteriorly of a rhomboidal plate of
cartilage to the sides of which are
articulated the sternal portions of
two thoracic ribs, and of a narrower
posterior portion, also cartilaginous,
which soon bifurcates and has at-
tached to it from five to seven pairs
of sternal ribs. A slender inter-
clavicle lies on the ventral surface
of the rhomboidal part of the ster-
num.
The thoracic ribs (Fig. 202) con-
sist of a vertebral portion of which
the distal part is feebly ossified, and
of a sternal portion also feebly ossi-
fied and joining the sternum. The
former in the case of several of the
anterior ribs carry on the hinder
side of their dorsal more ossified
portion an uncinate process in the
form of a small cartilaginous (some-
times partly ossified) plate.
The so-called " abdominal ribs "
FIG. 203.^entrai view of skuii of (Fig. 202, Sta) are membrane bones
Belodon kapffi to show the para- , , p p
suchai choanae (after zittei). placed on the ventral suriace ot
, , . .
rectus abdomims muscles.
are usually seven in number
' , . . , f
and consist on each side of
two curved rods ; they are not joined in the middle line.
In the skull the dorsal and lateral bones are roughly pitted.
There is a low cartilaginous interorbital septum with a mem-
branous interspace, and the presphenoid and orbit osphenoid
region remains cartilaginous. There is an alisphenoid, and a
separate prootic, but the epiotic fuses with the supraoccipital
and the opisthotic with the exoccipitai. The occipital condyle
Bo basioccipital ; Ch choanae ; . ,
EXO exoccipitai ; ju jugai ; MX the
maxilla ; PI palatine ; Pmx pre-
maxiiia ; Pt pterygoid ; QU quad-
rate ; Vo vomers.
SKULL.
375
is formed by the basi-occipital only, and the exoccipitals meet
above the foramen magnum. The parietals and f rentals are
unpaired in the adult. The nostrils are single, placed at the
front end of the skull and entirely surrounded by the premaxil-
laries. The nasals are long, but do not reach the anterior nares.
They usually reach the premaxillaries, but in Gavialis are separ-
ated from them by the maxillaries. The vomers are double
and by their opposed vertical plates separate the narial passages.
The premaxillae, maxillae, and palatines develop palatal plates
which unite in the middle line and form a
hard palate, and in all living crocodiles and
in extinct crocodiles from the Cretaceous
onwards, the pterygoids are modified in the
same way, so that the internal narial open-
ing is placed far back on the base of the skull
(Eusuchia of Huxley, Fig. 205). In precre-
taceous crocodiles the pterygoids do not de-
velop palatal plates and the posterior nares
are behind the palatines (Mesosuchia of
Huxley. Fig. 204). An ectopterygoid or
transpalatine connects the pterygoid with
the maxilla and jugal (Fig. 204, T).
Prefrontals, lacrymals (unperf orated), and
postf rentals are present. The orbit is sepa-
rated from the temporal fossa by the post-
orbital bar formed by processes of the post-
frontal and jugal. Both supra- temporal and
infra-temporal arcades are present, the
former constituted by the postfrontals and
squamosals, the latter by the jugal and quad-
rato-jugal. The quadrate is large, projects backwards and is
overlaid by the squamosal ; it is immoveably fixed to the skull.
The tympanic cavity is well surrounded by bone. It com-
municates with the pharynx by a complicated system of eusta-
chian canals, and gives off air-passages into the surrounding
bones. Of these, the air-passages of the quadrate communicate
by a membranous tube (siphonium) with an air space in the
os articulare of the mandible, and a passage running through the
bones of the posterior part of the roof of the skull puts the two
tympanic cavities in communication.
FIG. 204. — Ventral
view of skull of
Pdagosaurus tern-
poralis Blv., to
show the meso-
suchal choanae
(after Zittel). Bo
basioccipital ; Ch
choanae ; J jugal;
MX maxilla ; PI
palatine ; P t
pterygoid ; Q u
quadrate; T
traaspalatine (ec-
topterygoid).
376
CROCODILIA.
The eustachian passages * are surrounded by bone and open close to-
gether into the pharynx by a median opening behind the posterior nares.
From this opening (Fig. 206) there passes off three tubes, one median and
two lateral. The median tube (o) is contained in a canal between the
basioccipital and basisphenoid, where it bifurcates into an anterior branch
(q) which passes into the basisphenoid, and a posterior into the basi-
occipital (r). The anterior branch divides into a right and left canal which
open into the tympanic cavity. The posterior also bifurcates and each of
the canals so formed (s) runs to open
into the tympanic cavity by a tube
(t), which joins one of the two lateral
canals (p) which pass from the pha-
"1 ryngeal opening.
2
The columella is bony and
extends from the fenestra ovalis
to articulate with a trifid car-
tilage— the extra-columellar car-
tilage (infra- + extra- + supra-
stapedial), which is attached to
the tympanic membrane.
The lower process of this cartilage is
continuous with a partly cartilaginous,
4 partly fibrous cord which lies in a
— 20 groove or canal on the hinder surface
of the quadrate immediately behind
the siphonium, and is connected with
the os articulare of the lower jaw.
The upper cartilaginous part of this
cord is called by Huxley the styloid
cartilage. In the embryo this cord
tor "(Catiwnl^trorfrt*)4 to^oweusu^al was a continuous cartilaginous con-
choanae (after Reynolds). 1 premaxilla ; nection between the lower process
2 ( maxilla; 3 palatine ; 4 pterygoid ; 5 ... .. ,. , , ,
choanae; 6 transpalatine ; 7 posterior, (mfra-stapedial) of the extra-columel-
8 anterior palatine vacuity ; .9 basioc- ]ar cartilage and Meckel' s cartilage,
cipital ; 10 median opening of the eusta-
chian tube ; 11 jugal; 12 quadrato-jugal ; 13
quadrate; 20 lateral temporal fossa ; 21 rpVio Tnrnirl r>rmei«te nf a rartila
vascular channels leading into openings lne ny°ld COUSlStS C
ginous body and a pair of partly
ossified cornua.
The lower jaw consists of six bones, the dentary which suturally
unites with its fellow at the symphysis and bears the sockets in
which the teeth are implanted ; the splenial (operculare), the
angular, the surangular, the articular which is pneumatic, and
the coronoid. In the long-snouted forms the splenial may take
part in the symphysis.
13 9 10
FIG 205. — Ventral view of skull of analliga-
Owen, Phil. Trans., 1850; v. Beneden, Arch, de Biologic,. 3, 1882, p. 497r
SKELETON.
377
The pectoral girdle consists of a scapula with a dorsal cartila-
ginous suprascapula margin, and of a coracoid without a fenestra.
The coracoid articulates with the sternum. There is no clavicle,
but an interclavicle lies on the sternum. There are five digits
in the manus.
The carpus consists of six pieces : a radiale, an ulnare which articulates
with the pisiform and radiale, but does not reach the ulna, and a pisiform
in the proximal row ; in the distal row there is a piece of cartilage repre-
senting carpale 1 and 2, and a bone (lenticular) representing carpale 3,
4, and 5. In addition there is a small cartilaginous centrale on the distal
surface of the radiale. The three radial digits are stronger than the two
ulnar and bear claws.
FIG. 206. — Diagram
of the passages
connecting | t h e
tympanic cavities
with the pharynx
in Crocodilu? (after
Owen .from Gegen-
baur) . n valve at
the pharyngeal
opening ; o median
canal, which
divides into an
anterior q and a
posterior r ; for
s, t, p see text.
FIG. 207. — Pelvis and sacrum of an alligator
(Caiman latirostris) x£ (after Reynolds). 1
ilium ; 2 ischium ; 3 forward process of ischium ;
4 pubis ; 5 acetabular foramen : fi neural
spines of sacral vertebrae ; 7 symphysis ischii,;
8 prezygapophysis.
In the pelvis (Fig. 207) the ilia are attached to the two sacral
ribs ; the ischium is large and is joined to its fellow in a ventral
symphysis by synchondrosis. The pubis is directed forwards
and is excluded from the acetabulum by a forward process of the
ischium. The ventral end of the pubis remains cartilaginous,
and extends forwards as an epipubis. In front the two epipubes
are separate, but behind they are united by a broad and strong
ligamentous band. There are four digits in the pes, No. 5 being
absent.
It is sometimes stated that there is no pubic or ischiadic symphysis.
But though it is true that the bones do not meet and appear separate in
378
CROCODILIA.
dry specimens, it must not be forgotten that they are close together and
connected by strong cartilaginous or ligamentous bands.*
The acetabulum is perforated. It has been contended that the pubis
is represented by a small patch of cartilage between the anterior end of
the ilium and the ischium, and that the pubis should be called an epipubis.
It is doubtful if this contention can be maintained (v. Huxley op. cit.).
The tarsus consists of two large proximal bones, an astragalo-navicular
and a calcaneum, of which the calcaneum. has a strong heel-process (Fig.
202) ; and of two small distal bones. The fifth digit is represented by an
imperfect metatarsal attached to the
fused tarsalia 4 and 5. The three pre-
axial digits are clawed.
The skin is horny on the scales
but soft between. Each scale pos-
sesses a small pit in which the epi-
dermis is not cornined ; at the
bottom of these pits are a number
of tactile bodies in the cutis.
There are two pairs of musk
secreting glands, one pair which
can be everted on the throat, and
another pair within the lips of the
cloaca.
In the brain f the cerebellum is
rather more developed than in
other reptiles and possesses a me-
dian vermis and two small lateral
lobes (Fig. 208). The eye J is
provided with a small (abortive)
pecten. Lacrymal and harderian
glands are present.
Alimentary canal. The teeth are
in a single row on the premaxil-
lae, maxillae and dentaries. They
are lodged in sockets (thecodont) and
are hollow, conical structures with-
out roots. They are shed at intervals and replaced by new teeth
formed behind them and projecting as they grow into the pulp
cavities of their predecessors. The fourth mandibular tooth is
* Huxley, Proc. Roy. Soc., 28, 1879, p. 395.
t Rabl-Ruckhard, Z. /. w. Z., 30, 1878, p. 337.
j D. W. Soemmerring, De oculorum section-horizontal, Gottingen,
1818, p. 59.
FIG. 208.— Brain of Alligator, dor-
i .sal view (after Rabl Riickhard,
Pfrom Claus). Cb cerebellum; Mh
Coptic lobes; Mo medulla oblongata;
Vh cerebrum ; roman numerals are
\^ cranial nerves ; 1C, 2C first two
^ spinal nerves.
VASCULAR SYSTEM. 379
generally larger than the others. The tongue is flat and not
protrusible. Salivary glands are absent. There is a transverse
fold of the mucous membrane of the palate just in front of
the choanae, which can shut off the mouth from the pharynx.
The stomach is a gizzard-like sac, with muscular walls and
tendinous discs. The pylorus is near the oesophageal opening.
There is a gall bladder, but no caecum.
The cloaca is divided into two parts by a muscular fold. Into
the anterior chamber open the urinary and generative ducts by
separate and paired openings. There is no bladder. On the
ventral side of the posterior chamber of the cloaca is a grooved
penis * very similar to that of the Chelonia (p. 410). Peritoneal
canals are present in both sexes and open on either side into the
cloaca at the base of this organ.
The testes are oval, the kidneys lobed, and the ovaries elon-
gated.
The trachea is long and provided with complete rings. There
is a larynx with vocal chords. The epiglottis is absent, and the
larynx has an annular cartilage corresponding to the cricoid and
thyroid of higher forms, and arytenoid cartilages. The lungs
hang freely in the body cavity and are well developed and spongy.
The bronchus enters at about the middle of the organ and is
continued to its hind end ; it soon loses its rings, and is beset
with openings which lead into pouches, the walls of which are
honeycombed.
The lungs lie in the anterior horns of the body-cavity. These
are partitioned off from the rest by a septum t which is partly
muscular and partly membranous and has peculiar relations to
the liver and stomach. It is analogous but not homologous to
the mammalian diaphragm and is said to assist in the inspira-
tory movements.
Vascular system. The sinus venosus is closely applied to
the heart and receives the three great systemic veins. The
ventricle is double. The right aortic arch proceeds from the left
ventricle and gives off the arteries to the head and anterior
limbs. These are an innominate and a right subclavian ; the
innominate divides into left subclavian and carotis primaria
which divides into the two common carotids. The left aortic
* Boas, Gadow op. cit.
t G. W. Butler, P.Z.S., 1889, p. 452.
380
CROCODILIA.
arch arises in the right ventricle and after giving off a large
visceral artery is connected by a narrow vessel with the right
arch (Fig. 209). The pulmonary artery also arises from the right
ventricle. Each of these three great arteries is guarded at its
ventricular end by two semi-lunar valves. At the point
where the two systemic arches cross one another there is an
aperture (foramen Panizzae}
putting them in communica-
tion, so that the arterial and
venous blood are not com-
pletely separated. The Croco-
dilia are the only Vertebrata
with two separate ventricles,
and both right and left aortic
arches.
Crocodiles are fierce rapa-
cious animals and live for the
most part in fresh water ; the
gavials being more exclusively
aquatic than the crocodiles and
caimans. They inhabit the
mouths and lagoons of great
rivers in the warmer parts of
the Old and New Worlds, and
seek their prey by night. Some
are dangerous to man. They
all have a voice which is des-
cribed as a " short bark."
They appear to grow through-
out life which is a long one.
The eggs are hard-shelled and
are laid in the sand or in holes
on the banks.
The oldest Crocodilia which appear in the Upper Trias, belong
to the Parasuchia and Pseudisuchia. Though undoubtedly
Crocodilia, they present some features which are characteristic
of the Dinosauria and Rhynchocephalia. The Eusuchia do not
appear till .the Upper Lias, and the earliest of these possess
biconcave vertebrae, and choaiiae in front of the pterygoids.
The earliest crocodiles appear to have been marine, and it is not
-JC
FIG. 209.— Heart and arterial arches of
Alligator Indus (from Claus). The right
auricle and right ventricle are opened and
the arteries springing from the right ven-
tricle. Ad right, As left aorta ; Ba dilata-
tion on right aorta ; C carotis primaria ;
D right auricle ; FP position of foramen
Panizzae ; M visceral arteries ; 0 opening
of sinus venosus into right auricle ; Ov
opening of right auricle into right ven-
tricle ; P pulmonary artery ; PC band con-
necting to pericardial wall : S left auricle ;
Sd right, Ss left subclavian ; V narrow
continuation of left aortic arch after giving
off the coeliac artery.
EXTINCT CROCODILIA. 381
till after the Jurassic period that the majority are found in
association with fresh-water and land forms. The living forms
are inhabitants of fresh water, a few species extending into
estuaries.
Huxley in his classical memoir on the " Crocodilia of the Elgin Sand-
stones" (loc. tit.) divided the Crocodilia into three groups which form a
series in respect of certain osteological characters, viz. the structure of the
palate, the condition of the eustachian passages, the form of the vertebrae,
and one or two other points. These groups he named ( 1 ) the Parasuchia
in which the palatines and pterygoids have no palatal plates (Fig. 203),
the eustachian passages are unenclosed by bone and the vertebrae are
amphicoelous ; (2) the Mesosuchia with amphicoelous vertebrae, eusta-
chian passages partly enclosed in bone, and palatal plates to the palatines
but not to the pterygoids (Fig. 204) ; (3) the Eusuchia with procoelous
vertebrae, eustachian passages completely embedded in bone, and palatal
plates to both pterygoids and palatines (Fig. 205). He also showed that
these groups succeed one another in time in a manner which is consistent
with regarding them as having being derived successively from one another,
i.e. the Mesosuchia from the Parasuchia, and the Eusuchia from the Meso-
suchia. In short he showed that the Parasuchia appear in and are con-
fined to the Trias, the Mesosuchia appear in the Upper Lias and are con-
tinued to the Wealden, while the Eusuchia extend from the Later Cre-
taceous to the present time. To use Huxley's words : " The order of
occurrence of the three divisions of the Crocodilia in time coincides with the
order in which they depart from the lacertilian type and put on special
crocodilian characters ; and this palaeontological fact is in precise accord-
ance with the needs of the theory of evolution."
In the following systematic treatment of the group, this division of
Huxley has been partly followed, but the Mesosuchia, which more closely
resemble the Eusuchia than they do the Parasuchia, have been united with
the Eusuchia, and a new group the Pseudosuchia has been established for
certain imperfectly known forms discovered since the date of Huxley's
memoir.
Order 1. PARASUCHIA.*
Extinct Crocodilia of considerable size, confined to the Triassic forma-
tion (Keuper), Europe, Asia, and N. America. With two longitudinal
rows of dorsal scutes, and more numerous rows of ventral scutes (composed
of one piece only), biconcave vertebrae, long premaxillae, external nostrils
placed far back near the upward directed orbits, internal nares at the
front end of the palatines ( Fig. 203). The palatines and pterygoids do not
meet in the middle line, and the eustachian passages are not enclosed by
bone. A postorbital behind the orbit. Parietals and frontals paired.
Acetabulum formed of ilium, ischium and pubis. A clavicle is present.
In the separate, posteriorly placed nostrils, in the large preorbital fossae,
in the form of the pterygoids and basiphenoid they resemble the Dino-
saurs. In some other characters (e.g. the separate postorbitals, the
paired parietals and frontals, the palate, the well developed ventral ribs,
and the clavicle) they approach the Rhynchocephalia. Belodon v. Meyer,
Stagonolepis Ag., Parasuchus, Huxl.
* Huxley, Quart. J. Geol. Soc., 1859, 15, p. 440, and 1875, 31, p. 423.
382 CROCODILIA.
Order 2. PSEUDOSUCHTA.*
Extinct Triassic (Keuper) Crocodilia found in Germany, Scotland, and
Xew Mexico. With short premaxillae, anterior and laterally-placed
nostrils, large orbits, teeth in anterior part of jaw only, two rows of bony
plates on the back. Aetosaurus Fraas, Or nithosuchus Newton, and Erpeto-
saurus Newton from the Elgin Sandstone, Typothorax Cope, New Mexico.
Order 3. EUSUCHIA.
(Mesdsuchia and Eusuchia of Huxley, Crocodiles proper.)
With biconcave (in extinct forms) or procoelous vertebrae, short pre-
maxillaries enclosing the nostril which is single and placed at the end of the
snout ; internal nares placed far back behind the palatines (Fig. 204), in
recent forms in the hinder part of the pterygoids (Fig. 205). In the pre-
cretaceous forms and in some of the cretaceous, the median eustachian
canal is enclosed in bone, but the lateral canals are represented only by
grooves ; parietals unpaired, clavicles absent, pubis not entering into the
acetabulum. Anterior feet with five, posterior with four toes and traces
of a fifth. When the snout is long, its elongation is due to the maxillaries.
They are known since Lower Jurassic times. The living forms which
with the exception of one species of Alligator found in China are inter-
tropical, are grouped in two families and six genera.
Fam. 1. Teleosauridae. Snout long and slender, vertebrae biconcave,
internal nares at the hinder end of the palatines, anterior limbs half the
length of the posterior, nasals separated by a wide interval from the small
premaxillaries, a small preorbital foramen, prefrontal small, lacrymal
large. Two rows of large dorsal and several rows of smaller ventral bony
plates. Lias and Oolite of Europe, marine. Mystriosaurus Kaup., Pela-
gosaurus Brown, Steneosaurus Geoffrey, Teleosaurus Geoff.
Fam. 2. Metriorhynchidae. Vertebrae biconcave, snout fairly long,
nasals broad, internal nares at hind end of palatine, prefrontals large,
lacrymal small, eyes with bony ring in sclerotic, skin without bony plates,
Upper Jurassic, marine. Metriorhynchus v. Meyer, Geosaurus Cuv. etc.
Fam. 3. Maerorhynehidae. Vertebrae biconcave, snout long and
slender, nasals narrow and long, internal nares at the hind end of the pala-
tine, dermal armour of dorsal and ventral plates, in the fresh-water de-
posits of the Purbeck, Wealden and Greensand of Europe. Macroryhnchus
Dunker, Petrosuchus Owen.
Fam. 4. Atoposauridae. Body small, lizard-like ; snout short, rounded ;
vertebrae biconcave ; without ventral dermal armour ; Upper Oolite of
France ; marine. Atoposaurus v. Meyer, Alligatorium Jour dan, Alli-
gatorellus Jourd.
Fam. 5. Goniopholidae. Vertebrae biconcave ; snout moderately
elongated ; choanae far back between the palatines and pterygoids ;
with dorsal bony plates. Fossil in Purbeck, Wealden of Europe and
Upper Jurassic of N. Amer. Goniopholis Owen, Nannosuchus Ow., Therio-
suchus Ow., Bernissartia Dollo.
Fam. 6. Gavialidae. Vertebrae procoelous, teeth subequal, snout long
and slender, nasals widely separate from nasal aperture, internal nares
* Fraas, "Aetosaurus ferratus," Wurttemb. naturw. Jahreshefte, 23,
1867. Newton E. T. Phil Trans., 185, 1894.
EUSUCHIA. DINOSAURIA. 383
within the pterygoids ; maxillae, palatines, and pterygoids with palatal
plates. Littoral and marine deposits of the Upper Cretaceous of Europe
and North America to present clay. Thoracosaurus Leidy, Upper Ore-
on_9~l
taceous of N. Amer. and France ; Tomistoma Miiller, -^-^ teeth on each
side ; nasals in contact with premaxillaries, separate from nasal aperture ;
living in Borneo, fossil in Tertiaries of Europe. Gavialis Oppel, 2_~"
teeth on each side ; nasals separated from premaxillaries and from nasal
aperture ; without ventral bony scutes ; living in India and Burma, fossil
in the Pliocene of the Sivalik Hills ; G. gangeticus Gray, N. India, Bom-
bay, Aracan ; harmless, and living on fish, to 20 feet. Rhamphosuchus
from the Pliocene of the Sivalik Hills, to 50 feet.
Fam. 7. Crocodilidae. Vertebrae procoelous, nares anterior, nasals
almost always reaching nasal aperture ; choanae far back surrounded by
the pterygoids ; maxillaries, palatines, and pterygoids with palatal plates ;
orbit communicating with the infra-temporal fossa ; ribs with uncinate
processes ; clavicles absent ; pubis excluded from the acetabulum ;
5 fingers, 4 toes ; dorsal armour ; pupil vertical. From the Upper Cre-
taceous to the present day, found in Europe until the Pleistocene. Diplo-
cynodon Pomel, extinct, Oligocene and Miocene of Europe ; Bottosaurus
Ag., Upper Cretaceous of North America. Crocodilus, Laur.,
head long, teeth unequal, fourth mandibular tooth usually fitting into a
notch in the upper jaws, -* - teeth on each side, without bony nasal
l-±— 15
septum, without ventral armour ; Afr., S. Asia, N. Australia, trop.
Amer., from the Upper Cretaceous to the Pleistocene in Eur. Osteolaemus
Cope, fourth mandibular tooth as in the last, nasal bones dividing the nasal
aperture, ventral scutes bony, W. Afr. one species. Alligator Cuv., head
short and broad ; teeth very unequal, fourth mandibular tooth fits into
a pit of the upper jaw ; jsris teeth on each side ; nasal bones dividing
nasal aperture ; dorsal bony scutes not articulated together, ventral scutes
without or with thin ossifications ; two living species, one in China, and
the other in N. Amer. ; from fluviatile deposits of Upper Cretaceous to
Pliocene in Eur. Caiman Spix (Jacare Gray), head, teeth, and fourth
mandibular tooth, as in the last, -.g^Hn teeth on each side, without bony
nasal septum, with dorsal and ventral armour of articulated bony scutes,
5 species, Central and South Amer.
Sub-class 4. DINOSAURIA.*
Long-tailed reptiles usually of considerable, often of gigantic size, with a
superior and inferior temporal arcade, a fixed quadrate, and thecodont den-
tition ; without pineal foramen. The limbs are adapted for the habitual
support of the body, the ilium is extended antero-posteriorly, and the pelvis
and hind limbs are generally bird-like in structure. The ribs are two-headed.
The Dinosauria make their appearance in the Trias and persist until the
Cretaceous. Their remains have been found in Europe, Asia, S. Africa,
Madagascar, N. and S. America, and in Australia. It has been suggested
that they were amphibious. This suggestion is based on the large size of
* Also called the Ornithoscelida.
384
DIXOSAURIA.
the tail which might conceivably have served as a swimming organ. How-
ever this may be the great number of them which have been found as
fossils seems to indicate that they lived in swamps or in the neighbourhood
of water, that is to say in places where their bodies would after death bo
rapidly covered by sediment. They have left their footprints in the
sandstone (Triassic) of the Connecticut valley, and other parts of N.
America. By their skull and one or two other features the Dinosauria pre-
sent resemblances to Crocodilia and Rhynchocephalia, but in many of them
the shoulder girdle, pelvis and hind limb are strongly avine in character.
Order 1. THEBOPODA.
^-TjDigitigrade carnivorous Dinosaurs with cutting teeth, and small sk\ill
set at a right angle with the neck. The cranium is incompletely ossified
Flo. 210.— Anchisaurus colurus, skull, A from the side, B from above, C from behind (from
Woodward, after Marsh), x \. Trias, Connecticut, a external nostril ; b preorbital vacuity ;
bp basipterygoid vacuity ; c'lateral temporal fossa, d supratemporal fossa ; / frontal ; j jugal ;
n nasal ; o orbit ; oc occiptal condyle ; p parietal ; p' paroccipital process ; pj prefrontal
pm premaxilla ; q quadrate.
and there is a large preorbital vacuity (Fig. 210). The vertebrae are some-
times and the limb bones are always hollow. The fore-limbs are smaller
than the hind-limbs and the progression was probaby mainly bipedal.
Both pubis and ischium meet in a ventral symphysis and there is no post-
pubic process. The digits are from three to five and have prehensile
claws. The astragalus sends up a process which is firmly fixed to the front
side of the tibia. They vary much in size. Compsognathus the smallest
Dinosaur was no larger than a cat, while Megalosaurus attained the
dimensions of an elephant
They extend from the Trias to the Cretaceous. They are the earliest
Dinosaurs as yet known and are usually regarded as being the most
generalised of the group.
DIXOSAURIA. 385
Anchisaurus Marsh (Fig. 210), small forms with bird-like skull, Trias,
Connecticut; and other allied genera from the U.S. Zanclodon Plien.,
Keuper, Wiirtemburg, and several allied genera from France, England,
India and S. Africa. Ceratosaurus Marsh, 17 feet, skull larger than usual,
nasal bones with a median projection, which may have supported a horn,
U. Jura, Colorado, and other genera. Megalosaurus Buckland, the largest
Theropod, Lias to Wealden, Europe and N. America. Allosaurus Marsh.
Compsognathus Wagner, vertebrae and limb bones hollow ; the cervical
vertebrae are elongated ; the skull is bird-like ; tail long ; small anterior,
long posterior limbs ; manus and pes with 3 functional digits, digits 1 and 5
reduced ; femur shorter than tibia ; pelvis not avine, with pubic and
ischiadic symphysis ; pubis directed forwards ; hind-limb very avine ;
astragalus with ascending process ; one specimen only known, from the
Solenhofen slates. Hallopus Marsh, very similar to preceding, manus with
4 digits, pes with 3, calcaneum with a heel process, astragalus without
ascending process, U. Jura, Colorado. Coelurus Marsh, skull unknown,
all bones hollow, U. Jura, England and N. America.
Order 2. SAUROPODA.
Herbivorous, quadrupedal, plantigrade Dinosaurs with five hoofed
FIG. 211. — Brontosaurus excelsus x Tis (from Woodward, after Marsh).
digits on each limb. The teeth are spatulate with anterior and posterior
cutting edges. The cranium is completely ossified and there is a large
preorbital vacuity. The anterior vertebrae are much hollowed out
laterally. Limbs nearly equal in size. The neural canal in the sacrum is
expanded to two or three times the size of the brain cavity. The bones
of the pelvis are distinct and the acetabulum is perforated. The pubes
project ventral wards and meet in a cartilaginous symphysis ; there is no
postpubis ; the femur is without a prominent inner (fourth) trochanter ;
distal row of carpals and tarsals unossified ; astragalus without ascending
process. Some of them are of enormous size, and they are remarkable
for the relatively minute size of the skull ; Ailantosaurus estimated to
have attained a length of 115 feet. The skull is in most of them imper-
fectly known. Their remains are known from the Jurassic and Cretaceous.
Cetiosaurus Owen, skull unknown, M. Jura, England. Atlantosaurus
Marsh, probably the largest land animal known, to 115 feet, U. Jura,
Wyoming, Colorado. Morosaurus Marsh, U. Jura, Wyoming. Bronto-
saurus Marsh (Fig. 211), to 60 feet, very small skull and minute cranial
cavity, U. Jura, Wyoming, Colorado. Diplodocus Marsh, teeth slender
and cylindrical, continued to the anterior end of the jaws ; the external
narial opening is single and is placed at the apex of the skull, the nasals
z.— II. c c
386 DIXOSAURI A.
being extremely shortened as in Cetaceans ; cervical vertebrae elongated,
15 in number ; 11 dorsals, 4 sacrals and 37 or more caudals ; the neck
and tail constitute the greater part of the animal, the head is very small ;
chevron bones double, each half with anterior and posterior prolongation ;
the curious position of the external nares may suggest aquatic habits,
U. Jura, Wyoming and Colorado.
Order 3. PREDENTATA.*
^ Large herbivorous quadripedal or bipedal Dinosaurs, with an edentu-
lous predentary bone at the front end of the mandible, and a fully ossified
brain case. The premaxillae are edentulous. The teeth are laterally
compressed with serrated anterior and posterior cutting edges and are
FIG. 212. — Iguanodon bernissartensis; restoration of skeleton by Marsh xJgV Wealden,
Bernissart (from Woodward).
borne by the maxillae and dentaries. The pubis is slender, directed ven-
trally, but does not form a symphysis ; there is a slender postpubis
directed backwards parallel with the ischium which is also slender and
meets its fellow in a ventral symphysis. The limb bones are solid or
hollow. The manus has four or five digits, the pes three or four ; the
femur has a prominent distal inner (fourth) trochanter, and the astragalus
is without an ascending process ; dermal armour is present or absent.
Jurassic and Cretaceous.
Tribe 1. ORNITHOPODA. Unarmoured, bipedal, digitigrade forms, with
hollow limb bones. U. Jura and Cretaceous. Iguanodon Mantell (Fig.
212), so called from the resemblance of its teeth to those of Iguana, from
the Wealden of England, Belgium and Germany, several complete skele-
tons of /. bernissartensis about 30 ft. in length have been discovered in the
colliery of Bernissart in Belgium about 1,000 feet below the surface. The
* Also called Orthopoda.
DIXOSAURIA.
387
skull is laterally compressed, has a small orbit, and small preorbital
vacuities ; the premaxillae have a cutting edge and are edentulous ; the
maxillae and mandible bear the teeth which are often worn down to a
grinding surface ; the jugal is a crescentic bone below the orbit, and the
quadrate is elongated. There are about 80 vertebrae (10 cervical, 18
dorso-lumbar, 4-6 sacral and 40-50 caudal) ; all bear ribs except the atlas,
two or three lumbar, and the posterior caudal ; the neural spines of the
back and tail are very strong and frequently show traces of ossified ten-
dons. The caudals have chevrons. The scapula is long, the coracoid
small and there is a pair of sternal bones. Manus with 5 digits of which,
the pollex is a spur-like process ; digits 2 and 3 are tipped with hoof-like
nails. The ilia are greatly extended antero-posteriorly : there is an ischi-
adic symphysis, and a slender postpubic process. The femur has a
prominent inner (4th) trochanter and the pes has 3 digits with claw-shaped
terminal phalanges. Hypsilophodon Huxley, complete skeleton from the
FIG. 213. — Skeleton of Stegosaurus ungulatus (after Marsh, from Woodward) ; U. Jura,
Colorado, x SV
Isle of Wight. Laosaurus Marsh, U. Jura, Colorado ; Claosaurus Marsh,
U. Cretaceous, Wyoming ; Trachodon Leidy, U. Cretaceous, U.S.A.
Tribe 2. Stegosauria. Armoured, quadrupedal plantigrade forms,
with solid bones and small skull. Lias to U. Cretaceous. Stegosaurus
Marsh (Fig. 213), head small ; brain minute, smaller than the large sacral
swelling of the spinal cord ; teeth numerous and small ; cervical vertebrae
with ribs, neural spines expanded to support the dermal armour ; sacrum
of 4 fused vertebrae ; anterior caudal vertebrae very large ; fore-limb short,
powerful, ulna with large olecranon process ; ilium extends far forward ;
astragalus and calcaneum united with the tibia and fibula whch are short ;
dermal armour of large triangular plates along the back and indications
of small rounded ossicles on the throat, to 28 feet, U. Jura of Colorado
and Wyoming. Scelidosaurus Owen, L. Lias, England.
Tribe 3. Ceratopsia. Gigantic probably herbivorous, quadrupedal
reptiles with a large skull, which carries a pair of horn-like processes in the
frontal region just above the orbit and an unpaired process in the nasal
388 DINOSAURIA. PTEROSAURIA.
region. The parietals and squamosals project back over the neck as a
shelf -like crest, the edge of which carries projections. There is a toothless
rostral bone in front of the premaxilia, and a predentary, also edentulous,
on the mandible. Small supra-temporal fossae are present, but no lateral -
temporal. All the bones are solid. The teeth with forked roots and
crushing crowns are borne by the maxilla and dentary. The fore -limbs are
a little shorter than the posterior and have five hoofed digits. The sacrum
is reinforced by adjacent lumbar and caudal vertebrae, and the ilium is
extended antero -posteriorly. The pubis is directed forwards and meets
its fellow ; there is no postpubis. The astragalus is fused with the tibia.
There are three hoofed toes. A dermal armour appears to have been pre-
sent. They are known from the Cretaceous of Europe (fragments) and
N. America. Triceratops Marsh (Fig. 214), skull 7 feet long, larger than
in any other known land animal ; body 20 feet. Upper Cretaceous of
Wyoming ; Rterrholophus Marsh.
FIG. 214.— Triceratops prorsus x ^ (after Marsh).
Sub-class 5. PTEROSAURIA.
With a superior and inferior temporal arcade, a fixed quadrate, and the-
codont dentition ; without pineal foramen. The fore-limbs are adapted for
flight and the bones are hollow.
The Pterosauria, or Pterodactyls, as they are sometimes called, were
flying reptiles the remains of which are found in the Mesozoic rocks from
the Lower Lias to the Cretaceous. In their external appearance and habit
of life they present great resemblances to birds, but in the absence of
feathers and the structure of the skeleton they differ considerably from
these animals. They possess an elongated head which is set on the neck
at a right angle, a long neck composed of elongated vertebrae, a very
large anterior limb, the ulnar digit of which is enormously elongated to
form the support of a patagial expansion of the integument (Figs. 215,
216), and a keeled sternum. Moreover the bones are hollow, and casts
of the skull which have been obtained in one or two cases show that
the brain possessed a large cerebellum extending forwards to the well-
developed cerebral hemispheres and pushing apart the large optic lobes.
There is evidence also of flocculi on the cerebullum.
The vertebral column is divided into cervical, dorsal, sacral and caudal
regions, with about seven, fifteen, three to five and ten to forty vertebrae
respectively. The precaudal vertebrae are procoelous the caudal amphi-
coelous. The cervical and anterior dorsal ribs are two-headed. The
PTEROSAURIA.
389
sternum has a keel and there is no clavicle. The skull is rounded and
bird-like. The occipital condyle is single and on the base of the skull.
Tha cranial bones ankylose early as in birds, the orbits are large and with
FIG. 215. — Dimorphodon macronyx restoration x |, L. Lias (after Owen, from Woodward)
a antorbital fossa ; n external nares ; o orbit.
sclerotic plates, and there is a wide antorbital fossa as in Aves and Dino-
sauria. There is a postf rental, and both upper and lower temporal arcades
are present. Teeth are frequently present (on the margins of the jaws only),
390
PTEROSAURIA.
but some genera are without them, in which case the jaws may have
possessed horny beaks. The quadrates slope forward. The pterygoids
enclose an interpterygoid vacuity and extend forwards to the vomers
between the palatines.
The shoulder girdle is avine, and in some of the larger forms the scapula
is attached to some of the dorsal vertebrae. The hand has four separate
metacarpals and four digits (probably 1-4) of which the first three are
clawed, the last enormously elongated and without a claw. The phalangeal
formula is 2. 3. 4. 4. A splint-like bone is sometimes attached to the
radial side of the carpus.
The pelvis is small and not at all avine. The ilia are expanded antero-
posteriorly, and the ventral part consists of broad ischia meeting in a
ventral symphysis and pierced by a small foramen. The pubis is
separate and excluded from the acetabulum (as in crocodiles). The fibula
is small and splint-like. There are two proximal and two distal tarsals,
of which the proximal are sometimes fused with the tibia. The pes pos-
sesses five separate toes, of which four bear claws. The fifth digit is often
shorter than the rest and is sometimes divaricated from them as
FIG. 216. — RhampJtorhynchus phyllvrus restored by Marsh x }. U. Jura (from Woodward).
though it assisted in the support of the patagium. There was no dermal
armour, but abdominal ribs were present.
From this account it is clear that the Pterosauria resemble birds in the
structure of the shoulder girdle, in certain features of the skull, but they
differ from them completely in the structure of the organ of flight and of
the limbs, in the presence of postfrontal bones, and of both temporal
arcades in the skull, and in the structure of the vertebral column and
pelvis.
They make their appearance in the Lower Lias, and the earliest known
genus Dimorphodon (Fig. 215) presents all the features of specialisation of
the group.
Dimorphodon Owen (Fig. 215) with teeth and long tail, Lower Lias,
England. Rhamphorhynchus v. Meyr (Fig. 216) with teeth and long tail,
U. Jura (Lithographic Slate). Pterodactylus Cuvier, with teeth, tail
short, Lithographic Slate. Pteranodon Marsh, contains the largest form
(skull to 2 feet, wing spread to 20 feet), without teeth, tail short, Creta-
ceous, U. S. Ornithochirus Seeley, similar to last but with teeth, Cam-
bridge Greensand.
ICHTHYOSAURIA.
391
Sub -class 6. ICHTHYOSAURIA.
Very peculiar large extinct fish-like marine reptiles with biconcave verte-
brae, four paddle-shaped limbs with very short long-bones ; a, large number
of phalanges and often more digits than five, with pineal foramen, pterygoids
reaching forward to the vomers, and fixed quadrate^ Trias to Cretaceous.
The Ichthyosauria were large fish-like reptiles, which inhabited the
seas of a considerable part of the earth during the secondary period.
Their remains are found in Europe, Africa, America, Australia, New
Zealand, and India. Some of the larger kinds appear to have reached
a length of from 30 to 40 feet. They are distinguished externally by the
large size of the head and of the eyes (Fig. 217), by the absence of a neck,
by the two pairs of flipper-like appendages, by the dorsal median fins,
and by the vertical caudal fin, into the lower lobe of which the vertebral
FIG. 217. — Ichthyosaurus quadristissus. A Fossilised skeleton. B Outline restoration show-
ing outline of integument with dorsal and caudal fins. L. Jurassic (U. Lias),A\Yurtemburg
(after E. Fraas, from Woodward).
column is prolonged. The size and form of the head, the absence of the
neck and the form of the anterior limb give them a certain superficial
resemblance to whales. They have indeed been spoken of as the whales
of the Mesozoic seas. That they are true reptiles must be considered
certain ; but they stand far apart from other reptiles and cannot be said
to show resemblances to one sub-class more than to another. By the
presence of a pineal foramen in the roof of the skull and the form of the
pectoral girdle they resemble the lizard group ; by the anterior extension
of the pterygoid to the vomers, the Rhynchocephalia ; and by the form
of the temporal arcade they recall the Anomodontia and Chelonia.
In the zoological language of the day this isolation in structure with regard
to other reptiles is expressed by saying that their descent is unknown ;
but in this they do not differ from other reptilian groups, of none of which
392
ICHTHYOSAURIA.
FIG. 218. — Diagrams illustrating the principal characters of Ichthyosaurus (from S.
ward). A side, B dorsal, C ventral, D posterior view of the skull of Ichthyosaurus
Wood
. , , , Ichthyosaurus longi-
jrons, L. Jurassic (U. Lias), ag angular ; art articular ; b.occ basioccipital ; b.s basisphenoid ;
d dentary ; ex.occ exoccipital ; f.m. foramen magnum ; fr frontal ; i.pt interpterygoid
vacuity ; / jugal ; la lacrymal ; mx maxilla ; na nasal ; nar external nares ; occ.c occipital
condyle ; op.o opisthotic ; pa parietal ; pas parasphenoid ; pin pineal (parietal) foramen ;
pi palatine ; pmx premaxilla ; prf prefrontal ; pt pterygoid ; pt f postfrontal ; pt.nar posterior
nares : pto postorbital ; qj quadratojugul ; qu quadrate ; s.ag surangular ; scl. sclerotic plates ;
s.occ supraoccipital ; spl splenial ; sq squamosal ; s.t supratemporal (prosquamosal) ; s,t.f
UNIVERSITY
or
C*
393
supratemporal vacuity ; x space for ectopterygoid (?);?; vomer. Restored from specimen
in British Museum.
E Upper tooth of Ichthyosaurus communis showing enamelled crown and fluted base,
xi (L. Lias).
F transverse section of base of tooth.
G atlas and axis of Ichthyosaurus lon^ifrons, U. Lias. 6. occ occipital condyle of skull ;
ef centrurr of atlas ; c* centrum of axis ; n' paired neural arch of atlas ; »2 single neural arch
of axis ; r ribs ; w subvertebral wedge-bones (hypocentra) (after Owen).
H dorsal vertebra and ribs of Ichthyosaurus, anterior aspect, L. Lias, abd abdominal
rib ; r rib (after Owen).
/, «/, K vertebra from base of tail and two caudals of Ichthyosaurus, anterior aspect, eh.
chevron bone ; r rib (after Owen).
L section of caudal vertebra of Ichthyosaurus.
M ventral view of pectoral girdle of Ichthyosaurus (restored from specimen in Brit. Mus.).
ac glenoid cavity ; cl clavicle ; co coracoid ; i.cl interclavicle ; sc scapula ; x edges originally
bordered by cartilage.
N. Outer aspect of left pelvic arch of Ichthyosaurus communis (from specimen in Brit.
Mus.). il ilium ; is iscl ium ; pb pubis.
can it be said that the descent is even approximately known. The pro-
gress of palaeontological research has made known to us the immense
variety which has characterised the organisation of reptiles, but it is at
the same time rendering more difficult the elucidation of pedigrees. For
the greater the variety in organisation that is revealed to us, the more
involved become the interrelationships between the different groups.
The skull (Fig. 218 A-D) has a long rostrum which consists almost eji-
tirely of the premaxillae. The maxillae are small and the anterior nares
are placed far back just in front of the large orbits. The teeth which are
conical and crocodilian are placed in a continuous groove (rarely in
separate pits) on the premaxillae, maxillae and mandibles. They some-
times show a folding of the enamel as in Labyrinthodonts. The eye has
a circle of bony sclerotic plates and the orbit is closed behind by the post-
frontal, postorbital, and jugal. There is a single broad temporal arcade
which consists of squamosal, supratemporal (prosquamosal) and quadrato-
jugal, and corresponds to the superior and inferior temporal arcades of
Rhynchocephalia etc., the lateral temporal fossa being closed. There is
a supratemporal fossa bounded by the parietal, squamosal and post-
frontal. The nasals are large, the parietals and frontals are small and
paired ; there is a large pineal foramen between the parietals and frontals.
All the occipital bones are present and separate, as are the opisthotic
and prootic. The single occipital condyle is formed by the basioccipital
alone. There is a basisphenoid, but alisphenoids, presphenoid and orbito-
sphenoids are absent. There is said to be an epipterygoid reaching from
the pterygoid to the prefrontal. A median splint extends forwards from
the basisphenoid in the vacuity between the pterygoids ; this may be
called the parasphenoid or basisphenoidal rostrum. The pterygoids are
large and widely separate except in front where they touch ; behind they
join the basisphenoid and quadrate, and extend anteriorly between the
palatines to the vomers. The internal nares are between the vomers on
the inside and the maxillae and palatines on the outside. The quadrate
is fixed. The mandible is long and narrow and without a coronoid pro-
cess. The hyoid appears to be represented by a pair of stout, rib-like
bones beneath the pterygoids.
The vertebrae (Fig. 218 G-L) are very numerous, 150 or more in number,
of which 100 are caudal. They are divisible into caudal and precaudal
only. The centra are amphicoelous and very short anteroposteriorly.
The neural arches are separate from the centrum and the zygapophyses
are feeble and sometimes even absent. The centra possess on each side
two short lateral processes, to which the double headed ribs are attached.
394
ICHTHYOSAURIA.
The atlas and axis vertebrae (G) are usually fused together and possess
three wedgelike hypocentra, one in front of the atlas, the next between
the atlas and axis, and the third behind the axis. Chevron bones are
found on the caudal vertebrae but their halves generally remain separate.
The hind end of the vertebral column is bent ventralwards into the ventral
lobe of the caudal fin. Abdominal ribs are present consisting of a median
piece and two or three lateral pieces on each side (Fig. 218 H). There is
no bony sternum. The shoulder girdle is lizard-like and very strong ;
it is shown in Fig. 218 M. The pelvic girdle is feeble (Fig. 218 N) ; all the
bones join in the a-cetabulum, but the ilia are not attached to the vertebral
column and it is doubtful if there was a pubic or ischiadic symphysis.
The skeleton of the limbs is highly peculiar (Fig. 219). The long bones
(humerus. femur, radius, ulna, tibia, fibula, metacarpals) are all much
shortened, sometimes broader than
long. Moreover the phalanges are
very numerous and the digits some-
times appear to be more than five
(to eight or nine). This is caused
partly by bifurcation of some of the
digits and partly by the presence
of an additional row of phalanges
on the preaxial and postaxial side
of the manus and pes(m.r,m.u,m.tb).
The carpalia of the distal row are
three or five, and the number of
digits is said to vary from three to
five, but this is not allowing for
the extra rows of phalanges above
referred to. It is important to
notice that the relatively large size
of the manus and pes (as compared
with the rest of the limb) is obtained
not by an increase in length of the
phalanges but by an increase in
their number. This is a peculiarity
of the Ichthyosauria which is met
with to a very small extent if at all
in other reptiles or in mammals.
The apparent increase in the num-
ber of the digits as indicated by the
number of rows of phalanges is a most remarkable feature met Math in no
other pentadactyle form. Whether it is to be regarded as a polydactyle
condition such as must have existed in forms connecting the piscine with
the pentadactyle type is uncertain ; no remains of animals with such inter-
mediate types of limbs being known to us. The skin appears to have
been leathery and without scales or dermal plates.
' That the Ichthyosauria were viviparous appears to be indicated by
the fact that specimens of them are found containing the remains of fair
sized young individuals in what must have been the abdominal cavity.
Their coprolites are known and they contain scales and bones of fishes and
fragments of Cephalopoda. The coprolites also show indications of having
passed through an intestine with a spiral valve.
There is very little variation in structure in the species known to us.
FIG. 219. — A anterior, B posterior limb
of Ichthyosaurus intermedms (after
Huxley). Cp. carpalia ; E femur ;
/ fibulare ; Fb fibula ; H humerus ;
i intermedium ; Me metacarpals ;
m.r extra radial digit ; Mt metatarals ;
m.tb extra tibial digit ; m.u extra ulnar
digit ; Ph phalanges ; R radius ;
T tibia ; Uibiale ; Ts tarsalia ; U ulna ;
1, 2, 3, 4, 8 digits.
PLESIOSAURIA. 395
They are all placed in one family and in about four to six genera. Con-
sidering the great abundance of individuals as indicated by the frequency
with which their remains are found, this is a remarkable fact.
In Mixosaurus Baur, the genus to which all the Triassic remains are
assigned, the teeth are more variable in size, and the limbs are less paddle-
shaped, the radius and ulna being longer than broad and having a small
space between them. Shastasaurus Merr. from the Upper Trias of Cali-
fornia may possibly belong to this genus. Ichthyosaurus Konig is the
typical and most common genus. It is most common in the Lias but
extends into the Cretaceous. Ophthalmosaurus Seeley is edentulous or
almost so, and the carpal and metacarpal bones and phalanges are round
and not pressed together as in the preceding genera ; Upper Jurassic and
Cretaceous of England. Baptanodon Marsh is completely edentulous, pos-
sibly belongs to the last named genus, Jurassic of Wyoming. It is quite
clear from this small amount of diversity of structure that we are acquainted
with but a minute fraction of the group. There must have been, possibly
in Triassic and earlier times, an immense number of forms the remains
of which have yet to be discovered, and which may, when they are
discovered, enable us to relate these isolated creatures to other repti-
lian groups.
Sub-class 7. PLESIOSAURIA.*
Amphibious or marine lizard-like reptiles with long neck, two pairs of
five-toed limbs, and strongly developed pectoral and pelvic girdles. The
skull has a supratemporal fossa only, a single broad temporal arcade, large
pterygoids which reach the vomers and meet in the middle line, fixed quadrates,
and a pineal foramen. Triassic to Cretaceous of Europe, N. and S. America,
N. Zealand, and India.
In the triassic forms the limbs appear to have been less modified than
in the post-triassic and to have been adapted for walking. In the post-
triassic forms they are paddle-like and provided with an increased number
of phalanges though not of digits. The larger species may attain a length
of 40 feet. The vertebrae are weakly biconcave or flat, and the neural
arches are usually suturally united to the centra. The number of cervical
vertebrae is always great (20 to 40) and the tail, especially in the marine
forms, is short. All the vertebrae carry ribs except the atlas and the
axis and the hinder caudals. The cervical ribs are articulated to an arti-
cular surface on the centra alone ; they are two-headed in the earlier
genera, single-headed in the later forms. In the trunk the ribs are one-
headed and articulated to a transverse process of the neural arch or more
rarely directly to the neural arch. There are two to four sacral vertebrae,
which are not fused. The caudal vertebrae have chevrons, and their
ribs are articulated to the centrum.
The features of the skull are clearly shown in the diagrams (Fig. 220)
illustrating the skull of Plesiosaurus. The premaxillae are large and form
the short rostrum. The anterior nares are near the orbit. The orbit is
closed behind by the jugal and a bone which corresponds to the post-
orbital and postfrontal. There are large supratemporal fossae, and the
temporal arcade is formed by the backward continuation of the jugal
and of the bone which is supposed to consist of postfrontal and post-
* Called by O\ven Sauropterygia.
396
PLESIOSAURIA.
A.
H.
Fl«. 22O. — Diagram illustrating the principal characters of the Plesiosauria (from S. Wood-
ward).
A, B, C Lateral, dorsal, and ventral view of the skull of Plesiosaurus maerocephalus x J,
PLESIOSAURIA. B(J7
L. Lias (modified after C. W. Andrews), ag angular ; art articular ; b.occ basloccipial ;
bs basisphenoid ; d dentary ; ecpt ectopterygoid (transpalatine) ; fr frontal ; i.pt inter-
pterygoid vacuity ; / jugal ; mx maxilla ; nar external nares ; orb orbit ; pa parietal ;
pas parasphenoid ; pin pineal foramen ; pi palatine ; pmx premaxilla ; prf prefrontal ; pt
pterygoid ; pt.f postfrontal ; pt.nar internal nares ; pto postorbital ; qj quadratojugal ;
qu quadrate ; s supratemporal vacuity ; s.ag surangular ; so suborbital vacuity ; st supra-
temporal (prosquamosal) ; sq. squamosal ; v vomer.
D Plesiosaurus dolichodirus : cervical vertebra, left side ; x J. L. Lias, r rib.
E Cryptoclidus oxoniensis, transverse section of abdomen of immature specimen, x T\y
U. Jurassic, abd abdominal ribs ; r rib.
F. Plesiosaurus dolichodirus ; caudal vertebra, anterior end, x J, L. Lias ; ch chevron
bone ; r rib.
G1 dorsal, 62 side view of pelvis of Muraenosaurus leedsi, x TV> Oxford Clay (after C. W.
Andrews), fe femur ; it ilium ; is ischium ; pb pub is.
H pectoral, I pelvic limbs of the same specimen of Plesiosaurus dolichodirus, x -^, L. Lias
(Brit. Mus.). fe femur ; ft fibula ; h humerus ; i intermedium ; r radius ; t tibia; u ulna ;
x pisiform.
J humerus or femur of Plesiosaurian in median longitudinal section, x j^, U. Jurassic.
c central cavity ; ep epiphyses ; s;shaft. (Brit. Mus.)
orbital, to meet a large bone which overlaps the fixed quadrate and is
supposed to be equivalent to the supratemporal, squamosal and quadrato-
jugal. There is a pineal foramen. The internal nares are between the
vomers and the maxillae. The palatines are separated by the pterygoids
which touch for the greater part of their length, but are separated by an
interpterygoid vacuity behind. In the middle of the latter is the basi-
sphenoidal rostrum. In the triassic genera the pterygoids are in contact
throughout. The occipital condyle is single and mainly formed by the
basioccipital. Sclerotic plates have not been observed. The dentition
is thecodont and teeth are borne by the premaxillae, maxillae and man-
dible, and occasionally in the triassic genera by the pterygoids.
In the triassic genera the pectoral girdle is on the ordinary reptilian
type, except that the coracoids meet in a ventral symphysis and there
is no sternum preserved. In the post-triassic forms however the pectoral
girdle presents some remarkable features. The symphysis of the coracoids
is much prolonged anteroposteriorly and the scapulae extend ventral-
wards towards each other, so as nearly or completely to meet in the median
ventral line in front of the coracoids. At the same time the clavicles and
interclavicle become reduced.
The pelvic girdle is well developed (Fig. 220 G). The ilia articulate
with the ribs of the sacral vertebrae and all three bones enter into the
acetabulum, but the ilium joins the ischium only. There is a pubic and an
ischiadic symphysis. The limbs are more elongated and leg-like in the
triassic genera and have the normal number of phalanges, but in the
later forms they are more paddle-like and the bones of the fore-arm and
fore-leg shortened, and the phalanges are more numerous.
Numerous close-set abdominal ribs are present, and the skin appears
to have been without scales and dermal plates. Vertical fins have not
been certainly made out.
Fam. 1. Nothosauridae. Triassic Plesiosauria with elongated limbs
adapted for moving on land as well as in water. The palate is without
an interpterygoid vacuity. There are about 20 cervical vertebrae and the
cervical ribs are double-headed. The number of phalanges in both limbs
is normal. The coracoidal symphysis is not much extended longitudinally,
and the clavicles are well developed. Lariosaurus Curioni, Triassic shales
of Lake Como ; Pachypleura Cornalia (N eusticosaurus Seeley) U. Trias,
Lombardy etc. ; Dactylosaurus Giirich. Anarosaurus Dames, Cymato
saurus Dames, Muschelkalk, Silesia and Thuringia ; Pistosaurus, Simosau-
rus v. Meyer, Muschelkalk ; Nothosaurus Miinst., Muschelkalk, Germany
398 AXOMODONTIA.
and France. Mesosaurus(p, 334) is supposed by some authors to belong here.
Fam. 2. Plesiosauridae. The limbs are paddle-shaped and adapted
for swimming ; the radius and ulna and tibia and fibula are shortened,
and the number of phalanges, which are elongated, is increased. An inter-
pterygoid vacuity is present in the palate. An epipterygoid is present.
The neck is long with 30 to 40 cervical vertebrae. The cervical ribs are
single- or double-headed. The coracoid symphysis is much extended
antero-posteriorly and the scapulae tend to meet in a median ventral
symphysis. Plesiosaurus Conybeare, Lias of England and Germany.
Eretmosaurus Seeley, L. Lias, England. Rhomaleosaurus, Colymbosaurus,
Muraenosaurus Seeley, U. Jurassic, England. Cryptoclidus Seeley, all
ribs single-headed, U. Jurassic, England. A number of diverse genera
from the U. Cretaceous of N. and S. America and N. Zealand. Plio-
saurus Owen, with relatively large head and short neck (20 vertebrae),
Lias to U. Jurassic. England, Europe, India. Megalneusaurus Knight,
largest known Plesiosaur, U. Jurassic, Wyoming, U.S. Elasmosaurus
Cope, U. Cretaceous, Kansas, U.S. Polyptychodon Owen, M. and U.,
Cretaceous, England, Germany, Russia.
Sub-class 8. ANOMODONTIA.*
Terrestrial reptiles with limbs adapted for the support of the body, with
biconcave vertebrae, fixed often reduced quadrate, and pineal foramen. The
temporal fossa is completely closed by the bones of the temporal region or there
is a broad temporal arcade. The bones of the pectoral and pelvic girdles are
fused or immoveably connected by suture. Permian and Triassic formations
of Europe, N. America, S. Africa, and India.
The Anomodontia form a somewhat diverse group of apparently terres-
trial reptiles. They are known by remains which are in most cases
imperfect, and it is highly probable that the sub-class will eventually have
to be broken up. The group however as it stands combines a number
of reptilian features not found together in any other reptilian sub-class
with some highly remarkable mammalian characteristics. Of their
essentially reptilian features, we may mention the pineal foramen, the
quadrate, the compound mandible, the general presence of pre- and post-
frontals. To show the peculiar combination of characters found in no
other reptilian group, we may draw attention to the union of the upper
and lower temporal arcades into one broad arcade, unpierced as a rule by
a lateral temporal fossa and found elsewhere only in Plesiosauria and
Ichthyosauria ; to the frequent presence of a secondary palate, which
recalls that of the Chelonia ; to the thecodont dentition which is found
also in Plesiosauria, but not in the two other groups ; to the structure of
the pelvis which is quite different from that of any of the three above-
mentioned groups ; and to the absence of abdominal ribs.
The mammalian characters are however those which preeminently
distinguish them from other reptiles. These are : the frequent differentia-
tion of the teeth into incisors, canines and molars (Fig. 222) ; the resem-
blance of the single temporal arcade to the mammalian zygomatic arch ;
the mammalian character of the limbs which carry the body high above
the ground (Fig. 221) ; the union of the pelvic bones into an osinnomina-
tum (Fig. 221) ; and the continuity of the pubic and ischiadic symphysis ;
* Sometimes called Theromorpha.
AXOMODOXTIA. 399
the shape and frequent presence of a spine on the scapula, and many fea-
tures of the limb bones in the different sub-orders, e.g. fore-limb of Therio-
desmus. Moreover the sqtiamosal often descends far down outside the quad-
rate (Fig. 223), and may contribute to the articular surface for the lower jaw.
The vertebrae are amphicoelous and the cervical ribs are double-headed.
Hvpocentra are either much reduced or absent. Abdominal ribs are never
found. The skull has a well-marked supra-temporal fossa (except in the
Pareiasauria), and in one or two forms the temporal arcade is perforated
by a small aperture recalling the lateral temporal fossa. The quadrate is
fixed and frequently deduced in size. Secondary palatal plates of the pre-
maxillae, maxillae and palatines appear to be developed in many forms.
The pterygoids are large, extend back to the quadrates and meet in the
middle line. The occipital condyle is single or trifid, or double (Cynoq-
nathus}. The mandible usually shows a composition of several bones, but
this cannot always be seen. Pre- and post-frontals can usually be made out,
but sometimes, in consequence of the absence of sutures, they are indis-
tinguishable. In the pectoral arch there are clavicles, interclavicle and
ossified epicoracoids ; the scapula is frequently mammalian and has a
spine and all the bones are immoveably united. The pelvic girdle is
thoroughly mammalian ; all the bones are immoveably united and there
are two obturator foramina. The limbs are not well known ; but they
appear to have been stout pentadactyle structures.
From the above short description and from the subjoined account of their
orders it is clear that the Anomodontia present both reptilian and mam-
malian features. Which of these preponderate it is difficult to say.* By
most investigators they are regarded as reptiles, and there is undoubtedly
much to be said for this view, which has been followed in the present
work ; but it must not be forgotten that our knowledge of even the coarser
features of their skeleton is very imperfect, and that we know nothing of
the finer details or of the soft parts. On the whole we think that there
is much to be said for the view that the Anomodontia are neither reptiles
nor mammals, but that they represent an independent type of structure,
we will not say intermediate between these two, but combining features
belonging to each. There is no reason that we can see for regarding
them as ancestral to mammals, and we do not propose to consider the
matter from that point of view. Having regard to the extreme incom
pleteness of our knowledge of their anatomy such a discussion would hardly
be profitable, and might draw off our attention from wider problems of
evolution which are perhaps more ripe for settlement. There are two
additional facts with regard to this group which must be borne in mind.
In the first place they are almost the only purely terrestrial extinct reptiles
known, and in the second they are known to us in a very large number of
cases by their skull only. ^ .
Order 1. PARF.IASAUKIA.
The temporal fossa is completely covered over dorsally by bone. There
may be a small latero-temporal fossa. Teeth conical or with a compressed,
cuspidate crown ; those on the margin of the jaws in a uniform series.
Pineal foramen large. Vertebral centra pierced for the persistent noto-
chord. Permian and Triassic.
* See the " Discussion on the origin of Mammals " in the Proceedings
of the Fourth International Congress of Zoology, Cambridge, 1899.
400 AXOMODONTIA.
Pareiasaurus Owen (Fig. 221), heavy, massive creatures to 8 feet long,
with stout limbs, short tail ; bones of skull roughly sculptured ; bones of the
palate not suturally separated, with rows of small teeth, with inter-
pterygoid vacuity ; occipital condyle single ; the mandibular elements
are not separated by sutures ; 18 presacral vertebrae, 4 sacral not fused,
about 30 caudal with chevrons, all except the posterior caudal with
single-headed ribs attached to facets on the vertebrae ; wedge-shaped
hypocentra between the dorsal vertebrae ; the scapula slopes backwards
and possesses a longitudinal spine ; acetabulum closed ; limbs plantigrade
with 5 digits with claws, hind limbs larger than front ; sternum and
abdominal ribs unknown ; Karoo sandstone, S. Africa. Elginia Newton,
known only by the skull with spikes and horn-like projections, triassic
sandstones of Elgin. Procolophon Owen, a small animal the skull of
which shows the sutures ; there is a small lateral temporal fossa and small
teeth on the pterygoid and vomer ; Karoo sandstone, S. Africa. Aristo-
desmus Seeley, L. Trias, Switzerland. Otocoelus Cope, with a dorsal
carapace of 12 or more transversely extended bars of bone, Permian
Texas ; and other genera.
Fia. 221. — Skeleton of Pareiasaurus (Pareiasaurus) baini Seeley. Karoo Sandstone, Cape
Colony (after Seeley from Woodward).
Order 2. THERIODONTIA.
There is a single broad temporal arcade with a large superior and some-
times a small lateral temporal fossa ; the quadrate is small, the occipital
condyle bilobed ; palatal plates are developed by the maxillae and some-
times by the palatines ; the marginal teeth of the jaws are differentiated
into incisors, canines and molars ; teeth are almost always limited to the
dentaries, maxillaries and premaxillaries ; the external bones of the skull
are not sculptured ; the scapula has a mammal-like spine, but the skeleton
of the trunk and the appendages is imperfectly known : all from the Karoo
sandstone of S. Africa, but there are remains from the Permian of the
U.S.A. and of Russia, which may belong here.
Galesaurus Owen, known only by the skull, dentition i — - c -^— and an
undetermined number of molars laterally compressed and in part
tricuspidate. Lycosaurus Owen, skull only known ; Aelurosaurus Owen,
known only by skull ; Cynognathus Seeley, vertebral column and limb
arches found with skull ; skull (Fig. 222) very mammalian ; vertebrae
amphicoelous ; dentition i — c— m— , molars triconodont.
o i y
ANOMODONTIA.
401
The following genera with broad molar-like teeth have been united by
Seeley into a special order, the Gomphodontia :
Tritylodon Owen, with transversely expanded molar-like teeth and a
pair of large incisors probably growing from persistent pulps ; with a
secondary palate and reduced quadrate ; very mammal-like, known by
skull only ; molars multituberculate. Diademodon Seeley, Trirachodon
Seeley, both with multituberculate teeth. Theriodesmus Seeley, known
by a remarkably mammalian fore-limb and manus ; and other genera.
All the above are from S. Africa. Triglyphus Fraas, known only by its
molar-tike teeth is from the U. Trias, Stuttgart.
The following known from imperfect remains from the Permian of
Russia are probably Theriodontia ; Deuterosaurus Eichw., Rhopalodon
Fischer, with lanceolate molars and sclerotic ring.
•pou.
FIG. 222. — Cynognathus crateronotus, right side of skull with imperfect mandible (after Wood-
ward slightly restored). The molars possibly project further than in life and the crown
of the last is broken. d dentary ; j jugal ; l.t.f. small lateral temporal vacuity ; la
lacrymal ; mx maxilla ; na nasal ; orb orbit ; pa parietal ; pmx premaxilla ; prf prefrontal ;
pto postorbital ; ptf postfrontal ; st supratemporal ; sq squamosal.
Order 3. DICYNODOXTIA.
Highly specialised land-forms, known by fragments from the Trias of
S. Africa, East India, the Urals, and Scotland. There is a single temporal
arcade formed mainly by the squamosal which is very large and lies over
the small quadrate (Fig. 223). The jaws are edentulous except for the
occasional presence of a pair of tusk-like teeth in the maxillae growing from
persistent pulps. There do not appear to be any secondary palatal plates
and the pterygoids are large, meeting in front of the basisphenoid. The
cervical ribs are double-headed, the dorsal single-headed ; the vertebral
column consists of 7 to 8 cervical, 12 to 13 dorsal, 5 to 6 fused sacral and
about 20 caudal vertebrae. There appears to be a pineal foramen. The
scapula has an acromion, the pelvic bones are fused into an os innominatum.
Dicynodon Owen, Oudenodon Owen, Ptychognathus Owen, Karoo Sand-
stone of S. Africa. Gordonia and Geikia Newton, Elgin Sandstone
Scotland ; etc.
z.— ii.
D D
402
CHELONIA.
Pinx
Qu
Order 4. PLACODONTIA.
Known by their skulls only from the Middle Trias (Muschelkalk) of
Germany and Russia. With very peculiar dentition of large pavement-like
crushing teeth on the jaws and palate, which seem to indicate that they
probably lived on hard-shelled molluscs. The skull recalls that of Dicy-
nodonts. Placodus Agassiz ; Cyamodus v. Meyer.
Sub-class 9. CHELONIA.*
Body encased in a bony capsule, jaws without teeth but with horny
beaks, nasal opening single and at the front end of the snout, quad-
rate immoveable and appendages with five digits. The lower tem-
poral arcade alone is present. Anal opening round or longitudinal.
No other group of
Reptiles is so clearly de-
nned and characterised
to the same extent by
peculiarities of form and
organisation as is that
of the Chelonia, and
this applies to the ex-
tinct as well as to the
living forms. The in-
vestment of the body
by a shell composed of
an upper, more or less
arched osseous plate
(carapace], and by a
lower ventral plate (pla-
stron) forms a character
as distinctive of the Chelonia, as is the possession of wings and
feathers of the class Aves. This shell is covered, except in the
* A. ~Bo)a,nus, " Anatome Testudinis Europae," Vilnae, 1819. H. Rathke,
" Ueb. d. Entwick. der Schildkroten," Braunschweig, 1848. L. Agassiz,
" Embryology of the Turtle," Contributions to the Natural History of the
United States, 1 and 2, Boston, 1857. A. Strauch, " Chelonologische
Studien," Mem. de VAcad. St. Petersbourg, (7) 5, 1862. Gray & Sowerby,
Tortoises, Terrapins and Turtles drawn from life, London, 1872. W.
K. Parker, " Development of the Green Turtle," Challenger Reports, 1,
1880. J. E. Gray, " Notes on the families and genera of Tortoises, and on
characters of their skulls," Proc. Zool. Soc. London, 12, 1869. Mitsukuri,
Contributions to the embryology of Reptilia, Journal Coll. Sci. Imp. Univ.
Japan, 4, 1890 ; 5, 6 ; 1893, 10, 1896. Th. Huxley, " The Anatomy of Verte-
brated Animals," London, 1871. G. A. Boulenger, " Catalogue of Chelo-
nians in the British Museum," London, 1889. Hoffmann, Gadow, Cope,
Zittel, op. cit.
FIG. 223. — Ptychognathus declivis Owen, Karoo Sand-
stone. Side view of skull (from Zittel after Owen).
ang angular, c maxillary tusk, d dentary, Ju jugal,
MX maxilla, N external narial opening, Na nasal,
Pa parietal, Pmx premaxilla, Prf prefrontal, Ptf
postfrontal, Qu quadrate, Sq squamosal.
CARAPACE.
403
Trionychoidea and the Athecae in which the skin is soft, by a
horny epidermal exoskeleton consisting of horny plates which
constitute the so-called " tortoiseshell," and which have an
arrangement roughly resembling that of the subjacent bony
plates of the shell.
The carapace (Fig. 224), beneath which the head and tail can
often be retracted, owes its origin to the formation of bony plates
in the dermis, some of which become attached to the internal
skeleton. Allowing for some variation in details, it is constituted
as follows : there is a median row of usually eight neural plates,
which are fused (Fig. 224)
to the spinous processes
of eight of the thoracic
vertebrae (2nd to 9th) ;
in front of the first neural
plate and suturally joined
to it, is a large nuchal
plate (Fig. 224, Nu),
which lies over and is
joined by ligament to
the neural spine of the
last (8th) cervical verte-
bra. Behind the eighth
neural are the median
pygal (Py) plates (one to
three in number), of
fVio firaf f \i7-n OT-O FIG. 224. — Dorsal view of the carapace of
midas (from Huxley). Nu nuchal, Py pygal
•fri fl-io oirrVif Vi nr-a plates ; M marginal plates ; R ribs ; 1-8 neural
plates ; C1-C8 costal plates.
tal (CS) and the last to
the hinder marginal. The ribs of the second to the eighth
thoracic vertebrae, distinguished from the first and last ribs by
their greater length, are fused with the broad, transversely
arranged costal plates of the carapace (C). The costal plates
are joined with one another by sutures, and present the special
peculiarity of giving off broad transverse plate?, which arch
over the muscles of the back and join the neural plates (Fig. 225).
The ribs project beyond the costal plates and end, each of them,
in one of the marginal plates (M), of which there are usually
eleven pairs and a median posterior. The marginals form the
boundary of the carapace. The first marginal on each side is
404
CHELOXIA.
attached to the side of the nuchal, the last marginal is in the
middle line and attached to the last pygal. Of these plates the
nuchal, pygal, and marginal used to be considered as purely der-
mal structures, the neurals and costals being regarded as expan-
sions of the internal skeleton.
The plastron (Fig. 226) or ventral part of the shell is
attached directly or by ligament to the marginals and is quite
separate from the internal skeleton. It consists, like the rest
of the shell, of purely dermal bones, some of which lie behind
and some in front of the umbilicus. It is therefore partly a
thoracic and partly an abdominal structure. In the turtle it con-
sists of nine pieces — a median entoplastron (interclavicle), and foui
paired pieces, the epiplastra (clavicles), the hyoplastra, the hypo-
plastra and the xiphiplas-
tra (Fig. 226). It is sup-
posed that the entoplas-
tron and epiplastra
correspond to the inter-
clavicle and clavicle oi
other forms. In some
Chelonia the pieces of the
plastron are in contact
by their whole margin
and form a continuous
plate (Tesludinidae, etc.)
The shell is covered externally by the horny epiderma
shields. These are applied to the outer surface of both
the carapace and plastron. They are regularly arrangec
but by no means correspond with the subjacent bom
pieces, on the surface of which they leave sutural markings
There is some variation in their arrangement, but typically then
is on the dorsal surface, a median row of five shields (vertebral], twc
lateral rows of four shields (costal), and a marginal row of twenty
four or twenty-five shields (marginals) of which the anterio]
median is called nuchal, and the posterior pygal or supracaudal
On the ventral surface are six pairs of shields, called, from before
backwards, the gular, humeral, pectoral, abdominal, femoral, anc
anal. In front of the gulars, there is usually a paired or un-
paired intergular, and ventral to the marginal shields, betweer
them and the shields of the ventral surface there is a variable
FIG. 225. — Transverse section of the skeleton of
Chelone midas in the dorsal region (from Huxley).
C1 centrum; V neural plate; C costal plate ; R
rib ; M marginal plate ; P lateral element of the
plastron.
VERTEBRAL COLUMX.
405
number (often five or six) of inframarginals. In addition to
these scale-like plates, small horny structures are formed on
other parts of the body, especially on the limbs and head.
The horny plates are formed as cornifications of the outer parts of the
epidermis. They are added to throughout life, increasing both in area
and thickness. The annual additions often leave marks in the form of
rings.
Tiie vertebrae are few in number. There are usually eight
cervical, ten trunk (thoracic), two sacral and a variable num-
ber of caudal. The cervical vertebrae are without transverse
processes or ribs, and the neural spines are low or absent. They
are freely moveable upon
one another, and their
neurocentral sutures persist.
The trunk or thoracic
vertebrae bear ribs and are
firmly connected with the
carapace by their neural
spines and ribs They are
without transverse or articu-
lating processes, and the
neural arches are but loose-
ly attached to the centra.
The ribs are attached partly
to the neural arches and
partly to the centra. The
sacral vertebrae bear short
ribs which are not ankylosed either to them or to the ilia.
The caudal vertebrae are procoelous and freely moveable. They
bear short ribs which may be fused with the vertebrae and
appear as transverse processes.
The atlas is composed of three pieces, one ventral and two dorso-lateral.
The axis carries the centrum of the atlas as an odontoid process. The
character of the articulating surfaces of the centra varies considerably.
In Chelone midas the second and third vertebrae are opisthocoelous, the
fourth is biconvex, the fifth and sixth are procoelous, the seventh has a
flat anterior and a convex posterior surface, the eighth is concave in front
and convex behind. The centrum of the eighth is short, its neural spine
expanded (attached by ligament to the nuchal plate) ; its postzygapophyses
arch over the prezygapophyses of the first thoracic vertebra. The thoracic
vertebrae have flattened faces and are firmly united by cartilage. The
FIG. 226. — The plastron of the green turtle
(Chelone midas} (from Huxley). I.d inter-
clavicle ; d clavicles ; Hy.p hyoplastron ;
Hp.p hypoplastron ; Xp xiphiplastron.
406
CHELOXIA.
first differs from the others ; it is procoelous, it has a pair of prezygapo-
physes, its spine is not connected to a neural plate, and its rib has no costal
plate bu£ is connected with the costal of the next vertebra. The neural
arch of this vertebra occupies only the anterior part of its centrum. The
neural arch of the second thoracic overlaps the centrum of the first, occupy-
ing the anterior half of
its own and the posterior
half of the preceding cen-
trum. This applies to the
next eight thoracic verte-
brae, and also to their ribs
which are carried for-
wards with the arch
and articulate, not only
with their own centrum
and arch, but also with
the centrum and arch of
the preceding vertebra.
In the tenth vertebra the
neural arch is confined
to the anterior part of
its own centrum and the
20 2\ 13'' ribs, which are short and
without costal plates,
meet those of the pre-
ceding vertebra.
The skull (Figs. 227,
228) possesses only one
temporal arcade, the
lower, and the lateral
temporal fossa is there-
fore absent. In this
respect the skull is
mammal-like. The
roof consists of a sup-
raoccipital with a
strongly developed oc-
cipital crest, a pair
of parietals and a pair
of f rentals. There
is no pineal foramen.
Descending lamellar processes of the parietals (Fig. 228, 1) reach
down to the pterygoids and take the place of the alisphenoids,
which are absent. Presphenoid and orbitosphenoids are also
absent. The epiotic is united to the supraoccipital ; the opis-
—17
FIG. 227. — A. Posterior, B. Anterior view of the skull of
Chelone midas (from Reynolds). 1 parietal, 2 squa-
mosal, 3 quadrate, 4 basisphenoid, 5 basioccipital,
6 quadrato-jugal, 7 opisthotic, 8 exoccipital, .9 foramen
magnum, 10 splenial, 11 articular, 12 dentary, 13
angular, 14 supra-angular, 15 premaxilla, 16 maxilla,
17 jugal, 18 postfrontal, 19 vomer, 20 pref rental,
21 frontal, 22 external auditory meatus leading unto
tympanic cavity.
SKULL.
407
thotics remain separate, as does the prootic which forms part of
the side wall of the cranial cavity. All the parts of the maxillo-
palatine apparatus as well as the quadrate are firmly connected
with the bones of the skull. The naso-ethmoidal cartilage
largely persists, and is covered dorsally by two bones, which
assist in forming the anterior margin of the orbit and occupy the
position of the nasal, prefrontal and lacrymal (Fig. 227, 20).
The palatines usually have palatal plates which join with a ven-
tral expansion of the median vomer to form a hard palate.
The premaxillae are small. The maxillae are large and are
FIG. 228. — Longitudinal vertical section through the cranium of Chelone midas (from Rey-
nolds). 1 parietal, 2 squamosal, 3 quadrate, 4 basisphenoid, 5 basioccipital, 6' quadrato-
jugal, 7 prootic, 8 opisthotic, 9 pterygoid, 10 palatine. 11 rod passed through the narial
passage ; 12 exoccipital, 13 epiotic. 14 supraoccipital, 15 premaxilla, 16 maxilla, 17 jugal,
18 postfrontal, 19 vomer, 20 prefrontal, 21 frontal. V-XII foramina for exits of the corres-
ponding cranial nerves.
followed by the jugals and quadrat o-jugals which reach back
to the quadrate. The quadrate (Fig. 227, 3) projects down-
wards from the periotic and has an articular surface for the
mandible. It is overlaid by the squamosal (2). In many Chelo-
nia, particularly the marine forms, the temporal fossa is roofed
over by bone consisting of a horizontal shelf from the parietals
which meets the postf rentals and squamosals (Fig. 227 A). The
orbit is completely enclosed by bone, consisting of postfrontal,
frontal, prefrontal, maxilla, and jugal. In Cistudo and Geo-
emyda the quadrato- jugal is absent and the infra- temporal arcade
408
CHELOXIA.
therefore incomplete. The columella auris is bony and reaches
from the fenestra ovalis to a small cartilage in the tym-
panum. In the mandible, the two dentaries are fused, as in
birds, and five pairs of other bones are present (articular, angular,
m 990 SVpleton of Emvs europaea, in ventral view with plastron turned to one side
(from ChuS B plastron ; C costal plates ; Cl epiplastron (clavicle) ; Co cqracoid; F fibula ;
*v fpmiir • H humerus ; J d entoplastron (interclavicle) ; Jl ilium ; Js ischium ; M marginal
nlates • VM nuchal,
radius'; Sc scapula ; T tib
late ; Pb pubis ; Pco precoracoid (acromial process) ; R
ulna ; F neural plates.
surangular, splenial, and coronoid). The hyoid consists of a
cartilaginous basilingual plate and of two pairs of ossified cornua,
which have no direct connection with the skull.
Teeth are completely absent, but the jaws, both upper and
LrX(,S. ALIMKXTARY CAXAL. 409
lower, are covered by cutting horny plates, like the beak of
a bird, which enable some species to bite with great vigour and
to inflict considerable wounds.
Both sternum and sternal ribs are absent.
The four limbs enable the Chelonia to creep and run on land ;
in the aquatic forms, however, they are swimming feet or fins.
The position of the pectoral and pelvic girdles between the
carapace and plastron is remarkable (Fig. 229), but in the foetus
they are placed, respectively, in front of and behind the ribs,
and only become covered by the latter as development proceeds.
In the pectoral girdle the scapula, the upper end of which is
attached by cartilage or ligament to the first costal plate, and
precoracoid are ossified continuously and form one bone (Sc,
Pco). The coracoid (Co) is distinct. The precoracoids and
coracoids do not form a ventral symphysis but are connected by
ligament. There is no clavicle, unless the epiplastra can be
called such. The fore limb is typical. The manus has five digits
and the carpus consists of the typical nine ossicles, but there is
sometimes a certain amount of fusion. In the pelvis the ilia
unite with the sacral ribs, and in some genera by ankylosis with
the last costal plates. There is a pubic and ischiadic symphysis,
but the pubes and ischia are separate ventrally (Fig. 229, Pb,
IS). The hind limb has five digits, and the tarsus contains the
usual bones, but it is less typical than the carpus and there is
generally a certain amount of fusion amongst its elements.
The tongue is attached to the floor of the buccal cavity and is
not protrusible. The lungs are highly developed spongy struc-
tures attached by their whole length to the inner surface of the
shell. They are covered on their ventral surfaces by a muscular
diaphragm-like membrane, which is attached to the bodies and
ribs of the third and fourth dorsal vertebrae. The respiratory
movements of air are caused, partly by the protrusion from and
retraction into the shell of the head and limbs, and partly by
swallowing movements in which the hyoid apparatus partici-
pates. They can usually exist a long time without breathing.
A membranous epiglottis is sometimes present. There are no vocal
-chords, but some Chelonia have a feeble piping voice. In the genus
Cinyxis the trachea and bronchi are curved.
The intestine is without a caecum. The cloaca contains, at-
410
CHELONIA.
tached to its ventral wall, a large copulatory organ, and receives
the opening of the bladder.
In both sexes the urinary and generative ducts open separately
into the neck of the bladder, which must be regarded as
a urinogenital sinus.
The penis,* which is a development oflthe ventral wall of the cloaca,
ends freely in a glans penis, and is marked on its dorsal side by a groove
which contains in its front end
the opening of the bladder (Fig.
230). The penis consists of a
fibrous body (Fig. 231), which
bifurcates in front and is attach-
ed, not to the pelvis, but to
one of the dorsal vertebrae, and
of some erectile tissue (Fig. 231)
round the groove and in the
glans. In the female there is
an organ, the clitoris, similar to
the penis but less developed.
Peritoneal canals t are pre-
sent. Their abdominal openings
are placed in a recess of the per-
itoneum close to the neck of the
bladder. They lie in the penis
near the groove, and either end
blindly in the glans or open into
the cloaca at the base of the
glans. In the female they run
in the ventral wall of the cloaca
and open near the glans of the
clitoris.
The suprarenal bodies are two
rather long, yellow bodies on
the inner surface of the kidneys.
FlO. 230. — Cloaca and urinogenital organs
Chelydra serpentina (from Gegenbaur). The
cloaca is laid open from the dorsal side. c,c'
blind sacs of cloaca ; cl cloaca ; e epididymis
and vasdeferens ; p penis ; r kidneys ; r e rectum;
« groove on penis ; t testis ; u ureter ; vg
cloacal opening of urinogenital sinus ( bladder) ;
v bladder.
The eyes are contained in
closed orbits and possess
upper and lower lids and
a nictitating membrane.
There is no pec ten. Lacrymal and harderian glands are present.
There is always a tympanic cavity with a wide eustachian
tube not enclosed in bone, a long columella auris, and a tympanic
membrane visible externally.
Vascular system. The sinus venosus is distinct and receives
* Boas, Morph. Jahrb., 17, 1891, p.
178, p. 5.
f Gadow, I.e.
271. Gadow, Phil. Trans, 1887,
HABITS. EXTINCT FOHMS. 411
some of the hepatic veins as well as the three systemic veins.
The auricular septum is complete, but the ventricular septum
is incomplete. The pulmonary artery and the left aortic arch
arise from the right side of the septum, the right aortic arch from
the left. The right arch gives off two innominates (Fig. 232) ;
the left arch gives off the coeliac. The pulmonary artery is
connected with the systemic on each side by open ductus Botalli.
The apex of the ventricle is as in the Crocodilia connected with
the pericardial wall by a ligament. There are two anterior
abdominal veins (p. 326).
The copulation may last a day, and during its process the
male is carried on the back of the female. The eggs are laid in
small number except in the marine forms in
which they are more numerous. They contain
within the shell, which is either parchment-like
or hard and calcareous, a layer of albumen sur-
rounding the yolk, and are buried in the earth,
in the aquatic forms near the shore. Accord-
ing to Agassiz (I.e.] the North American
marsh tortoises lay eggs only once a year,
while they copulate twice (in the spring and
autumn). The first copulation, according to
this investigator, takes place in Emys picta, in
the seventh year, the first deposition of eggs
in the eleventh year of the animal's life.
These facts agree with the slow growth of the
body of tortoises and the great age which they
attain.
The Chelonians belong mainly to warmer climates, and live
principally on vegetables. Many of them, however, also eat
mollusca, Crustacea, fish, etc. Terrestrial, fresh-water, and
marine forms are known, and there are about 260 living species.
The earliest remains of Chelonia are from the Upper Trias
(Keuper) and present no approximation to any other form of
Reptile. According to the present state of our knowledge they
reached their greatest development towards the end of the
Mesozoic and in the earlier part of the Tertiary period.
As an interesting indication of the incompleteness of the
geological record, and of the inadvisability of concluding that
because fossil remains are not found at any particular period,
412
CHELONIA.
the animals were not then existing, it may be mentioned that
the earliest known Chelonians were in every way as specialised
as those now living.
Sub-order 1. ATHECAE. Vertebrae and ribs free, not fused
with the carapace, which consists of numerous juxtaposed poly-
gonal plates. The skin is leathery without horny plates. There
are eight plastral elements in the ventral part of the shell.
The parietal bones are without descending processes, and nearly
cover the supraoccipital ; the temporal fossa is roofed in. Neuro-
central suture on all the vertebrae except the posterior caudal,
the cervicals are short and the head
is not retractile. The limb-girdles
are essentially like those of other
Chelonians ; limbs paddle-shaped,
clawless ; digits of fore-limb elon-
gate. Marine, within the tropics of
the Indian, Atlantic, and Pacific
Oceans.
c'
Flo. 232. — Heart and great arteries
of a Cheloniann (Chelydra), (from
Gegenbaur). d right, s left auricle;
c carotid ; ad right, ps left aortic
arch ; pd right, ps left pulmonary
artery ; c.' coeliac artery ; ad right,
ss left subclavian artery.
The psdigree of this sub-order has been
much disputed. As an indication of the
slight value of all such speculations, it
may be mentioned that it has by some
authorities (Cope, Dollo, Boulenger) been
regarded as the most primitive of recent
Chelonia, by others (Baur, Dames, Case)
as the most specialised. Dermochelys
Blainv. (Sphargis Merrem) ; only one
species. D. coriacea L. reaches 6^ ft.,
small specimens (to 3 in. ) and large
specimens only known — breeds on sandy
shores, flesh unwholesome. Fossil forms
from the Upper Cretaceous and Ter-
tiaries, Prolostegz. Cope, Prctoftphargis Capellini, Psephophorus H. v.
Meyer, Eosphargis Lyd.
Sub-order 2. THECOPHORA. Thoracic vertebrae and ribs im-
moveably united with a series of median (neural) dermal plates
and a paired series of lateral (costal) dermal plates. Parietals
prolonged downwards meeting the pterygoids or separated from
them by an interposed epipterygoid.
Sectional. Cryptodira.
Carapace covered with horny shields ; neck bending in a sigmoid curve
in a vertical plane ; pelvis not fused with the carapace.
( -HKLONIA. 413
Fani. 1. Chelydridae. Nuchal plate with long costiform processes
underlying the marginals ; plastral bones nine ; tail long ; snout with
powerful hooked beak ; temporal region incompletely roofed over ; fingers
and toes webbed, with claws ; very fierce. Chelydra Schweigg. N. Amer.
to Ecuador, the snapping turtle, edible. Macroclemmys Gray, alligator-
turtle, N. Amer. Both genera may leave the water. Platychelis A. Wag.
Upper JUT.
Fani. 2. Dermatemydidae. Xuchal plate with costiform processes
underlying the marginals ; plastral bones 9 ; temporal fossa not roofed
over ; aquatic, shell to one foot ; Central Amer. Dermatemys Gray,
Staurotypus Wagl., Claudius Cope.
Fam. 3. Cinosternidae. Nuchal plate as above, 8 plastral bones,
temporal region not roofed ; America n. of Equator. Cine-sternum Spix.
Fam. 4. Platystern-dae. Nuchal plate without costiform processes ;
plastral bones 9, temporal region roofed over ; Burma, Siam, S. China,
aquatic. Platysternum Gray.
Fam. 5. Testudinidae. Nuchal plate without well-developed costiform
processes, 9 plastral bones, lateral temporal arch usually present, no
parieto-squamosal arch ; cosmopolitan except Australia and Papuasia ;
includes terrestrial and aquatic tortoises ; about 20 genera. Kachuga
Gray, India and Burma ; Callagur Gray, Malay P., Borneo. Batagur
Gray, Bengal, Burma, Malay P. ; Hardella Gray, N. India ; Morenia Gray,
N. India and Burma ; Chrysemys Gray, terrapins or water tortoises, America
from Canada to Argentina, carapace flat, feet webbed, tail short ; lively
and shy ; larger species are eaten. Ocadia Gray, China ; Malacoclemmys
Gray, N. Amer. ; M. terrapin extensively eaten in the U.S., and bred in
terrapin farms. Damonia Gray, E. Indies, China, Japan ; Beilia Gray,
Siam, Burma, Malay P. and Arch. ; Clemmys Wagl., N.W. Afr., S. Eur.,
S.\V. Asia, China, Japan, N. Amer., aquatic. Emys Dum., Eur., N.W.
Afr., W. Asia, E. N. Amer. ; E. orbicularis L. the European pond tortoise.
Cistudo Flem., N. Amer., a terrestrial tortoise but allied by its structure to
the water tortoises ; C. Carolina L., box-tortoise. Nicoria Gray, E. Indies,
C. and S. Amer. Cyclemys Bell, E. Indies, S. China. Geaemyda Gray,
Burma, Malay P. and Arch. Chaibassia Theobald, N.E. India. Cinixys
Bell, trop. Afr., posterior portion of carapace moveable. Pyxis Bell,
front lobe of plastron moveable, Madagascar. Homopus D. and B., S. and
W. Afr. Testudo L., plastron immoveable (except in T. ibera), since Oligo-
cene, herbivorous and frugivorous, occasionally taking worms, molluscs
and insects ; eggs hard shelled ; usually hibernate in ground or aestivate,
nearly 40 species, S. Eur., S. Asia, Africa, S. North Amer., S. Amer. ; T.
graeca the common Greek tortoise ; T. polyphemus the gopher tortoise of
N. Amer. Some tortoises attain a large size, shell to 55 in. (Giinther,
Proc. Lin.Soc., 1898) in some oceanic islands, e.g. the Galapagos Islands.
.Mascarenes, Aldabra, Seychelles, etc., where they have recently been
largely exterminated ; they may attain to a great age, 150 years or more ;
at the present time indigenous land tortoises are known only on the S.
island of Aldabra, representatives of other species only lingering as intro-
duced pets on tropical islands and in Europe.
Fam. 5. Chelonidae. Turtles. Nuchal plates without costiform
processes ; plastral bones nine ; temporal fossa completely roofed over ;
limbs paddle shaped, claws one or two ; marine, depositing their eggs in
the sand of unfrequented shores, cosmopolitan within the warmer zones.
Chelone Brong. Ch. midas L. the green edible turtle, Atl., Ind., and Pac.
414
CHELOXIA.
oceans, shell to 4 ft., herbivorous, the dense subcutaneous connective
tissue (callipash and callipee) within the shell, as well as the fat and meat,
is used in preparing the soup ; eggs round, parchment-shelled ; Ch. imbri-
cata, the hawksbill turtle, shell to 34 in., their horny epidermal shields are
used as tortoise shell ; Thalassochelys Fitzing., Th. caretta L. (Fig. 233),
the loggerhead turtle, trop. and sub trop. seas.
Two extinct families are allied here : —
The Chelonemydidae and the Thalassemydidae from the Jurassic, Cre-
taceous etc.
Section 2. Pleurodira.
Neck bending laterally ; pelvis fused to the shell, the ilia to the carapace,
the pubes and ischia to the plastron. Freshwater tortoises almost en-
tirely carnivorous, inhabiting S. America, Australia, Africa, and Mada-
gascar ; fossil forms from the Jurassic. The temporal region of the skull
is variable. The cara-
pace is covered with
horny shields except in
Carettochelys. Extinct
forms are known from
Trias and Jura of Eu-
rope, and are the old-
est fossil Chelonia.
(Psammochelys Quenst.
=Proganochelys Baur,
Keuper Sandstone.)
Fam. 1. Pelome-
dusidae. Neck com-
pletely retractile with-
in the shell ; carapace
without a nuchal
shield ; plastral bones
1 1 ; 2nd cervical verte-
bra biconvex. Africa,
Madagascar, S. Amer-
ica. Stern othaerus
Bell, skull without
supratemporal roof, quadrate -jugal widely separated from pari-
etal, digits short, 5 claws, trop. and S. Afr., Madagascar ; Pelo-
medusa, \VagL, skull with a slender parieto-squamosal arch, digits short,
5 claws, Africa and Madagascar ; Podocnemis Wagl., supratemporal roof
formed by junction of parietal with quadrato-jugal, digits webbed,
5 claws on- fore- and 4 on hind-foot, S. Amer., Madagascar ; P. expansa,
Arran turtle, edible, eggs collected for oil, S. Amer.
Fam. 2. Chelydidae. Plastral bones 9, temporal region diverse, S.
Amer., Australia, New Guinea. Chelys Dumer., digits webbed, S. Amer.
and Australia, Ch, fimbriata Schn., the matamata, aquatic. Hydro-
medusa Fitz., digits webbed, long neck, S. Amer. Chelodina Fit/., long
neck, neural plates absent, costals meeting, digits webbed, Australia and
New -[Guinea. Rhinemys Wagl., S. Amer. ; Hydraspis Bell, S. Amer. ;
Platemys Wagl., S. Amer. ; Emydura Bon., Australia and New Guinea;
Elseya Gray, Australia.
FIG. 233. — Thalassochelys caretta (RSgne animal).
CHELONIA. 415
Fam. 3. Carettochelydae. Horny shields absent, shell covered with
soft skin, limbs paddle-shaped, neck not retractile ; Carettochelys New
Guinea.
Section 3. Trionychoidea. Mud tortoises.
Shell flat oval and almost round, covered with soft leathery skin, without
horny shields, digits broadly webbed, the 3 inner digits only with claws,
articulation between the last cervical and first dorsal by zygapophyses
only, pelvis not anchylosed to shell ; 4th digit with 4 or more phalanges ;
marginals absent or incomplete, not joined to ribs. Head and neck re-
tractile, bending in vertical plane, nose as a short soft proboscis, temporal
fossa not roofed ; first in the Upper Cretaceous ; carnivorous, rivers of
Asia, Africa and N. America, in the muddy bottom of shallow waters.
Trionyx Geoff r., Africa, Asia, 1ST. Amer., T. ferox Schn., soft-shelled turtle,
U. S.A., voracious, active, edible, flesh surpassing that of the green turtle.
Pelochelys Gray, E. Indies ; Chitra Gray, E. Indies ; Cycloderma Ptrs.,
trop. Afr. ; Emyda Gray, E. Indies ; Cyclanorbis Gray, trop. Afr.
CHAPTER XII.
AVES. *
Warm-blooded oviparous bipedal animals, covered with feathers.
The chambers of the heart are completely separated. The right
aortic arch alone persists. There is a single occipital condyle. and
the anterior limbs have the form of wings.
Birds are warm-blooded animals possessing a temperature,
which is generally higher than that of Mammals, reaching in
some cases, it h said, 112° F. and is maintained pretty con-
stantly irrespective of that of the surrounding air. This condi-
tion demands on the one hand a great energy of metabolism and
on the other a regulating mechanism by which the loss of heat is
controlled. The metabolism is undoubtedly favoured by the
respiratory arrangements, which ensure, in birds, a very com-
plete oxidation of the blood. Not only do the lungs by their
complexity of structure expose a very large absorptive surface,
but the curious extensions of the bronchi into thin-walled air-
sacs, which extend among the viscera and into the bones, no
doubt assist in the oxidation processes by acting as reservoirs
* C. L. Nitzsch- System derPterylographie, Halle, 1840. Gray & Mitch-
ell, The Genera, of Birds, London, 1841-9. C.E. Sundevall, Tentamen,
Stockholm, 1872-3 ; English Edition, London, 1889. T. Huxley, On
the classification of Birds, Proc. Zool. Soc., 1867. Stejneger, Birds in
vol. 4 of the Standard Natural History, Boston, U.S.A. 1885. M. Fiirbringer,
Untersuchungen zur Morphologic u. Systematik der Vogel, Th. 1 and 2, 1888.
H. Gadow, Aves, Bronrfs Thierreich, 1 and 2, 1891, 1893. A. Newton,
Dictionary of Birds, London, 1893-6. A. H. Evans, Birds, in the Cambridge
Natural History, 1899. W. P. Pycraft, Morphology and Phylogeny
of the Palaeognathae (Ratitae and Crypturi) and Neognathae (Cari-
natae), Trans. Zool. Soc., 15, 1900, p. 149. W. K. Parker, an impor-
tant series of memoirs on the anatomy and development of various birds,
a list of which will be found in the above-cited Dictionary of Birds, Intro-
duction, p. 80, note 2.
POWER OF FLIGHT. 417
which supply unvitiated air to the pulmonary passages during the
expiratory act (see below). The regulating mechanism cannot be
properly treated here, indeed it is not fully understood, but the
protection against loss of heat by radiation from the external
surface by the feathers is one obvious factor and the loss by eva-
poration from the internal surface of the air-sacs must be another,
birds being without the cutaneous sweat-glands which are so
characteristic of mammals. Though during prolonged frost and
snow numbers of birds perish, it is rather from the want of
food than the inability to bear cold, and the habit of migra-
tion, which among birds is carried to such an extreme, is un-
doubtedly prompted rather by the desire to obtain food than
to avoid cold. This is obvious from the fact that in the most
northern regions the migratory movement southward begins
before the full summer warmth is there felt. This movement dis-
penses with the necessity of passing into a torpid condition
which is so common among many of the mammals that winter
in northern countries, and some of the land-birds which remain
to brave a temperature that might otherwise endanger life
are endowed with additional feather-clothing (Lagopus, Linota,
some owls, etc.).
The most essential peculiarity of birds is their power of flight.
Their whole organisation, both internal and external, is modified
in correlation with this peculiarity. In this connection we may
call attention to the great uniformity of structure presented by
the class, and the sharp definition of its characters. Between
the extremes of avine organisation there is less difference than
in a single order of mammals, and there are no forms transitional
between birds and other classes of vertebrata. It is true that
they are not the only vertebrates which have achieved the aerial
habit. The pterodactyls amongst reptiles and the bats amongst
mammals have also developed the power of flight. But in these
animals the power depends upon quite other modifications than
in birds, and although it is incontestable that reptiles are the
nearest allies of birds, there is no single family of reptiles from
which they can be derived, least of all from the pterodactyls.
Moreover these groups are comparatively small and unimpor-
tant, whereas birds are a dominant group at the present time
and exceed all other vertebrate classes in number of species
though not in variety of organisation. The origin of birds is a
z.-u. E E
418 AVES.
much-vexed question. As stated above they are reptilian in
their affinities, but there are no transitional forms connecting
them with reptiles. They make their appearance in the Upper
Jurassic, and the earliest bird known — Archaeopteryx — presents
almost all the features of specialisation characteristic of living
forms. Whatever may have been the origin — whether from
reptilian or from proreptilian creatures — of their peculiar type
of structure, the avine is the only vertebrate organisation which
has enabled its possessors to make a complete conquest of the
air and to fill it with a countless number of inhabitants. But
although a new world has been opened to them, their organisa-
tion, except in trivial details, has not responded to the infinite
diversity of the new environment. This is a fact not without
significance to the student of organic evolution, and one to which
we shall return when considering that subject in its wider aspects.
Meanwhile we may note that the achievement of the power of
flight by an animal of the bulk of a bird has been a rare phe-
nomenon in nature ; so rare indeed that birds are practically
without competitors in their aerial surroundings. This may
account for the small amount of structural modification met
with in the class, but on the other hand it suggests that the
adjustments of machinery necessary to enable an animal of the
weight of a fair-sized bird to fly with ease and certainty are so
delicate and minute that no departure from them is possible, a
suggestion which receives some corroboration from the con-
sideration that the most remarkable of the not very remarkable
deviations from the normal avine type are presented by birds
which have lost the power of flight and have become adapted
exclusively to a terrestrial or aquatic life ; we refer to the
Ratitae and the penguins. It is interesting to note that rising
from the ground or water appears to have been one of the greatest
difficulties which nature has had to overcome in enabling birds
to fly. Some of the strongest and most enduring flyers ex-
perience a difficulty in this respect, e.g. the albatrosses. A further
point to be noticed is that the power of flight appears to be in-
consistent with great size and weight. The largest flying birds,
e.g. the vulture, bustard, swan, turkey, etc., are not large or
heavy animals, and in no case in which considerable size and
weight has been attained is the power of flight present.
The flight of birds is entirely effected by the anterior extre-
PNEUMATICITY. EXTERNAL FEATURES. 419
mities, their movements on land by the posterior. They are
bipedal and their legs >re attached comparatively far forward.
In correspondence with this the union between the pelvis and
the vertebral column is both extensive and strong. Posteriorly
the body is prolonged into a short caudal stump (uropygium),
the last vertebrae of which serve for the support of a group of
stiff steering or tail feathers (rectrices). In front it is prolonged
into a flexible neck, on which is balanced a light rounded head
with a projecting beak. The anterior appendages, which are
transformed into wings, lie folded at the sides of the body.
Arrangements for lessening the weight of the body are dis-
cernible, especially in the structure of the osseous skeleton.
The bones contain air-spaces (pneumaticity), which communicate
with the air-sacs of the lungs through openings in the osseous
substance, which is in such cases confined to a relatively thin
layer. Pneumaticity is most developed in those birds which
combine a quick and enduring power of flight with a consider-
able size of body (albatross, pelican, etc.), and is, speaking
generally, least developed in small birds and in aquatic birds.
It is almost absent in passerine birds, swifts, divers, rails and
the Apteryx, and is not found in young birds. When air-spaces
are not present the larger bones contain marrow.
Teeth are not present at any stage of their existence in living
birds. Their place is taken by the horny coverings (rhampho-
theca) which ensheath the upper and lower jaws. The external
nostrils are placed on the upper surface near the root of the
upper beak, except in Apteryx where they are terminal. The
cere is the soft skin which covers the base of the upper beak.
The lore is the space between the beak and the eye. The eyes
are usually remarkably large ; they possess upper and lower
lids, and a well developed nictitating membrane which can be
drawn across the eye from its inner (anterior) angle. The ex-
ternal auditory meatus is short and its opening is often sur-
rounded by a circle of larger feathers (auriculars)* and in a few
birds (e.g. some owls) is overlapped by a cutaneous valve which
is likewise beset with feathers and constitutes a kind of pinna.
A proper pinna is never present.
The anus (vent) is at the hind end of the body at the root of
the tail. On the dorsal side of this part of the body is placed
the opening of the uropygial or oil-gland, a cutaneous gland the
secretion of which the bird uses when preening its feathers.
420 AVES.
The most important feature in the external appearance of birds
is their covering of feathers. The skin is naked in a few places
only — as on the beak, the cere, the toes, (with a few exceptions,
Lagopus, etc.), usually on the tarsometatarsus, sometimes on
the neck (vulture), or even on the abdomen (ostrich), and on the
cutaneous outgrowths of the head and neck (gallinaceous birds,
vulture). While the cere is soft, the edges of the rhamphotheca
are usually cornified, and are only exceptionally soft (ducks,
snipe), and are then richly innervated, serving as a fine tactile
organ. The skin on the toes and metatarsus is cornified so as
to form a firm horny covering, which is sometimes granular,
more often divided into scales, and which may afford important
systematic characters. When this integument is scaly in front
and smooth behind, the metatarsus is said to be laminiplantar
(thrushes and other Oscines). The following special horny
structures may be mentioned : the claws on the toes (and
sometimes on the first and second digit of the manus), the spurs
on the posterior and internal edge of the metatarsus in the male
Gallinaceae, and on the carpus (some Charadriidae, etc.).
Feathers are closely allied to scales. On the wings of pen-
guins the small feathers present are hardly distinguishable from
scales. They arise by the cornification of the epidermis of
papillae containing a vascular core. These papillae at first
project freely on the surface, therein differing from hairs, but
they very soon become secondarily enveloped in a pit (follicle)
which gradually deepens as the development continues.
A typical feather consists of the following parts : There is a
stiff axial rod, the scapus or stem, running the whole length of
the feather. This consists of two parts ; the proximal, hollow,
semitransparent calamus or quill, and a distal part, the shaft or
rhachis. The calamus is cylindrical, is partly embedded in the
skin, and encloses the dried up vascular papilla of the growing
feather ; at its proximal end is a small opening, the inferior
umbilicus, and at its distal end where it passes into the rhachis
there is on the ventral side, i.e. on the side adjacent to the body,
a second opening, the superior umbilicus. The rhachis is solid,
somewhat quadrangular, and grooved on its ventral surface ; it
carries a number of lateral processes, the barbs (rami), which
again carry still smaller processes the barbules (radii). The
barbs and barbules constitute the vane (vexillum) or web of the
FEATHERS. 421
feather. The barbs are narrow elastic laminae which, project
obliquely on each side from the rhachis. The barbules are also
set obliquely on each side of the barb, in such a way that those
on the distal side of a barb, i.e. those pointing towards the apex
of the feather, cross several of the barbules on the proximal side
of the next barb, i.e. on the side of the barb turned towards the
quill end of the feather. The distal barbules possess on their
lower face, i.e. on the face turned towards the body of the animal,
a number of minute processes (barbicels or cilia) with hooked
terminations (kamuli). The upper edges of the proximal
barbules are folded over so as to form a flange with
which the hamuli of the distal barbules of the adjacent
barbs interlock. In this way the barbs on each side of
the rhachis are closely connected together into an almost
air-tight web. The hyporhachis or after shaft is a second shaft
arising from the calamus just proximally to the superior um-
bilicus. In the cassowary it is as large as the main shaft, but
in other birds it is much smaller, and is sometimes absent. It
possesses barbs and barbules, but not barbicels. In the de-
veloping feather the vascular pulp of the quill extends through
the superior umbilicus along the ventral side of the rhachis. The
two rows of barbs converge at the proximal end of the rhachis
so as to run into one another proximally to the superior umbi-
licus.
According to the nature of the rhachis and barbs, the
following kinds of feathers may be distinguished : Contour
feathers (pennae) with stig^jhaft and firm vexillum ; down
feathers (plumulae) with soft shaft and v ane, and without hooks ;
filoplumes with slender hair-like shaft with few or no barbs.
The contour feathers appear on the surface and attain their
greatest development as the remiges (wing- quills) in the wing
and the rectrices (tail -quills) in the tail ; they usually possess
hamuli. The down feathers fonn the deep layer of the plumage
and are covered by the contour feathers ; they serve for the re-
tention of warmth, and in some cases are without a shaft, the
barbs arising in a tuft from the end of the quill. The filoplumes
are distributed among the contour feathers and arise near their
base. There are many forms of feather intermediate between
these principal forms. Powder -downs are down feathers the
ends of which break off into a fine dust ; they occur in patches
422
AVES.
(herons, some parrots, etc.). Nestling downs (neossoptiles) are
down feathers with certain characters of their own found on the
newly-hatched bird. In the autumn there is usually a complete
change of feathers (autumnal moult], whereas in the spring moult,
by which the bird acquires its breeding plumage, there is only
rarely a complete new formation of the plumage. As a rule, the
spring moult is accompanied by a change of colour of the fea-
thers (probably due to chemical change in the pigment already
FIG. 234. — Pterylae and apteria of Gallus bankiva (after Nitzsch) a ventral, b dorsal.
present), and sometimes by a mechanical breaking off of certain
parts of the feathers. The new feathers of the moult are formed
in the follicles and from the pulp of the old feathers.
The plumage is only rarely distributed evenly over the whole
of the body (Ratitae, penguins). Usually the contour feathers
are arranged in rows — the pterylae, between which there are
spaces — the apteria, which are naked or only covered with
down (Fig. 234). The form and distribution of these feather
tracts present modifications which can be used in classification.
FEATHERS.
423
Sc
The grouping ot the feathers on the anterior limb and on the
tail determines the utility of these organs as wings and steering
apparatus respectively. The wing can be folded at two points,
viz., at the elbow joint and the carpal joint ; its surface is
formed by the large remiges attached to the forearm and manus,
and partly by special folds of skin which stretch between the body
and the posterior side of the proximal part of the humerus (post-
patagium), and between the upper-arm and fore-arm on the pre-
axial side (prepatagium, Fig. 234). The prepatagium contains
an elastic band which
extends along its outer
edge from the humerus
to the wrist, and which,
when the fore-arm is ex-
tended, exercises a trac-
tion on the thumb side
of the carpal joint, and so
causes the simultaneous
extension of the hand.
The large wing quills
(remiges) are attached
along the post-axial bor-
der of the fore -arm and
manus to the bones of
these parts. Those
which are attached to
the manus are larger than
the others and are called
primaries or manuals
(Fig. 235 HS) ; while
those which are attached to the fore -arm are called second-
aries or cubitals (Fig. 235 AS). There are usually ten primaries ;
of these some are attached to the metacarpals (metacarpal
quills), the others to the phalanges of digits 2 and 3 (digitals) ;
none are attached to the pollex. The secondaries vary in num-
ber (six to thirty or more) ; they are attached to the ulna. It
happens in some birds (Anseres, Colymbidae, Psittaci, Accipitres,
Columbidae, etc.) that the fifth cubital (counting from the wrist)
is absent,there being a gap between the fourth and sixth (aquinto-
cubitalism). The variability of this character extends through
FIG. 235. — Nomenclature of the plumage and body-
regions of Ampelis garrulus (wax-wing). Slightly
modified (after Reichenbach). Al bastard wing ;
AS secondaries ; B tail-coverts ; Ba belly ; Br
breast ; Hh hind head ; HS primaries • K throat ;
N nape ; P scapulars ; R back ; Rt tail with tail-
quills ; S forehead ; Sc occiput ; St vent ; T
coverts ; W cheek ; Z lore.
424 AVES.
the whole class and is found even in members of the same family.
Covering the bases of the remiges and filling up the gaps be-
tween them are smaller pennae called wing-coverts (tectrices). A
small number of pennae attached to the humerus are called
scapulars (parapterum), and some feathers attached to the
thumb constitute the bastard wing (alula). In some birds the
wings become so much reduced that the power of flight is almost
or quite, as in Ratitae, penguins, etc., lost.
The great tail-quills are called rectrices (Rt), because during
flight they are used for steering. There are, as a rule, twelve
(sometimes ten or twenty and more) rectrices attached to the
last caudal vertebrae in such a way that they can be moved
singly, and unfolded laterally like a fan, as well as be all raised
or depressed together. The roots of the rectrices are covered by
a number of coverts, which in some cases attain an extraordinary
size and shape and constitute an ornament to the bird (pea-
cock). When the power of flight is absent the tail loses its sig-
nificance as a steering apparatus and the rectrices are reduced
or absent. In such cases, however, some of the coverts may
attain a considerable development as ornamental feathers.
Birds have no sebaceous or sweat glands, but as mentioned
above there is an oil-gland on the rump.
The hind limbs, which are principally used in movement
upon firm ground, present much diversity, according to the
mode of locomotion of the bird. In the first place walking feet
(pedes gradarii) and wading feet (pedes vadantes) are to be dis-
tinguished (Fig. 236). In the former the legs are much more
completely feathered, being covered at least as far as the tarsal
articulation ; but they vary considerably. As a rule four toes
are present (digit No. 5 being absent), and the first toe is directed
backwards, but the following varieties may be distinguished
(Fig. 236): All four toes are directed forwards (p. adhamantes),
e.g. Cypselus (a), sometimes the inner toe can be turned for-
wards and backwards (Colius) ; two toes directed forwards and
two (1 and 4) backwards (p. scansorii), Picus (b), sometimes the
outer toes of this type of foot can be turned both forwards and
backwards (Cuculus) ; three toes directed forwards and one
back, the anterior toes being free to their roots (p. fissi). Turdus
(d) ; three toes directed forwards, the inner toe backwards, the
middle and outer toes united at their roots (p. ambulatorii),
FOOT.
425
Phasianus (c) ; the inner loe is placed behind, the three ante-
riorly directed toes are fused as far as the middle (p. gressorii),
Alcedo (e) ; inner toe behind, the three anterior toes are united
by a short membrane (p. insidentes), Falco (/). The wading legs
FIG. 236.— The most important forms of birds' feet (b, c, ct, f, n, from the Regne animal).
a Cypselus apus ; b Picus capensis ; c Phasianus colchicus ; d Turdus torquatus ; e Alcedo
hispida ; f Falco biarmicus ; j Mycteria senegalensis ; h Siruthio camelus ; i Meryus merganser ;
k Recurvirostra avocetta ; I Podicipes cristatus ; m Fulica atra ; n Phaethon aethereus.
(p. vadantes) as opposed to the walking legs are characterised by
the partly or completely unfeathered tibial region ; they are
found principally in aquatic birds, some of which have a very
long metatarsus. The feet of birds with long wading legs
may be distinguished into those in which the anterior toes are
426 AVES.
united at their roots by a short membrane, Ciconia (g) ; and
those in which this membranous connection is confined to the
middle and outer toes. The short wading legs of the swimming
birds, as well as those with long wading legs present with regard
to the structure of their feet the following types : Swimming
feet, in which the three anteriorly directed toes are connected
as far as their extremities by an undivided swimming membrane
or web, Anas (i) ; half-swimming feet when the web only reaches
to the middle of the toes, Eecurvirostra (k) ; split swimming feet
when the toes have an entire cutaneous border, Podicipes (I) ;
lobed feet when the border is lobed at each joint, Fulica (m) ;
sometimes the hind toe is included in the web-membrane, Phae-
thon (n) ; finally the hind toe may be completely absent in
some wading birds. In the Eatitae the inner toe is always absent,
and in the ostrich the second digit as well.
Colour is highly developed in the feathers of birds and in some
cases in the skin of the head and neck (combs, wattles). It is
due either to pigments (absorption colours), or to the structure
of the parts acting upon the light after the fashion of a prism or
of thin plates (metallic lustre, iridescent colours). Sometimes
these two causes combine and produce wonderful effects as in
the humming birds, peacock, etc. The blacks, browns, reds,
yellows and rarely greens may be due to pigment ; blues and
violets are due to pigment and structure, there being no blue
pigment in birds. In the Touracos (Musophagidae) there is a
red pigment called turacin, which is soluble in water and washes
out of the feathers, colouring the water when the animal gets
wet or bathes ; the birds regain the colour when d^. It is
stated that the colour of fully grown feathers, in which the pulp
is dry, can in some cases change.
The brain-case (Fig. 237) is arched and spacious, and, except
in the Eatitae and one or two other groups, the bones become
early fused together and the sutures obliterated. The orbits are,
except in Apteryx, very large. There is a well-marked inter-
orbital septum and the facial part of the skull is prolonged into
a beak consisting mainly of the premaxillary bones. The infra-
temporal arcade is complete, the rod-like jugal (J) and quad rat o-
jugal (Q j) reaching back to the quadrate (Q). The supra-
temporal arcade is usually incomplete, but in some birds, e.g.
the fowl, the squamosal sends forward a process which joins the
SKULL.
427
postorbital process of the frontal. There are no pref rentals,
postfrontals, or postorbitals, and the orbit is not closed pos-
teriorly from the temporal fossa, though in parrots the post-
orbital process of the frontal meets a backwardly directed
process of the lacrymal beneath the orbit.
Hi Pt
Pcil
FIG. 237. Skull of Otis tarda (bustard), a from the
side; & from below (from Claus). Als alisphenoid ; j
Ang angular ; Art articular ; Bt basitemporal (para-
sphenoid) ; G occipital condyle ; D dentary ; Et
median ethmoid ; F r frontal ; J jugal ; Jmx premaxilla ;
L lacrymal ; MX maxilla ; N nasal ; Ob basioccipital ;
01 expccipital ; Os supra-occipital ; Pa parietal ; Pal
palatine ; Pt pterygoid ; Q quadrate ; Qj quadrato-ju-
gal ; Sm inte'forbital septum ; Spb basisphenoid ; Sq
squamosal ; Vo vomer.
Vo
• The squamosal (Sq) is closely applied
to the skull and is ankylosed with the
periotic bones (pro-, epi-, and opis-
thotic) ; it often sends a process down-
wards over the quadrate bone. There
are 110 par otic processes. The quad-
rate is moveably articulated with the
squamosal, the prootic and the alisphe-
noid. The palate is very imperfect,
the posterior nares are between the
palatines and the vomer which is
usually much reduced, and the maxil-
laries usually have a maxillo-palatine
process (Mx). There is no second-
ary hard palate. The occipital condyle is single and
there is no parietal foramen. Parasphenoidal elements are
present in the form of the basitemporals which are fused with
the base of the skull and as the basisphenoidal rostrum. The
custachian tubes are included in the basisphenoid and the aper-
428
AYES.
tures are near together on the base of the skull. The lower jaw
contains, as in other Sauropsida, six osseous elements, viz.,
articular, angular, surangular, coronoid, dentary and splenial.
The hyoid bone is prolonged into a posterior rod and consists of
three basal pieces, of which the anterior is called the entoglossal
bone (Fig. 238, Ent), the middle the basihyal (Co) and the
posterior rod the urohyal. It carries one pair of cornua (Zh),
which are the homologues of the first branchial arches ; these are
usually two -jointed and not connected with the skull, but in
most woodpeckers they are much elongated and arch over the
skull as far as the forehead, constituting in connection with the
muscles of their sheath a mechanism
for the protrusion of the tongue. The
columdla, auris consists of an osseous
rod, the inner end of which fits into
the fenestra ovalis while the outer end
expands into a triradiate cartilage
which is attached to the tympanic
membrane.
-Ent
The above are the main features in the
avine skull. The following additional points
may be noted. The foramen magnum looks
downwards as well as backwards. All the
occipital bones enter into the foramen mag-
num, but the condyle is formed almost en-
tirely by the basioccipital. The epiotic and
opisthotic fuse with the occipital bones before
FIG. 238.-H void bone of CO/TU* they unite with the prootic. Basisphenoids
comix (from Claus). Co basi- ?
hyal ; Zh cornua ; Ent ento- and alisphenoids are well developed, but
glossal bone. ^he presphenoid and orbitosphenoids, which
enter into the interorbital septum are
often imperfect. The interorbital septum (to a varying extent
cartilaginous) is formed anteriorly by the mesethmoid (Et), which is
continuous in front with the (mainly) cartilaginous internasal septum,*
and may appear on the surface of the skull between the nasals and fron-
tals. It is underlaid by the basisphenoidal rostrum. The turbinals or
lateral ethmoids are poorly developed. The lacrymals (L) are large and
perforated by the lacrymal canal. The nasals (N) are well developed
and form the upper and lateral boundaries of the external nares.f The
* When the internasal septum is complete the" nostrils are said to be
impervious (nares imperviae), when it is incomplete they are described as
pervious (n. perviae).
f The term holorhinal is applied to those cases in which the external
narial opening is oval, the posterior border being curved and in front of
the posterior end of the premaxillae. In the so-called schizorhinal arrange-
ment the openings are elongated, the posterior border being angular or
slitlike and behind the posterior ends of the premaxillae.
SKULL. 429
premaxillae (Jmx) are united into a large triradiate bone. The upper
beak is in some birds slightly moveable upon the skull at the posterior ends
of the nasals and premaxillae, and in the parrots there is a joint at this
point in virtue of which the upper beak has considerable mobility.
There are two vomers but they early unite into a single bone, which is
sometimes extremely small or even absent. They underlie the median
ethmoid and, except in the ostrich, unite posteriorly with the palatines.
The maxillae, which are slender, possess maxillo-palatine plates which
may or may not unite with the vomer or with each other ventral to the
vomer. The palatines (Pal) are elongated bones extending from the pre-
maxillae backwards to the pterygoids, passing ventral to the maxillo-
palatines ; their hind ends usually join the basisphenoidal rostrum (Spb)
by an articular surface which allows of their movement on the rostrum.
The ptergyoids (Pt) in front articulate with the palatines and usually with
the basisphenoidal rostrum ; in some birds there is an additional articu-
lation with the rostrum by means of the basipterygoid processes of the
latter (Ratitae, some Carinatae). Posteriorly the pterygoids articulate with
a process of the quadrate. In struthious birds the pterygoids articulate
in front with the vomer (except in the ostrich). This also happens in the
embryos of many birds, in which the pterygoid extends forwards to the
vomer dorsally to the palatine. This forward process in later growth
loses its connection with the pterygoid, appearing to segment off from it ;
it sometimes remains as a separate splint called the hemipterygoid (pen-
guins, etc.), but it usually disappears, fusing indistinguishably with the
palatine. In Tinamus the pterygoid articulates with the vomer in the
adult as in struthious birds.
The principal forajnina are as follows : the condylar foramen for the
12th nerve, through the exoccipital bone slightly in front of and ventral
to the foramen magnum. Slightly external to and behind the condylar
foramen is the jugular foramen for the 9th, 10th, and llth nerves and for
the internal jugular vein, between the periotic (petrosal) and the exocci-
pital bones. To the outer side of the jugular foramen is a depression, the
tympanic recess, at the median anterior end of which is the opening into
the carotid canal for the internal carotid artery. The 7th nerve traverses
the periotic bone and emerges by a small foramen in front of the fenestra
ovalis. The eustachian canals open into a deep notch at the anterior end
of the basitemporal, and just external to these are the anterior openings
of the carotid canals. The foramen for the trigeminal is just in front of
the articulation of the quadrate and is between the prootic and alisphenoid.
The optic foramen is a large foramen in the hinder end of the interorbital
septum ; and just behind it are two or three small openings for the oph-
thalmic branch of the 5th, the 3rd, 4th, and 6th nerves. The olfactory
foramen is dorsal to the optic and is continued as a groove between the
interorbital septum and the frontal.
Huxley * pointed out the following different arrangements in the palatal
bones of birds : In the Ratitae and Tinamus the vomer is large and
broad, and the palatines do not articulate with the rostrum, the vomer
intervening ; there are well marked basipterygoid processes, which arti-
culate with the hinder parts of the pterygoid ; the maxillo-palatines unite
with the vomer. This is the dromaeognathous arrangement. In Carinatae
(excepting Tinamus} the palatines and pterygoids articulate with the
* P. Z. S. 1867.
430 AVES.
rostrum at the point where they join one another. When the vomer is
small and pointed in front (or absent), and the maxillo-palatines do not
unite with one another and the vomer, the arrangement is termed schizo-
gnathous * (plovers, gulls, penguins, fowls, pigeons, etc.). The aegitho-
gnathous f arrangement (passerines, swifts) is similar to the schizogna-
thous excepting in the fact that the vomer is truncated in front. Lastly
when the vomer is small and the maxillo-palatines are large and spongy,
uniting with the maxillo-palatines or with each other across the middle
line ventral to the vomer the palate is described as desmognathous { —
(anserine birds, birds of prey, parrots, etc.).
In the vertebral column (Fig. 239) a long flexible cervical
region, a rigid thoracic, lumbar, and pelvic region, and a slightly
moveable, short, caudal region may be distinguished.
The cervical and thoracic regions are not sharply distinct from
each other, since the cervical vertebrae, as in crocodiles, bear
double-headed ribs, the capitulum of which is fused with the
centrum and the tubercle with the transverse process, enclosing
between them the vertebrarterial canal. The last two cervical
ribs are free, but do not reach the sternum. The atlas is a ring-
like bone, and the axis possesses a peg-like odontoid process.
The articulating surfaces of the remainder of the cervical verte-
brae are saddle-shaped and without epiphyses (except in the
parrots). The neck is long and freely moveable and contains
nine to twenty- three (swan) vertebrae. The thoracic vertebrae
are fewer in number ; they all carry ribs which are united to the
sternum by a sternal portion (Stc), and to the vertebrae by a
capitulum which is attached to the centrum or lower part of the
arch and by a tuberculum to the transverse process of the neural
arch. The vertebral portions of the ribs carry backwardly
directed bony uncinate processes. The thoracic vertebrae are
sometimes slightly moveable upon one another, sometimes anky-
losed ; in the former case the articulating surfaces are saddle-
shaped, or as in the penguins, plovers, etc., are rounded, the
anterior surface being convex, the posterior concave.
The rib-bearing thoracic vertebrae are followed by a tolerably
extensive region of the vertebral column in which the vertebrae
are fused with one another and with the long iliac bones of the
pelvic girdle. This is the compound sacrum and includes as
many as sixteen to twenty or more vertebrae. Of these one or
* Alluding to the cleft between the maxillopalatine and vomer.
f &iyi$os, a finch.
J Setr/wi, a bond.
SKELETON.
431
two bear ribs which reach the sternum and are clearly thoracic ;
these are followed by a variable number (about six) of vertebrae
Fio. 239.— Skeleton of Neophron percnopterus (from Claus). CC' carpus ; Cl clavicle ;
Co coracoid ; Du inferior spinous processes of the thoracic \ ertebrae ; F fibula ; Fe femur ;
II humerus ; Jl ilium ; Js'ischium ; Me metacarpus ; P', P", P'" phalanges of the fingers ;
Pb pubis ; Pu uncinate processes of the ribs ; R radius ; Rh cervical ribs ; Sc scapula ; St
sternum ; Stc sternal portions of ribs ; T tibia ; Tm tarso-metatarsus ; U ulna ; Z toes.
432 AVES.
which are clearly lumbar (presacral) ; then follows the true
sacrum consisting of two vertebrae with their sacral ribs ; finally
comes the postsacral portion of the compound sacrum, which
consists of from three to seven of the anterior caudal vertebrae.
The short caudal region, which succeeds the postsacral, consists,
as a rule, of from seven to eight moveable vertebrae, of which the
last is represented by a vertical, laterally compressed plate, the
pygostyle, which supports the tail-feathers and the uropygial
gland. This deep ploughshare-shaped terminal bone is com-
posed of from four to six fused vertebrae, so that the reduction
of the number of caudal vertebrae, as compared with the num-
ber in the tail of Archaeopteryx, is not very great.
The moveable vertebrae are separated by synovial cavities,
each of which is divided into two by a plate of fibro -cartilage,
called the meniscus. The meniscus is perforated by an aperture
which transmits a fibrous cord which is a remnant of the noto-
chord.
The sternum (St) is a broad bone which covers not only the
thorax but a great part of the abdomen and bears a projecting
keel -like crest which serves for the attachment of the great
pectoral muscles (Carinatae). The keel is reduced or obsolete
only when the power of flight is feeble or absent (Eatitae, Strin-
gops). The postero -lateral part of the sternum may be fenes-
trated, giving rise to vacuities or notches in the bone.
The spina sternalis or rostrum is the anterior continuation of the sternum
between the articulation of the coracoids. In some birds it consists of a
dorsal (spina internet) and ventral (spina externa) portion.
The pectoral girdle consists of a scapula, a coracoid, and a
clavicle. The scapula (Sc) is a sabre-shaped bone lying along
the dorsal side of the thoracic framework. Its anterior end is
expanded and firmly united by ligament (usually not ankylosed)
with the coracoid (Co), which is directed ventralwards and
articulates with a groove on the anterolateral edge of the ster-
num. In the Eatitae the long axis of the scapula is nearly in the
same straight line as that of the coracoid, but in most birds it
forms an angle less than a right angle with the coracoid (Fig. 239).
Both bones contribute about equally to the glenoid cavity.
The glenoidal end of the scapula is produced into an acromial
process, to which the clavicle is attached. The clavicle is also
SKELETON. 433
attached to a process — the clavicular process — of the dorsal end
of the coracoid. A foramen, called the foramen triosseum, is
thus left between the three bones of the shoulder girdle at the
point where they meet one another. The two clavicles are
ankylosed together ventrally and may at this point be attached
by ligament or even ankylosed to the keel of the sternum. The
clavicles are small and remain distinct from one another ventrally
in some birds (parrots, owls, toucan, emeu) and are rarely absent
(some Batitae, some parrots).
The humerus has an expanded head, a preaxial and postaxial
tuberosity, of which the postaxial is the larger, and a deltoid
ridge which extends for a short distance down the shaft of
the bone from the preaxial tuberosity. The pneumatic foramen
is on the proper dorsal face of the proximal end of the bone
close to the postaxial tuberosity. The ulna is stouter than
the radius and often presents a number of tubercles caused
by the attachment of the wing quills. The carpus con-
sists of two bones only, but hi the young bird it is said that a
distal carpal row of three pieces which later fuse with the meta-
carpus can be made out. Three digits are present, viz. digits
1, 2, and 3. The metacarpals of these are all fused together ;
that of the pollex is much shorter than the others and carries two
phalanges. The metacarpals of the other two digits are united
at each end ; digit No. 2 has two or three phalanges and digit
No. 3 has one phalanx (two in the ostrich). The terminal pha-
lanx of the pollex is often unguiculate, as is in rare cases (ostrich)
that of the second digit. In the emeu and apteryx the first and
third digits are absent in the adult, and in some birds the wing
bones are considerably reduced (Hesperornis) and almost or
quite absent (Moas). In Archceopteryx the metacarpals are
separate and all the digits bear claws. In some embryo birds
a rudiment of digit No. 4 is said to have been detected.
In the pelvic girdle the ilia are remarkably expanded antero-
posteriorly both in front of and behind the acetabulum, and at-
tached by their whole length to the compound sacrum. The
ischia are directed backwards parallel to the hinder part of the
ilium to which they are attached posteriorly converting the ilio-
ischiatic notch into a foramen. The pubes are slender bones
directed backwards parallel to the ischia, with which they often
unite posteriorly. The pubes and ischia do not unite with each
z— ii F F
434 AVES.
other ventrally except in the ostrich in which there is a sym-
physis pubis. and in Ehea in which there is a symphysis ischii ;
but the symphysis ischii of JRhea is peculiar in being dorsal to
the intestine and ventral to the kidneys ; it is associated with a
curious weakening of the postsacral part of the vertebral column
in the adult. All three bones enter into the acetabulum which
is perforated, and the pubis has in some birds (Apteryx) a for-
wardly directed preacetabular process (pectineal process).
This process appears to be more marked in embryos, in which it
was discovered by Miss Johnson * in the chick. In a few birds
the ilia are quite separate from the ischia except in the aceta-
bulum (Tinamus, Struthio, Apteryx, Hesperornis, etc.). The
short and powerful femur is directed obliquely horizontally for-
wards and concealed beneath the flesh and feathers of the abdo-
men, so that the knee-joint is not visible externally. The head
is rounded and stands out at right angles to the bone. A patella
is usually present. The crus, which is much longer, is chiefly
composed of the tibia, the fibula being reduced (especially dis-
tally) and represented by a styliform bone on the outer side of the
tibia. The proximal end of the tibia is expanded and has on its
anterior face a great ridge, the cnemial crest. There appears
to be no tarsus, but two rows of tarsal elements are present in
the embryo, of which the proximal row unites with the tibia and
the distal with the metatarsus, so that the bone which we have
called tibia is really the tibio-tarsus, and the ankle joint is inter-
tarsal. In the same way the metatarsus is in reality a tarso-
metatarsus. The tarso -metatarsus varies much in length and
is the cause of the differences in the length of the leg. It is
composed of the distal tarsalia and of three long metatarsal
bones of digits 2, 3, and 4, fused together. At its lower end it
discloses its composite nature by dividing into three processes
which are provided with articulating surfaces for the proximal
phalanges of the corresponding digits. When a fourth toe
(digit No. 1) is present, its metatarsus is distinct from the tarso-
metatarsus and has the form of a small bone on the inner side
of the metatarsus ; it carries the phalanges of the inner digit or
hallux. The usual phalangeal formula is 2, 3, 4, 5. No bird
has digit No. 5,j* though a trace of its metatarsal is said to be
present in the embryo.
* Q.J.M.8., 23, 1883, p. 399.
f The fifth digit seen in some breeds of fowl is not the true fifth digit,
but an abnormality.
BRAIN.
435
When three toes only are present the hallux is suppressed.
In the ostrich digit No. 2 is also absent. In the penguins the
fibula has the same length as the tibia, and the metatarsals
though fused, are more distinct than in
other birds.
In the development of the foot there are
said to be at first three proximal tarsals and
five distal. The proximal elements unite
while still in the cartilaginous condition into
one piece which then ossifies and fuses with
the tibia. The five distal elements are also
said to unite to one cartilage which ossifies
and fuses with the second, third, and fourth
metatarsals. The latter are at first separate,
but later fuse. When the compound meta-
tarsal so formed elongates, as it generally
does, the first rmetatarsal does not share in
the » elongation but remains distinct at the
distal end ; in one or two cases (e.g. Phaethon)
it fuses with the lower end of the tarsometa-
tarsus. A centrale (or sometimes two) is
said to be sometimes detectable in the embryo
and even to persist in the adult as a distinct
bone on the posterior surface of the joint.
The brain of birds (Fig. 240) is much
more highly developed than that of
reptiles, and completely fills the roomy
cranial cavity. The hemispheres are,
indeed, still without superficial con-
volutions. They cover not only the
thalamencephalon, but also the two
large, laterally displaced corpora bige-
mina. The differentiation of the cere-
bellum is still further advanced, since
there is a median part corresponding
to the so-called vermis of Mammalia
and marked by transversely directed
sulci and small lateral lobes.
In consequence of the cervical
flexure of the embryo the medulla
oblongata forms an angle with the spinal cord, the posterior
columns of which diverge from one another in the posterior
FIG. 240.— Brain and spinal
cord of a pigeon. O cere-
bellum ; Cb optic lobes ; H
cerebral hemispheres ; Mo
medulla oblongata ; Sp spinal
nerves.
436
AVES.
enlargement of the lumbar region so as to form a second sinus
rhomboidalis (Fig. 240). The cranial nerves are all separate
and their distribution is essentially the same as in the Mammalia.
The spinal cord reaches almost to the end of the neural canal of
the vertebral column.
Sense organs. The eyes always attain a considerable size and a
high development. The eyelids are always moveable, especially
the lower lid and the transparent nictitating membrane, which
is drawn over the eye by a peculiar muscular apparatus. The
eyeball (Fig. 241) has an unusual form, in that the hind part on
which the retina is spread is a segment of a much larger sphere
than is the small anterior part. The two parts are connected
by a median portion, which has the
shape of a short truncated cone,
with the smallest end directed for-
wards. This form of the eyeball
is most marked in the nocturnal
birds of prey, and least in the
aquatic birds in which the axis of
the eye is short. There is always a
bony sclerotic ring behind the edge
of the cornea. The cornea is
strongly arched, while the anterior
surface of the lens only possesses
a considerable convexity in noc-
turnal birds. The pecten ' (wanting
only in Apteryx) is a peculiar
structure of the avine eye. It
consists of a process of the cho-
roid, which traverses the retina near the optic nerve and
passes obliquely through the vitreous humour to the lens. It
corresponds to the falciform process of the piscine and reptilian
eye. The avine eye is characterised not only by the sharpness
of vision consequent on the large size and complicated structure
of the retina (many birds possess two foveae centrales in each
eye): but also by the highly-developed power of accommodation,
which is principally due to the muscle of the so-called ciliary
ligament (Crampton's muscle), and also to the great mobility of
the muscular iris, which possesses both sphincter and dilator
muscles. The sphincter is supplied by the third nerve and is
Rt
FIG. 241. — Eye of a nocturnal bird
of prey (after Wiedersheim) .
CM ciliary muscle ; Co cornea ;
L lens : N.o optic nerve ; P pec
ten ; Rt retina ; Sc ossifications of
the sclerotic.
SENSE ORGANS. 437
under the control of the will. Lacrymal and harderian glands
are both present. They are placed within the orbit, the former
on the outer side of the eyeball and the latter on the inner and
upper side. The harderian gland opens within the nictitating
membrane. The secretion of both glands is carried off by a wide
lacrymo -nasal duct which leaves the inner angle and opens in the
nasal cavity immediately above the internal nares.
The auditory organ is contained in the periotic bone. It
possesses three large semicircular canals which open into the utri-
cle, and a saccule which gives off a slightly bent cochlea (lagena)
and a ductus endolymphaticus ; the latter enters the cranial
cavity and ends in the dura mater in a flattened sac. The coch-
lea is without an organ of Corti. The vestibule has two
openings : the fenestra ovalis which is closed by the terminal
piece (operculum) of the columella and looks into the tym-
panic cavity, and a second more rounded opening, the
fenestra rotunda, which is closed by membrane only. The
eustachian tubes after leaving the bone join to form a short
membranous duct, which opens into the pharynx by a median
opening. The tympanic cavity also communicates with air-
spaces in the neighbouring bones of the skull. Externally the
tympanic cavity is closed by a tympanic membrane, to which
the long rod-shaped auditory ossicle (columella), corresponding
to the auditory ossicles of Mammalia, is fastened. On the outer
side of the tympanic membrane there is a short external audi-
tory meatus, the opening of which is often surrounded by a circle
of large feathers, and in the owls is overlapped by a cutaneous
valve which is likewise beset with feathers, and constitutes a
rudimentary pinna.
The olfactory organ has three pairs of turbinal bones in the
spacious nasal cavities. The two nasal apertures,* except in
Apteryx, lie more or less near the root of the upper beak ; some-
times (crows) they are covered and protected by stiff hairs ; in
the Procellariidae they are elongated into a tube and join one
another. A so-called nasal gland usually lies on the frontal bone,
more rarely beneath the nasal bone or at the inner corner of the
eye ; it opens by a simple duct into the nasal cavity.
The sense of taste is connected with the soft base of the tongue
* In Phalacrocorax and apparently in other Steganopodidae the external
nostrils are said to be closed in the adult.
438 AVES.
which is rich in papillae. The tongue is soft throughout its
whole extent only in the parrots. In most other cases it has a
firmer covering, and in many cases lends important aid in mas-
tication. In general the tongue as well as the beak may be
regarded as a tactile organ. In rare cases (snipe, duck) the beak
is the seat of a finer tactile sensibility, owing to the possession
of a soft skin rich in nerves and in the end-corpuscles of Vater.
Alimentary canal. In spite of great differences in the mode
of nourishment the avine digestive organs present a fairly uni-
form structure ; their peculiarities have relation to the power
of flight. The jaws are covered by a hard horny sheath (rham-
photheca) and transformed into the beak. The rhamphotheca
is often composed of several pieces * (compound). True teeth
are entirely absent, at least in living birds as opposed to some
fossil forms (Ichthyornis, Hesperornis, Archaeopteryx). While
the upper beak is formed by the fused praemaxillae, the maxillae
and the nasal bones, the lower corresponds to the two rami of
the lower jaw, the fused extremities of which are known as the
myxa. The lower edge reaching from the angle of the chin to
the extremity is termed the gonys, the edge of the upper beak
is the culmen, the region between the eye and the base of the
beak which is covered by the cere (ceroma) is the lore. The form
and development of the beak vary extremely according to the
special mode of subsistence (Fig. 242).
The tongue, which is always moveable, lies on the floor of the
buccal cavity. It consists of the horny or fleshy covering of two
cartilages attached to the anterior end of the hyoid bone, and
serves for deglutition, and frequently for seizing food. The
buccal cavity, which in the pelicans is dilated into a large
gular sac supported by the rami of the lower jaw, receives the
secretion of a number of small salivary glands (sublingual, sub-
maxillary and parotid ; in the woodpecker the sublingual glands
are large). There is no velum palati. The muscular, longi-
tudinally folded oesophagus, the length of which in general
depends on that of the neck, frequently possesses— especially
in the birds of prey, but also in the granivorous birds — a crop-
like dilatation, in which the food is softened (Fig. 243). In the
pigeons the crop bears two small round accessory sacs.
The lower end of the oesophagus is dilated into a glandular
* Lounberg, Arkiv for Zoologi, 1, 1904, p. 479.
ALIMENTARY CANAL.
439
proventriculus, which is followed by the wide muscular stomach
(gizzard). While the proventriculus has, as a rule, an oval form
and is smaller than the gizzard, the gizzard is provided with
muscular walls, which are weaker (birds of prey) or stronger
(granivorous birds), according to the kind of food eaten. In the
granivorous bird^ the gizzard is excellently adapted for the
Fia. 242. — Forms of beaks (a, b c, d, k, after Naumann ; g, i, m, o, R£gne animal ; I from
Brehrn). a Phoenicopterus antiquorum ; b Plttalea leucorodi-a ; c Emberiza citrinella ;
Turdiis cyanus ; e Falco candicans ; / Mergus merganser ; g Pdicanus perspiciUatus ; h Re-
cj'.rrirostra avocetta ; i Rhynchops nigra ; k Columba livia ; I Balaeniceps rex ; m Anastomui
coromanddianus ; n Pteroglossus discolor ; o Mycteria senegalensis ; p Falcindlus igneus ;
q Cypsdus apus.
mechanical preparation of the softened food material by the
possession of two solid plates, which form the horny internal
wall and work against one another. It contains small stones
which the bird swallows to aid in the grinding of the food. The
440
AVES.
K
first loop oi the small intestine (corresponding to the duodenum)
surrounds the elongated pancreas, the ducts of which (one to
three in number), as well as the usually double bile ducts, open
in this region. A gall-bladder is usually present. The begin-
ning of the short large intestine is marked by a circular valve,
and by the origin of two caeca ;
it presents no distinction into
colon and rectum, and passes
into the cloaca, into which the
urinogenital apparatus also
opens. At its entrance into
the cloaca it presents a
sphincter-like circular fold.
A peculiar glandular sac — the
bursa Fabricii — opens into the
dorsal wall of the cloaca.
There is no bladder in the adult.
The falciform ligament has
a considerable extension, pass-
ing back from the pericardium
to the hinder part of the body
cavity as a median septum.
The large omentum is well
developed.
The cloaca usually presents
three fairly well-marked divi-
sions separated by folds.f The
anterior of these, often called
the coprodaeum, is the dilated
hind end of the rectum ; its
lining is however different from
that of the rectum from which
it is often separated by the
fold above referred to. The
middle chamber is called
the urodaeum ; it is smaller than the others and receives
the openings of the urinogenital ducts. The posterior chamber
which opens by the vent, may be termed the vestibule (some-
times erroneously called proctodaeum) ; it receives the bursa
Fabricii dorsally. Most birds are without an organ of copula-
FIG. 243.— Digestive canal of a bird. Ad
large intestine (rectum) ; C the two
rectal caeca ; D small intestine ; Dm
proventriculus ; H liver ; K crop ; Kl
cloaca ; Km gizzard ; Oe oesophagus ;
Ov oviduct • P pancreas placed in the
duodenal loop ; U ureter.
VASCULAR SYSTEM. 441
tion, sperm -transference being effected by a slight eversion of
the cloaca. In the Ratitae (except Rhea] there is solid grooved
penis attached to the ventral wall of the vestibular division of
the cloaca ; it is very similar to the corresponding organ of
Chelonia, contains erectile tissue and can be extruded or re-
tracted by special muscles. In Bhea and anserine birds a very
similar organ occurs, but its terminal portion is invaginated
during rest and evaginated in erection like the finger of a glove.
The heart is completely divided into a right and left half, and
lies in the median line, enclosed by the pericardium. As a pecu-
liarity of the heart may be mentioned, the special development
of the right auriculoventricular valve, which, unlike the tri-
cuspid valve of the mammalian heart, is a simple strong mus-
cular fold. The left auriculoventricular valve is membranous
and possesses chordae tendinese as in mammals. There is no
diaphragm in the mammalian sense and the thoracic cavity is
directly continuous with the abdominal. The pulsations of the
heart, in correspondence with the more active respiration, are
repeated more rapidly than in Mammalia. The right aortic
arch alone persists. The carotids converge and run close to-
gether in a furrow on the ventral side of the cervical vertebrae.
In some birds they unite, and in some only one of them is-prje-
sent. In some cases superficially placed vessels (superficial
carotids) coexist with or take the place of the normal carotids
(deep carotids). There is no sinus venosus. The veins open by
two superior and one inferior Yena cava into the right auricle.
The renal-portal circulation appears to be absent, all the blood
from the hinder part of the body passing either directly into the
inferior vena cava or by the coccygeo-mesenteric into the hepa-
tic-portal system. The coccygeo-mesenteric vein is peculiar to
birds ; starting from the point where the caudal vein bifurcates
into the two veins (called variously internal iliacs, hypogastric,
renal portal) which run forward on the ventral surface of the
kidneys to join the femoral veins, it passes in the mesentery of
the rectum to join the portal system as one of the roots of the
portal vein ; it receives blood from the hinder end of the small
intestine, the rectum and the cloaca. There appears to be a
representative of the anterior abdominal vein in the form of a
vessel which collects blood from the abdominal wall and great
omentum and falls into the left hepatic vein ; it does not how-
442 AVES.
ever anastomose with the system of the femoral as in reptiles
and amphibians.
The red blood corpuscles are oval and nucleated.
The lymphatic system opens by two thoracic ducts (ductus
thoracici) into the superior venae cavae, but also very generally
communicates with the veins of the pelvic region. Lymph
hearts are only found at the side of the coccygeal bone in the
ostrich and cassowary, and in some wading and swimming birds.
They are, however, often replaced by vesicular non-contractile
dilatations.
A spleen, thymus, and thyroid glands are present. The thy-
roid is paired and placed at the base of the neck attached to the
carotid artery and jugular vein. The thymus is an elongated
body on each side of the neck along the jugular vein. The supra -
renals (adrenals) are a pair of elongated yellow bodies attached to
the ventral surface of the kidneys along the iliac veins.
The respiratory organs * are perhaps the most remarkably
modified of all the organs. The lungs are small and but slightly
if at all distensible. They are prolonged into a number of thin-
walled air-sacs which extend amongst the viscera, into the bones,
and sometimes beneath the skin. The organ of voice is not in
the larynx but lower down on the trachea, usually at its bifur-
cation into the bronchi. These peculiarities are associated with
three remarkable properties, viz. flight, the extraordinary power
of voice production, and the intense activity of the metabolic
processes.
The slitlike glossis is placed behind the root of the tongue, and
leads into a larynx, which is supported by cricoid, thyroid and
arytenoid cartilages, but is devoid of vocal chords. An epi-
glottis is absent or represented only by a small transverse fold.
The trachea is supported by bony rings which are usually com-
plete, and on reaching the thorax bifurcates into the two bronchi.
It is not unfrequently longer than the neck, and in such cases,
principally in the male sex, is thrown into a number of coils,
which either lie outside the thorax beneath the skin (capercally),
etc.) or even penetrate into the hollow crest of the sternum
(whooper swan).
* Sappey, Recherches sur Vappareil respiratoire des Oiseaux, 1847, and
Compt. Rend. 22, pp. 250, 508. Huxley, On the respiratory organs of
Apteryx, Proc. Zool. Soc. 1882, p. 560. Strasser, Jen. Zeitschr., 19. pp.
174, 330. Butler, P. Z. S., 1889, p. 452.
SYRIXX
443
The lower larynx or syrinx. Except in the ostrich, storks,
and some vultures, the vocal organ is placed lower down on the
trachea usually at the point where the trachea divides into the
bronchi, so that both divisions take part in its formation (Fig.
244). The last tracheal rings and the anterior bronchial rings
have a modified form, and are often intimately connected with
each other ; the end of the trachea and the beginning of the
bronchi are compressed or dilated into a vesicular form and
transformed into the so-called tympanum, which in the males of
many ducks is dilated into unsymmetrical secondary cavities
(tympanic cavity and labyrinth), which serve as a resonating
apparatus. The part of the trachea from which the bronchi
FlO. 244.— Lower larynx of raven (from Owen), a side view of larynx laid open ; b larynx
after removal of m'useles ; c larynx with muscles from the front ; d from the side. M
muscles ; Ms membrana semilunaris ; Mty membrana tympaniformis interna ; Rh the
modified three first bronchial rings ; lit modified last tracheal ring ; St pessulus.
pass off (i.e. tympanum) is traversed in a horizontal direction
by a projecting osseous band — the pessulus — which forms a ver-
tical septum between the anterior apertures of the two bronchi.
This septum, at its anterior (ventral) and posterior (dorsal) ends,
gives off on each side two arched processes, which pass down-
wards— one along the dorsal, and the other along the ventral
edge of the bronchus of its side ; and between these cornua the
internal wall of each bronchus, which is here membranous, is
stretched, and constitutes the membrana tympaniformis interna.
In the singing birds (Oscines) there is, in addition, a semi -lunar
fold (membrana semilunaris} on the pessulus, as a prolongation
444 AVES.
of the membrana tympaniformis interna. In many cases a
membranous fold — the mcmbrana tympaniformis externa — is
developed on the external side of the tympanum, and forms with
the free edge of the internal tympaniform membrane (i.e. with
the membrana semilunaris), a vocal slit or glottis on either side.
The tension of these folds, which function as vocal chords, is
regulated by a muscular apparatus, which connects the trachea
with the lateral parts of the tympanum, or also with the an-
terior bronchial rings, and is most highly developed in the singing
birds, in which the syrinx may possess five or six pairs of such
muscles. This is the usual form of syrinx. It is occasionally
placed at the lower end of the trachea or at the upper end of
the bronchi ; in such cases its structure though essentially as
described presents some modifications.
The bronchi are relatively short and lead, at their entrance
into the lungs, into a number of wide membranous bronchial
tubes, which traverse the pulmonary tissue. The lungs which
are of relatively small bulk are not, as in mammals, freely sus-
pended in a closed thoracic cavity and invested by a pleural sac,
but are attached to the dorsal wall of the body cavity by cellular
tissue, and sunk in the interspaces between the ribs at the sides
of the vertebral column. The behaviour of the bronchial tubes
and the structure of the finer respiratory air-spaces of the lungs
present essential differences from those of the Mammalia. The
air-sacs are expansions of the blind ends of some of the main
bronchial tubes ; they have thin, somewhat stiff membranous
walls, and project for the most part into the general body-cavity.
There are five pairs of them, called, in order from before back-
wards, the cervical (prebronchial), the interclavicular (infra-
bronchial), the anterior thoracic (anterior intermediate), the
posterior thoracic (posterior intermediate) and the abdominal
(posterior). The main bronchus enters the lung of its side on
the ventral surface a short distance from the anterior end. It
is continued as the mesobrcnchium through the lung to its hind
end where it dilates into the large abdominal air-sac (Fig. 245,
La) which lies along the dorsal wall of the body-cavity in the
pelvic region on the ventral side of the kidneys, to which and to
the adjacent walls of the pelvis its dorsal wall is adherent
ventrally it is covered by peritoneum and is in contact
with the coils of the intestine.
AIR SACS.
445
The mesobronchium * a short distance before its termination
in the abdominal air-sac gives off a branch which passes to the
lung surface and dilates into the posterior thoracic air-sac.
This lies on the outer side of the anterior end of the abdominal
sacs on the ventral side of the hind end of the lung andTbehind
the lung. Its outer side
is united with the side
wall of the posterior part
of the thorax and of the
anterior part of the abdo-
men, and the anterior
part of its dorsal wall
with the lung surface.
Mesially the anterior dor-
sal end of it is in contact
with its fellow (forming
part of the median sep-
tum, see below). The
tubes which pass to the
other air-sacs are second-
ary bronchi and are called
entobronchia ; they come
off from a dilatation on
the m e s o bronchium,
called the vestibule, soon
after it enters the lung.
There are four entobron-
chia. The fourth runs
to the hind end of the
lung and ends there Cae-
T'V. 4.V.* J
±ne tmra runs
iTrifl-» fl-,;-,
Wltll tlllS , It
gives off close to its point
of origin from the vesti-
bule a tube which immediately dilates into the anterior thoracic
sac. This lies on the ventral surface of the middle part of the
lung to which its dorsal wall is adherent and extends back so as
to overlap the outer side of the anterior part of the posterior
thoracic sac. Its outer wall is adherent to the side walls of the
" The following description of the bronchi refers mainly to the pigeon.
FIQ. 245.— Lungs and .ilr-^o 01 the pigeon (dia-
grammatio, after C. Heider). C connection of
the Interclavienlar sac with the sternal air-spaces;
La abdominal air-sacs; Lp meaian part (peri-
tracheal) of interclavicular air-sac with its diver-
446 AYES.
thorax, and its inner walls are in contact with the pericardium,
except anteriorly and dorsally where it is adherent to its fellow
(forming part of the median septum).
The second entobronchium gives off a wide branch which passes
to the interclavicular sac and is joined just where it opens into
this sac by a branch from the first entobronchium. The pos-
terior part of the interclavicular air-sac lies on, and its dorsal wall
is united with, the ventral surface of the anterior part of the lung ;
this part overlaps the anterior part of the anterior thoracic. The
anterior part is united with its fellow and surrounds the hinder
end of the trachea between the two clavicles ; it gives off lateral
diverticula one of which passes outwards behind the coracoid
and dilates into a large axillary chamber near the shoulder joint
which communicates with the air-cavities in the humerus.
The first entobronchium is directed forwards and, after giving
off the tube to the interclavicular sac already mentioned, is
continued to the anterior end of the lung, where it opens into
the small cervical sac, which lies in front of the lungs at the base
of the neck and dorsal to the anterior part of the interclavicular
sac. It lies between the longus colli muscle with the vertebral
column dorsally and the oesophagus and bronchus ventrally,
and is widely separated from its fellow. In many birds the cer-
vical air sacs are continued up the neck close to the ventral sides
of the vertebrae communicating with the air-cavities in these
structures and in front with the air-cavities in the bones of the
upper beak.
The communications (ostia} on the surface of the lungs by
which the secondary bronchi communicate with the air-sacs are
for the most part well-marked openings. The ostia of the
abdominal sacs are at the postero -external angle of the lung ;
those of the posterior thoracic just anterior and external to the
last ; those of the anterior thoracic are nearer the middle line
not far behind the entrance of the main bronchus into the lung ;
those of the interclavicular are just anterior to the entrance of
the main bronchus, and the cervical air-sacs are given off from
the anterior end of the lung.
The ventral surface of the lungs is invested by a thin fibrous
membrane called the pulmonary aponeurosis which is perforated
by the ostia of the air-sacs. This membrane is continuous in the
midd'e line with a median vertical septum which separates the
AIR SACS. 447
lungs of the two sides and is continued a little ventral to the lungs
by the opposed median walls of the thoracic air sacs (see above).
The outer edges of the pulmonary aponeurosis are inserted into the
thoracic wall at the edge of the lung, and the posterior part of
it contains muscles which arise from the vertebral parts of the
ribs. The dorsal walls of the interclavicular, anterior thoracic
air-sacs, and of a small part of the posterior thoracic sacs, and
possibly of a small part of the anterior region of the abdominal
air-sacs are adherent to this aponeurosis. The pulmonary apo-
neurosis has been compared to the mammalian diaphragm, but
it is very doubtful if this homology can be maintained, for it does
not cut off the whole of the lung from the body cavity, the air-
sacs extending through it, and the pericardium lies altogether
outside it.
However this may be, there can be no question that the so-called
septum has nothing to do with a diaphragm with which it also has been
compared. Indeed the oblique septum which is described by authors as
dividing the body cavity into a dorsal pulmonary part and a ventral
visceral part, containing the pericardum and viscera, has no separate ex-
istence. It consists merely of those parts of the walls of the interclavicular
and thoracic air- sacs, and possibly also of the anterior end of the abdo-
minal, which are not adherent to the body wall, to the lung surface, or
to each other, i.e. it consists mainly of the ventral walls of these sacs, and
does not divide the body cavity at all, there being no portion of that cavity
dorsal to it.
The abdominal sacs lead into the cavities of the femora and
pelvic bones, while the interclavicular sacs are prolonged into
the air-spaces of the bones of the arm. and may extend into the
sternum and into the pectoral muscle. The extensions of the
cervical sacs have already been referred to. In many birds the
extensions of the air-sacs are much greater than those described.
In some they send extensions beneath the skin. In some of the
large swimming birds the cutaneous prolongations are so numer-
ous that the skin emits a crackling sound when touched. The
pneumaticity of the bones has been already referred to. It is
greatest in the screamers and hornbills. in which all the bones
are pneumatic and an extensive system of subcutaneous air-sacs
exists. The air-cavities in the bones of the head are diverticula
of the nasal passages, tympanic cavity, etc.
The mesobronchium and secondary bronchi (entobronchia)
give off tertiary bronchi (parabronchia) which sometimes anas-
448 AVES.
tomose. The tertiary bronchi give off the fine canaliculi through
the walls of which the respiratory exchanges take place.
From the above account it becomes quite clear that the
mechanism of respiration of birds must be quite different from
that of mammals. In birds, when the thorax and abdomen
dilate, air rushes, not into the lungs, which being but slightly
distensible are but little affected, but right down the main bron-
chi into the air-sacs. These therefore act as reservoirs of air
which affects by diffusion the composition of the air in the peri-
pheral extensions of the air- sacs, and of the air in the ultimate
pulmonary passages, which latter must be almost entirely of the
nature of what physiologists call residual air.
The rate of respiration in birds is considerably greater than in
mammals. But whereas in mammals the tidal air, i.e. the air
taken in and given out in each inspiration and expiration, is only
renewed once by each respiratory act, i.e. by inspiration, in birds it
is renewed twice : for the air in the bronchial passages is renewed
in inspiration from the outside, and again in expiration by the
unvitiated air of the air-sacs. It follows therefore that each
respiratory act is practically twice as effective in birds as it is in
mammals. It seems clear then that the respiratory mechanism
of birds is a much more efficient apparatus than that of a mammal
and that the oxidation of the blood must be much more com-
plete. This is what we should expect when we remember the
much greater activity of birds, and the wonderful way in which
they are able to combine intense muscular action with the most
remarkable production of voice.
The exact means by which the thorax and abdomen are
dilated and compressed in the act of respiration are not fully
understood. But having regard to the fact that in a bird the
air-sacs are always found distended after death, it seems pro-
bable that under ordinary circumstances expiration is a mus-
cular action, by which the thorax and abdomen are diminished
in size, and that inspiration is a purely passive action due to the
rebound of the thoracic framework and abdominal wall, in virtue
of their elasticity, after the muscular tension is relaxed. Whether
the backbone is raised or the sternum lowered in this rebound
no doubt depends upon what the bird is doing. If it is standing,
the sternum will be lowered, while on the other hand if it is sup-
ported on its wings in flight the backbone will be raised.
URIXOGEXITAL ORGANS. 449
The large elongated kidneys are placed in the excavations of
the sacrum between the transverse processes, and are divided
by indentations into a number of lobes (usually three). The
ureters run backwards and open into the middle chamber of the
cloaca internally to the genital aperture. The urinary excretion
is not liquid, as in Mammalia, but is a white semifluid mass
which contains a considerable quantity of urates. The absence
of water in the urine of birds is a remarkable fact. In mammals
the nitrogenous waste comes away in solution, which causes a
considerable loss of water from the blood. In birds, in which
this loss does not take place and in which there are no sweat
glands, loss of water must be mainly confined to the internal
surface of the air passages. No doubt the evaporation which
takes place on the very extensive internal air-passages and sacs
is an important factor in the regulation of the body temperature.
The generative organs closely resemble those of the Reptilia.
The males are generally distinguished, not only by their superior
strength, but also by the brighter colour of their plumage and
the greater power of their song. There are two oval testes at
the anterior end of the kidneys ; they become much enlarged
at the breeding season, and the left is usually the larger. The
epididymis, which is but little developed, leads into the vas
deferens, which passes back along the outside of the ureter.
The ends of the vasa deferentia are frequently swollen so as to
form seminal vesicles, and open on two conical papillae placed
on the hinder (dorsal) wall of the cloaca.
A copulatory organ is, as a rule, wanting ; in some of the
larger water birds, however (Ciconia, Platalea, etc.) a rudimen-
tary penis is present as a wart-like process on the front (ventral)
wall of the cloaca. It is larger in most of the Struthionidae, the
ducks, geese, swans, and in the curassows and guans (Penelope,
Urax, Crax). In these birds a curved tube, supported by two
fibrous bodies, is attached to the ventral wall of the cloaca.
The end of the tube can be retracted by an elastic band. A
superficial groove serves to conduct the sperm during copula-
tion. In the ostrich, the penis attains a still higher structure,
analogous to that of the male copulatory parts of the Chelonia
and Crocodilia. Below the two fibrous bodies, the broad bases
of which arise from the front wall of the cloaca, there is a third
cavernous body the extremity of which is non-retractile and
z -ii. G G
450 AVES.
passes into an erectile bulb — the rudiment of a glans penis.
In the female generative organs the ovary and oviduct of the
right side are reduced or entirely absent. The generative organs
of the left side, however, are correspondingly larger at the breed-
ing season. The oviduct is much coiled,, and is divided into
three regions : (1) The wide abdominal ostium in front ; (2) the
coiled glandular part which secretes, from the glands of its longi-
tudinally folded mucous membrane, the albumen which is added
in layers and is twisted together at the ends to form the chalazae ;
(3) a posterior short and wide portion — the so-called uterus —
which serves to produce the variously coloured egg-shell, and
opens by a short
and narrow ter-
minal region into
the cloaca on
the outer side
of the corres-
ponding ureter.
When there are
copulatory parts
in the male,
there are also
clitoris-like struc-
IG. 246. — Diagrammatic longitudinal section through an un- 4~,tV£*0 a f fV>A
developed hen's egg (after Allen Thomson). Bl germinal L
disc; Ch chalazae; DM vitelline membrane; EW albumen; anma Wlano in
GD yellow yolk ; KS calcareous shell : LR air-chamber ; S shell san
membrane ; WD white yolk. the female>
Nothing seems to be known as to the actual process of copu-
lation in birds.
Development. — Birds are, without exception, oviparous. The
egg is remarkable for the large amount of yolk (distinguishable
into white and yellow yolk), and its porous calcareous shell (Fig.
246). The development requires a high temperature, at least
equal to that of the blood. The necessary heat is usually sup-
plied by the bird during incubation.
Fertilization takes place in the upper region of the oviduct
before the secretion of the albumen and of the shell membrane,
and is at once followed by the partial (discoidal) segmentation
(Fig. 247) which only implicates the clear part cf the yolk (for-
mative yolk) around the germinal vesicle — the germinal disc or
so-called tread of the cock (cicatricula).
DEVELOPMENT.
451
When the egg is laid, the segmentation is already completed
and the cicatricula has developed into the blastoderm. The
embryo, which later projects from the yolk, develops, as in
reptiles, the characteristic foetal membranes — the amnion and
allantois. The duration of the embryonic development varies
according to the size of the egg and the relative development
of the young when hatched. The bird, when ready to come out.
breaks the blunt end of the shell by means of a sharp tooth
placed at the extremity of the upper beak.
The young when hatched have essentially the organisation of
the adult animal,
although they may
be still far inferior
to it in the degree
of their bodily de-
velopment. While
the GalJi; Limicolae,
Lari, Ratitae,. etc.,
have when hatched
a complete covering
of down, and are so
far advanced in de-
velopment, that
they at once follow
the mother on land
or into water and
there seek their own
food (praecoces) ;
others like the Pas-
seres, Columbinae,
etc. leave the egg membranes very early (altrices) ; they
are naked, or only covered with down in places, and incapable
of free locomotion or of feeding themselves, and remain for some
time in the nest, in which they are fed and tended by their
parents.
The mental qualities of birds are incomparably higher than
those of reptiles. The higher development of the senses (sight)
renders them capable of a sharp discernment, with which is
combined a good memory. Under the guidance of its parents
the young bird in some instances learns to fly and sing ; it
FIG. 247.— Segmentation of the germinal disc of a fowl's
egg ; surface view (after Kolliker, from Claus). A germinal
disc with the first vertical furrow. E the same with two
vertical furrows crossing one another at right angles. C
and D more advanced stages with small central segments
452 AVES.
collects experiences, which it combines so as to arrive at judg-
ments and conclusions ; it recognises the surroundings of its
nest, distinguishes between friends and foes, and selects the
proper means both for the preservation of its existence and for
the care of its brood. In some birds the capacity for profiting
by instruction and the faculty of imitation are extraordinarily
developed (starling, parrot). The emotional side appears no
less developed, as may be inferred not only from their general
behaviour and the varying expression of their song, but especi-
ally from the behaviour of the two sexes at the breeding season.
Their instinctive actions are directed to the preservation of the
individual, and as in insects, but in a far higher degree, to the
care of their offspring.
In general the manifestations of intelligence as well as of
instinct attain their maximum at the time of reproduction,
which in the temperate and colder climates usually takes place
in the spring (in the crossbill at almost any time of the year).
The voice is clearer and richer in the breeding season ; the male
endeavours to excite the female by his song and the beauty of
his plumage. In addition to the changes of plumage and song,
the whole behaviour of birds is modified under the influence of
sexual excitement (love -gestures, etc.).
Most birds build nests, and seek for this purpose a suitable
place in the district they inhabit. Only a few birds (goat-
suckers, stone-curlew, Alcidae) make no sort of nest, but those
which breed on the ground (Laridae, Limicolae, Galli, and
Ratitae) scoop out a pit or make a depression in moss and grass.
The most skilfully constructed, however, are the nests of those
birds which glue particles of extraneous matter together with
their sticky saliva or which weave fine tressworks of moss, wool
and grass-stalks (weavers). As a rule it is the female alone
which builds the nest, the male merely helping in collecting the
materials. There are, however, instances in which the male
takes a share in the construction (swallows, weavers) ; while in
other cases (Galli, chaffinch) the male takes no share at all in
building the nest. Many sea-birds, as the auks and penguins,
lay but one egg, and most of the large birds of prey, pigeons,
and humming-birds, lay two eggs. The number of eggs is larger
in the singing birds and still greater in the swimming birds of
ponds and rivers, and in the fowls and ostriches. The duration
INCUBATION. MIGRATION. 453
of the period of incubation is equally various ; it seems to
depend upon the size of the egg and the degree of development
of the young when hatched.
Incubation essentially consists in keeping the eggs at a warm,
uniform temperature ; this is effected by the body of the sitting
bird, and is often facilitated by the presence of naked places on
the body. As a rule, the mother alone sits, and the male occu-
pies himself with bringing her food. Not unfrequently, how-
ever, as in the pigeons, lapwings, and many swimming birds, the
two parents relieve one another regularly, and in many Limi-
colae the male seems to do all the sitting. In the ostrich the
female alone sits during the first period of incubation ; later
the parts are changed, and the male undertakes the chief part of
the incubation, especially sitting almost all night. The beha-
viour of the cuckoos of the Old World and certain grackles (Molo-
brus) of the New is very remarkable ; they leave the building
of nests and the care of their brood to other birds, and place
their small eggs, singly, amongst the eggs of various birds.
Leaving out of consideration the activities which relate to
reproduction, the instinct of birds manifests itself, principally
in late summer and autumn, as an impulse to migrate, and still
more mysteriously as a true guide on the journey. Few birds
of the colder and temperate climates pass the winter in the
places where they breed (resident birds). Many of them rove
over larger and smaller regions in search of food. Others
migrate before the beginning of the cold season of the year,
when nourishment is deficient, from the northern climates to the
temperate, from these to southern regions. In the majority of
cases when a bird is resident as a species, it is migratory as an
individual. It is also to be noted that a vast number of birds
ordinarily strictly diurnal in their habits, chiefly if not always
migrate by night.*
There are but scanty materials for the geological history of
this class. The oldest known bird — Archaeopteryx of the Jurassic
formation — is typically avine. From the Cretaceous, remains
of toothed, swimming and wading birds are known (Hesperornis,
Ichthyornis, etc.). In the Tertiary Period the remains are more
numerous and belong to groups now existing.
More than 12,000 species of birds have been described. The
* See Reports of the Migration Committee of the British Association.
454 AVES.
differences between many of them are slight and the classifi-
cation presents considerable difficulties.
The system here adopted, which in its main feature is that of
Fiirbringer and Gadow, is as follows :—
Order 1. ARCHAEORNITHES,
Order 2. NEORNITHES.
Sub-order 1. Ratitae.
„ 2. Odontolcae.
3. Carinatae.
Tribe 1. Ichthyornithex.
„ 2. Colymbi formes.
„ 3. Sphenisci formes.
,, 4. Procellarii formes.
„ 5. Ciconiiformes.
„ 6. Anseri formes.
,, 7. Falcom formes.
,, 8. Tinami formes.
,. 9. Galliformes.
,, 10. Grui formes.
„ 11. Ch aradriiform es.
„ 12. Cuculiformes.
, , 13. Coracii formes .
„ 14. Passeriformes .
It must not be supposed that the divisions here called orders,
and sub-orders at all correspond in value with the similarly
named divisions in other classes : for as already pointed out '(p.
417) the differences between them are hardly if at all greater
than those which distinguish families in other .classes of Verte-
brata.
Order 1. ARCHAEORNITHES (SAURURAE).
This order contains only one germs, the extinct Archacopteryx
v. Meyer from the lithographic slates of Solenhofen (Upper
Jurassic).
Archaeopteryx is the oldest known bird and possesses most of
the features of avine specialisation. The peculiar characters
ARCHAEORXITHES. 455
are as follows : Teeth, embedded in socket?, are present in both
jaws (Fig. 249). The manus has three clawed digits and the
metacarpal bones are separate from one another. The digits
FlG. 248. — Archaeopteryr Hthographica (from British Museum specimen).
456 AVES.
are supposed to be the same as those present in living birds, and
possessed two, three, and four phalanges respectively. There
is a long tail composed of about twenty separate vertebrae which
carry the rectrices on each side (Fig. 248).
The vertebrae appear to be amphicoelous, and the ribs are
devoid of uncinate processes. Abdominal ribs appear to have
been present.
The beak is short and blunt, arid a circle of sclerotic plates
is present (Fig. 249). The sternum is not well preserved. The
scapula and coracoid appear to have been inclined to one an-
other, and the clavicles are united into a U-shaped bone. The
pelvic bones are separate at the acetabulum, and the preace-
tabular portion of the ilium is shorter than the postace tabular.
The hind limb is avine with four clawed digits, the phalangeal
formula of which is 2. 3.
,•• .S?^^*^. 4 . 5. The hand carries six,
and the ulna ten remiges.
The rectrices are arranged
in pairs and are attached to
the caudal vertebrae (Fig.
248).
Archacopieryx appears to
FIG. 249.— skull and lower jaw of Arcfiae.op- have been of about the size
teryy, mar.rura, Berlin specimen, rieht side, „ „ . 1
nat. size (from S. Woodward, after Dames). OI a rOOK. 1 WO I airly com-
plete specimens are known,
of which one is in the British Museum and the other at Berlin.
Order 2. NEORNITHES.
The Neornithes includes all other birds known. The meta-
carpals are fused with one another ; the thoracic ribs have
uncinate processes (except in the Palamedeidae) ; the tail is
much reduced in length and the last five or six of the caudal
vertebrae are usually united to form a pygostyle. They are
divided into three sub-orders, viz. Ratitae, Odontolcae, Carinatae.
Sub-order 1. RATITAE.
The ratite birds differ from all others in the combination of the
following peculiarities : (1) The sternum is devoid of a keel. (2) The
long axes of the adjacent parts of the scapula and coracoid are nearly
parallel or identical. (3) The posterior ends of the palatines and the an-
terior ends of the pterygoids are very imperfectly, or not at all, articu-
RATITAE. 457
lated with the basisphenoidal rostrum, being visually separated from it,
and supported, by the broad, cleft, hinder end of the vomer (dromaeo-
gnathous). (4) Strong basipterygoid processes, arising from the body of
the basisphenoid and not from the rostrum, articulate with facets which
are situated nearer the posterior than the anterior ends of the inner edges
of the pterygoid bones. (5) The upper articular head of the quadrate
bone is not divided into two distinct facets. (6) The barbs of the feathers
are disconnected, the barbules being without hooks. (7) There is no
syrinx. (8) The wings are reduced in size, there is no pygostyle and no
oil gland, and the uncinate processes of the ribs are small or absent.
The plumage covers the whole body with tolerable uniformity, except
that there are naked places on the head, the neck, the extremities, and
the abdomen. It dees not present any regular arrangement of pterylae.
The down is much re-
duced, but the contour
feathers have a down-
like appearance on ,
account of their flexible
shaft and lax vane, or
they may be stiff and
hairlike, with setiform
barbs, or sometimes,
as in the wings of the
cassowary, they are
spinelike. The rham-
photheca is composed
of several pieces. There
is a large penis and the
young are praecoces.
Fossil remains are not
numerous ; the oldest
are those of Struihio
from the Upper Mio-
cene of the Siwalik
Hills, etc. The other
genera do not for
the most part go back
beyond the Pleisto-
cene.
Fam. 1. Struthion- FlG" 250-
idae. Ostriches. With
naked head and neck, pubic symphysis, and long, naked legs. The
maxillopalatines articulate with facets on the sides of the vomer ; the
vomer is short and does not articulate either with palatine or pterygoid.
The pes has only two digits, viz. Nos. 3 and 4. The feathers are with-
out an aftershaft. They inhabit the plains and deserts of Africa and
Arabia. They live in companies and are polygamous. The cock under-
takes the greater part of incubation. Struthio camelus L.
Fam. 2. Rheidae. With partially feathered head and neck, with
three-toed feet, and with ischiadic symphysis. The -palate is dromaeo-
gnathous. The feathers have no aftershaft. South America. Rhea
Americana Lam., the rhea.
Fam 3. Casuariidae. With high almost compressed beak, and usually
458 AYES.
with a helmet-shaped bony knob on the head ; with short neck, and
three-toed feet. The palate is dromaeognathous. The feathers have an
aftershaft as large as the main shaft. The vomer is large, articulating
with the palatines and pterygoids. The wings are very small. They
are confined to the Australian Region. Casuarius L., cassowary, New
Guinea, North Queensland, and some islands of Papuasia. Most species
with bony helmet-like knob on the head, and with brightly-coloured
naked lobes on the head and neck. About 6-10 species. Dromaeus
Gray, emeus. Without helmet or cutaneous lobes. Confined to the
Australian continent, and formerly in Tasmania. D. novae hollandiae
Gray.
Fam. 4. Apterygidae. Kiwis (Fig. 250). Small, four-toed birds,
with short neck, long weak beak having the nostrils near the extremity.
The palate is dromaeognathous. The feathers have no aftershaft. The
eyes are remarkable for their small size. These birds, which are about
the size of a large hen, are entirely covered with long, hairlike feathers
which hang down loosely and completely hide the very small, practically
f unctionless wings. The short powerful legs are covered with scales ;
the three anteriorly directed toes are armed with claws for scratching ;
the hind toe (No. 1) is short and raised above the ground. The kiwis are
nocturnal birds, which by day remain concealed in holes. They feed on
insect larvae and worms, live in pairs, and at the breeding time they lay
in holes scraped in the earth a strikingly large egg, which according to
some is incubated by the male, and according to others by the male and
female in turn. They are confined to New Zealand. Apteryx mantelli
Bartl., North Island ; A. australis Shaw, South Island ; A. oweni Gould,
both islands (Fig. 250).
Fam. 5. Dinornithidae. Moas. This is a second group of terrestrial
birds of New Zealand, which were incapable of flight. It includes a num-
ber of forms which are wholly extinct, and some of which attained an enor-
mous size (up to ten feet high). Of heavy, unwieldy build, and incapable
of raising themselves from the ground, they were unable to resist the
pursuit of the natives of New Zealand. The remains of some have been
found in the Pleistocene, and in some cases the bones appear so recent,
that it cannot be doubted that they co-existed with man. The traditions
of the natives about the gigantic Moa, and numerous discoveries of the
fragments of eggs in caves, also point to the fact that these
gigantic birds have lived in comparatively recent times. The restoration
of the skeleton of gigantic species (Palapteryx ingens, Dinornis giganteus,
elephantopus, etc.) has been effected from the bones which have been
collected. The wing bones appear to have been absent ; the hind limbs
are large and massive ; the hallux is sometimes present. They are con-
fined to New Zealand and no remains are known older than the Pliocene.
Fam. 6. Aepyornithidae. Recently extinct large birds from Mada-
gascar, with long, stout four-toed legs, very small sternum and wings,
and very large eggs. Aepyornis.
Sub-order 2. ODONTOLCAE.
Extinct marine flightless birds without sternal keel, with teeth im-
planted in grooves in the jaws. Hesperornis Marsh. Upper Cretaceous
of Kansas. A highly specialised diving bird. The wing-bones are
much reduced, the humerus only is known ; the clavicles are not
ODONTOLCA K.
459
united. The teeth are found all along the lower jaw, butjare confined
to the maxilla in the upper jaw. The palatal structure is not fully
known, but there are no basipterygoid processes ; the head of the
quadrate is single. The vertebral centra are saddle-shaped, and the
Fir;. 251,—Hesperornis regalis,
U. Cretaceous, Kansas (from S. Woodward, after
Marsh).
bones of the pelvis are free posteriorly. There is no pygostyle Ena-
liornis from the Cambridge Greensand, and Baptornis from the North
American Cretaceous are probably here.
The so-called Stereor n it hes include a number of large extinct land birds,
the skeletons of which have been found in the lower Tertiaries of South
* Andrews, Ibis, 1890, p. 1. Lydekker, Ibis, 1893, p. 40, and Dictionary
of Birds, p. 904.
460
America. They are probably not a natural group,* but include forms which
properly belong to different tribes of the Carinatae. The principal genera
are Phororhacos, Brontornis, Stereornis, Patagornis, Dryornis.
Sub-order 3. CARINATAE.
This sub-order includes the great majority of birds. In the skull the
palatines and pterygoids articulate with the basisphenoidal rostrum at
the point where they join one another, and the head of the quadrate is
double or has two articular facets ; basipterygoid processes are present
or absent. The sternum is keeled except in the flightless forms (Didus,
Stringops, etc.). The coracoid and scapula meet at nearly a right angle.
The barbules carry hooks.
Tribe 1. ICHTHYORNITHES.
Extinct, toothed birds with amphicoelous vertebrae and well developed
wings ; the teeth are implanted in sockets ; from the Middle and Upper
Cretaceous of Kansas. Ichythornis Marsh, a bird of powerful flight ;
with teeth all along the lower jaw, but confined to the maxilla in the upper
jaw ; the head of the quadrate is single as in Ratitae and Odontolcae. A
pygostyle is present.
Tribe 2. COLYMBIFORMES. Divers and grebes.
Water-birds with webbed or lobed toes and flattened metatarsus. Body
carried upright, feet far back. Tail feathers short. Nestlings with com-
plete covering of down. Feathers with aftershaft. Aquintocubital.
Holorhinal with nares perviae. Schizognathous, without basipterygoid
processes.
Fam. Colymbidae. Divers. Marine birds breeding on the shores of
inland waters, two eggs; periarctic. Colymbus glacialis L., great northern
diver.
Fam. Podicipedidae. Grebes. Body short, they construct nests of
water weeds ; the young use their wings as fore-feet ; cosmopolitan ex-
cept in arctic and antarctic regions. Podicipes cristatus L., great crested
grebe.
Tribe 3. SPHENISCIFORMES, Penguins.
Flightless marine birds with anterior limbs covered with scalelike
feathers, without remiges, and used as paddles when the birds are sub-
merged ; plumage covering the whole body. The horny sheath of the
maxilla of from 3 to 5 pieces ; schizognathous, without basipterygoid pro-
cess ; nares imperviae ; bones of the anterior extremity strong, flattened ;
hallux without a web ; metatarsals united at their extremities only ;
feathers with or without barbs, with aftershaft ; with much subcutaneous
fat ; nests of grass or leaves in depression in the ground ; two eggs, both
sexes incubate ; young blind ; coasts of antarctic continent, southern
temperate zone, one tropical species (Galapagos). Aptenodytes patagonica
Forst., king-penguin (Fig. 252) ; Spheniscus demersus L., the Cape penguin ;
Eudyptes chrysocome L., Southern ocean, Falklands to New Zealand.
Fossil forms from the Eocene of New Zealand (Palaeeudyptes) and from
the Miocene of Patagonia (Paraptenodytes, etc.).
CARIXATAE.
461
Tribe 4. PROCELLARIIFORMES (TUBINARES). Petrels.
Ocean forms with great powers of flight, with webbed feet (palmate)
and hallux absent or reduced to a stump. Horny sheath of the^upper and
lower beaks composed of several pieces ; skull schizognathous ; nostrils
tubular. They usually select rocky and precipitous coasts for their
breeding places. The female lays one egg and takes turn with the male
in incubation. The young are nurtured for a long period. Cosmopolitan.
Fam. Proeellariidae. With the characters of the tribe. About 100
species, more numerous in the S. hemisphere. Procellaria pelagica,"L.,
storm petrel or Mother Carey's chicken, Atlantic ; Diomedea exulans L.,
wandering albatross, S. ocean ; Puffl-
nus Briss., Shearwater ; Daption
Steph., Cape pigeon ; Fulmarus glaci-
alisL., fulmar petrel ; Oceanites, Prion.
Tribe 5. CICONIIFORMES.
Aquatic or marsh birds with wading
feet. The vomer is complete, the
palate desmognathous, without basi-
pterygoid processes.
Fam. Steganopodidae. Large swim-
ming birds with well - developed,
often long and pointed, wings, and all
the four toes united by a web. The
newly-hatched young are blind and
helpless and visually naked ; known
fossil since the Eocene. Phaethon L.,
tropic - bird, boatswain bird. Sula
Briss., gannets and boobies, with sub-
cutaneous extensions of the air-sacs,
cosmopolitan except in the cold zones ;
S. bassana L., Solan goose. Pha-
lacrocorax Briss., cormorants and
shags ; with many species (especially
inNew Zealand) cosmopolitan. Plotus
L., Australia, Indo-Malaya, Afr., C.
and S. Amer. ; P. anhinga, the snake-
bird or darter. Fregata Cuv. (Tacy-
petes Vieill.), frigate-bird, tropical. Pelecanus L., pelicans, cosmopolitan
except in cold zone.
Fam. Ardeidae. Herons, bitterns. Wading birds with long legs and
neck ; aquintocubital, with aftershaft ; the young are long helpless.
Ardea L., herons ; Botaurus Steph., bitterns ; Nycticorax Steph., night-
heron ; Balaeniceps Gould, shoebill ; Scopus Briss., hammerhead.
Fam. Ciconiidae. Storks and ibis. The syrinx is without muscles ;
fossil from the Oligocene. Ciconia L., storks ; C. alba L., Eur. to C. Afr.
Asia. Leptoptilus Less., L. crumenifer, marabou stork, Afr. ; L. dubius
the adjutant, India. Tantalus, Abdimia, Mycteria, Eudocimus ruber
Vieill., the scarlet ibis of C. Amer. ; Ibis religiosa Cuv., the sacred ibis of
the Egyptians. Platalea leucorodia L., spoonbill.
Fam. Phoenieopteridae. Flamingos. With long legs and necks, beak
FIG. 252. — Aptenodytes patagonica (from
Brehm).
462
AVES.
bant down in the middle, cove red 'with soft membrane, with horny lamel-
lae at the sides, maxilla very rnoveable ; hallux reduced or absent, toes
fully webbed. Eocene to present. Phoenicopterus L., India, Afr., trop.
Amsr., S. Amer. Palaelodus M. Edw., extinct, Miocene.
Tribe 6. ANSERIFORMES.
Aquatic birds with desmognathous skull, basipterygoid processes, with
two pairs of sterno-tracheal muscles, an evaginable penis, without or with
rudimentary aftershaft. The beak is covered by a soft sensitive mem-
brane and edged both above and below with horny lamellae. The young
leave the nest early. From the Oligocene onwards.
Fam. Palamedeidae. Without uncinate processes and syrinx muscles.
Pneumiticity very highly developed, air-cavities extending beneath the
FIG. 253. — Chauna chavaria (R6gne animal).
skin and even into the fingers and toes. With two sharp spurs 011 the
wings. Chauna chavaria 111., the crested screamer or chaja (Fig. '253).
Paraguay and Brazil, can be domesticated and used to herd flocks of
fowls and geese in S. Amer. Palamedea cornuta L., the horned screamer.
Fam. Anatidae. Swans, geese, and ducks. Beak usually broad and
depressed. The anterior toes usually fully webbed, hallux short and
elevated. Neck unusually developed with extra vertebrae in the swans.
Trachea often with elongations and dilatations especially in the male.
Usually good flyers, but a few forms flightless (Nesonetta, Tachyeres).
Good swimmers, frequenting either sea or fresh-waters. Cosmopolitan.
About 150 living species. From the Eocen iwards. Cygnus L., swans
( AHIXATAE. 463
C. olor L, mute swan ; C. musicus Bechst., whooper. Anser L., geese ;
A. cinereus Meyer, gray goose, origin of the domestic race ; A. hyperboreus
L., snow goose ; A. segetum L., bean goose. Cereopis, Anseranas.
Anas L., ducks ; A. boscas L., wild duck, origin of the domestic races.
Tadorna cornuta Leach, sheld-drake. Aex, Plectropterus. Fuligula,
Somateria mollissima Leach, eider duck ; Erismatura. Mergus merganser
L., goosander ; M. serrator L., redbreasted merganser ; M< altellus L.
smew.
Tribe 7. FALCONIFORMES.
Carnivorous birds with desmognathous skull, with curved beak hooked
at the extremity, and with basal cere, without functional caeca. The
feet are perching, and the strong toes are always armed with powerful
claws which are admirably adapted for the seizure of prey which usually
consists of warm-blooded animals. As a rule the female, which is larger
than the male, alone incubates, but the male assists in procuring food for
the helpless young. Fossil from the Eocene.
Fam. Cathartidae. With pervious nostrils and naked uropygial gland,
without syrinx muscles, with complete basipterygoid processes. Western
hemisphere. Cathartes atratus Baird, turkey-buzzard ; Catharista, Pseudo-
gryphus, Gyparchus papa Dum. the king- vulture ; Sarcorhamphus Dum.
S. gryphus Geoff r., the condor.
The remaining families of the tribe are grouped under the head
Accipitres ; with nares imperviae, feathered uropygial gland, and
tracheo-bronchial muscles. The basipterygoid processes are not complete
and the postacetabular part of the ilium is bent ventrally except in Ser-
pentariidae.
Fam. Serpentariidae. The African secretary bird, Serpentarius Sagit-
tarius Cuv., feeds on insects and reptiles ; with complete basipterygoid
processes, about 4 ft. high, with long legs which easily break.
Fam. Vulturidae. Old-world vultures. Head and upper part of neck
naked or with small down -like feathers. Old world from S. Central
Europe to the Cape, absent from China, Malay Islands, Australia, Sum-
atra, Ceylon, Madagascar. Vultur cinereus Gm., S. Eur. ; Neophron
percnopterus Sav., Egyptian vulture. Gyps fulvus Briss., griffon ; Oto-
gyps, Lophogyps.
Fam. Falconidae. Head and neck feathered.
Sub-fam. Gypaetinae. Gypaetus Gray, cere feathered ; G. barbatus
Cuv., the lammergeier, high mountains of Eur., Afr., Asia.
Sub-fam. Polyborinae. Carrion hawks. America. Polyborus, Ibyc-
ter, Phalcobaenus, Senex.
Sub-fam. Accipitrinae. Hawks. Circus cyaneus L., hen harrier ;
C. cineraceus Mont., Montagu's harrier ; C. aeruginosus L., marsh
harrier. Astur palumbarius L., goshawk. Accipiter nisus L., sparrow
hawk.
Sub-fam. Aquilinae. Eagles. Aquila chrysaetus L., golden eagle ;
A. naevia Briss., spotted eagle. Haliaetus albicilla Briss., sea-eagle,
erne.
Sub-fam. Buteoninae. Buzzards and kites. Archibuteo lagopus
L., rough-legged buzzard. Buteo vulgaris L., buzzard ; Milvus
ictinus (regalis), red kite, once common in London ; M. ater Daud.
black kite. Pernis apivorus Cuv., honey-buzzard.
Sub-fam. Falconinae. Falcons. Falco gyr/alco L., gyrfalcon ;
464 AYES.
F. peregrinus L., peregrine falcon ; F. aesalon Tunst., merlin ; F.
subbuteo L., hobby ; F. tinnunculus L., kestrel.
Fam. Pandionidae. Without aftershaft, with long feathered tibia ;
outer toe reversible. Pandion haliaetus Cuv., osprey or fish-hawk, nearly
cosmopolitan.
Tribe 8. TINAMIFORMES (CRYPTURI).
Terrestrial birds with the power of strong and swift flight. The skull
is dromaeognathous, the vomer being broad behind, fused with the pala-
tines and interposed between the palatines, pterygoids and basisphenoidal
rostrum. The quadrate articulates with the skull by a single facet. In
this character, as well as in the posterior separation of the ischium and
ilium, the absence of a pygostyle, they resemble Ratitae. The tail is
abbreviated, usually with 10 weak rectrices, and the hallux is elevated.
The tongue is small, there is a small penis ; and the male takes part in the
incubation. The eggs have a metallic gloss and the young are praecoces.
They are confined to the Neotropical Region (extending into Mexico),
with 30-40 species. Fossil forms are unknown. Their position is uncer-
tain ; by some zoologists they are placed with the Ratitae (see Pycraft,
op. cit.).
Fam. Tinamidae. Tinamous, with principal genera, Tinamus, Cryp-
turus, Ehychotus Nothura, Eudromia.
Tribe 9. GALLIFORMES.
Terrestrial or arboreal birds with a schizognathous skull, simple rham-
photheca, nares imperviae, and ten carpal remiges. They are quinto-
cubital, and the feet are adapted for perching. They are good runners
and seek their food on the ground, either in forests or in fields, feeding
especially on berries, buds and seeds, and on insects and worms. They
form rude nests usually on the surface of the ground or in low bushes,
more rarely on high trees ; and they lay a considerable number of eggs.
Many are polygamous, but the male takes no part in building the
nest or in the care of the brood. The young are for the most part prae-
coces. The hens are easily domesticated and, on account of their eggs
and well-favoured flesh, have been made useful as domestic animals from
the earliest times.
Fam. Mesitidae.* With the single genus and species Mesites varie-
gatus J. Geoffr. from Madagascar, to which it is confined. The bill is long
and slender, the clavicles are absent, there are seventeen cervical vertebrae
and 16 rectrices ; there is no aftershaft. The condition of the young and
the structure of the viscera are unknown.
Fam. Turnicidae. Quintocubital, with aftershaft, without hallux, with
only left carotid. Small, solitary, non-migratory forms, which run
quickly. The male incubates and feigns' lameness. Turnix Bonn.
(Hemipodius Reinw.) with about 9 species in S.-Eur., Africa, India.
Fam. Pedionomidae. Aquintocubital, with small hallux, with both
carotids. Pedionomus torquatus Gould, Australia.
The three next families, Megapodiidae, Cracidae, and Phasianidae are
grouped together as Galli.
* This form is of very uncertain position. A. Milne-Edwards, who is
the only man who has dissected it, placed it near the rails (Ann. Sc. Nat.,
(6), 7).
GALLIFORMES. 465
Fam. Megapodiidae. Megapodes. The feet are large, the bill short, and
the wings abbreviated. The eggs are placed in mounds or in holes in the
sand, and develop without incubation. The young can fly almost im-
mediately. Austro-Malayan, but not found in Borneo (?), Sumatra, or
Java. Megacephalon maleo Temm., N. Celebes. Megapodius tumulus
Gould, N.-E. of Australia. Lipoa Gould, S. Australia. Talegallus.
Fam. Cracidae. Curassows. Arboreal birds, with very pneumatic
skeleton, feathered bursal glands and both carotids. Neotropical (except
the Antilles). Several species are easily domesticated, but rarely breed
in confinement. Hybrids with domestic fowls have been recorded.
Crax alector L., cura^sow, S. Amer. Penelope, Ortalis, Oreophasis, etc.
Fam. Phasianidae. Essentially terrestrial birds, which, however, often
roost in trees. Many polygamous, the male being larger and more
brightly coloured than the female. The nests are placed on the ground,
and the eggs are usually numerous. The head is usually adorned with
coloured comb, cutaneous lobes or tufts of feathers. The hallux is ele-
vated and usually without a claw, and the male frequently has spurs.
They are mainly vegetable feeders, and nearly cosmopolitan in distribu-
tion. They are for the most part easily domesticated, and the breast
muscle 5 are well developed. From the Eocene onwards.
Sub-fam. 1. Numidinae. Guinea-fowls ; Africa and Madagascar.
Numida meleagris L., the guinea-fowl ; W. Africa. Acryllium,
Guttera, Phasidus.
Sub-fam. 2. Meleagrinae. Turkeys ; N.-Amer., Central Amer. ;
M. gallopavo L., the origin of our farm- yard turkey, S. Canada to
Mexico. M. ocellata Cuv., Honduras.
Sub.-fam. 3. Phasianinae. Fowls. Inhabitants of the Old World.
Pavo cristatus L., peacock, with long tail-coverts, India. Argusianus
giganteus Tern., the argus-pheasant, Malay Penins., Sumatra. Poly-
plectron Tern., peacock-pheasant, Indo-China, Malaya. Gallus L., 4
species, India, Malaya; G. ferrugineus Gm. (bankiva Tern.), the red
jungle-fowl and the origin of our domestic breeds, India, Malaya ;
G. sonnerati Tern., the grey jungle-fowl, India ; G. Stanley i Gr.,
Ceylon ; G. varius Shaw, Java. Chrysolophus pictus L., golden phea-
sant, China, E. Thibet. Phasianus L., pheasants, Eur., Asia ; Ph.
colchicus L., Caspian to S.-E. Eur., main origin of the introduced form,
which has largely interbred with Ph. torquatus Tern., China, and
Ph. versicolor of Japan, etc. Catreus, Pucrasia. Gennaeus nycthe-
murus L., silver-pheasant of S. China. Crossoptilon, Lobiophasis,
Lophura, Acomus, Lophophorus, Ceriornis, Ithagenis.
Sub-fam. 4. Tetraoninae. Grouse, partridges, and quails. Nearly
cosmopolitan except in S. Amer. Ophrysia, Galloperdix, Synoecus.
Coturnix communis Bonn., the common quail, Eur., Asia, Africa.
Perdix cinerea Lath., the common partridge, Europe. Francolinus,
Caccabis rufa L., the red-legged partridge. Tetraogallus. Odonto-
phorus. Bonasa sylvestris L., hazel grouse. Tympanuchus americanus
Reich., the prairie-hen. Tetrao urogallus L., cape really. Lyrurus
tetrix L., black grouse. Lagopus scoticus Lath., red grouse, probably
the insular form of the willow grouse, the only species of bird (except
the St. Kilda wren) confined to the British Islands, not found south
of Shropshire (except in S. Wales); L. albus Gm., willow grouse, be-
comes white in winter. Colinus and other genera (American " par-
tridges ").
Z.-Il. H H
466 AVES
Fam. Opisthoeomidae.* Fowl- like arboreal bird, without basipterygoid
process ; the anterior part of the keel of the sternum is aborted. Single
genus and species Opisthocomus cristatus Gm., the hoazin, stink-bird,
Guiana and Venezuela.
Tribe 10. GRUIFORMES.
Schizognathous, for the most part marsh birds, without basipterygoid
process, with vomer, without crop, with an elevated hallux and a tracheo-
bronchial syrinx. The nares are pervious in all except Rhinochetus. The
young are covered with down.
Fam. Rallidae. Rails, coots, water-hens. Cosmopolitan, with about
150 species. The family includes some flightless forms in which the keel
of the sternum is reduced. Most inhabit marshes or damp localities, but
some (e.g. Crex pratensis) live on dry lands. The young are praecoces.
Fossil from the Cretaceous onwards. Rallus aquaticus L., water-rail,
N. and C. Eur. to C. Asia. Crex pratensis L., corncrake. Pennula ecau-
data King, Sandwich Islands, flightless, extinct. Gallinula chloropus L.,
moorhen ; G. nesiotis Scl., flightless, Tristan d'Acunha. Fulica atra
L., coot, on the reedy lakes and ponds of Europe. Himantornis Tern.,
W. Africa ; Eulabeornis Gould, Australia, Malaya, Madagascar,
Polynesia. Notornis, Aptornis, flightless extinct birds from New Zealand ;
Aphanapteryx, Mauritius and Erythromachus, Rodriguez were probably
extirpated by man. Ocydromus Wagl., the weka, New Zealand.
Fam. Grudiae. Cranes. Cosmopolitan except N. Zealand and Pacific
Islands. Long-necked, long-legged waders. They have a powerful flight.
The young are praecoces. Grus cinerea Beckst., the common crane of
Eur. and N. Asia. Balearica, Anthropoides, Aramus.
Fam. Psophiidae. Trumpeters, trop. S. Amer.
Fam. Cariamidae. Sometimes placed with the secretary bird. Cari-
arna Briss. (Dicholophus 111.) ; C. cristata L., the seriema or crested
screamer (a name also applied to Chauna cristata), Brazil, Paraguay ;
easily domesticated, will guard their owner's fowls.
Fam. Otididae. Bustards. Old World and Australia ; about 25
species. Otis tarda L., great bustard, temp. Eur., and Russia to Persia,
extinct as a native in England since 1838 ; 0. tetrax L., little bustard,
S. E. Eur.
Fam. Rhinochetidae. One genus and species, Rhinochetus jubatus Verr.
and Des Murs, kagu, New Caledonia, with nares imperviae, somewhat
larger than a fowl, and described as a generalised form.
Fam. Eurypygidae. With long neck, slender bill and pervious nostrils.
One genus and two species : Eurypyga helias Pall., the sun-bittern, N.S.-
Amer., E. major Hartl., Central Amer.
Fam. Heliornithidae Finfoots. With small head, thin neck, toes with
broad flaps and pointed claws, quintocubital, young are altrices, trop.
S. Amer., Africa, Assam to Sumatra. Heliornis, Podica.
Tribe 11. CHARADRIIFORMES.
Terrestrial, arboreal, or marine birds with a schizognathous skull,
* Of doubtful position. This family was placed by Huxley in a special
group, Heteromorphae, and regarded by him as belonging to a more ancient
type than the Galliformes (Proc. Zool, Soc., 1868, p. 304 ;' also Garrod,
Proc. Zool. Soc. 1879, p. 109).
CHARADRIIFORMES. 467
eleven primary remiges, a V-shaped furcula, and two carotids. They are
aquintocubital. They fall into four groups, the Limicolae, the Lari, the
Pterocles and the Columbae.
Group 1. Limicolae.
The Limicolae are typically waders and good flyers. They are not, as
a rule, habitual swimmers. The young are praecoces.
Fam. Charadriidae. Plovers, etc. They usually lay four spotted eggs.
About 100 species ; cosmopolitan.
Sub-fam. 1. Charadriinae. Premaxillary part of the beak hard. Eu-
dromias morinellus L., the dotterel, Europe. Charadrius pluvialis L.,
the golden plover. Aegialitis hiaticola L., the ringed plover. Ana-
rhynchus frontalis Q. and G., the wry-bill of N. Zealand. Vanellus L.,
lapwings ; V. cristatus Mey., the lapwing, peewit or green plover.*
Strepsilas interpres L., the turnstone. Haematopus ostralegus L.,
the oyster-catcher. Himantopus Barr., the stilts. Recurvirostra
avocetta L., the avocet.
Sub-fam. 2. Tringinae. Premaxillary part of the beak soft and
covered with a richly innervated skin ; beak long, narrow, weak.
Phalaropus fulicarius L., the grey phalarope. Tringa alpina, the
dunlin. Totanus calidris L., the redshank ; T. (Actitis) hypoleucus
Temm., the sandpiper. Machetes pugnax Cuv., the ruff. Limosa
Briss., the godwits. Numenius arquata L., the curlew.
Sub-fam. 3. Scolopacinae. The beak is long, and its premaxillary
part is soft, covered by a richly innervated skin, and somewhat
swollen. Scolopax rusticula L., the woodcock. Gallinago caelestis
L., the common snipe ; G. gallinula L., the jack snipe.
Fam. Chionididae. Sheathbills. Antarctic Seas.
Fam. Glareolidae. With Glareola, the pratincole ; Cursorius, Pluvianus.
Fam. Dromadidae. Dramas.
Fam. Thinocoridae. With Thinocorys, Attagis.
Fam. Oedicnemidae. Without the hind toe. Oedicnemus scolopax
Gm. (crepitans Tern.), the stone-curlew.
Fam. Parridae. Long-toed jacanas, with Parra, Hydrophasianus, etc.
Group 2. Lari.
The Lari are typically swimmers and good flyers. The anterior toes
have swimming membranes. Hallux small or absent. Mainly pisci-
vorous. Young covered with down when hatched, but remaining for
some time in the nest and fed by the parents.
Fam. Laridae. Wings long and pointed, praecoces. The sexes are
similar.
Sub-fam. 1. Larinae. Gulls and skuas. Beak usually shorter than
the head. About 50 species, cosmopolitan, mainly marine. Ster-
corarius pomatorhimis, the pomatorhine skua ; Megalestris catarractes
L., the great skua. Eissa tridactyla L., the kittiwake. Larus L.,
gulls.
* Often served by cooks of a certain class as golden plovers. Diners
who are unable to distinguish between the two by the coarser flavour of
the lapwing, may do so by means of the sternum. In the golden plover
there are two emarginations on each side of the posterior end of this bone ;
in the lapwing the inner of these is bridged so as to become a fenestration.
468 AVES.
Sub-fam. 2. Sterninae. Terns or sea-swallows. Beak long, straight,
tail usually forked. About 50 species, cosmopolitan. Sterna hirundo
L., terns ; St. fluviatilis Naum., common tern, coasts and inland
waters of Europe, etc. Gygis Wagl. Anous Leach, noddies.
Sub-fam. 3. Rhynchopinae. Rhynchops L., skimmers, Indian
Ocean and Atlantic side of Amer.
Fam. Alcidae. Auks. Piscivorous, marine, periarctic birds, with short
wings (functionless in Alca impennis), heavy body, close plumage and fully
webbed anterior toes. Most species fly strongly. Their common breeding
places are on the coasts, where they lay their generally single egg on bare
ledges of rock, in crevices, or in holes in the earth. Alca impennis L.,
great auk, flightless, extinct since 1844. A. torda L., razorbill.
Mormon arcticus (Fratercula Temm.) 111., puffin. Uria troile Lath.,
guillemot; U. grylle Cuv. black guillemot, tysty. Mergalus alle L., the
little auk.
Group 3- Pterocles.
Desert birds with short, feathered metatarsus ; hallux small or absent ;
crop and caeca large. With nares imperviae, rudimentary vomer. The
short front toes are enclosed in a casing which is covered as far as the claws
with hairy plumage. Eggs three in number. The young are praecoces.
Fam. Pteroclidae. Sand-grouse. Pterocles alchata Gray, Eur.,
Africa, Asia. Syrrhaptes paradoxus Pall., Pallas' sand-grouse, Central
Asia, occasionally wanders into and breeds in Europe.
Group 4. Columbae.
The Columbae are most nearly allied to the Pteroclidae. They are of
medium size, with small head, short neck, and short legs. The beak is
longer than in the Galli, but weaker, and gently arched at the horny ex-
tremity. At the base of the beak the scaly cover of the nasal openings is
swollen, naked and membranous. The rather long, pointed wings enable
the bird to fly quickly and skilfully. The tail is weak and rounded, and
•contains usually 12, rarely 14, 16 or 20 rectrices. The plumage presents
hardly any difference in the two sexes. The short legs are unfitted for
rapid locomotion. The well-developed hind toe rests on the ground.
The vomer is small and often absent, and the nares impervious. The
crop is paired and large, and at the breeding season secretes, in both sexes,
a, creamy fluid for the nourishment of the young.
There are about 350 species, distributed over all parts of the world.
They live in pairs, or in flocks in forests, and feed mainly on grain and
seeds. The species which live in the north are migratory ; others make
short migrations ; while others are residents. They live in a state of
monogamy, and lay two eggs (rarely one) in a rudely constructed nest.
Both sexes take part in hatching and in bringing up the young, which
are hatched almost naked ("pipers" ), with closed eyelids, and, as
altrices, require the care of the parents for a considerable time.
Fam. Columbidae. The beak with smooth edges, never dentated.
Columba lima L., rock-pigeon (Fig. 254) ; slate-blue, with white wing cov-
erts and two black bands on the wings and the tail ; is the ancestral form
of the numerous races of domestic pigeon ; nests on rocks and ruins, and
is distributed from the coasts of the Mediterranean over a great part of
CUCULIFORMES.
469
Europe and Asia. C. aenas L., the stock-dove ; Columba palumbus L.
the ring dove, wood pigeon. Ectopistes migratorius L., the passenger
pigeon, N-.Amer. Turtur auritus Bp., the turtle-dove ; T. risorius
Sws. Goura coronata Flem., New Guinea. Treron, Vinago, Carpophaga,
fruit-pigeons of tropical parts of the Old World ; Otidiphaps, New Guinea.
Fam. Didunculidae. Beak compressed, lower jaw toothed, with hooked
extremity. Didunculus strigirostris Gould, Samoan Islands.
Fam. Dididae. Large, extinct, flightless birds. Furcula and wings
small, coracoid fused with scapula. Didus ineptus L., the dodo, Mauritius,
found by the Dutch in 1598, and was last known as living in 1681. Several
brought alive to Europe ; pictures of these still exist ; nearly complete
skeletons in the museums of Cambridge, Paris, and Port Louis, one scarcely
less so in the British Museum. It was an unwieldy bird, larger than a
turkey, with lax plumage, powerful four-toed scraping feet, and strongly
cleft beak. D. borbonicus Reunion, only known from travellers' descrip-
tions. Pezophaps solitarius Gm., the solitaire, Rodriguez, was larger than
a swan, extirpated about
the same time as the
dodo ; two nearly com-
plete skeletons in the
Cambridge Museum, one
scarcely less so in the
British Museum.
Tribe 12. CUCULI-
FORMES.
Arboreal birds with a
desmognath o u s skull.
The first and fourth toes
are directed backwards
(zygodactylous), but the
fourth toe may be rever-
sible. The young are
altrices.
"-«^
FIG. 251.— Columba livia (after Xauiuann).
Group 1. Cucuh.
Quintocubital, zygodactylous arboreal birds. Cosmopolitan.
Fam. Cuculidae. Cuckoos. With gently-curved, deeply-cleft beak,
long pointed wings, with ten primaries, and wedge-shaped pointed tail.
The fourth toe can be directed forwards. About 200 species, cosmo-
politan. Cuculus canorus L., the European cuckoo, adult somewhat like a
sparrowhawk ; it lays its eggs upon the ground and transfers them in its bill
to the nests of other birds, usually of the meadow-pipit, the reed-warbler, the
hedge-sparrow and the robin ; the egg is incubated by its foster-mother and
about 30 hours after hatching the young bird ejects the rightful
young and eggs of the nest ; the adults migrate to the South in July and
August, but the young not till September or October, reaching as far as
S. Africa, Ceylon, Celebes. The familiar cry is uttered by the male in the
breeding season. They seem in some cases at least to use the nests of
birds the eggs of which resemble their own. Other species of cuckoo have
the same parasitic habit ; e.g. Coccystes glandarius L., the great spotted
cuckoo of S. Europe. Other genera of cuckoos are Chrysococcyx, Caco-
470 AVES.
mantis from the Old World, and Saurothera, Diplopterus, Piaya, Coccyzus
from America ; some of these are said to be parasitic, but most of them
certainly build nests.
Other genera usually grouped under different sub-families are Eudy-
namis, Phoenicophaes, Pyrrhocentor, Centropus, Coua, Geococcyx, Croto-
phaga, Guira. Some of these build their own nests. In the case of
Crotophaga ani, the black witch, several females unite to lay their eggs in
a common nest.
Fam. Musophagidae. Touracos or plantain-eaters. About 20 species,
at present confined to Africa. The fourth toe is reversible. The red fea-
thers of the birds of this family owe their colour to a red pigment called
turacin and containing 5 to 8 p.c. of copper and soluble in weak alka-
line solutions. It is washed out by rain in the living bird, the feathers
regaining their colour after an interval. A green pigment called turaco-
verdin is also found among these birds ; it contains iron but no copper
and is the only instance of a green pigment in the class. Turacus (Cory-
thaix) fischeri of E. Afr. ; T, persa L., W. Afr. ; Musophaga violacea Isert,
W. Afr. ; Schizorrhis Wagl. Necrornis fossil in the Miocene of France.
Group 2. Psittaci.
Aquintocubital, zygodactylous, arboreal birds, with strongly bent beak,
fleshy tongue and short metatarsus. The upper beak, which is covered
at its base by a cere, is articulated with the frontal, and its long hooked
extremity overlaps the short and broad lower beak. The parrots form a
very sharply marked group, and the oldest known form, Psiltacus verreauxi
from the Lower Miocene of France, shows all the feculiar features of the
group. Cosmopolitan, except in the colder regions ; but their head-
quarters are Austro-Malaya ; about 80 genera, and 500 species. The color-
ation is commonly gaudy. They are monogamous, but usually roost and
feed in company.
Fam. Trichoglossidae. The tip of the tongue has fine horny fibres.
Nestor meridionalis L., the kaka parrot of N. Zealand ; N. notabilis
Gould, the kea of the south island of N. Zealand, eats fruits, seeds and in-
sects, but has lately acquired the habit of pecking holes with its powerful
beak in the back and sides of sheep ; there was a recently extinct species
in Norfolk Island. The lories form the bulk of this family, Austro-Malaya,
Polynesia except N. Zealand ; with principal genera, Eos, Lorius, Tricho-
glossus, Oreopsittacus. Cyclopsittacus also here.
Fam. Psittacidae. Parrots. With smooth tongue.
Sub-fam. 1. Cacatuinae. Cockatoos, Australian Region and
Philippines ; head with moveable crest, orbit complete, usually with
only left carotid. Calyptorhynchus, Cacatua, etc. Lophopsittacus
mauritianus, a contemporary of the dodo in Mauritius.
Sub-fam. 2. Psittacinae. Orbit and carotids vary, include the
bulk of the parrots. Melopsittacus undulatus Shaw, the grass-para-
keet or budgerigar, Australia. Platycercus Vig., Australia, N. Zea-
land, Society Islands. Loriculus, Agapornis Selby, Africa, Psittacula
111., America, are the love-birds. Palaeornis Vig., Australia, Asia, Africa.
Psittacus erithacus L., the grey parrot, the best talker, Africa. Chrys-
otis Sw. Ara Cuv., the macaws, Neotropical. Nasiterna Wagl.,
New Guinea and islands.
Fam. Stringopidae. Kakapo, of N. Zealand ; with normal carotids, orbit
CORACIIFORMES. 471
complete. Stringops habroptilus Gray, owl-like, with incomplete disc of
feathers round the eye ; a ground parrot which hides in holes in the day-
time, with small power of flight ; crista sterni hardly developed, clavicle
dwindled to a mere spine united neither to its fellow nor to the sternum.
Tribe 13. CORACIIFORMES.
Arboreal forms with short legs"; they often nest in holes and have blind
and helpless young. The tribe is difficult to characterize. It is divided
into seven groups, the cross affinities of which with each other and with
other tribes (Cuculiformes, Passeriformes, etc.) bring out clearly the im-
practicability of the so-called natural system of classification in linear or
tree-like series.
Group 1. Coraciae.
Fam. Coraciidae. Rollers. Beautifully coloured birds, with wide
gape ; beak with recurved extremity and sharp edges. With long wings
and pedes fissi. Leptosoma discolor Herm., the kirombo, Madagascar
and the Comoro Islands. Coracias garrula L., Eur., Afr., India. Eury-
stomus widely distributed ; Brachypteracias, peculiar to Madagascar.
Fam. Momotidae. Motmots and todies. Neotropical, inhabiting
forests. Momotus, Todus.
Fam. Alcedinidae. Kingfishers. With large head, long keeled angular
beak, relatively short wings and tail ; metatarsus short. Alcedo ispida
L., kingfisher of Britain and Europe. Alcyone Sw., Austro-Malaya.
Dacelo gigas Glog., the laughing jackass of Australia. Ceyx, Halcyon,
Tanysiptera. Ceryle rudis L., black and white kingfisher, Africa.
Fam. Meropidae. Bee-eaters. The beak is compressed and gently
curved downwards. The plumage is variegated, the legs are weak. The
wings are pointed, with long coverts. The flight is rapid and swallowlike.
Temperate and tropical parts of the Old World, about 30 species. Merops
apiaster L., S. Europe. Nyctiornis, Melittophagus.
Fam. Upupidae. Hoopoes. Beautifully coloured birds with long
laterally-compressed beak, short triangular tongue, and long rounded
wings. About 65 species ; Old World except Australia. Upupa epops
L., Europe, Africa, Asia. Irrisor, Ehinopomastus.
Fam. Bucerotidae. Hornbills. Birds of considerable size, with colos-
sal, always slightly dentated, and downwardly-curved beak and usually
with hornlike head-dress at the base of the upper beak. Bones very
pneumatic. Ethiopian and Indo-Malayan. Bttcorvus abyssinicus Gni.
Bucerus rhinoceros L., Sumatra. Rhinoplax, Aceros, Lophoceros, Ano-
rhinus, etc.
Group 2. Striges.
With single Fam. Strigidae. Owls. Nocturnal birds of prey which
hunt insects and small mammals, birds, reptiles, etc. WTith large ante-
riorly directed eyes which are surrounded by a circle of stiff feathers, some-
times in a veil-like manner ; with strong hooked beak, bent downwards
from the base. The ear usually has a membranous operculum and exter-
nal cutaneous fold, on which the feathers may be grouped so as to give the
appearance of a pinna. Cosmopolitan, about 150 species. Fossil from
the Eocene. Strix flammea L., screech, or bam, owl (Fig. 255), cosmo-
472 AYES.
politan. Syrnium aluco L., the tawny or wood owl, Britain except Ireland,
Africa, Asia. Asio otus, long-eared owl, Europe, Asia, etc. ; A. brachyotus
Gm., short-eared owl. Bubo ignavus, eagle owl, Eur., Asia, N. Afr.
Nyctea nivea Daud. (scandiaca L.), snowy owl, a diurnal owl. Surnia>
Ssops, Sceloylaux, Carive.
Group 3. Caprimulgi.
Nocturnal, wide-mouthed birds, owl-like in appearance.
Fam. 1. Capri mulgidae. Night-jars or goatsuckers. Cosmopolitan
with about 80 species and several genera. Their size varies from that of
a lark to that of a crow. The plumage is soft, owl-like, mottled and pen-
cilled with grey, chestnut, brown, black and white. The beak is short, flat,
and triangular, gape enormously wide and often beset with stiff bristles.
The legs are weak and short. Hind toes reversible ; outer toe with 4
phalanges only, a most unusual character among birds ; middle toe long
and sometimes with a serrated claw. They live for the most part in
forests and feed especially on moths, which they catch during flight. As
a rule they lay two eggs on the bare ground, without even scraping a hole
for their reception. Caprimulgus L., the
buccal slit extends to close behind the
eyes ; edge of beak not dentated, fringed
with stiff bristles ; cosmopolitan. C.
europaeus L., night-jar, goat-sucker,,
or fern-owl, Britain, Eur., Afr., Asia.
C. ruficollis Temm., Spain. Nyctibius,
Macrodipteryx, Hydropsalis, etc.
Fam. Podargidae, Australia, Papuasia,
Indo-Malaya, with Podargus, Batrochos-
tomus, Aegotheles.
Fam. Steatornithidae. With the single
genus and species Steatornis caripensis
{ FIG. 255.— Head of Strix flammea ., , . v, .
Humb., the guarcharo or oil-bird, in
mountainous country from Trinidad to
Peru, lives on fruit or oily nuts.
Group 4. Cypseli.
Swifts and humming-birds, with long wings and deep-keeled sternum,
without intestinal caeca.
Fam. Cypselidae. Swifts. Swallow-like, with narrow wings forming
an almost continuous curve when extended, short feathered metatarsus
and strongly-clawed feet (p. adhamantes), sometimes with inwardly directed
hallux. In Cypselus and Panyptila the digital formula is unique, being
2, 3, 3, 3. There are 10 rectrices and 10 secondary remiges. Cosmo-
politan, except in N. Zealand and the cold zones ; about six genera and
80 species. They are extraordinarily strong flyers, and they spend a great
part of their time on the wing, catching the insects which form their food.
They are remarkable for the development of their salivary glands, the
secretion of which is of a glutinous character and serves to glue together
the materials of which the nest is composed. In the genus Collocalia the
nest is entirely formed of this secretion (the edible nest used by Chinese
epicures for making soup). The nest is sometimes of remarkable archi-
tecture. Cypselus apus L., the common swift ; C. melba L., the alpine
CORACI1 FORMES.
473
swift. Panyptila Cab., America. Collocalia G. R. Gr., India and Aus-
tralia, chiefly the islands of the Indian Ocean ; they breed in company
and make their nests in caves or on the surface or bare face of a cliff.
Macropteryx, Acanthyllis Ag. (Chaetura), with the shaft of the rectrices
projecting in spines.
Fam. Trochilidae. Humming-birds. Among them are the smallest
of birds. The plumage is variegated with a metallic lustre. The beak is
long and awl-shaped, and the long tongue which is cleft to the root can be
projected in the form of a double tube. There are 10 primary remiges and
10 rectrices. They are insectivorous, spending most of their time flitting
from flower to flower in which they find their food. Confined to America
and West Indies ; 400 to 500 species. Rhamphodon naevius Less., Brazil.
Phaethornis superciiiosus Sw., Brazil. Trochilus colubris L. Lophornis
magnified Pp., Brazil. Loddigesia mirabilis Gould, Peru. Patagona
gigas, the largest of the group, 8i inches long, Patagonia ; Mellisuga
minima, the smallest 2f inch, Jamaica.
Group 5. Colii.
This group includes the single family Coliidae. called the mouse-birds
either from their creeping habits or from their colour. The hallux is re-
versible, but commonly directed forwards. They are small frugivorous
forest birds with long tail and short dense plumage and are confined to
Africa ; about 9 species, Colius Briss.
Group 6. Trogonss.
With the single family Trogonidae. The only heterodactylous birds,
i.e. the first and second toes are directed backwards, the third and fourth
forwards. Tropical, usually brightly-coloured, insectivorous and frugi-
vorous forest birds. The skull is schizognathous ; the beak is short and
strong, usually writh serrated edges ; the mouth is wide with bristles at
the corners. There are 10 primaries and 12 rectrices. About 40 species ;
Central and South America, Africa, and Indo-Malaya. Trogon curucui
L., Brazil. Pharomacrus mocinno de la Llave, the quesal, Vera Paz
and Guatemala. Haploderma Ag., Africa. Harpactes Sw., Indo-Malaya.
Trogon gallicus M. Edw., from the Miocene of France.
Group 7. Pici.
Zygodactylous birds, i.e. 1st and 4th toes directed backwards, the
other toes forward with a variable palate (schizognathous, aegithogna-
thous, or desmognathous).
Fam. Galbulidae. Jacamars. Desmognathous, with large precoracoid
process, functional caeca and normal carotids, 10 primaries, and 10 or 12
rectrices. Confined to Central and tropical South America. Galbula
Moehr., jacamars. Jacamarhalcyon, Picoides, Urogalba. Bucco, L.,
puff-birds.
Fam. Capitonidae. Aegithognathous, without caeca, with left carotid
only.
Sub-fam. 1. Capitoninae. Barbets. Asia, Ethiopian, Neotropi-
cal, about 100 species in tropical forests. With brilliant plumage.
Capita, Cyanops, Barbatula, Gymnobucco, Megalaema, Pogonorhyn-
chus.
474 AVES.
Sub-fam. 2. Indicatorinae. Honeyguides. About 12 species,
Ethiopian and Indo-Malayan. They conduct travellers to bees'
nests, their object being to get the young bees. Indicator, Protodiscus.
Fam. Rhamphastidae. Toucans. Extraordinary birds with huge but
quite light bills, marginally serrated beak and horny, brushlike non-
protractile tongue. About 50 species in the tropical forests of Central
and South America. Rhamphastus toco L. Pteroglossus aracari 111.
Selenidera, Aulacorhamphus.
Fam. Picidae. Woodpeckers. Powerfully built birds, with schizo-
gnathous palate, strong chisel-shaped beak pointed in front, without cere.
Metatarsus with transverse scales, feet with strong claws, with hard, firm
tail used as a prop in climbing trees. The tongue is long, flat, and horny,
and bears at its end short recurved hooks ; it can be rapidly protruded to
a considerable distance in consequence of a peculiar mechanism of the
hyoid bone. The cornua of the hyoid are bent into wide arches and in
some extend over the skull to the base of the beak. There are about 350
species found in all temperate and tropical lands except Madagascar,
Australia, and Polynesia.
Sub-fam. 1. Picinae. Woodpeckers. For the most part solitary
woodland birds of a shy and retiring nature, with powerful chisel-like
beak and very extensile tongue. They bore holes in trees, in which they
lay their eggs. Picus martins L., black woodpecker, Europe and Asia,
not in Britain. Dendrocopus major L., the greater spotted, and
Dendrocopus minor, the lesser spotted woodpecker, both British,
also in Europe and N. Asia. Gecinus viridis, the green woodpecker,
British, also in Europe and N. Asia. There are about 50 genera, of
which we may mention, Melanerpes, Picoides (with 3 toes only),
Meiglyptes, Tigan, Picumnus, Sasia.
Sub-fam. 2. lynginae. Wrynecks, with one genus lynx L.,
Europe, Asia, Africa, with soft tail and naked nostril and extensile
tongue. They feed chiefly on the ground and utilise ready-made
cavities for their eggs. /. torquilla L., wryneck, British.
Tribe 14. PASSERIFORMES.
The passerine birds are quintocubital ; the palate is aegithognathous,
without basipterygoid process, generally with large backwardly directed
processes of the palatines ; hallux invariably large and backwardly directed ;
front of shank covered with a small number of large scales ; left carotid
only present. The caeca are small, and the young are altrices. The num-
ber of species is enormous, about 5,500 or more than half the total
number of living birds, but the variation in structure is very small, and
the families have not the value even of those of the other tribes of birds.
The families are grouped according to the arrangement of the muscles of
the syrinx.
Group 1. Passeres Anisomyodae (Clamatores).
The syrinx muscles are either entirely lateral, or only dorsal or only
ventral.
Fam. Eurylaemidae. Broad-bills, Indo-Malaya ; 10 species. Eurylae-
mus, Psarisomus, Calyptomena.
Fam. Pittidae. Tropics of the Old World, about 50 species. Pitta,
Afr., Ind., Aust. Philepitta, Madagascar.
PASSERIFORMES. 475
Fam. Xenicidae. New Zealand, 3 species. Xenicus.
Fam. Tyrannidae. America. Over 400 species. Tyrannus carolinensis
Gm., the king or tyrant bird, temp. N. Amer. Oxyrhamphus.
Fam. Pipridae. Trop. Amer. Pipra Bonn., mannakins, S. Amer. ;
Tityra.
Fam. Cotingidae. Trop. Amer. Cotinga ; Eupicola, cock of the rock ;
Gymnoderus, Coracina, etc.
Fam. Formicariidae. South and Central America. Some are schizo-
gnathous, and some have lost the tracheo-bronchial muscles. About 520
species Thamnophilus, Formicarius, Grallaria, Furnarius, Dendrocolaptes
etc.
Fam. Pteroptochidae. South America ; about 30 species. Pteropto-
chus, Hylactes, Conopophaga.
Group 2. Passeres Diacromyodae (Oscines).
The syrinx muscles are inserted both on the dorsal and on the ventral
ends of the bronchial rings.
A. Abnormales, Suboscines.
Fam. Menuridae. Lyre-birds. Large birds with a stout beak. With
11 primaries and 16 rectrices of which the two outer are curved like a lyre
in the male. Incompletely aegithognathous. They live in forests with
tangled undergrowth, and are good mimics. M. superba Dav.
Fam. Atriehornithidae. Scrub-birds. Australia. Small birds inhabit-
ing dense scrub or grassy lands ; good mimics. Australia. Atrichornis.
B. Normales, Oscines verae.
Fam. Alaudidae. Larks. The plumage is earth-coloured ; the beak
is of medium length, the wings broad and long and the tail short. Alauda
arvensis F., skylark ; A. arbor ea L., woodlark ; A. cristata L., crested lark ;
A. alpestris L., shore lark.
Fam. Motaeillidae. Wagtails and pipits. Body slender ; beak fairly
long and notched at the point. Anihus pratensis Bechst., meadow pipit
Motacilla alba L., white wagtail.
Fam. Henicuridae. Fork-tails.
Fam. Timeliidae.
Fam. Pycnonotidae. Bulbuls.
Fam. Muscicapidae. Flycatchers. Beak short, broad, and depressed
at the base, somewhat compressed anteriorly, with hooked curved point.
Muscicapa grisola L., M. atricapilla L.
Fam. Turdidae. Thrushes, warblers, etc. The beak is tolerably long,
somewhat compressed, slightly notched before the point, and furnished
with vibrissae at the base. The metatarsus is long, and covered with an
anterior and two lateral scales (laminiplantar). Turdus merula L., black-
bird ; T. viscivorus L., mistletoe thrush ; T. musicus L., thrush ; T. tor-
quatus L., ring-ousel ; T. iliacus L., redwing ; T. pilaris L., fieldfare ;
T. migratorius L., American robin ; T. (Monticola) saxatilis L., rock-
thrush ; T. cyanus L., blue thrush. Saxicola Bechst., wheatear. Pra-
ticola rubetra, L., whinchat ; P. rubicola L., stonechat. Ruticilla phoe-
nicurus L., redstart. Accentor modularis L., hedge-sparrow. Luscinia
philomela Bechst., thrush nightingale, large nightingale in E. Europe ;
L. luscinia L., nightingale ; L. (Erithacus) rubecula L., robin redbreast.
476
Fam. Cinclidae. Dippers or water-oiisels. Cinclus aquaticus Bechst.
Fam. Troglodytidae. Wrens, principally in trop. America. Tro-
glodytes parvulus Koch, the common wren.
Fam. Chamaeidae. One genus, N. Amer.
Fam. Hirundinidae. Swallows and martins. With 12 rectrices and
anteriorly scutellated metatarsus. With broad, triangular beak, split
nearly to the eyes. Feet small and weak. Tail long and forked. Cos-
mopolitan ; the European species pass the winter in Central Africa. The
nests are formed of small lumps of moist earth and short straws and slender
sticks. Hirundo rustica L., the swallow. Chelidon urbica L., the house-
martin. Cotile riparia L., the sand-martin, nests in holes in the earth,
which it digs for itself.
Fam. Campephagidae. Cuckoo-shrikes. Oirynotus of Mauritius and
FIG. 256. — Cincinnurus regius, male and female (from CLaus).
Reunion has two species in which the males are alike, the females being
very different.
Fam. Dicruridae. Drongos. Ethiopian, Indian and Australian Regions.
Fam. Ampelidae. Ampelis garrulus L., the waxwing, Arctic Europe,
Asia and America ; A. carolinensis, cedar bird of N. Amer., A. japonicus
Japan and Amuria.
Fam. Artamidae. Wood-swallows, from the Australian to the Indian
Regions.
Fam. Laniidae. Butcher-birds or shrikes. Large powerful passerines,
with hooked, strongly serrated beak, strong rictal vibrissae, and tolerably
long, sharply clawed, feet. Lanius excubitor L., grey shrike ; L. minor L.,
lesser grey shrike ; L. rufus L., woodchat shrike ; L. collurio L., red-backed
shrike. These birds prey on small mammals, birds., etc., and impale them
on thorns to be devoured at leisure.
PASSERIFORMES 477
Farn. Vireonidae. Greenlets, America.
Fam. Sittidae. Nuthatches. Sitta caesia W. & M., the British species
of nuthatch.
Fam. Paridae. Tits. Small, beautifully coloured and agile birds of
stout build, with sharp, short, almost conical beak. Parus major L.,
great titmouse ; P. ater L., coal titmouse ; P. caeruleus L., blue titmouse ;
P.c.ristatus L., crested titmouse; P. palustris L., marsh titmouse; P.
caudatus L., long-tailed titmouse. Aeqithalus pendulinus L., penduline
titmouse.
Fam. Oriolidae. Old-World orioles. Palaearctic, 'Oriental and
Australian Regions. Oriolus galbula, the golden oriole, Europe.
Fam. Paradiseidae. Birds of Paradise ; Australian Region. With
slightly curved, compressed beak, large toes, and strong feet. The males
are gorgeously attired, with tufts of lax feathers at the sides of the body
and on the neck and breast. The two middle rectrices are often elon-
gated and filiform, with small vane only at the extremity. Paradisea
apoda L. Cincinnurus regius L., New Guinea (Fig. 256). Pteridophora
alberti, New Guinea.
The bower-birds of Australia (Ptilorhynchus, Chlamydera, Sericulus
Amblyornis, Prionodura, etc.) are placed here. They construct "runs"
or " playing houses " with pieces of sticks and grass, and in some cases
ornamsnt them with mosses, flowers, feathers, shells, etc. It is not clear
whether the bowers are constructed by birds of both sexes or by the males
only.
Fam. Corvidae. Beak strong and thick, somewhat curved anteriorly
and slightly notched. Corvus corax L., raven ; C. comix L., hooded crow ;
C. corone L., carrion crow ; C. jrugilegus L., rook ; C. monedula L., jack-
daw. Pica caudata, magpie ; Garrulus glandularius L., jay. Nucifraga
caryozatactes L., nutcracker. Pyrrhocorax V., choughs.
Fam. Sturnidae. Starlings. With straight or slightly curved, strong
beak, the point of which is rarely only slightly notched ; without rictal
vibrissae. Old World, not America. Sturmts vulgaris L., starling.
Pastor roseus Temm., rose-coloured starling. Buphaga africana L., ox-
pecker.
Fam. Drepanididae. Sandwich Islands.
Fam. Meliphagidae. Honey-eaters. Australian Region. Small beau-
tifully-coloured birds of stout build, with muscular vocal apparatus, long
gently-curved beak, wings of medium length and long tail. Meliphaga
auricomis Sw.
Fam. Zosteropidae. White-eyes. Ethiopian, Indian, Australian Re-
gions.
Fam. Nectariniidae. Sun-birds. With brilliant metallic coloration.
India, Papuasia, N. Australia, Africa. Nectarina splendida Cuv., S.
Africa.
Fam. Dicaeidae- Flower-peckers. India, Australia, W. Africa.
Fam. Certhiidae- Creepers. With long slightly-curved beak, horny
tongue, and long hind toe with sharp claw. Palaearctic, Nearctic, Ethio-
pian, Australian Regions. Cerihia familiaris L., common creeper. Ticho-
droma muraria 111., wall-creeper.
Fam. Coerebidae. Quitquits. America.
Fam. Mniotiltidae. American warblers.
Fam. Tanagridae. America.
Fam. Ploceidae. Weaver-birds. So called from the elaborately woven
478 AYES.
nests which many of them build. Ethiopian, Indian, and Australian
Regions ; about 250 species.
Fam. Icteridae. American orioles or starlings.
Fam. Fringillidae. Finches. With short thick swollen beak, without
notch, with a basal swelling. Emberiza citrinella L., yellow bunting ;
E. cia L., meadow bunting ; E. nivalis L., snow bunting. Fringilla
coelebs L., chaffinch ; F. spinus L., siskin ; F. montifringilla, brambling ;
F. carduelis L., goldfinch. Passer domesticus L., house-sparrow ; P.
montanus L., tree-sparrow. Coccothraustes vulgaris Pall., hawfinch.
Pyrrhula vulgaris Briss., bullfinch ; P. canaria L., canary. Loxia cur-
virostra Gm., crossbill. Linota cannabina, linnet.
CHAPTER XIII.
CLASS MAMMALIA.*
Warm-blooded hairy animals with double occipital condyle, a
heart with two ventricles and two auricles, a left aortic arch, non-
nucleated red Mood-corpuscles, and mammary glands with which
they suckle their young. The lower jaw consists of a single piece
on each side and articulates ivith the squamosal, and the ureters
always (except in Monotremeata) open into the bladder.
In addition to the characters mentioned in the definition
which absolutely characterise the Mammalia, we may mention
the following which are almost universally present.
The external auditory meatus is tubular arid its opening is
almost always marked by a fold of skin called the pinna. There
are three ossicles, the malleus, incus and stapes, connecting the
tympanic membrane with the fenestra ovalis. The cochlea is
spirally coiled. The retina contains blood-vessels. The 'tym-
* J. C. D. v. Schreber, Die Sdugethiere in Abbildungen nach der Natur
mit Beschreibungen, fortgesetzt von J. A. Wagner, 1-7, and sup: 1-5,
Leipzig 1775-1855. E. Geoffrey St. Hilaire et F. Cuvier, Histoire Natu-
relle des Mammiferes, Paris 1840-45. A. E. Brehm., Illustrirtes Thierleben,
1-3. De Blainville, Osteographie, 1835-54. Huxley, Anatomy of the
Vertebrata, London, 1 871. Flower, Osteology of the Mammalia, 3rd ed. 1885.
Flower & Lydekker, Mammals living and extinct, London, 1891. Beddard,
Mammalia, vol. 10 of the Cambridge Natural History, 1902. K. Owen, Odon-
tography, 2 vols., London, 1840-45. Tomes, Dental Anatomy, 5th ed.,
London, 1898. Wallace, Geographical Distribution of Mammals, 2 vols.
London, 1876, and Island Life, London, 1880. W. L. & P. L. Sclater,
The Geography of Mammals, London, 1899. Lydekker, Geographical
History of Mammals, Cambridge, 1896. Trouessart, Catalogus Mamma-
Hum tarn viventium quam fossilium, Berlin, 1897. Zittel, Handbuch der
Palaeontologie, vol. 4, Leipzig, 1891-3, and Grundzuge der Palaeontologie,
Leipzig, 1895. Woodward, Outlines of Vertebrate Palaeontologie, Cam-
bridge, 1898. F. M. Balfour, A Treatise on Comparative Embryology,
vol. 2, London, 1882. C. S. Minot, Human Embryology, New York, 1892.
A. M. Marshall, Vertebrate Embryology, London, 1893.
480 MAMMALIA.
panic cavity is bounded ventrally by a tympanic bone, and the
quadrate is not present as a distinct element being probably
absorbed into the squamosal. There is 110 postfrontal bone and
only one temporal arcade (see p. 319). The vertebral centra
almost always carry epiphyses. There are almost always seven
cervical vertebrae. The coracoid is with one exception reduced,
and fused with the scapula, not reaching the sternum. Except
in whales, the pollex and hallux usually have two phalanges, the
other digits three. When the digits are reduced the order of
disappearance is almost always No. 1, No. 5, No. 2, No. 4, so that
if there is only one digit it is No. 3, if two Nos. 3 and 4. In the
brain the cerebellum has two lateral lobes as well as a median,
there are four optic lobes (corpora quadrigemina), and the cere-
bral hemispheres are connected by a broad commissure, the
corpus callosum. The portions of the body cavity containing
the lungs are always separated from the general body cavity by
a muscular septum, the midriff or diaphragm. There is a urino-
genital sinus, called urethra in the male and vestibule in the
female, which receives the opening of the bladder and of the
generative ducts ; it opens independently of and ventral to the
anus except in the Monotremata and a few other forms.
The testes and ovaries have nearly always shifted backwards
in the body cavity from their primitive position near the kidney ;
in the case of the male the shifting is considerable and the testes
very generally lie in pouches of the body cavity called the scrotal
sacs, placed close to the root of the penis. A penis is always pre-
sent, consisting of two corpora cavernosa attached to the ischia
and of a corpus spongiosum which swells terminally to form the
glans penis. With very rare exceptions the penis is traversed
by the urethral canal. The female has a reduced homologue of
the penis, the clitoris, which is only rarely traversed by the
urethra.
In addition to the peculiarities in the vascular system men-
tioned in the definition, viz. the four- chambered heart and the
presence of an aortic arch on the left side only, it ought to be
mentioned that there is no renal -portal circulation.
The ovum is always small and provided with but little food
yolk. As might be expected the cleavage is total and the greater
part of the development (excepting in the Monotremata in which
the cleavage is partial) takes place in that portion of the oviduct,
AFFINITIES. 481
to which the term uterus is applied. The embryo is provided
with an amnion and allantois and, excepting in the Monotremata
and most Marsupialia, is always connected with the uterine wall
by means of the allantois ; the combined structure formed
by the union of foetal and maternal tissues being called the
placenta.
Such are the principal characters of the Mammalia. It will
be seen that the group is a very well defined one and clearly
marked off from the other vertebrate classes. As to its origin in
evolution we have nothing to say for the very good reason that
there are no facts by which we ca.n arrive at any conclusion on
the subject. It may however be noted here that, if we except
certain doubtful forms from the Eocene, the Monotremata are
not found fossil till the Pleistocene, and that the earliest known
fossil mammals appear, so far as can be judged from their some-
what scanty remains, to have been of a small and rather special-
ised type. It is true that these Triassic and Jurassic Mammalia
are classified with or in the neighbourhood of the Marsupialia,
but it cannot be asserted that this is done on any substantial
evidence.
But we may say something with regard to the relations of
Mammalia to other classes of Vertebrata. Though a well defined
group they present rather close points of contact with living rep-
tiles through the Monotremata (p. 525) and especially with the
extinct Anomodontia (p. 398). The resemblances between
Monotremata and living reptiles are specially interesting be-
cause they concern the soft (urinogenital organs, ovum, etc.) as
well as the hard parts (shoulder girdle, etc.). Taking the totality
of these resemblances they reduce the important features of soft
parts which are peculiar to mammals to the red blood-corpuscles,
the aortic arch, the mammary glands and the hairs. Treating
the skeleton in the same way, we find that, having regard to the
Anomodontia and the Monotremata there is hardly a character
of any importance which can be said to be peculiar to Mam-
malia. We thus reach the conclusion that the gap between
reptiles and mammals is not a large one, that it is not indeed
larger than that between reptiles and birds, and that reptiles,
birds, and mammals constitute a natural group, more homo-
geneous than the group Ichthyopsida or even than the class
Pisces. Among the characters of the group so constituted w.>
z.— ii 1 1
482
MAMMALIA.
may mention the terrestrial habit and the absence of gills,
the presence of an amnion and allantois, the universal pre-
sence and relative importance of the hyomandibular cleft, the
presence of a primitive streak, of twelve pairs of cranial nerves,
the absorption of the persistent part of the mesenephros into the
testis, the presence of a ureter, the abortion in the adult
female of the mesonephric duct, and lastly the complete dis-
appearance of the conus arteriosus and the breaking up of the
ventral aorta.
By these important characters the reptiles, birds, and mammals
are sharply marked off
from both Amphibia
and Pisces ; the more
we consider them, the
more difficult it be-
comes to understand
on what grounds the
contention has been
made that mammals
are more closely related
to Amphibia than to
reptiles and have been
directly derived from
them in evolution.
We shall now pro-
ceed to give some
account of such fea-
tures of mammalian
anatomy as seem to re-
quire a fuller explana-
tion to enable the reader to comprehend the detailed descriptions
of the orders which follow. Space does not permit of our giving
anything like a complete account of mammalian morphology.
For such we must refer the reader to special works on Anatomy
and Embryology.
Hairs are to mammals what feathers are to birds. They are
never entirely absent ; even Cetacea and the hippopotamus
which seem to be without them, possess hairs on certain parts
even if only a few short bristles on the lips. Hairs are cornified
modifications of the epidermis. The bulbous root is placed
FIG. 257. — Section of human skin (from "Wiedersheim.
Co dermis (corium, cutis) ; D sebaceous glands ;
F subcutaneous fat ; G bloodvessels of dermis ;
OP vascular papilla of hair ; H hair ; N nerves in
dermis; #Pf nerve ending in dermis ; Se horny layer
of epidermis (stratum corneum), SD sweat gland ;
SD' duct of sweat gland ; SM malpighian layer of
epidermis (stratum 'malpighii).
HAIRS. CUTANEOUS GLANDS. 483
upon a vascular papilla at the bottom of an epidermal pit (hair-
follicle) which projects into the dermis some distance below the
level of the epidermis (Fig. 257) ; the upper part or shaft pro-
jects freely on the surface of the skin. Each hair is composed
of an axial part — the pith, which contains air, and of an outer
horny part — the cortex, in which there is no air. The cortical
part is frequently imbricated so as to appear scaly, e.g. bats ;
in the sloths it is fluted longitudinally. In some cases the pith
predominates, while in others, as in bristles, the horny cortical
part is the more important. Two kinds of hairs may be distin-
guished according to the nature of the shaft ; contour hairs
which are stronger and longer, and woolly hairs which are deli-
cate and curled and surround the base of the contour hairs.
The woolly hairs constitute the under-fur ; they frequently have
the power of cohering (felting) by their rough scaly surface.
Hairs 'are usually cylindrical, but sometimes they are flattened ;
in the latter case they tend to curl. In some animals the hair is
renewed periodically, and in some the hair in winter is longer than
and of a different colour from the hair of summer. Smooth mus-
cular fibres are often attached to the sheaths of the stronger
hairs, by means of which each of them can be moved singly.
The bristling of the hairy covering and the erection of the spines
over larger extents of surface is caused by the striped muscular
system of the dermis. Horny epidermal scales are found in
some Edentates (Manis), and occasionally on the under surface
of the tails of rodents. The horny scales of armadillos are placed
over bony dermal plates. Special cornification of the epidermis
is also found over the terminal phalanges of the digits in the
form of nails, claws, and hoofs.
Cutaneous glands. Sweat glands and sebaceous glands
(Fig. 257) are widety distributed. Sebaceous glands are almost
invariably found opening into the hair-follicle, but they are also
found on naked parts of the skin. They secrete a fatty grease
which keeps the surface soft and the hair glossy. Sweat glands
have the form of coiled glandular tubes with sinuous ducts, and
are rarely absent (Cetecea, Mus, Talpa). The larger glands with
strongly smelling secretions, which open on various parts of the
integument of many mammals are to be regarded as modified
sebaceous, or more rarely sweat-glands. As examples of such
glands may be mentioned the occipital glands of the camel, the
484
MAMMALIA.
glands (crumeri) which are placed in a depression of the lacrymal
bone of antelopes and deer, the temporal glands of the elephant,
the facial glands of the bat, the pedal glands of ruminants, the
lateral glands of the shrew-mouse, the sacral glands of the
peccary, the caudal glands of the desman, the preputial glands
of the musk-deer and beaver, etc. These glands are often found
near the anus or in the inguinal region and then often open into
special cutaneous pits, e.g. the anal glands of many Carnivora,
Rodentia, and Edentata, the civet gland of the Viverridae, the
musk pouch of Moscftus and the preputial glands of the male
beaver. The lacrymal glands may
also be placed in the category of
cutaneous glands.
The mammary glands occur in all
mammals. In monotremes they are
said to be modified sweat glands, but
in all other mammals there can be
little doubt that they are modified
sebaceous glands. In monotremes
they open on a slight depression of
the skin called the mammary areas
or pouches (Fig. 258). In many
mammals this area is much deepened
and the surrounding skin rises up
around it to form the teat, in
this case called a false teat, of
the gland (Ruminantia, Carnivora, etc.. Fig. 258). In others
there is no mammary pouch, but the area of skin on which the
glands open is simply raised into a papilla, the so-called true
teat (primates, marsupials. Fig. 258). The position and number
of the mammary glands vary considerably.
The skeleton consists of heavy bones, usually containing
marrow.
The skull (Figs. 259, 260) differs from that of reptiles in the
following features. The primordial cartilage is completely
ossified and the separate bones, which are fewer than in rep-
tiles, meet and are separated only by sutures, which in old ani-
mals tend to disappear. In a few cases the bones become fused
in early life (Monotremata). There are no prefrontal or post-
frontal bones, and no membrane bone in the floor corresponding
Fid. 258.— Diagrams showing the
different kinds of nipple[met with
in mammals (from Gegenbaur).
A the monotreme condition. K
the true teat. C the false teat:
a periphery [of glandular area ;
6 glandular area (mammary
pouch) ; gl glands.
SKULL. LOWER JAW. 485
to the parasphenoid. There is only one temporal arcade formed
of the jugal and zygomatic process of the squamosal and corre-
sponding either to the lower temporal arcade 6f reptiles or to the
upper and lower temporal arcades combined into one and not
perforated by a lateral temporal fossa.
The maxillary and palatine bones are firmly united with the
skull, and there is a hard palate formed by palatal plates of the
premaxilla, maxilla and palatine, and occasionally, as in croco-
diles, by the pterygoid (some cetaceans and edentates). The
pterygoid, so conspicuous in the lower forms, is a small scale-
like bone connected with the palatine but without relation
with the suspensorial region.
The quadrate has been absorbed into the squamosal so that
the lower jaw articulates with the squamosal direct. The arti-
cular surface for the condyle of the lower jaw is called the glenoid
cavity. The squamosal enters largely into the side wall of the
skull. The lower jaw consists of the fused articulare and den-
tary and is formed of one piece on each side. The periotic con-
sists of the petrous portion (petrosal) in the skull (Fig. 260, Pe)
and the mastoid portion which appears on the surface between
the exoccipital and the squamosal (Fig. 259, Pe) ; it ossifies from
three centres which constitute the epiotic, prootic and opisthotic
elements ; these unite with each other before joining any neigh-
bouring bones. The periotic usually unites with the squamosa
and the tympanic to form the temporal bone. The tympanic
bone (Ty) is a membrane bone which frequently forms the floor
and front wall of the tympanic cavity and may be prolonged
outwards in a tubular or spout-like manner, bounding the bony
external auditory meatus. It is often considerably swollen
to form the tympanic bulla. The complex of bones, called
the temporal, fills in a gap in the skull wall between the
exoccipital and the alisphenoid, leaving only a small unfilled
portion in front and behind. The former is called the
foramen lacerum medium basis cranii and transmits the in-
ternal carotid artery ; the latter is larger and constitutes the
foramen lacerum poster ius basis cranii which transmits the
internal jugular veins, and the 9th, 10th, and llth cranial
nerves.
The occipital bone always articulates with the atlas vertebra
by two condyles, and its lateral portions frequently possess a
486
MAMMALIA.
well-marked process on each side, the paroccipital or 'jugular
(paramastoid) processes (Pm). The base of the skull is well ossi-
fied in cartilage bone. The basisphenoid (Spb) usually remains
distinct from the presphenoid (Ps) for a considerable time/- Its
upper surface is hollowed out as the pituitary fossa (sella lurcica}
which lodges the pituitary body. The alisphenoid (Als) and
parietals (Pa) complete the basisphenoid section of the skull and
the orbitosphenoid and frontals (Ors, Fr) the presphenoid region.
There is no interorbital septum, and the ethmoid with its per-
forated or cribriform plate (lamina cribrosa) constitutes the
anterior boundary of the cranial cavity. In the Primates only
01
FIG. 259. — Skull of a goat, from the side (from ClausK C occipital condyle, .Fo'optic
foramen, Fr frontal," Jmx premaxilla, Ju jugal, La lacrymal, MX maxilla, Na nasal,
01 exoccipital, Os supraoccipital. Pa parietal, Pal palatine, Pe mastoid portion of
petrosal, Pm paroccipital process, Pt pterygoid, Sq sciuamosal, Ty tympanic.
do the lateral parts of the ethmoid (lamina papyracea) take part
in forming the inner wall of the orbit. In all other cases the
ethmoid is placed in front of the orbit and its lateral portion
(os planum) is covered by the maxillae. Two parts may be dis-
tinguished in the ethmoid, (1) a median plate (lamina per-
pendicularis) which is continued in front into the cartilaginous
nasal septum and is underlaid by the vomer and covered dor-
sally by the nasals, (2) the lateral masses. The lateral masses
of the ethmoid, or spongy bones as they are called, result from
the ossification of the complexly folded cartilage of the nasal
capsule, over the surface of which the terminal .fibres of the
SKULL.
487
olfactory nerves are spread. On their outer sides these laminae
are connected by a thin plate of bone, the os planum, which usu-
ally lies as above stated against the inner wall of the maxillae.
Behind they are all connected together to form the sieve-like
cribriform plate which is joined to the hind end of the median
ethmoid and blocks up the anterior end of the cranial cavity.
The os planum and the ossified laminae constitute together the
lateral mass of the ethmoid bone above referred to. The laminae
are usually divided into two sets, which, though all parts of the
same bone, have received different names according to their
mode of attachment to neighbouring bones. These are the
ethmoturbinal (superior and middle turbinals, Fig. 260, C) and
Fr
No.
Pe
FIG. 260. — Median longitudinal section of a sheep's skull (from Cla us). -Als alisphenoid ; O
ethmoturbinal, Ci maxilloturbinal, Eth ethmoid, Fr frontal, Jmx premaxilla, MX
maxilla, Na nasal, Ob basioccipital, 01 exoccipital, Ors orbitosphenoid, Os supraoccipital,
Pa parietal, Pal palatine, Pe petrosal, Ps presphenoid.FY pterysjoid, Sf frontal sinus,
Spb basisphenoid, Vo vomer. The median plate of the ethmoid is not seen.
the maxillo-turbinal (Ci). The uppermost lamellae of the
ethmoturbinals lie immediately beneath the nasals and are fre-
quently united to them ; they constitute the so-called naso-
turbinal. The maxillo- turbinals (inferior turbinals) are the
portions lying farther forward : they owe their name to the
fact that they unite with the maxillae. The maxillo-turbinal
being placed farther forwards lies in the direct current of
respiratory air and its mucous membrane is not innervated by
the olfactory nerve, but by the fifth nerve. The lateral masses
of the ethmoid are generally held to correspond with the pre-
488 MAMMALIA.
f rentals of the lower types. The lacrymal bone (absent in the
Pinnipedia and some Cetacea) is placed in the anterior wall of
the orbit, and often also appears as a facial bone on the face
(Fig. 259, La).
The most important foramina in the cranial wall are, typically,
as follows. (1) 1'he perforations in the cribriform plate which
transmit the fibres of the olfactory nerve. (2) The optic foramen
in the orbitosphenoid. (3) The foramen lacerum anterius
(sphenoidal fissure), a space between the orbitosphenoid and
alisphenoid, which transmits the 3rd, 4th, 6th cranial nerves
and the anterior division of the 5th. (4) The foramen rotundum
and (5) the foramen ovale, both perforations of the alisphenoid
which transmit respectively the second and third divisions of
the 5th nerve. (6) The foramen lacerum medium between the
alisphenoid and the periotic (just internal to the opening of the
bony eustachian passage) for the passage of the internal carotid
artery. (7) On the inner surface of the periotic is the opening
of the meatus auditorius internus which transmits the auditory
and facial nerves, the former to terminate in the walls of the
membranous labyrinth, the latter to traverse the bone and
emerge by (8) the stylomastoid foramen, which is placed imme-
diately behind the bull a and just anterior to the paroccipital pro-
cess. (9) The foramen lacerum posterius between the periotic
and exoccipital for the 9th 10th and llth nerves and the internal
jugular vein. (10) A foramen in the exoccipital just in front of
the condyle, called the condylar foramen, for the transmission
of the 12th nerve. (11) The foramen magnum by which the
spinal cord enters the skull.
The alisphenoid canal, present in some mammals, is a hori-
zontal canal in the alisphenoid at the root of the pterygoid
process, through which the external carotid passes in part of
its course ; it begins behind just in front of the foramen ovale
and ends in front at the foramen rotundum.
The brain so completely fills the cranial capsule in the Mam-
malia that the internal surface of the skull presents a relatively
accurate impression of its surface. Owing to the considerable
size of the brain the cranial capsule is far more spacious than in
any other class of Vertebrata ; but it presents great variations
in this respect in the different groups, being smallest in some
of the extinct orders.
FACIAL ANGLE. VERTEBRAL COLUMN. RIBS. STERNUM. 489
The prominence of the facial part of the skull also varies
4 greatly. It may be said, speaking generally, to vary inversely
with the development of the intellectual faculties. The condition
of the skull in this respect is expressed by reference to the cranio-
facial angle, which is the angle between the basicranial .axis, i.e.
the line drawn from a point midway between the occipital con-
dyles through the median plane of the skull to the junction be-
tween the ethmoid and presphenoid,' and the facial axis, i.e. the
line drawn from the anterior end of the premaxilla to the an-
terior end of the basicranial axis. When the face projects straight
out in front of the cranium this angle is nearly 180°, i.e. the two
axes are nearly in the same straight line ; when on the other
hand the face lies below the anterior end of the cranium it is less
and in man approaches a right angle. The first condition, viz.
that of projecting face and large facial angle, is known as prog-
nathism, the other condition, in which the facial angle is smaller,
is called orthognathism.
The hyoid bone is reduced to a transverse bar (body) carrying
two pairs of cornua.
The vertebral column, except in the Cetacea, is divid-ed into
five regions, viz. cervical, thoracic, lumber, sacral and caudal
(Fig. 261). In the aquatic Cetacea, which are without hind
limbs, the lumbar region passes gradually into the caudal ; on
the other hand the cervical region is strikingly shortened, and
the fusion of its anterior vertebrae renders it rigid and immove-
able. The vertebral bodies are only exceptionally (neck of
Ungulates) connected by articular surfaces, but are usually
joined by elastic discs (intervertebral ligaments). The first
cervical vertebra (atlas) is a bony ring with broad, wing-like,
transverse processes. The axis has an odontoid process. The
dorsal vertebrae are characterised by high, crest-like, spinous
processes, and by the possession of ribs. The anterior ribs are
attached by cartilage to the sternum, which is usually elongated
and composed of a number of bony pieces arranged one behind
another ; the posterior ribs (the so-called " false ribs ") do not
reach the sternum. The ribs articulate with the vertebrae by
means of a capitulum and tuberculum. The first piece of the
sternum, which is sometimes keeled (bats, moles, etc.), is called
the manubrium ; the last piece is called, as in the lower types,
the xiphoid process or ensiform cartilage. In monotremes alone
490
MAMMALIA.
is there a distinct interclavicle (episternum). While the number
of cervical vertebrae is almost constantly seven, that of the
dorsal vertebrae is subject to a greater variation. As a rule
there are thirteen, sometimes twelve dorsal vertebrae ; but there
is a less number in some bats and armadillos, while there are
fifteen or more in some animals. The horse has eighteen, the
rhinoceros and elephant nineteen to twenty, and the three-toed
sloths have twenty-three to twenty-four. The lumbar verte-
brae, which have long lateral processes in place of ribs, are
usually seven in number. The number rarely sinks to two as
in Ornithorhynchus and the two -toed sloths, and still more
rarely rises to eight or nine (Stenops). The sacral vertebrae.
.77
FIG. 261.— Skeleton of the Lion (after Giebel). <; calcaneum ; Cp carpus ; F fibula ; Fe femur ;
H humerus ; Jl ilium ; Js ischium ; Me metacarpus ; Mt metatarsus ; P patella ; P pubis
R radius ; Se scapula ; St sternum ; T tibia • Ts tarsus ; U ulna.
which vary in number from two (marsupials) to four, more rarely
nine (Armadillo), are firmly united with one another, and by
their transverse processes (with the rudiments of the ribs) with
the iliac bones. In whales and Sirenia there is no union of ver-
tebrae to form a sacrum. The caudal vertebrae, which vary
considerably in number and mobility, become narrower towards
the end of the axis of the body, and often (kangaroo and ant-
eaters) possess inferior spinous processes (chevron bones or
LIMB-GIRDLES. 491
intercentra) ; but all the processes become less and less conspicu-
ous towards the posterior extremity.
The outer surface of the scapula is traversed by a ridge called
the spine which divides it into a prescapular and postscapular
portion. The spine usually projects at the lower end as the
acromion process, from which a backwardly directed process, the
metacromion, may arise. The anterior pair of extremities is
never absent. The clavicle is absent when the anterior limbs
serve only for the support of the anterior part of the body in
locomotion, or perform simple, pendulum-like movements, as
in swimming, walking, running, jumping, etc. (Cetacea, Ungu-
lata, Carnivora). Otherwise the acromion process of the scapula
is connected with the sternum by a more or less strong, rod-
shaped clavicle. The coracoid is almost always reduced to the
coracoid process of the scapula ; in the Monotremata only is it
a large bone which reaches the sternum/'' The posterior ex-
tremities are more firmly connected with the body than are the
anterior. In the Cetacea and Sirenia alone is the pelvic girdle
rudimentary, and is represented by two rib-like bones which are
quite loosely connected with the vertebral column. In all other
mammals the pelvic girdle is fused with the lateral parts of the
sacrum, and is closed ventrally by the symphysis of the pubis
and sometimes also of the. ischium (except in a few Insectivora).
The three bones are always united into one, the os innominatum,
which is pierced in the ischio-pubic region by a fontanelle called
the obturator foramen (corresponding to the coracoid fenestra
of the shoulder girdle of some lower types). The appendages
articulated to the pectoral and pelvic girdles are considerably
shortened in the swimming Mammalia, and either constitute,
as in the Cetacea, flat fins, the bones of which are immoveable
upon one another (in the Sirenia there is a joint at the elbow),
and in which there is a great number of phalanges, or, as
in the Pinnipedia, have the form of fin-like legs, which can
also be used in locomotion on land. In the Chiroptera (bats),
the anterior limbs present a large surface in consequence of an
expansion of the integument (patagium) uniting the limbs
with the sides of the body, and extended between the elongated
fingers.
In the land Mammalia the extremities present considerable
variations both in their length and special structure. The
492 MAMMALIA.
humerus often has a foramen above the inner condyle called the
entepicondylar foramen. Its presence is supposed to be a
primitive feature, as it is chiefly found in the lower and older
(extinct) forms. It is characteristic of some ancient reptiles
e.g. Hatteria, Anomodontia, etc. The radius and ulna in the
fore -limb and the tibia and fibula in the hind-limb are almost
always longer than the humerus and femur respectively. The
ulna forms the hinge-joint of the elbow, and is prolonged at this
point into a process called the olecranon ; the radius, on the
other hand, is connected with the carpus, and can often be
rotated round the ulna (pronation, supination) ; in other cases
it is fused with the ulna, which then constitutes a rudimentary,
styliform rod continued from the olecranon process. In the
hind-limb the knee-joint projects forwards, and is usually
covered by a knee-cap, the patella ; the fibula is sometimes
(marsupials) moveable on the tibia, but as a rule these twro bones
are fused, and the fibula which is placed posteriorly and ex-
ternally is usually reduced.
The variations in the terminal parts of the limbs are far
more striking (Fig. 262). The number of digits is never greater
than five, and is often less. The order of their disappearance
has already been described (p. 480).
In the carpus of Mammalia the three proximal bones remain
distinct, a centrale is occasionally present (Hyrax, many Insecti-
vora, Primates, etc.) and carpalia 4 and 5 of the distal row are
always fused together. There is always a radial sesamoid de-
veloped in the tendon of the flexor muscles and called the pisi-
form. There may also be a smaller ulnar sesamoid. The names
given to these bones are shown in the following table, with the
equivalent terms used by Comparative Anatomists.
Radiale — Scaphoid (Naviculare).
Intermedium = Lunar (Semilunare).
Ulnare = Cuneiform (Triquetrum).
Centrale = Centrale (Intermedium).
Carpale 1 = Trapezium (Multangulum ma jus).
Carpale 2 = Trapezoid (Multangulum minus).
Carpale 3 = Magnum (Capitatum).
\= Unciform (Hamatum).
Carpale 5 J
FORE-LIMB.
493
In stating the number of the carpal bones the pisiform is
generally included, so that a carpus with a centrale is said to con-
sist of nine bones, without a centrale of eight.
The radial and ulnar sesanioids have been regarded as vestiges of extra
digits, viz. of a prepollex and postminimus respectively. Another view is
that the radial sesamoid is in reality the radiale, the scaphoid being a
second centrale. It cannot be said that these views are generally held, but
it may be noted that occasionally the radial sesamoid is double and
bears a nail-line structure (Pedetes caffer).
It frequently happens that when the digits are reduced in
number, the persisting metacarpals and metatarsals, to which
the single name metapodium may for convenience' sake be given,
are elongated, or even fused together to form the so-called
cannon bone.
FIG. 262. — Skeleton of the manus of a orang, b dog, c pig, d ox, e tapir, / horse (from Claus).
A scaphoid ; B lunar ; C cuneiform ; D trapezum ; E trapezoid ; F magnum ; G unci-
fonn ; P pisiform ; C centrale ; M metacarpus ; 1-5 digits numbered.
The number of phalanges characteristic of the Mammalia has
already been given (p. 480).
The ungual phalanges are the terminal phalanges which bear
the claws, nails, or hoofs. A plantigrade animal is one which
places the whole of the lower surface of the manus (carpus, meta-
carpus, phalanges) or pes on the ground in walking. The term
digitigrade is applied when the two distal phalanges only are
applied to the ground, the first phalanx and the metapodia being
vertical. When the last phalanx and hoof alone carry the
weight the animal is said to be unguligrade. There are also
494 MAMMALIA.
conditions intermediate between these, to which such terms as
semiplantigrade. semidigitigrade have been applied.
In the tarsus the tibiale and intermedium are always fused
(according to the ordinary view), the centrale is always present,
and tarsalia 4 and 5 are fused as are the corresponding bones in
the wrist. Tibial and fibular sesamoids are very generally pre-
sent, but the tibial sesamoid is not so important as the pisiform
of the wrist. But, as in the case of the manus, sesamoid bones
may be developed in tendons in other situations, as in the
tendons on the plantar surface of the tarsus, on the plantar
surface of the metatarso-phalangeal articulation.
The following table shows the names of the tarsal bones.
Tibiale 1
,. Y= astragalus (talus).
Intermedium J
Fibulare = calcarieum (os calcis).
Centrale = navicular (scaphoideum).
Tarsale 1 — internal cuneiform (entocuneiform).
Tarsale 2 = middle cuneiform (mesocuneiform)
Tarsale 3 = external cuneiform (ectocuneiform).
Tarsale 4 1
1= cuboid.
Tarsale 5 J
The ankle joint is always between the cms (tibia and fibula) and
the tarsus, never between the two rows of tarsal bones as in birds
and some reptiles ; and the calcaneum always possesses a well-
marked heel process.
The nervous system is characterised by the size and high de-
velopment of the cerebrum, the hemispheres of which are so large
that they not only fill the anterior part of the cranial cavity but
even partly cover the cerebellum (Fig. 263). In Ornithorhyn-
chus, various small rodents and insectivores and some of the
smaller primates the surface of the hemispheres is smooth or
nearly so (Fig. 263, a), but in most Mammalia it is marked by
depressions and ridges, which in the higher forms (Fig. 263, d)
become furrows or fissures (sulci) and convolutions (gyri). The
number and complexity of the convolutions may be said, speak-
ing generally, to vary directly with the intelligence of the animal,
but they seem, in some cases at least, to depend upon the size of
the animal, for we frequently find that in the smaller members
of a group the convolutions are less marked than in the larger.
BRAIN. SENSE-ORGANS. 495
They reach their highest development in the Cetacea, the brain
of which is even more complexly convoluted than that of mail.
A broad commissure, the corpus callosum, connecting the
two hemispheres is always present except in Monotremata
and Marsupialia. When this is absent the anterior commis-
sure is large, and there is an important commissure taking the
place of the body of the fornix and called the hippocampal
commissure. The latter is placed just above the anterior com-
missure. The lateral ventricles possess anterior and descending
cornua, and in the Cetacea and Primates a posterior cornu as
well.
The optic lobes, which are four in number and known as the
corpora quadrigemina, are reduced in size and are in great part
or entirely covered by the posterior lobes of the hemispheres
(Fig. 263). The pituitary body (hypophysis) and the pineal body
(epiphysis) are always present. There is no parietal organ.
The cerebellum consists of a median lobe or vermis and of two
lateral lobes each of which carries a small accessory lobe, the
flocculus. A transverse commissure, the pons varolii, lying on
the ventral surface of the anterior part of the medulla bblongata
and connecting the lateral lobes of the cerebellum, is always
present, but varies in its development in the different forms.
There are twelve pairs of cranial nerves as in Sauropsida. The
spinal cord usually extends only as far as the sacral region where
it ends with a cauda equina ; there is no posterior rhomboidal
sinus.
Sense organs. The sense of touch is most acute in the skin of
the face, lips, tongue and ends of the extremities, the skin in
these regions being provided with special organs in which the
nerves terminate called tactile corpuscles. The vibrissae or long
bristle-like tactile hairs which are often found on the face, and
the papillae of which are richly innervated, are special organs of
touch. In the same category may be placed the wings and the
cutaneous expansions on the faces of bats, which are so sensitive
as to enable the animal to detect obstacles without touching
them, by the mere alteration in the pressure of the air in their
neighbourhood.
The sense of taste has its seat principally at the root of the
tongue (papillae circumvallatae) and on the soft palate.
|ii The sense of smell appears to be present in all Mammals
496
MAMMALIA.
except the toothed whales in which there are no olfactory nerves.
It is effected by the mucous membrane which covers the^ethmo-
turbinal bone of the nasal labyrinth ; it is in this mucous mem-
brane that the olfactory nerve fibres terminate. The two nasal
FIG. 263. — Mammalian brains (from Claus). a brain of rabbit, dorsal view ; the roof of
the right hemisphere is cut away, so as to expose tho lateral ventricle, b the same
from below, c brain of cat ; on the right side the lateral and posterior part of the
hemisphere is removed, and almost as much on the left side, and the greater part of
the cerebellum has been removed, d brain of orang. Cb cerebellum ; H hypophysis
cerebri ; Lo olfactory lobe ; Mh corpora quadrigemina ; Mo medulla oblongata ; Sr
sinus rhomboidalis ; Th optic thalamus ; Vh cerebral hemispheres ; V root of trigeminal
nerve ; II roots of optic, VII, VIII of facial and auditory nerves.
cavities, which are separated by the median nasal septum,
communicate with the nasal passages passing from the external
nostrils to the internal narial openings. They also often com-
municate with spaces in 'the adjacent cranial and facial bones
EYES. LACRYMAL GLANDS. 497
(sinus frontales, sphenoidales, maxillares}. In the Cctacca the
external nostrils are sometimes united to form a single opening.
The nasal openings are often placed at the end of a prolongation
of the face, which is sometimes greatly developed, as in the
trunk of the elephant. In the aquatic mammals they can be
closed by muscles or a valvular apparatus. Jacobson's organ is
present in many mammals (Marsupialia, Edentata. Insectivora,
Carnivora, Ungulata), in the form of two tubes placed ventrally
to the septum nasi and receiving a branch of the olfactory nerve.
They generally join Stenson's duct and so open into the mouth.
The eyes present the - normal vertebrate structure. Their
most noticeable features are perhaps the presence of retinal
bloodvessels and the absence of any structure corresponding to
the pecten. They are always much reduced and may be quite
vestigial in burrowing animals In some rodents and insecti-
vores (Talpa, Chrysochloris) and in the marsupial Notary ctes
they are hidden beneath the skin, and in the freshwater cetacean
Platanista they are very imperfectly developed. Both upper
and lower lids, which are usually covered with hair, are present,
and in addition there is a third transparent eyelid at the inner
angle of the eye, the nictitating membrane. The nictitating
membrane is absent in Primates where it is represented by the
plica semilunaris, and in the Cetacea. The cornea is fairly con-
vex in most forms, but flattened in the Cetacea. There is a
tapetum, which reflects the light, in the choroid coat in many
mammals (Carnivora, Ungulata, etc.).
Both harderian and lacrymal glands are present in most
Mammalia (absent or reduced in the whales, and reduced
in the Pinnipedia). The lacrymal gland has several openings
on the conjunctival surface beneath the upper lid towards the
posterior (outer) side of the eye ; the harderian gland (which
lies at the inner side of the eyeball and mainly on its lower
surface, opens in connection with the nictitating membrane at
the inner angle. The harderian gland is absent in Primates.
The nasal ducts open on the puncta lacrymalia of which there are
two at the inner angle of the eye one above and one below the
caruncula lacrymalis. These two ducts join to form the nasal
duct which opens into the nasal passage. The meibomian
glands are sebaceous glands placed in the lids beneath the con-
junctiva and opening on the free edges of the latter.
z.— ii K K
498 MAMMALIA.
The auditory organ differs from that of the Sauropsida prin-
cipally in the greater development of the external auditory
meatus and of the external ear (pinna), in the greater number of
sound-conducting bones (malleus, incus, stapes), in the presence
of the organ of Corti, and except in Monotremata in the spiral
winding of the cochlea and the absence of a papilla acustica
lagenae. The ductus endolymphaticus proceeds from the narrow
canal connecting the saccule and the utricle ; it perforates the
periotic bone, enters the cranial cavity and ends in the dura mater
in a small dilatation, the saccus endolymphaticus. The auditory
nerve has six terminations, the papilla acustica lagenae and the
macula neglecta being absent. The windings of the cochlea vary
in number from IJin Erinaceus europaeus to 5 in Coelogenys
paca.
The tympanic cavity is more spacious than in the lower forms,
being frequently swollen into the bulla ossea which is formed
by the alisphenoid in the Marsupialia, and by the os tympanicum
in other forms. It communicates with the pharynx by a wide
opening in Monotremata, but in other Mammalia there is along
eustachian tube. It is also in communication with cavities
in the adjacent bones (air-cells of the mastoid, etc.).
The stapes is usually perforated, but it is columelliform and
unperf orated in Monotremata, Perameles, Manis and some other
Mammalia. The homologies of the mammalian auditory ossicles
have been much disputed'.* By Huxley the stapes was regarded
as the columella auris of the Sauropsida and the incus as the
suprastapedial part of the same structure (see especially Spheno-
dori). On this view the malleus is the homologue of the quad-
rate. Others regard the malleus as the os articulare, the incus
a-s the quadrate and the stapes as the columella. Finally it is
held by some anatomists that the whole chain of ossicles is
comparable to the columella auris and its various processes of
the Sauropsida, the quadrate appearing in mammals as the os
tympanicum.
Huxley's view is based largely upon the arrangement of the parts in
Sphenodon, and upon the fact that in the mammalian embryo, the pro-
cessus gracilis of the malleus is continuous with Meckel's cartilage.
* Huxley, On the representatives of the malleus and incus of the Mam-
malia in the other Vertebrata, P. Z. S., 1869. Gadow, " On the modifi-
cations of the first and second visceral arches, " Phil. Trans., 179.
AUDITORY OSSICLES. DEXTITIOX. 499
Huxley considered the suprastapedial( mammalian incus) to be homologous
with the hyomandibular or top of the hyoid arch of fishes (hence its con-
nection with the malleus which he regards as the proximal end of
the mandibular arch in mammals), the stapes or columella affording
a secondary connection with the periotic capsule. By the up-
holders of the view that the malleus, incus, and stapes are all differentia-
tions of the columella auris of reptiles (top of the hyoid arch) the con-
nection of the processus gracilis of the malleus with Meckel's cartilage in
the mammalian embryo would be regarded as secondary, and as
another example of the arrangement in the Crocodilia in which
Mecke!' s cartilage is connected with the columella by a cartilaginous
band (p. 376). We are inclined to accept the last view so far as the
homologies of the ossicles are concerned, but we differ in thinking that
the quadrate has been absorbed into the squamosal in mammalia (pp. 399,
479) and has nothing to do with the tympanic, which is largely a
membrane bone.
Dentition. Teeth are entirely absent in the adults of some
mammals, e.g. whalebone whales, the monotremes, many eden-
tates, but in many of these small calcined teeth, which do not cut
the gums but are absorbed early, are found in the foetus. Echidna
and some of the American ant-eaters appear to be as edentulous
as birds, no trace of teeth having been found even in the foetus.
When present they may be found on the premaxillae, maxillae
and mandibles, never on the palatal bones. They are imbedded
in sockets in the bone, (thecodont) the dental alveoli, which are
lined by a vascular membrane, the alveolar dental membrane.
They do not become ankylosed to the jaws. The part of the
tooth which projects above the gum is called the crown ; the
part below the gum and embedded in the socket is called the root
or fang. The neck of the tooth is where the root and crown join.
The back-teeth (grinders) commonly have more than one root
embedded in separate sockets, and this occasionally applies to
some of the anterior teeth (some Insectivora, etc.). The tooth con-
tains a central pulp-cavity which has an opening at the apex of
the root, or, if there are more roots than one, at the apex of each
root (Fig. 264, ///, IV). This cavity contains a connective tissue
pulp with bloodvessels and nerves. In young growing teeth
and in the so-called rootless teeth which grow throughout life
(Fig. 264, /), the openings of the pulp cavity are wide, but they
become narrow when growth has ceased and the pulp becomes
relatively less important ; pulp, however, usually persists
throughout life conferring sensibility on the dentine which is
traversed by the protoplasmic processes of the cells which line
500
MAMMALIA.
the pulp cavity (odontoblasts). These processes are continued
in the dentinal tubes of the dentine and only extend into the
enamel in rare cases.
The teeth consist of
dentine, which is covered
by enamel on the cro\vn
and by a. thin layer of
cement, which has the
staucture of bone, on the
root (Fig. 264). Occa-
sionally cement is found
outside the enamel on
the crowns (see below).
In a few cases, e.g. most
edentates, the tusks of
elephants, enamel is en-
tirely or almost entirely
absent. The dentition
of mammals is almost
always heterodont, i.e. it
consists of different kinds
of teeth in different parts
of the jaws. There are
commonly four kinds of
teeth in each jaw. There
are : the incisors in front ;
they are usually chisel-
shaped and in the upper
jaw are the only teeth
placed in the premax-
illae : next to the incisors
and often separated from
them by a gap, called
diastema, come the can-
ines ; these are never more
than one on each side in
each jaw 5^ they are al-
most always strong conical projecting teeth and are developed
in (or behind) the premaxillo-maxillary suture : the canines are
followed by the grinding teeth or back-teeth, which- are almost
Flft. 264. — Diagrammatic sections of various forms
of teeth. I Incisor (tusk) of elephant with pulp
cavity persistently open at the base. II Human
incisor during development with tooth imperfectly
formed and pulp cavity widely open at base.
/// Completely formed human incisor with pulp
cavity contracted to a small aperture at the apex
of the root. IV Human molar with broad crown
and 'two roots. V Molar of the ox with long
tubercles or as it is sometimes described, with the
enamel covering the crown deeply folded and the
depressions filled in with cement; the surface is
worn by use ; in the unworn tooth the enamel would
be continuous at the tops of the ridges. In all
the figures, the enamel is black, the pulp white,
the dentine represented by horizontal lines, and
the cementlby dots (after Flower and Lydekker).
DENTITION.
501
always in a continuous series, but frequently separated by a
diastema from the canines. The anterior grinding teeth are
called the premolars, the posterior are the molars. The grinding
teeth have usually more complex crowns than the anterior teeth,
and the premolars have nearly always simpler crowns than the
molars. The distinction between them is least marked in herbi-
vorous animals, in which the posterior premolars at least resemble
the molars. Speaking generally it may be said that there is a
serial increase m complexity in proceeding from the front to the
hind end of the premolar-rnolar series. But this does not always
apply : in some forms, e.g. many Carnivora, the hinder molars
are smaller and less complex than the teeth immediately in front
of them. The molars are usually distinguished from the pre-
molars not only by their more
complicated crowns, but also by
the fact that they have no func-
tional predecessors in the milk
dentition (but are only formed
once in the life of the animal).
This brings us to another charac-
teristic feature of the mammalian
dentition. Most mammals are
diphyodont, i.e. they have two
functional sets of teeth and
never more than two sets. Occa-
sionally there is only one set
(toothed whales, many edentates, etc.) which last through
life : in this case they are said to be monophyoiont. When
there are two sets, the first set is called the milk or
deciduous dentition, because it is usually found in the young
animal during the period of active growth. Typically the
milk teeth are shed as the jaws attain their full size and are
replaced by the permanent dentition (Fig. 265). The first back
tooth of the permanent dentition to appear is usually the first
molar, which in consequence presents a more worn appearance
than the later appearing posterior molars. This frequently
gives us a means of determining the limit between the premolars
and the molars, when the posterior premolars resemble the
molars in the form of their crowns, as they SDmetimes do.
A dental formula is a short way of expressing the number and
FIG. 265. — Dentition of Cebus while
changing the teeth (from Claus, after
Owen). The small letters point to
the milk teeth, the capital letters to
the permanent teeth.
502 MAMMALIA.
kinds of teeth present. In the normal complete mammalian
dentition, which is found in but few living mammals (e.g. 8us>
Gymnura, Talpa, Myogale) there are on each side and in each jaw
three incisors, one canine, four premolars, and three molars.
This is expressed by the formula : i f c T p •£• m f = 44.
In such a case the deciduous dentition would consist of three
incisors, one canine, and four molars on each side in each
jaw and the formula would be written thus : di f dc T dm 4
= 32. Frequently however the first premolar in the complete
mammalian dentition has no predecessor in the milk series (a few
ungulates and Hyrax may be mentioned as cases in which there
are four milk molars), so that the milk dentition would be, di -|
dc y dm f-=:28. Sometimes the dental formula is written more
fully, so that each tooth receives its special number, thus : —
* rt~f c T P rrrl m Hrt rj"nis method of writing the formula
enables us to express our views shortly as to the homologies
between teeth in different animals, in which the full number of
teeth are not formed. Thus the first premolar of the permanent
dentition, the tooth which frequently has no predecessor in the
milk dentition (it is disputed however whether this tooth belongs
to the milk or to the permanent series) often falls out very early.
We could express its absence thus : p ^ I' "' 44
Such determinations must not however be pressed too far, as
it is usually quite impossible to determine homologies between
teeth of the same category in different dentitions, as has been
shown by Bateson,* and sometimes it is even difficult to deter-
mine whether a tooth as distinctive as the canine is present or
absent. The canine tooth in the upper jaw is the first tooth in
the maxillary bone, and the canine in the lower jaw is the tooth
which bites in front of this. But as the first premolar may
simulate a canine in appearance and the real canine may simulate
an incisor, it is sometimes difficult to be certain as to whether
we are dealing with a canine or not. The canine may be looked
upon as the first tooth of the premolar series ; it is usually but
not always enlarged and caniniform in appearance.
If it is difficult in doubtful cases to settle whether a tooth so distinctive
as a canine is present, much more difficult must it be to decide which tooth
of a given category is absent, in cases in which the full number is not pre-
sent. It is usual to assume that the incisors are diminished from the
posterior end, i.e. if there are only two, it is the 3rd incisor which has gone.
* Materials for the Study of Variation, London, 1894.
DENTITION. 503
In the same way the molars are supposed to be cut off at the hind end of the
series also, but if the premolars are incomplete it is the anterior which are
supposed to be missing. No doubt these are rules in some cases, but there
are many cases in which they do not apply, as will be seen in the account
of the different orders.
The anterior milk molars as a rule resemble premolars in the
permanent dentition, while the hind milk molars are molar-like
in form.
The dentitions of the Cetacea, Edentata, and Marsupialia
present important variations from the normal mammalian
arrangements. For a description of them we refer the reader
to the systematic account of these orders.
Much might be written about the form of teeth. We must
content ourselves with the following remarks. The incisors are
generally chisel-shaped, with a cutting edge ; the canines conical
and pointed ; the premolars compressed and either conical or
cutting ; the molars with broad crowns and crushing. But
the posterior premolars frequently resemble or approximate to
the molars in form. There is frequently a ridge round the base
of the crown just above the neck called the cingulum. The crown
of the premolars is frequently elongated antero -posteriorly and
provided with smaller accessory cusps, as a rule one on each side
of the main cusp or tubercle. Such a three -cusped tooth with
the cusps all in one plane is called triconodont. Sometimes the
three cusps are not arranged in a line, but in a triangle, the teeth
of the upper jaw having one inner and two outer cusps ; those
of the lower jaw having two inner and one outer cusp. This
form is called the tritubercular (sometimes trigonodont) : it is
more commonly found amongst the molars than the premolars.
It is frequently complicated by the addition of a posterior heel
or talon (Fig. 283) which may have one or two cusps. Such a
form of tooth which is usually in the molar series is called tuber-
cular-sectorial. Farther additional cusps may be developed be-
tween the three primary cusps. Most commonly there is one
such additional cusp, so that if the tooth has no talon it becomes
quadricuspidate, the cusps or tubercles being arranged in an
anterior and in a posterior pair. To these four cusps one or
two may be added ; if one, it may be placed between the
cusps of the posterior pair, or between those of the ante-
rior pair ; if two, one of them is between the cusps of the
anterior and the other between the cusps of the posterior pair.
504 MAMMALIA.
We thus get the 5-cusped and 6-cusped teeth, which are usually
in the molar series. Finally the teeth may have more than six
cusps, in which case they are multicuspidate. When there is a
well marked talon the anterior part of the tooth has typically,
though not always, three cusps arranged in the triangular
manner.
Professors Cope and Osborn * have endeavoured to show that all cusped
mammalian grinding teeth may be referred to the tritubercular tooth,
usually with the addition of a cusp-carrying talon (tubercular-sectorial).
The cusps in this supposed primitive tooth and on its talon have been
named, and their homologies with the cusps of different mammalian teeth
determined. In this manner a theory of very great complexity, called
the tritubercular theory or simply trituberculism has been elaborated.
Without offering any opinion as to the validity of this theory, we have
decided not to make use of it in this work, because the facts of tooth
structure in the different orders can be made sufficiently cleajr without it,
and because it does not appear to us to render that assistance in reducing
the facts to order which would justify us, at present, to ask the student
to make the considerable effort needed to master its complexities.
Such grinding teeth in which the crown is elevated into blunt
or pointed cusps are called bunodont teeth. It frequently hap-
pens however that the cusps are spread out in one direction at
the base and connected by ridges. These ridges commonly run
transversely across the tooth, and when they are well developed
the crown of the tooth appears to be traversed by ridges of
enamel ; such teeth are called lophodont. In some cases the cusps
or tubercles are flattened at the base and spread out in a cres-
centic manner (as in fiuminantia). The crowns of such teeth
appear to be traversed by crescentic ridges of enamel arranged
of course partly in a longitudinal and partly in a transverse
direction. Such teeth are called selenodont. Lophodont and
selenodont teeth are found in herbivorous animals in which the
food, often dry and hard, requires much mastication. They are
thus subjected to considerable wear and the projecting enamel
on the crown becomes worn down. In this way the tops of the
cusps and ridges become worn off and the dentine exposed, and
the crowns of the teeth appear to be traversed by laminae of
enamel containing between them exposed dentine. It is clear
that when the crown is short, a tooth exposed to such hard wear
must soon be worn down to the neck. To obviate this, it fre-
quently happens that the crown, with its tubercles and cusps,
* Trituberculy, Amer. Nat., 1897, p. 993.
DENTITION. 505
is much elongated vertically, the neck of the tooth being deeply
imbedded in the socket. Such long crowned teeth are called
hypsodont in contradistinction to the first described teeth with
short crowns which are called brachyodont. It is evident that
to render a hypsodont tooth effective, it must gradually rise in
its socket as the crown is worn down. This is sometimes partly
effected by continued growth at the base of the tooth, the pulp
cavity remaining open and the pulp active. But hypsodont
grinding teeth are rarely rootless throughout life. They are
often rootless in the young animal, continuing to grow for a time,
but as a rule the roots are soon formed and growth ceases. In
such cases the subsequent elevation of the tooth to meet the
continual wear of the crown is effected in a manner which is not
fully understood.
Hypsodont teeth are found constantly in some groups of the
Ungulata. In the Rodentia in which they also often occur, con-
siderable variety is found, closely allied species differing in this
respect.
In hypsodont teeth the cusps and ridges are of course much
elongated vertically, and there are deep chasms and valleys be-
tween them. These are usually filled with cement (Fig. 264, V),
which confers strength and holds the elongated tubercles to-
gether. The result of this is that the surface of the worn tooth
presents a pattern caused by the three materials of different
degrees of hardness which compose the crown. These patterns
consist of the laminae of hardest material, enamel, bounding
areas of the next hardest substance, the dentine, and surrounded
by the softer cement which pervades the whole crown between
the cusp and ridges.
Development of teeth (Fig. 266). There is formed in the
embryo at a comparatively early stage of development an in-
growth, in the form of a double lamina, of the lower layer (stra-
tum Malpighi) of the buccal epithelium. This ingrowth extends
along the whole length of the jaws and constitutes the primitive
tooth-band. There is frequently a groove in the lining of the
mouth placed immediately over it and called the dental groove
(zf) ; this, however, appears to be without significance in the
tooth development.
The tooth-band has at first the appearance of a tubular gland
projecting into the subjacent mesoblast. The definitive tooth-
506
MAMMALIA.
germs are formed as buds from the outer (labial) side and near
the free end of this structure (Fig. 266, .4). The first formed of
these buds give rise to the milk teeth. As soon as the rudiments
of these are established the free edge (zl) of the tooth -band
grows deeper into the subepithelial mucosa and gives rise, on its
labial side as before, to a second series of buds : these are the
rudiments of the permanent teeth (Fig. 266, B, C). Inasmuch
as the deeper part of the tooth -band becomes inclined inwards
towards the middle line the first formed buds and the tooth-
germs developed from them lie on the labial (outer) side of the
buds formed later. Each of the epithelial buds formed from
the outer lamina of the tooth-band gives rise to the enamel organ
(se, sp, sm) of a tooth and ultimately loses its connection with
c
FIG. 266.— A, B, C, Three stages in the development of a milk and permanent tooth of a
mammal in diagrammatic section (after O. Hertwig). h neck by which the enamel organ
of the milk tooth is connected with the tooth-band ; k bone of dental alveolus ; s enamel ;
se, sm inner and outer epithelium of enamel organ ; sm2 inner epithelium of enamel organ
of permanent tooth ; sp enamel pulp ; zf dental furrow ; zl tooth-band ; zl' free deep end
of tooth-band, from which the permanent tooth will be developed ; zp dental papilla ;
zs dental sac ; zp2- dental papilla of the permanent tooth ; zb dentine.
the tooth-band. The conversion of a bud into an enamel organ
is associated with the formation of a dentine-papilla or dentine-
germ (zp) which gives rise to the dentine of the tooth and the
cement of the root. The process is as follows : the bud becomes
swollen at its end, and then bell-shaped, the concavity of the
bell being directed inwards, i.e. away from the lining of the
mouth. The subepithelial mesoblastic tissue in the concavity
of the bell is the dentine -papilla. We thus get a bell-shaped
enamel organ (Fig. 266, C) consisting of ingrown buccal epithe-
lium, connected by a narrow stalk (h) with the tooth-band and
DEVELOPMENT OF TEETH. 507
placed upon a papilla-shaped dentine germ which is derived
entirely from the mesoblast. The subsequent formation of the
enamel from the enamel organ, of the dentine and cement from
the dentine-germ, and of the tooth-sac from the adjacent meso-
blastic tissue are fully described in works dealing with histology
and development to which we must refer the reader.
In addition to the tooth-germs of the milk and permanent
dentitions, already described, other tooth-rudiments, which
never attain full development, are formed in many mammals.*
These are developed as buds from the outer side of the tooth -
band in precisely the same way as are the rudiments of the
functional teeth. There is usually only one set of these ves-
tigial rudiments, the relation of which to the rudiments of the
functional teeth varies in different mammals. In marsupials,
the pig, and the guinea-pig, the vestiges in question are formed
from the tooth-band before the rudiments of the milk-teeth and
lie on the labial side of these. In the seals, hedgehog, dog, and
man they arise after the rudiments of the permanent teeth and
lie on their lingual side. In the former case these buds are re-
garded as vestiges of a prelacteal dentition, in the latter of a-
post permanent series of teeth. In those groups, such as the
Cetacea and Marsupialia in which the dentition is functionally
monophyodont or nearly so, and in which traces of two or three
dentitions can be made out there is some dispute as to which of
these dentitions the functional teeth belong to, as is shown in the
subjoined table. In man there are said to be four sets of tooth-
rudiments, viz. of the prelacteal vestigial dentition, of the milk
and permanent dentitions, and of the postpermanent vestigial
series. In short it would appear that in Mammalia there are traces
of four dentitions, of which never more than two become func-
tional^ To this extent the dental condition of mammals may be
said to approximate to the polyphyodont condition of reptiles.
If the four dentitions of Mammalia be called premilk, milk,
* Leche, Entwick. d. Zahnsystems der Saugethiefe, Biblioiheca
Zoologica, 1895. Kiikenthal, Jena. Zeitschrift, 28, 1894, p. 76. Rose,
Das Zahnsystem der Wirbelthiere, Ergebnisse, d. Anatomie u. Entwick.,
1894. Wilson and Hill, Q.J.M.S., 39, 1897, p. 427. Adloff, Jena. Zeit-
schr., 32. 1898, p. 347. Marett Tims, Journal Anat. and PhysioL, 36, 1902,
and 37, 1903. M. F. Woodward, P. Z. S., 1893, p. 450, and 1896, p. 557.
t It has recently been stated that in the extinct Toxodont, Nesodon,
there were possibly three functional incisor dentitions (W. B. Scott,
British Association, Cambridge meeting, 1904).
508
MAMMALIA.
permanent, and post-permanent, respectively, the present state
of our knowledge with regard to their occurrence may be ex-
pressed by the subjoined table, in which v indicates vestigial
and / functional dentitions.
Number
of Den-
titions.
Premilk.
Milk.
Perma-
nent.
Post
Perma-
nent.
View of.
Marsupialia
3
V
f
V
absent
Leche, Deppendorf , M.
Woodward etc.
,,
ii
absent
V
f
V
Wilson, Hill, Tims, etc.
Cetacea
(toothed)
g
absent
f
V
absent
Kukenthal.
»
M
absent
V
f
absent
Tims.
Seal . .
8
absent
f
f
V
Leche, Kiikenthal.
Hedgehog ,,
and Dog
3
absent
f
f
V
M. Woodward, Tims.
Pig ... | 3
V
f
f
absent
Adloff.
Guinea-pig .
3
V
f
f
absent
Adloff.
Man . .
4
V
f
f
V
Rose, Tims.
The vestiges on the labial side of the permanent molars clearly belong
to the milk series (which in Diphyodonts erupt in the anterior part of the
mouth). The presence of these vestiges raises the question as to whether
there is any morphological distinction between the premolar and molar
series. For the homology of the replaced tooth of marsupials the reader
is referred to the systematic account.
In most lower Vertebrata the succession of teeth appears to be indefi-
nite, and except in Teleostei all the teeth are formed, as in mammals,
from a tooth-band, the inner end of which continues to grow and produce
new buds on the lingual side of those last formed. In the Teleostei the
successive teeth appear to be in many cases formed independently from
the buccal epithelium and not from a tooth-band.
Alimentary Canal. In addition to the hard structures at
the entrance to the digestive cavity, soft moveable lips which
bound the mouth opening, and a fleshy tongue which is of very
various form and lies on the floor of the buccal cavity, are of
special importance for the prehension and preparation of the
food (Eig. 267). In the Monotremata the lips are replaced by
the edges of the beak. The tongue, however, is never absent,
but it may be immoveable, and completely fused with the floor
of the mouth, as in the whales. Its front part is mainly tactile
in function, but in some cases it is used to seize (giraffe) or cap-
ture food (ant-eaters). Variously shaped papillae, which are
often cornified and bear recurved hooks, project from its upper
MOUTH.
509
surface. The papillae circumvallatae alone have a relation to
the sense of taste. The tongue is supported by the hyoid bone
and by a cartilaginous rod, which represents the os interglossum.
The anterior cornua of the hyoid are attached by ligament to
FIG. 267. — Entrance to the digestive apparatus and the respiratory organs of the cat (after
C. Heider). a head with exposed salivary glands. P parotid ; M sub-maxillary ; Su
sub-lingual. & Longitudinal section through the head and thorax ; the respiratory organs
are seen from the side, c Longitudinal section through the larynx ( L) and the first part
of the trachea (Tr.). B thymus ; C corpus callosum ; Cb cerebellum; Cg corpora quad-
rigemina ; D Diaphragm ; E epiglottis ; H cerebral hemispheres ; Hy hypophysis ; L
larynx ; M mouth ; a nasal aperture ; Nm turbinal bones ; Oe oesophagus ; P lung ;
Pa velum palati ; R spinal cord ; S vocal cord ; St sternum ; T thyroid ; Tr trachea :
Tu opening of eustachian tube into the pharynx ; W vertebral column ; Z tongue ; Zb
hyoid.
the styloid processes of the temporal bone or its equivalent, the
posterior bear the larynx. Beneath the tongue there is some-
times (most developed in the Insectivora) a single or double
projection, which is termed the sublingua. The sides of the
buccal cavity are soft and fleshy, and are not unfrequently in
510 MAMMALIA.
the rodents, apes, etc., dilated into wide sacs — the so-called
cheek-pouches. The soft palate (palatum molle) must be men-
tioned as a structure peculiar to the Mammalia ; it constitutes
the boundary between the buccal cavity and pharynx. All
mammals, with the exception of the carnivorous Cetacea, have
salivary glands, — a parotid, a submaxillary, and a sublingual, —
the fluid secretion of which is poured out in large quantities,
especially in herbivorous forms. The oesophagus, which follows
the wide gullet, only exceptionally presents crop-like dilations ;
it is usually of considerable length, and opens into the stomach
behind the diaphragm. The stomach is, as a rule, a simple
transversely placed sac, but is frequently divided by the gradual
differentiation and constriction of its anterior, lateral, and pos-
terior regions* into a number of parts, which are most completely
separated in the ruminants and distinguished as four separate
stomachs. The pyloric region is principally distinguished by
the presence of gastric glands, and is more or less sharply sepa-
rated from the beginning of the small intestine by a sphincter
muscle and by an inwardly projecting fold (pyloric valve). The
intestine is divided into a small and a large intestine, the boun-
dary between which is indicated by the presence of a valve and
a caecum, which is especially developed in herbivorous animals.
The anterior part of the small intestine, or duodenum, contains
the so-called Brunner's glands in its mucous membrane, and
receives the secretion of the large liver and the pancreas. The
liver is multilobed, and is sometimes without a gall bladder.
When a gall bladder is present the bile duct (d. cysticus), and
the hepatic duct (d. hepaticus) unite to form a common duct
(d. choledochus). The small intestine is longest in animals
which eat grasses and leaves, and is characterised by the numer-
ous folds (valvulae conniventes) and villi of its mucous mem-
brane; and by the possession of a great number of groups of glands
(Lieberkuhn's) and by Peyer's patches which are composed of
adenoid tissue. The terminal region of the large intestine or
rectum opens, except in the Monotremata which are character-
ised by the possession of a cloaca, behind the urinogenital opening,
though the two openings are sometimes surrounded by a common
sphincter (Marsupialia, some Insectivora and Pinnipedia).
The heart (Fig. 268) of Mammalia, like that of Birds, is divided
into a right venous and a left arterial portion, each with a ven-
VASCULAR SYSTEM.
511
5rrf
tricle and auricle (sometimes as in Halicore the division is marked
externally). It is enclosed in a pericardium, and sends off an
arterial trunk, which forms a left aortic arch, from which two
vessels frequently arise, viz. (1) a right anonyma, with the two
carotids and right subclavian ; and (2) the left subclavian ; or,
as in man, three vascular-
trunks, viz. (1) a right
anonyma, with the right
carotid and right subcla-
vian ; (2) the left carotid ;
and (3) the left subcla-
vian, all close to one
another. As a rule, one
superior vena cava (right)
and an inferior vena cava
open into the right aur-
icle : more rarely, as in
the rodents, monotremes,
and elephants, etc., there
are two superior venae
cavae. Retia mirabilia
have been recognised
principally for the ar-
terial vessels, and are
found on the extremities
of burrowing and climb-
ing animals (Stenops,
Myrmecophaga, Brady-
pus, etc.) ; on the caro-
tids round the hypophy-
sis, and on the ophthal-
mic arteries in tjie orbit
in ruminants ; finally on
the intercostal arteries
and the iliac veins of the
dolphin. The red blood
corpuscles are devoid of a nucleus and are discoidal, except in the
Camelidae in which they are elliptical. They vary in size : in
man they are 3 2*0 0 th of an inch : in the elephant 2 /0 0 th of an
inch ; they are smallest in the chevrotains in which they are
04- .'
FIG. 268. — Circulatory apparatus of man (from
Owen, after Allen Thomson). Ad right auricle ;
Ao aortic arch ; Aod descending aorta ; Ap pul-
monary artery ; As left auricle ; Br bronchi ;
Cd right carotid • Cs left carotid ; D intestine;
Jd right jugular ; Jl common iliac artery ; J I
common iliac vein ; Js left jugular ; L liver ;
M mesenteric artery ; N kidney ; P lungs ; Sd
right subclavian artery ; Ss left subclavian artery ;
Srd right subclavian, Svs left subclavian vein ;
Tr trachea ; Va inferior vena cava ; Vd superior
vena ca\a ; Vd right ventricle ; Vp vena portae ;
Vpu pulmonary vein ; Vs left ventricle.
512 MAMMALIA.
about 12Q00th of an inch. A renal-portal system is always
absent, and in no Mammalia, except Echidna, is there an
anterior abdominal vein carrying blood to the liver.
The lymphatic system is provided with numerous lymphatic
glands, and its main trunk (ductus thoracicus), which is placed
on the left, opens into the left brachiocephalic vein.
Of the so-called vascular glands the spleen, the thymus, and
the thyroid, which is especially developed in the young, are very
generally present.
The body- cavity of mammals is distinguished by the fact that
the two anterior horns, which in Amphibia and many Reptilia ex-
tendforwards on each side of the pericardium, are cut off from the
general body cavity and constitute the closed pleura! cavities.
The diaphragm or midriff, a muscular partition with a central
tendinous portion, is developed in the tissue placed between
the pleural and pericardial cavities and the abdominal cavity.
Abdominal pores are never present and the kidney tubes never
have nephrostomata.
The paired lungs (Fig. 268, p) are freely suspended in the
thoracic cavity, and are distinguished by the numerous ramifi-
cations of the bronchial tubes, the finest branches of which end
with conical, funnel-shaped dilations (infundibula), which are
provided on their lateral surfaces with swellings. Respiration
is mainly effected by the movements of the diaphragm, which
forms a complete, usually transversely placed, septum between
the thoracic and abdominal cavities : by the contraction of its
muscular parts it acts as an inspiratory muscle ; that is, it
dilates the thoracic cavity. The elevation and depression of
the ribs also have an effect in dilating the thorax. The trachea
is, as a rule, straight, without coils, and divides at its lower end
into two bronchi leading to the lungs. There may be, in addi-
tion, a small accessory (third) bronchus on the right side. The
trachea is supported by cartilaginous half-rings which are open
dorsally, and only exceptionally by complete rings of cartilage.
The first part of the trachea, or larynx, is placed at the lower end
of the pharynx, behind the root of the tongue ; it is supported
by the posterior horns of the hyoid bone, possesses vocal chords,
complicated pieces of cartilage (cricoid, thyroid, and arytenoid
cartilages) and muscles, and constitutes a vocal organ.
In the Cetacea alone is the larynx, which projects in the base
URINOGENITAL ORGANS. 513
of the pharynx as far as the posterior nares, used exclusively for
respiration. A moveable epiglottis (almost tubular in the Ceta-
cea), attached to the upper edge of the thyroid cartilage, pro-
jects over the glottis. When food is being swallowed it sinks
and closes the glottis. Accessory cavities, with membranous
or cartilaginous walls, are sometimes attached to the larynx.
These sometimes function as air reservoirs, e.g. the air-sacs of
Balaena, sometimes as a resonating apparatus for the strength-
ening of the voice, as in many monkeys (Mycetes). In many
mammals the nasal passages are connected with air-spaces in
the bones of the head (frontal, ethmoidal, maxillary bones, etc.),
and the tympanic cavity communicates with air-sinuses in the
mastoid.
The kidneys (Fig. 268, N) sometimes consist (seals, dolphins)
of numerous lobes united together at the pelvis of the kidney.
As a rule, however, they are compact bean-shaped glands, lying
in the lumbar region, outside the peritoneum. The ureters
arise from the so-called pelvis of the kidney, and always open,
except in Monotremata, into a urinary bladder, placed in front
of (ventral to) the intestine. The duct of the bladder joins the
ducts of the generative organs, and forms a urogenital canal
called vestibule in the female and unethra in the male, opening
ventral to the anus. Anterior to the kidneys there is' a glandular
organ termed the suprarenal body.
The male sexual organs (Fig. 269) of most Mammalia are
characterized by the change in the position of the testes. In only
a few cases (Monotremata, Cetacea, etc.) do the testes remain near
the kidneys ; in most mammals they descend in front of the pelvis,
and, pushing the peritoneum before them, enter the inguinal
canal (many rodents), or, still more frequently, pass through
the inguinal canal into a cutaneous fold, which is transformed
into the scrotum. Not unfrequently (rodents, bats, insecti-
vores) they pass back through the open inguinal canal into the
abdominal cavity after the breeding season : this is affected by
the cremaster, a slip of muscle separated from the oblique
abdominal muscle. The scrotum, as a rule, lies behind the
penis ; but in the marsupials it is formed by an invagination of
the integument directly at the entrance of the inguinal canal in
front of the male copulatory organ. The coiled excretory ducts
of the testes, which are derived from the wolffian body and ducts,
Z.-H. L L
514
MAMMALIA.
constitute the epididymis, and lead into the two vasa deferentia,
which, after forming glandular dilations (seminal vesicles), open
close together into the urethra. At this point open the ducts of
the prostates, which differ much in form, and are often divided
into several groups of glands. Further down a second pair of
glands, known as Cow-
per's glands, opens into
the urethra. Remains of
the miillerian ducts, which
in the female are used as
the oviducts, frequently
persist between the open-
ings of the vasa deferen-
tia. They are called the
organ of Weber (uterus
masculinus), and in the
so-called hermaphrodites
their parts are much en-
larged, and may be dif-
ferentiated in the manner
peculiar to the female sex.
In all cases the end of the
urethra, which functions
as a urinogenital canal, is
in connection with ex-
ternal copulatory organs :
these alwayshave the form
of an erectile penis, which,
in the Monotremata, is
concealed in a pouch in
the cloaca. The penis
is supported by cavernous
erectile bodies, which in
the Monotremata are con-
fined to paired corpora
cavernosa urethrae ; but in all other Mammalia there are, in
addition to the corpus cavernosum urethrae (c. spongiosum)
which is unpaired and surrounds the urethra, two upper corpora
cavernosa penis, which are attached to the ischium, and only
rarely fuse with one another. A cartilaginous or bony support,
Flo. 269. — Urinary and sexual organs of Cricetus
vulgaris (after Gegenbaur). Cp corpora cavernosa
penis ; Cu corpu3 cavernosum urethrae ; E glans
penis ; F funiculus spermaticus (spermatic cord) ;
Gc Cowper's glands ; Gt Tyson's glands ; H urinary
bladder ; N epididymis ; Pp prepuce ; Pr pros-
tate ; R kidney ; Sq urogenital sinus (urethra) ;
T testis ; U ureter ; Vd vas def erens ; Vs vesiculae
seminales.
GENERATIVE ORGANS.
515
the so-called os penis (Carnivora, Rodentia), may also be de-
veloped, especially frequently in the glans. The glans, which
is formed by the corpus cavernosum urethrae (Fig. 269, E),
and which is bifid only in exceptional cases (Monotremata,
Marsupialia,) varies greatly in its form, and lies retracted in a
reduplication of the skin (foreskin or prepuce) which is richly
glandular (gl. tysonianae).
Female sexual organs. The ovaries (Fig. 270) are unsym-
metrical only in the Monotremata, in consequence of the reduc-
tion of the right ovary. In all other cases they are equally
FIG. 270. — Female generative organs, a of Ornitfiorhynchus (after Owen) ; b of Viverra
genetta ; c of Cercopithecus nemeslrinus ; D intestine ; F opening of ureter ; H urinary
bladder ; Kl cloaca ; M mouth of uterus ; Ov ovarv ; S urinogenital sinus ; T oviduct
U uterus ; Ur ureter ; V vagina. A style is passed through the opening of the intestine
into the cloaca in a.
developed on either side ; they are placed in folds of the peri-
toneum, close to the funnel-shaped dilated mouths of the ovi-
ducts, by which they are sometimes completely surrounded.
The oviduct is divided into (l)the fallopian tube, which is always
paired and begins with a free ostium ; (2) the dilated, sometimes
paired, more frequently unpaired, middle portion— the uterus ;
and (3) the terminal part, or vagina, which is unpaired, except in
marsupials, and opens behind the opening of the urethra into the
short urinogenital sinus, or vestibule. In the Monotremata the
516 MAMMALIA.
two tubular uteruses open, without forming a vagina, on papilli-
form prominences into the urinogenital sinus, which is still con-
nected with the cloaca (Fig. 270).
According to the different degrees of duplicity of the uterus
(when a vagina is present), we may distinguish : the uterus
duplex, with more or less complete external separation and
double os uteri (rodents, marsupials) : the uterus bipartitus, with
single os uteri, but almost complete internal partition (rodents) ;
the uterus bicornis (Fig. 270, 6), in which the upper parts, or
horns of the uterus are separate (Ungulata, Carnivora, Cetacea,
Insectivora) ; and finally the uterus simplex (Fig. 270, c) with
single cavity and' very muscular walls (Primates).
The vestibule, with its glands of Duvernoy (Bartholin), which
correspond to the Cowperian glands of the male, is separated
from the vagina by a constriction, and in Homo also by a fold of
the mucous membrane, called the hymen. The external gener-
ative organs consist of the labia majora and labia minora, at the
sides of the sexual opening, and of the clitoris. The labia majora
are two external folds of skin, and are equivalent to the two
halves of the scrotum ; the labia minora are two smaller internal
folds, and are not always present. The clitoris possesses erectile
tissue and a glans, and is the equivalent of the penis. The
clitoris may sometimes (as in Ateles) reach to a considerable size
and be perforated by the urethra (rodents, moles, lemurs). In
such cases of perforated clitoris, there is, of course, no common
urinogenital sinus. Morphologically, the female genitalia repre-
sent an earlier stage of development of the male organs, which,
in the cases of the so-called hermaphrodite formation, may in
consequence of arrest of development preserve a more or less
female structure. As a rule the two sexes are easily distin-
guished by the different form of the external generative organs.
Frequently there is a marked dimorphism in the whole external
appearance ; the male being larger, having a different hairy
covering, being possessed of a louder voice, and provided
with stronger teeth or special weapons (horns). On the
other hand, the milk glands, which are situate in the inguinal
region, on the abdomen, and on the thorax, and which almost
always project into teats or nipples, are rudimentary in the
male sex.
There is in Mammalia a breeding period which may be called
OESTRUS CYCLE. 517
the sexual season.* In males this season is characterized by
testicular activity and sexual excitement, and is generally called
rut. In females the matter is more complicated. In them the
sexual season comprises a series of phenomena which constitute
the " oestrus cycle.'" The typical course of the oestrus cycle is
as follows. It begins (1) with a congestion cf the external
generative organs which spreads to the uterus and leads to (2) a
growth which causes a thickening of the mucosa. This is fol-
lowed by (3) a rupture of the capillaries and extravasation of
blood into the uterine mucous membrane, which extravasated
blood in some cases (Primates, some Rodentia, Ungulata and
Garni vora, etc.), in consequence of tissue degeneration, finds its
way into the uterus and thence to the exterior. This pheno-
menon is in the Primates known as the menstrual flow.f The
uterus then rapidly heals and the last stage (4) of the cycle is
reached. This is known as the oestrus or period of desire.
During it copulation takes place and the cycle comes to an end.
The different stages of this cycle, the first three of which con-
stitute the prooestrum, vary in their severity in different animals,
and in some of them,. as stated above, the extravasated blood
does not break through the mucosa and the menstrual flow of
blood does not occur, but the homology of the phenomena
throughout the series is, undoubted.
Ovulation is supposed to take place at some period during the
oestrus cycle, but the course of this phenomenon is not fully
understood and there is probably considerable variation in it,
in different animals and even in the same animal, at different
periods of life. In some cases (e.g. ferrets, domestic rabbits)
the stimulus of copulation seems necessary to bring about ovu-
Jation ; e.g. in the domestic rabbit ovulation occurs 9J hours
after copulation. In other cases, probably the majority, ovu-
lation is independent of copulation and takes place in its absence
during some period of the oestrus cycle (in bitches it takes place
during the external bleeding or later). The case of the bat
is peculiar. In this animal the sexual season occurs in the
* W. Heape, " The sexual season of Mammals and the relation of the
prooestrum to menstruation, Q.J.M.S., vol. 44, 1901, p. 1. F. H. A.
Marshall, The oestrus cycle and the formation of the corpus luteum in,
the sheep, Phil. Trans., 1903, p. 47.
f W. Heape, The menstruation of Semnopithecus entellus, Phil. Trans.,
1894. Id., " The menstruation and ovulation of Macacus rhesus," Phil.
Trans., 1897.
518 MAMMALIA.
autumn and copulation then takes place, but it is not until spring
that ovulation occurs, so that the spermatozoa live all the winter
in the uterus. It is recorded, however, that young female bats
experience their sexual season in the spring (compare the case
of Salamandra, p. 307).
The occurrence and frequency of the sexual season also vary
to a considerable extent in different mammals. In many it
occurs more than once in each year, in others not more than once
in two years. Climatic and nutritive conditions are important
factors in determining its onset and periodicity, and there is
considerable variation in accordance with local conditions even
amongst individuals of the same species. Thus woodland deer
breed earlier than those which live above the tree-level, and
foxes at a high altitude breed later than those which live in the
plains. Walruses, which are compelled to expend their energies
for twelve months in feeding their calf, breed only once in two
years. Scarcity of food and a rigorous climate tend to reduce
sexual activity, while the luxury attending domestication re-
sults in greatly increased breeding powers.
The graafian follicle after expelling its ovum becomes filled with cells
and is called the corpus luteum. This structure undergoes a series of
changes which differ (Homo) according to the occurrence or non-occur-
rence of gestation. Considerable importance has been ascribed to these
changes (ovarian secretion *), and it is said that destruction of the corpus
luteum by electric cautery or other means will bring about cessation of
development and degeneration of the uterine foetus.
The ova of the Mammalia were first discovered by C. E. von
Baer. They are extraordinarily small (with very little yolk) and
are surrounded by a strongly refractile membrane (zona radiata),
round which a layer of albumen is sometimes deposited in the
oviduct.
The fertilization appears to take place in the oviduct (fallo-
pian tube), and segmentation, which except in Monotremata is
complete, is effected either in the oviduct (rabbit, mole, etc.) or
in the uterus (ferret, sheep, etc.). Amnion and allantois are pre-
sent. In the uterus the embryo becomes connected with the
uterine wall by means of its outer epithelial layer, now known as
the trophoblast. This, later, becomes coated wholly or in part
on its inner side by somatic mesoblast and constitutes the mem-
brane known as the subzonal membrane (false amnion and
* Marshall, op. cit.
DEVELOPMENT.
519
somatic wall of yolk-sac of avine embryos, Fig. 271, Sh). Later
on, the mesoblast of the peripheral part of the allantois becomes
applied to the subzonal membrane and the two structures
FIG. 271. Diagrammatic figures illustrating the formation of the foetal membranes of a
mammal (after Kolliker). a embryo before appearance of amnion ; b embryo with yolk-
sac and developing amnion ; c embryo with amnion closing and developing allantois ;
d embryo with villous subzonal membrane, and with mouth and anus ; e embryo in which
the vascular layer of the allantois is applied to the subzonal membrane, and has grown
into the villi of the latter, yolk-sac reduced, the amniotic cavity is increasing ; A embry-
onic thickening of the external layer ; Ah amniotic cavity ; Al allantoic stalk ; Am amnioni ;
Ch chorion ; Chz chorionic villi ; D, D' zona radiata ;" Dq umbilical stalk ; Dh intestinal
cavity ; Ds cavity of the embryonic (blastodermic) vesicle, later of the yolk-sac (umbilical
vesicle) ; E embryo ; J embryonic thickening of the inner layer, M of the middle layer ;
Sh subzonal membrane (serous envelope) ; Sz villi of subzonal membrane.
520 MAMMALIA,
constitute the embryonic membrane called the chorion (Fig. 271
«, ch}. The chorion develops vascular villi which enter into close
relation with the uterine wall. In this manner there is de-
veloped a relatively large surface, permeated with branches from
the foetal vessels, the blood of which is in intimate osmotic
connection with the blood of the uterine wall. This connection
of the chorion of the foetus with the uterine walls gives rise to
the placenta, by means of which the nourishment and respiration
of the foetus are provided for in the body of the mother. The
placenta is wanting only in the Monotremata and most Mar-
supialia, which, therefore, have been called Aplacentalia, as
opposed to the rest of the Mammalia, which have a placenta and
have been called Placentalia. The placenta presents great varia-
tions in the individual orders, in its special development and in
the mode of its connection with the uterine walls. Either the
villi of the placenta are loosely connected with the uterine walls,
and separate from the latter at birth (Adeciduata), or they be-
come so intimately united with the uterine mucous membrane
that the latter comes * away with the embryo at birth, as the
decidua or after-birth (Deciduata). In the first case the villi
may be numerous and uniformly distributed over the whole
chorion (diffuse placenta of Ungulata, Cetacea, etc.), or be
aggregated in special places, forming small tufts, the so-called
cotyledons (ruminants). In the other case, the placenta with
its villi is confined either to an annular zone on the chorion (pi.
annularis or zonary placenta of Carnivora, Pinnipedia), or to
a discoidal area (metadiscoidal placenta of man and apes, dis-
coidal placenta of rodents, insectivores, bats).
The trophoblast of the mammalian embryo is a structure of
great physiological importance. It is the layer in relation with
the uterine wall, and in the early stages is employed in secreting
fluid into the cavity of the blastodermic vesicle and so facili-
tating the nourishment of the embryo in the earliest stages.
Later, it is the layer by which the attachment of the embryo to
the uterine wall is effected. It becomes much thickened and
vascularised from the allantoic vessels, and its outer wall be-
comes phagocytic and in many cases eats its way into the uterine
wall, so that the embryo actually becomes imbedded in the
* In some cases a portion of the foetal tissues remains in the uterus and
is absorbed (mole, etc.).
DEVELOPMENT.
521
maternal tissues. In the deciduate forms it sometimes grows
into the uterine walls round the maternal capillaries, the endo-
thelium of which remains throughout (Garni vora), or disappears
(Chiroptera) so that the maternal blood is actually in contact
with the foetal tissues in lacunae of the trophoblast. In other
cases it develops lacunae which become filled with blood through
the rupture of the maternal vessels.
In many lower
Mammalia (Marsu-
pialia, Rodentia,
etc.) the walls of
the sac which cor-
responds with the
yolk-sac of birds de-
velops an area vas-
culosa which plays
an important part
in the nutrition of
the embryo.
The early de-
velopment of the
mammalian embryo
is frequently ren-
dered apparently
abnormal by the
precocious forma-
tion of that part of
the trophoblast and
adjacent mesoblast
which plays later on
an important part
in the formation of
the placenta. This
is notably the case
in Homo and his
allies, and in those
forms which dis-
play the so-called
inversion of the
layers.
In the foetus, respiration is effected through the placenta
and the lungs are functionless. In correspondence with this the
circulation of the foetus differs from that of the animal after
birth (Fig. 272). From the heart the blood is driven into the
descending aorta, which sends off behind two large vessels to
the placenta (umbilical or allantoic arteries). The blood, return-
ing from the placenta in the allantoic vein, passes in great part
through a connecting vessel (ductus venosns Arantii) into the
Am
Fio. 272. — Diagram of the arrangement of the principal vessel3
in a human foetus (after Huxley). Am amnion ; Ao aortic
trunk ; And descending aorta ; Az azygos vein ; C anterior
cardinal vein ; Cc common carotid ; Ce external carotid ;
Ci internal carotid ; D ductus venosus arantii ; DC ductus
cuvieri ; Dv yitelline duct (ductus omphalomeseraicus) ; H
ventricle ; L liver ; N umbilical vesicle (yolk-sac) ; 0 ompha-
lomeseraic (vitelline) artery ; 0 omphalbmeseraic (vitelline)
vein ; P lungs ; S subclavian artery ; U umbilical (allantoic)
arteries with their placental ramifications ( U") ; Ur umbilical
(allantoic) vein ; V auricle ; Vc vena cava inferior ; Fr portal
vein ; 1, 2. 3, 4, 5 the arterial arches — the persistent aortic
arch is not visible.
522 MAMMALIA
inferior vena cava, and thence in part passes into the right
auricle, but the greater part passes, in consequence of a special
arrangement of valves, directly into the left auricle through an
opening in the interauricular septum, called the foramen ovale.
The blood which reaches the right ventricle passes through a
vessel (ductus arteriosus Botalli), connecting the pulmonary
artery with the aorta, directly into the systemic circulation,
except a small portion which goes to the lungs. From
this condition of the circulation, it results that all the
arterial vessels contain mixed blood. The allantoic vein alone
contains pure arterial blood.
As remains of the first stage of. the circulation before the de-
velopment of the placenta, the omphalomeseraic (vitelline)
vessels — an artery and a vein — which belong to the umbilical
vesicle (yolk-sac), still persist.
The duration of gestation depends on the size of the body and
the stage of development at which the young are born. It is
longest in the large terrestrial and the colossal aquatic animals
(Ungulata, Cetacea), which live under favourable conditions of
nourishment. The young of these animals are so far advanced
in their bodily development at birth, that they are able to follow
the mother (to a certain extent like praecoces). The period of
gestation is relatively shorter in the Carnivora, the young of
which are born naked and with closed eyes and, like altrices, are
for a long time completely helpless, and need the care and pro-
tection of the mother. It is, however, shortest in the aplacental
monotremes and marsupials. In these animals the young,
which are born at a very early stage (in the kangaroo they are
no larger than a nut), pass into a pouch formed by cutaneous
folds in the inguinal region, and here adhere firmly to the nipples
of the mammary glands. In this pouch, as in a second uterus,
they are nourished by the secretion of the mammary glands,
which assume at this early stage the nutrient function of the
absent placenta. The number of the young, which are born,
also varies very greatly in the different genera. The large
Mammalia, of which the period of gestation is longer than six
months, as a rule bear only one, more rarely two young ; but in
the smaller Mammalia and some domestic animals (pig) the
number is considerably larger, so that twelve to sixteen, or even
twenty young may be born at one time. The number of teats on
. HABITS. 523
the mother usually indicates the greater or smaller number of
the progeny.
Many Mammalia live a solitary life, and pair only at breeding
time ; they are principally such carnivorous animals as find their
subsistence by hunting in definite hunting grounds, like the
mole in its subterranean passages. Others live united in com-
panies, in which the oldest and strongest males frequently under-
take the protection and leadership. Most mammals seek their
food by day. Some, e.g. the bat, leave their hiding places in the
twilight and at night. Most Garni vora and numerous Ungulata
also sleep in the daytime. Some Rodentia, Insectivora, and
Carnivora fall, during the cold season of the year when food is
scarce, into an interrupted (bear, badger, bat) or continuous
(dormouse, hedgehog, marmots) winter sleep in their hiding
places, which are often carefully protected, or in nests formed in
the earth. During this time the temperature is lowered, the
respiration is less active, the heart beat is slowed, and they take
up no food, but consume the fat masses which were stored up
in the autumn. The following animals are known to migrate :
the reindeer, the South African antelopes, and the North
American buffalo ; the seals, whales, and bats, but more especially
the lemmings, which migrate in enormous herds from the nor-
thern mountains southwards to the plains, are stopped by no
obstacles on their journey, and even cross rivers and arms of the
sea.
The intellectual faculties are more highly developed than in
any other class of animals. The Mammalia possess the faculty
of discrimination and memory; they form ideas, judgments,
and conclusions ; they exhibit affection and love to their bene-
factors, dislike, hate, and anger to their enemies ; each individual
has a definite character. Further, the intellectual faculties of
mammals are capable of being developed and improved, but,
except in Homo, to a relatively small extent on account of the
absence of articulate speech. The more docile of them have been
chosen by man as domestic animals, and in this capacity have
played an important and indispensable part in the history of
civilisation (dog, horse). Instinct always occupies an important
place in their life. It leads many of them to construct
spacious passages and ingenious nests above or below the
earth, in which they rest and bring up their offspring. Almost
524
MAMMALIA.
all make special nests for their brood, which they often line with
soft materials ; some even construct true nests, like those of
birds, of grass and stalks. Many of those which inhabit sub-
terranean holes and passages store up winter provisions,
which they consume in the sterile season, or in autumn
and spring (winter-sleepers).
Geographical distribution.* Some orders, as the rodents and
bats, are represented in all parts of the world. Of the Cetacea
and Pinnipedia most species belong to the polar regions. In
general, the Old and New Worlds have each their own fauna.
The mammalian fauna of Australia consists almost exclusively
of marsupials. The oldest fossil remains (lower jaw) of mam-
mals are found in the Trias (Keuper Sandstone and Oolite,
Stonesfield slate) and are supposed to belong to the Marsupialia
(p. 539). But it is not until the Tertiary period that the mam-
malian fauna presents a rich development.
The classification of Mammalia adopted in this work is as
follows : —
Order 1. Monotremata.
„ 2. Marsupialia.
Sub-order 1.
2.
3.
„ 3. Edentata.
Sub-order 1.
2,
" 3.
4. Sirenia.
,, 5. Cetacea.
Sub -order 1.
2.
. 3.
6. Hyracoidea.
7. Proboscidea.
8. Ungulata.
Sub-order 1.
9
9. Amblypoda.t
10. Toxodontia.t
11. Typotheria.t
12. Tillodontia.t
13. Aneylopoda.t
14. Condylarthra.f
15. Creodonta.
Diprotodonta.
Polyprotodonta.
Allotheria. t
Xenarthra.
Gravigrada. t
Nomarthra.
Mystacoceti.
Odontoceti.
Zeuglodonta. t
Artiodactyla.
Perissodactyla.
Lipoterna.
* Wallace, Sclater, Lydekker, op. cit. f Extinct.
MONOTREMATA. 525
Order 16. Garni vora.
17. Pinnipedia.
18. Rodentia.
19. Insect! vora.
20. Chiroptera.
21. Prosimiae.
22. Primates.
There are about 2,300 living and over 3,000 extinct species of
mammalia known at the present time. Many of the extinct
groups are very imperfectly known, and it seems advisable in
the present state of knowledge to give some of these the rank
of orders.
Order 1. MONOTREMATA.*
(Sometimes called Ornithodelphia and Prototheria.)
Oviparous Mammalia with meroblastic ova.
The monotremes differ from all other mammals in possessing
the following characters, some of which may be described as
reptilian. The mammary glands are without teats, and the
brain is without a corpus callosum. The pectoral girdle has a
large coracoid which reaches the sternum, and a precoracoid.
There is also a large T-shaped interclavicle. The vertebrae
are without epiphyses, and the ribs are provided only with a
capitulum. Marsupial bones are present. The right auriculo-
ventricular valve is incomplete and partly muscular. The
testes retain their abdominal position. The ureters do not
open into the bladder but into a urinogenital sinus, which com-
municates with the alimentary canal, so that there is a cloaca.
The eggs are large and meroblastic, and are laid at an early
stage of development. They are however undoubtedly mam-
mals, being provided with hairs, warm blood, non- nucleated
red blood-corpuscles and a left aortic arch.
There are but three living genera, and very few fossils are
known. The living forms are confined to Australia, Tasmania,
and New Guinea.
The form of the body and tl^e mode of life partly recall the
anteaters and hedgehog (Echidna, Fig. 273) and partly the
* " Monotremen u. Marsupialen " in Demon's Zoologische Forschungs-
reise in Australian, etc. Bd. 2, 1897. R. Owen, " Monotremata " inTodd's
Encyclopaedia of Anatomy and Physiology, 1847. W. H. Caldwell. The
Embryology of Monotremata and Marsupialia, Phil. Trans. 178, 1887,
p. 463.
526 . MAMMALIA,
otters and moles (Ornithorhynchus, Fig 274) ; in fact Orni-
thorhynchus received the appropriate name of " watermole "
from the Australian settlers. Echidna is covered with strong
spines, and possesses an elongated edentulous snout, with a
vermiform protrusible tongue. The short five-toed legs end
with powerful scratching claws, which are adapted for rapid
burrowing. Ornithorhynchus, on the contrary, has a close soft
fur, a flattened body and. as in the beavers, a flat tail. The
FIG. 273. — Echidna hystrix.
jaws, like the beak of a duck, are adapted for burrowing in mud,
but are covered by a soft integument which projects at the
base of the beak so as to form a kind of shield. The legs are
short, with five toes furnished with strong claws and very exten-
sible webs : they are equally well adapted for swimming and
burrowing.
FIG. 274. — Ornithorhynchus paradozus.
>jThey lay eggs, with a white membranous shell ; Echidna
deposits them in its pouch ; and Ornithorhynchus, which
has no pouch, is believed, though this has not been absolutely
proved, to lay them in its nest.
That the Monotremata are oviparous was suggested soon
after their discovery, and has been asserted several times since
(on one occasion with good reason), but the best authorities
regarded them as viviparous, or at least ovoviviparous, until
Caldwell in 1884 definitely settled the matter in the case oi
Echidna by obtaining a specimen with an egg in the pouch.
He also found the eggshells of Ornithorhynchus in the nest.
MQXOTREMATA, 527
The mammary glands consist of two groups of glandular tubes which
open in a tuft of hairs on two, slightly less hairy, patches of the skin of
the abdomen, by numerous openings. The gland-tubes are of the sudori-
parous type, being dichotomously branched and provided with smooth
muscular fibres outside their epithelium. In Echidna, but not in Ornitho-
rhynchus, these mammary areas are at the breeding season slightly de-
pressed and placed on the side walls of a forwardly opening pouch of the
ventral integument. The egg is placed by the mother in this pouch,
where it is hatched and undergoes its early development. The pouch
and the depression of the mammary area disappear when the breeding
season is over. In Ornithorhynchus there is no pouch and no depression
of the mammary area (for oviposition see p. 526). In the absence of
teats it would appear that the young take up the mammary secretion
by licking the mammary area.
The ear is without a pinna. The males possess on the inner side of the
hind leg a horny spur, which is attached to an accessory ossicle on the
tibial side of the tarsus. This spur is perforated, and transmits the duct
of a gland placed beneath the skin of the back of the thigh. The use of
this apparatus is not understood, but it is suspected that the gland secretes
a poisonous fluid and that the spur is used in fighting, though this has
been denied. The young female possesses a small spur which however
disappears in the adult.
In the skeleton the following points may be noticed in addition to those
already mentioned. The skull-cavity is large, and the cranial walls thin
and smooth. The sutures between the bones are largely obliterated.
The tympanic bone is annular and slender, and does not form a bulla.
The malleus is large, but the incus is small ; the stapes is imperforate
and columelliform. The mandible is slender and with but slightly marked
coronoid process. The odontoid process long remains separate from the
axis, and the cervical ribs remain distinct for some time. In the scapula
the spine is placed on the anterior border and not in the middle of the
bone. In the pelvic girdle of Echidna the acetabulum is perforated.
The cerebrum is a fair size, and is convoluted in Echidna, smooth in Orni-
thorhynchus. There is a large anterior commissure, but no corpus cal-
losum. The cochlea* is only slightly bent, and alone amongst mammals
possesses a lagena with its papilla acustica. Echidna is edentulous, but
Ornithorhynchus possess ten or twelve multituberculate molar teeth, f
These are shed at a certain age (half-growth), being ejected and replaced
by horny teeth developed beneath them from the epidermal lining of the
mouth. The right auriculo-ventricular valve J is deficient on the septal
side, and there are no chordae tendineae, the papillary muscles being
attached to the edge of the valve (the left valve is also without chordae
tendineae). In Ornithorhynchus (not in Echidna) the muscular tissue
invades the membranous valve, and the muscular bands are inserted
directly into the margin of the opening, so that the valve is partly fleshy.
There is in Echidna an anterior abdominal vein § arising on the bladder
and distributed to the liver.
The testes are in the abdomen, immediately behind the kidney, to
which they are suspended by a fold of peritoneum. There is a urino-
* Pritchard, Phil. Trans., 1881.
i Poulton, Q.J.M.S., 29. Stewart, Q.J. M.S., 33, 1892, p. 229.
j Lankester, P.Z.S., 1883, p. 8.
§ Beddard, P.Z.S, 1884.
528
MAMMALIA.
genital sinus which posteriorly opens into the cloaca. Anteriorly it
receives the openings of the bladder, vasa deferentia and ureters. There
is a penis attached to the ventral wall of the cloaca and retractile into a
sheath (Fig. 275). It is traversed by a canal (penial urethra) which
ooens in front into the urinogenital sinus, and behind by more than one
opening at the end of the penis. There is a pair of large Cowper's glands
opening into the canal of the penis. The corpus fibrosum is not cavernous,
but there is cavernous tissue round the urethra and in the glans penis.
The prostate and vesiculae seminales are absent. The ovaries are in the
same position as the testes, but the right ovary is smaller (never functional
in Ornithorhijnchus, rarely in Echidna] than the left (Fig. 270). There
is no vagina. The lower ends of the oviducts are dilated into a kind of
uterus, and open into the urinogenital sinus in front of the ureter. There
are two glands opening
into the sheath of the
clitoris which are com-
pared by Owen to the
Cowper's glands of the
male.
The ova when they enter
the oviduct are larger than
in all other mammals (3 to
4 mm. ), and contain a con-
siderable quantity of yolk.
They acquire an albumi-
nous coat and a shell in the
oviduct, where they un-
dergo their incomplete
cleavage and the early
stages of development.
The ovum increases con-
siderably in size in the
oviduct by the intussus-
ception of fluid and is
about 15 X 12 mm. when
extruded.
In Echidna one egg is
laid at a time and placed
by the mother in the pouch (p. 526). In Ornithorhynchw two eggs
appear to be laid and placed in the nest in the burrow.
The temperature * is lower (about 28-29° C.) than is usual in mammals
and appears to exhibit considerable variation. Echidna hibernates in the
cold weather. Fossil remains, closely allied to living forms, have been
found in the Pleistocene of Australia, and Ameghino f has ascribed some
fossils in the Eocene of Patagonia to this group (Dideilotherium, etc).
Fam. 1. Echidnidae. Skin covered with spines with which hairs
are mingled ; snout elongated ; edentulous ; tongue long and protractile ;
salivary glands large ; tail very short. They burrow in sand and earth.
Echidna Cuv. (1798), with 5 clawed digits on each limb, with a temporary
* Martin, Thermal adjustment and respiratory exchange in Mono-
tremes and Marsupials, Phil. Trans., 195, 1903, p. 1.
f Bol. Acad. Cordoba, xiii, 1894.
B
FIG. 275. — Diagram of the cloaca, urinogenital sinus
and penis of a Monotreme, A with the penis pro-
truded, B retracted, bi connective tissue ; bl bladder ;
d cloaca ; / corpus fibrosum ; p ureter ; ps sheath
(preputial) of penis ; ps1 opening of this ; r canal
traversing the penis (sperm tube) ; s vas deferens ;
u urinogenital sinus (after Boas).
MARSUPIALIA. 529
pouch in which the single egg is placed, Australia, Tasmania, N. Guinea ;
E. aculeata Shaw. Proechidna Gervais (1877), Xew Guinea, usually with
three clawed digits on each limb and traces of the other digits.
Fam. 2. Ornithorhynchidae. Covered with a dense soft fur ; with
the facial portion of the snout broad and elongated and covered with a
leathery skin produced into a fold at the base of the snout ; with horny
molar teeth in old specimens and true teeth up to half growth (p. 527) ;
feet webbsd, with 5 clawed toes, the web on the fore foot extending beyond
the claws ; they are aquatic in habit, and form burrows in the banks of
streams, with two openings, one above and one below the water ; they
are believed to lay two eggs in a nest in the burrow. Australia and Tas-
mania. Ornitherhynchus Blumenb. (1800), water mole, duck-billed Platy-
pus ; O. anatinus Shaw.
Order 2. MARSUPIALIA.*
(Sometimes called Metaiheria, or Didelphia.)
Mammalia with various dentition and epipubic (marsupial)
bones. The mimmary glands have teats which are usually enclosed
in a marsupial pouch in which the young are carried. An allantoic
placenta is usually absent.
The principal characteristic of the Marsupials is the possession
by most of them of a sac or pouch (marsupium) which is supported
by two epipubic (marsupial) bones (Fig. 276), encloses the
teats of the mammary glands, and receives the helpless young
at birth. Birth takes place at an early stage of development.
Even in Macropus giganteus, the males of which attain almost
the height of a man, the period of gestation does not last more
than thirty- nine days, and the embryo at birth is blind and
naked, and not much more than an inch in length. It is
placed in the pouch by the mother, sucks firmly on to one of
the teats, and remains in the pouch for a considerable period.
As additional characters may be mentioned the double
vagina, the position of the scrotum in front of the penis, the
inclusion of the anus and of the opening of the urinogenital
sinus by a common sphincter, the vacuities in the palate, the
participation of the alisphenoid in the tympanic bulla, the
inflection of the angle of the lower jaw, the absence of the
corpus callosum, the absence of a fossa ovalis from the auricular
* Owen, " Marsupialia," in Todd's Encyclopaedia of Anat. and Physiol.
1847. Waterhouse, Natural History of Mammalia, 1, London, 1846. Oldfield
Thomas, British Museum Catalogue of Marsupialia and Monotremata,
London, 1888. R. Lydekker, Handbook to the Marsupialia and Mono-
tremata, in Allen's " Naturalists' Library," 1894. Bensley, Involution
of the Australian Marsupialia, etc., Trans. Lin. Soc. (2), 9, p. 83.
z— II M M
530 MARSUPIALIA.
septum and, except in Perameles, of an allantoic placenta.
As a rule only one tooth (the last premolar) is replaced ; the glans
penis is generally bifurcated, and the crura penis are not united
to the ischia.
The odontoid process fuses early with the axis, and the cervical ribs
with their respective vertebrae. There are usually nineteen dorso-lumbar
vertebrae of which the anterior thirteen bear ribs. The sacrum consists
of two vertebrae, but it may be reinforced by caudal vertebrae. The
palate has large posterior vacuities. The alisphenoid assists in forming
the tympanic bulla. The carotid canal perforates the basisphenoid. The
tympanic, periotic and squamosal remain separate. The jugal reaches
back to the glenoid cavity and participates in forming it. The angle
of the lower jaw is usually inflected (except in Tarsipes). The teeth vary
in structure according to the mode of life. The usual formula is i ~
G \ p f m f . As may be seen from the formula the number of incisors
and molars is larger than in other mammals. The grinders are either
secodont, bunodont or lophodont, and canines are often absent in the
herbivorous forms. In some mesozoic forms the canines are two-rooted.
The marsupials are peculiar in the fact that only one tooth — the last
premolar — is replaced. In some forms this tooth remains until the
animal is full-grown (e.g. Potorous) ; in others (e.g. Thylacinus) it is
reduced and is absorbed or shed before the other teeth appear. In
others again it has not been detected at all, and there is no replacement
{Wombat, Dasyurus, Myrmecobius). In the extinct Sparassodontidae two
premolars and the canines are replaced. Various answers have been
given to the question whether the teeth belong to the permanent or
milk dentition (see Table on p. 508). By some it is held that all
the teeth belong to the milk series, except the tooth which replaces
the last premolar, which is regarded as belonging to the permanent series.*
According to this the permanent series must be supposed to have become
abortive, a view which is supported by the fact that tooth germs not
attaining full development are formed in the position of the permanent
tooth germs of the completely diphyodont mammals. However this
may be, there is undoubtedly a set of tooth germs which are developed
before those of the persistent teeth. These have been called by the up-
holders of the above-mentioned view prelacteal. Others hold that the
deciduous tooth and the persisting teeth belong to the permanent den-
tition, and that the deciduous tooth is the first of the molar series which in
consequence of the shortening of the jaw has been overlapped by the
fourth premolar which pushes it out (Tims).
The coracoid is reduced to a process of the scapula, as in the higher
forms. A clavicle is present except in the Peramelidae. There is no
interclavicle. The bones of the forearm are separate and generally
adapted for pronation and supination. The thumb is not opposable,
but the two inner digits of the manus can frequently be opposed to the
three outer in grasping. The manus possesses five digits except in Choe-
ropus, and the carpus is without an os centrale Epipubic bones (Fig.
276,'M) project forwards from the pubis in all except Thylacinus in which
* By some even this is regarded as belonging'to the milk series (between
the last and penultimate premolar), and arising late (M. Woodward,
P.Z.S., 1893, p.J4-67).
BRAIN. ALIMENTARY CANAL. GENERATIVE ORGANS. 531
The cerebral
Js
FIG. 276.— The pelvis
adjoining parts of
vertebral* column
Macropus. Jl ilium ;
Pb pubis ; Js ischium ;
M epipubic bones ; A
acetabulum ; S the two
sacral vertebrae.
and
the
phys philander
(after Otto,
from Gegen-
baur). E the
two halves of
the glaus.
they are represented by cartilage. The fibula is generally free, and can
sometimes be rotated on the tibia (Phascolomyidae, Didelphyidae, Phalan-
geridae), and in some cases the first digit can be used as a thumb. The
pes presents considerable variation ; the tarsus contains the usual seven
bones, and there are usually five digits, but the hallux is frequently absent.
The second and third digits are in many families very slender, and united
by the skin almost to their extremities (syndactylism, Fig. 280).
The brain is relatively smaller than in higher mammals. The corpus
•callosum is absent and the anterior commissure is large,
hemispheres vary in size and in
the extent to which their surface
is convoluted.
The stomach is usually simple,
but in the kangaroos it is much
elongated and sacculated, like the
colon, by three longitudinal muscu-
lar bands. There is a cardiac gland
in some forms (Phascolarctus, Phas-
colomys). The caecum is usually
present : it is large in the kangaroos,
small and provided with a vermi-
form appendix in the wombat, penkbf-D&W-
absent in the dasyures. A gall
bladder is always present.
The heart is without fossa ovalis,
the auriculo-ventricular valves are
membranous and attached to the
of papillary muscles by chordae tendineae, and there
are two superior venae cavae, each receiving an
azygos vein.
Generative organs. In the male there are no
vesiculae seminales, the glans penis is frequently
bifurcated, the crura penis are not attached to
the ischia, and the testes descend into scrotal sacs which are placed
in front of the penis.
In the female * the miillerian ducts remain separate posteriorly
and open separately into the long urinogenital sinus (Fig. 278.) They
are differentiated into oviduct, uterus and vagina on each side, and
the vaginal portion is curved. This is the arrangement in the simplest
cases (Didelphys, Fig. 278 A), but in other forms the anterior part of
the vagina gives off a backwardly directed caecum (Fig. 278 B), which
is so closely applied to its fellow that it is separated from it only by a
median septum. In yet other forms this septum breaks down so
that the two vaginal caeca unite into one, the hind end of which reaches
back to the front end of the urinogenital sinus. In some forms
(Macropodidae and others) the hind end of this blind sac acquires
at parturition, an opening into the urinogenital sinus at this point (ap-
parently by rupture), so that the foetus is delivered straight into the
urinogenital sinus without traversing the whole length of the vagina
(Fig. 278 C).
* Brass, A., Beitr. zur Kenntniss des weibl. Urorjenital-system der Marsu-
pialier, Inaucr. Dissert., Leipzig, 1880. Lister arid Fletcher, P.Z S., 1881,
p. 976.
532
MARSUPIALIA.
18'
FIG. 278.— Female urinogenital organs, A, a young Didelphys dorsigera (after [Brass),
ventro-lateral view, the urinogenital sinus is opened. B, Phalangista vulpina, dorsal
view, the. urinogenital canal and left vaginal pouch are opened. C, Macropus rufus,
dorsal view, the left uterus and vagina, the vaginal pouch or caecum, and the urino-
genital canal are laid open ; the two vaginal caeca have united and open directly into
the urinogenital canal, showing that the animal from which the preparation was made
had borne young. (B and C from original drawings by J. J. Lister.) 1, Kidney ;
2 ureter ; 3 ovary ; 4 fallopian tube ; 5 uterus ; 6 curve where the vagina passes into the
uterus ; 7 vaginal caecum ; 8 vaginal caecum united with its fellow and opening into
urinogenital canal ; 9 vagina ; 10 opening of vagina into urinogenital canal ; 11 opening
of coalesced vaginal caeca into urinogenital canal ; 12 bladder ; 13 opening of bladder
14 urinogenital canal ; 15 rectum ; 16 rectal gland ; 17 opening of rectum ; IS clitoris.
PLACENTA. HABITS. 533
In both the male and female the openings of the urinogenital sinus
and anus are enclosed by a common sphincter, so that there is a shallow
cloaca. In the male this sphincter is said, by compressing the veins
of the penis, to exercise an important influence on its erection.
A marsupial pouch is present in most forms. It is however absent
in Didelphys and the Dasyuridae. Its opening generally looks forward,
but in Thylacinus and some Peramelidae it is directed backwards. The
number of teats bears a relation to the number of young produced at a
birth. The kangaroo, with one young, has four nipples. The Virginian
opossum with several young has six on each side and one in the middle.
In Phascologale penicillata there are eight nipples arranged in a circle. The
young are carried in the mouth to the pouch and are attached by their
mouths to the nipples. The nipples are long and the milk is forced down
the mouth of the very imperfect young by the contraction of the cre-
master muscle. The epiglottis and arytenoid cartilages are elongated
and project into the posterior nares in very much the same fashion as in
whales. In this way the young are able to breathe while milk is being
forced down their throats. In the pouched forms the young return to
the pouch for nutrition and shelter after they have acquired the power
of locomotion. A rudiment of the pouch is occasionally present in the
male.
The ripe ovum appears to be of about the same size as that of higher
mammals (in Phascolarctus 0'17 mm.). The yolk sac becomes in part
vascular; its outer epithelium and that of the false amriion become
closely applied to the uterine wall. In some cases at least an epithelial
attachment * is formed, but as a rule no closer connection is established.
The majority of the marsupials are therefore truly aplacental, but in
Perameles | a definite discoidal (primary) allantoic placenta is developed.
The young of Peramelea at birth do not differ in degree of development
to any marked extent from other marsupials.
In their external appearance, in their mode of nourishment,
and in their habits, marsupials differ much amongst themselves.
Some (e.g. kangaroos) are purely herbivorous and in their
dentition approach the rodents and ungulates ; others (thyla-
cines and dasyures) are carnivorous ; but most of them are
omnivorous. In their general appearance and mode of loco-
motion they repeat a series of types of different mammalian
orders. Thus the wombats represent the rodents : the fleet
kangaroos, which move by huge bounds, correspond to ruminants.
The flying marsupials (Petaurus) represent the flying squirrels
(Pteromys) ; the climbing phalangers (Phalangistd) , in their
shape and mode of life, recall the lemurs ; while others, as the
Peramelidae, show a likeness to the shrews (Soricidae) and
insectivores. Finally the carnivorous marsupials approach in
* Caldwell, Q.J.M.S., 24, 1884. Selenka, Studien ub Entwiclc. d.
Thiere, iv, Das Opossum ; v, Phalangista u. Hypsiprifmnus, Wiesbaden,
1886-91.
f Hill, Q.J.M.S., 48, 1898, p. 385.
534 MARSUPIALIA.
their dentition to the true Carnivora as well as to the Insecti-
vora, which they resemble in the large number of their small
incisor teeth and tuberculated molars.
The marsupials are in the main confined to the Australian
region, but two families, the JMdelphyidae and Epanorthidae
(Caenolestes), are found in the neotropical region to which they
are peculiar, and the genus Phalanger extends into the island of
Celebes, where it is represented by two peculiar species.
The group is divided into eight families with about 180 species.
The geological history of the group is interesting. In Aus-
tralia, which is now its chief home, no fossil remains are found
prior to the Pleistocene. In America, in which both divisions
are represented by living forms, remains both of polyprotodonts
and diprotodonts are found as far back as the Eocene, and in
the case of the Epanorthidae in the Upper Cretaceous. Didel-
phyds are found in the Tertiaries of Europe, and there is a
number of fossil forms in the Jurassic Formation of Europe
and N. America, which are ascribed to the polyprotodont divi-
sion (p. 539). Finally there are the Allotheria or, as they are
sometimes called, the Multituberculata (p. 541), remains of
which are found fossil in the mesozoic rocks of Europe and
N. America, and the exact systematic position of which is still
very uncertain.
Sub-order 1. Diprotodontia.
Incisors three above (one in Phascolomyidae) and one below
(small second and third incisors sometimes present in Pha-
langeridae], the latter long and powerful. Canines usually
small, usually absent below. Molars bluntly tuberculate or
ridged. With two syndactylous toes except in Caenolestes.
Herbivorous, rarely insectivorous. Living forms confined to the
Australian and neotropical regions, but found fossil in the
Pleistocene of Australia and in the Eocene and Upper Cretaceous
of Patagonia and N. America.
Fam. 1. Macro podidae. Terrestrial, rarely arboreal ; hind limbs
longer than the fore, progression generally saltatorial ; manus with 5
digits ; pes syndactylous, with 4 digits, the hallux being absent (except
in Hypsiprymnodon), fourth toe very large. Tail long, carried hori-
zontally backwards in progression ; stomach sacculated ; caecum present ;
pouch opening forwards. Dentition i | c ^p p f m \ ; the milk pre-
molar is long persistent and molariforrn, the first premolar is shed with
DIPROTODONTIA.
535
Flfi. 279. — Skull and teeth of Bettongia lesuevri. c canine ; i in-
cisors ; 7>m premolar ; m molars (from Flower and Lydekker).
it but not replaced ; the milk premolar is shed usually before the fourth
molar appears, and all the grinding teeth move forward in the skull with
increasing age as in elephants and some sirenians ; the lower incisors
are long, and' can be used against one another in a scissor-like manner..
More than 60 species distributed all over the Australian region.
Sub-fam. 1. Macropodinae. With long hairy tail, without hal-
lux ; with minute or absent canine. Macropus Shaw (Halmaturus),
kangaroos and wallabies, about 23 species, varying in size from that
of a rabbit to
that of man,
Australia, X.
Guinea, E.
half of Aus-
tro - Malaya ;
M. giganteus
Zimm., Aus-
tralia, except
the extreme
north, and
Tasmania.
P etroga le
Gray, rock-
wallabies,
Australia, but
notTasmania,
6 species. Onychogale Gray, nail-tailed wallabies, with horny ex-
crescence at tip of tail, Australia, not Tasmania. Lagorchestes
Gould, hare-wallabies, Australia, not Tasmania, 3 species.
Dorcopsis Schleg. and Mull., 3 species, N. Guinea. Dendrolagus
Schleg. and Mull., tree kangaroos, arboreal, hardly macropodiform,
N. Guinea and North Queensland, 5 species. Lagostrophus Thomas,
1 species, W. Australia. Extinct
genera, Palorchestes Ow., Sthen-
urus Ow., Synaptodus de Vis ;
Pleistocene, Australia.
Sub-fam. 2. Potoroinae. Rat-
kangaroos, with long hairy tail,
without hallux ; with canines,
generally well developed ; pre-
molars with large compressed
crowns, and usually grooved
on the inner and outer sur-
faces* (Fig. 279) ; small animals.
Aepyprymnus Garrod, E. Aus-
tralia, 1 species. Bettongia Gray,
FIG. 280.-Phalanger celebensis. Pes show- Australia and Tasmania, 4
ing syndactylism (from 0. Thomas). species. Caloprymnus Thomas,
S. Australia, 1 species. Poto-
rous Dasm. (Hypsiprymnus 111.), Aust. and Tasmania, 3 species.
Sub-fam. 3. Hypsiprymnodontidae. With naked scaly tail and
au opposable hallux ; intermediate to Phalangeridae ; one species
* As in some of the extinct Allotheria, see p. 541.
536
MAR^UPIALIA.
and genus only. Hypsiprymnodon Ramsay, musk-kangaroo, Queens-
land.
Fam. 2. Phalangeridae. Arboreal, sometimes with parachute-like
expansions of the skin for flying leaps ; 5 fingers and toes, with nailless
opposable hallux ; pes syndactylous (Fig. 280) ; tail long and usually
prehensile ; stomach simple ; caecum present except in Tarsipes ; pouch
opening forwards ; dentition variable owing to the presence of minute
teeth which are not constant, even in the same species or on two sides
of the same jaw ; general formula i ' f c
p
FIG. 281. — Petaurus sciiirius, [squirrel flying-phalanger (from Flower
and Lydekker).
milk
premolar gener-
ally small and
early deciduous ;
Papuan Islands,
Australia and
Tasmania;
about 35 species.
Flying m e m-
branes are pres-
ent in" 3 genera,
which are more
closely allied to
genera without
fl y i n g me m-
branes than to
each other.
Sub-fam. 1.
Tarsipedinae.
Tail long ;
snout long
and slender,
tongue ex-
tensile ; with-
out caecum ;
grinding
teeth min-
ute ; lower
jaw without
i nflection.
Tarsipes G.
and V., about
the size of a
mouse, ex-
insectivorous ;
tracts honey from flowers with its tongue, also
1 species.
Sub-fam. 2. Phalangerinae. Dentition normal ; tail long, gener-
ally prehensile ; snout broad ; tongue not extensile ; without cheek
pouches ; with large caecum ; throughout the Australian region.
Acrobates Desm., with flying membrane, Queensland, N. S. Wales,
Victoria ; 1 species. Distoechurus Peters, New Guinea, 1 species.
Dromicia Gray, dormouse-like ; N. Guinea, W. Australia, Tasmania ;
4 species. Gymnobelideus McCoy, like Petaurus but without flying
membrane, Victoria, 1 species. Petaurus Shaw- (Fig. 281), with
flying membrane, medium or small size, fur soft and silky ; insecti-
niPROTODONTIA. 537
vorons and extracts honey from flowers ; Papua and Australia, 3
species. Dactylopsila Gray, Papua and N. Australia. Petauroides
Thomas, with flying membrane, Queensland to Victoria, 1 species.
Pseudochirus Ogilb., Tasmania, Australia, N. Guinea ; about 10
species. Trichosurus Less. (Fig. 282), large size, Australia and
Tasmania ; 2 species. Phalanger Storr (Cuscus), largish size, Austro-
Malaya from Celebes to Queensland, 5 species ; Ph. ursinus and
celebensis from Celebes. Archizonurus, Palaeopetaurus, Burramys
have been described from the Pleistocene of Australia.
Sub-fam. 3. Phascolarctinae. Muzzle short, tongue not extensile;
tail absent ; caecum large ; cheek pouches present. Phascolarctua
Blainv., the kaola or native bear, S. E. Australia, two feet in length
and a good climber, 1 species.
FIG. 282. — Trichoswvs mdpinus (from Claus).
Sub-fam. 4. Thylaeoleontinae. Large, extinct forms from the
Pleistocene of Australia ; dentition i ' -f c £ p f m £, last premolar
being large and trenchant, like that of the rat-kangaroos. The orbit
is completely surrounded by bone, which is not the case in any other
marsupial. It was probably a phalanger-like animal, mainly herbiv-
orous, but possibly partly carnivorous. Thylacoleo Owen, Pleis-
tocene, Australia.
Fam. 3. Phascolomyidae. Fossorial, root-eating forms with stout,
clumsy body. Limbs subequal ; manus with 5 subequal digits, pes
with 4 strong toes and a short nailless hallux, digits 2 and 3 showing a
slight tendency towards syndactylism ; tail reduced to a stump ; stomach
simple with cardiac gland ; caecum short, with vermiform appendix ;
pouch present. Dentition i \ c ^ p \ m £, all teeth with persistent
pulps, incisors rodent-like, with enamel only on front surface, milk pre-
molar not known ; Tasmania and S. Australia. Phascolomys E. Geoff.,
wombat, 3 species. Extinct forms from the Pleistocene of Australia are
Phascolonus Ow., nearly as large as a tapir, Sceparnodon Ow.
Fam. 4. Diprotodontidae. Extinct forms from the Pleistocene of
Australia. Diprotodon Ow., very large forms of the size of a rhinoceros,
resembling Macropus but with subequal limbs ; palate fully ossified ;
or THE
( UNIVERSITY j
£4LIFO«fii^
538 MARSUPIALIA.
humerus without entepicondylar foramen. Nototherium Ow., rather
smaller than Diprotodon.
Fam. 5. Epanort hidae. American Diprotodonts, without syndactylism ;
mostly extinct. The only living genus Caenolestes Thomas (Hyracodon)
with small vestigial pouch and dentition i£c\p%m%; mountains
of Ecuador and Colombia, 2 species, several extinct genera from the
Eocene of Patagonia. Cimolestes, Telacodon and Batodon are also found
in the Upper Cretaceous of N. America, and Epanorthus in the Upper
Cretaceous and Eocene of Patagonia. The extinct Abderitidae and
Garzonidae from the Eocene of Patagonia also come here.
Sub-order 2. Polyprotodontia.
Incisors numerous, sub-equal, four or five above and three
or four below ; canines large, molars cuspidate. Without
syndactylism except in the Pcramelidae. Mostly carnivorous
and insectivorous. America and Australia.
Fam. 1. Peramelidae. Bandicoots. Fossorial, insectivorous, hind
legs longer than fore, with syndactylism of digits 2 and 3 of the pes. Manus-
with 2 or 3 of the middle digits long and functional, the others small or
absent ; pes with 4 or 5 digits, unequal in size, digits 2 and 3 slender,
united ; hallux small or absent. Stomach simple, caecum present, pouch
opening backwards. Dentition i - — c \ p f in £. Australia and
Papua. Peragale Gray, rabbit-bandicoots, digits 2, 3 and 4 of manu&
large, digits 1 and 5 present but small and clawless ; hallux absent ; ears
large ; omnivorous ; Australia ; 2 species. Perameles Geoff., fore limbs
as in Peragale, hallux present, clawless, ears medium ; embryo with pla-
centa (p. 533) ; Australia, Tasmania and N. Guinea. Choeropus Ogilb.^
pig-footed bandicoots, fore-limbs with digits 2 and 3 only functional,,
digit 4 small, digits 1 and 5 absent ; hallux absent ; ears long ; omnivorous,.
Australia, 1 species.
Fam. 2. Dasyuridae. Predatory, carnivorous or insectivorous, with
subequal limbs, usually pentadactyle, but hallux sometimes absent -
no caecum ; pouch present or absent, opening forwards or downwards.
Dentition i £ c \ p ^~ m —^ ; canines large, 'molars cusped,
milk tooth minute, shed during infancy ; Papua and Australia. Thyla-
cinus Temm., Tasmanian wolf, size and build of a wolf, back transversely
banded with black, hallux absent, dentition i % c \ p f m £, Tas-
mania (fossil in N. S. Wales), 1 species. Sarcophilus F. Cuv. (Diabolus)?
Tasmanian devil, about the size of a badger, body powerful, blotched
with white, hallux absent, dentition i$c\p%m%, milk premolar,
reduced, and absorbed or shed before the other teeth cut the gums ; Tas-
mania (fossil in N. S. Wales), 1 species. Dasyurus E. Geoff., native cats,,
body viverrine, profusely spotted with white, hallux sometimes present,
dentition as in the last, but more insectivorous ; Papuan and Australian
regions, 5 species, feed on birds and eggs, nocturnal. Phascologale Temm. ,
small, not larger than a rat, hallux present, dentition i £ c-\ p f m £,
arboreal, insectivorous ; pouch absent, represented by fold of skin ;.
POLYPROTODONTIA. 539
Papuan and Australian regions, 13 species. Sminthopsis Thomas, small
forms with hallux and pouch, Australia and Tasmania, 4 species. Ante-
chinomys Krefft, jerboa-like, terrestrial, without hallux, Queensland and
N. S. Wales. Myrmecobius Waterh., arboreal and terrestrial, anteaters,
red and squirrel-like, tongue long, extensile ; lower lip pointed ; back
banded with white, hallux absent, molars and premolars exceeding the
usual number of 7 ; dentition i | c \ p | m ifor"7' with011* pouch,
allied by its dentition to the Jurassic potyprotodont marsupials, W. and
S. Australia, 1 species.
Fam. 3. Notoryctidae,* mole-marsupial, red colour, mole-like form
and habits, without externally visible eyes or ears, pentadactyle limbs,
upper molars tritubercular, pouch opening backwards, central South
Australia, one genus and species. Notoryctes Stirling.
Fam. 4. Didelphyidae. Opossums, arboreal (except Chironectes mini-
mus which is aquatic), carnivorous or insectivorous, pentadactyle forms
with an opposable hallux for climbing. Tail long, prehensile ; stomach
simple ; caecum small or moderate ; dentition i%c}p$m^; pouch
generally absent, sometimes represented by two folds of skin, N. and S.
America, fossil in Eocene, Oligocene and Miocene of Europe and America ;
two genera. Didelphys L., hind toes free, size from that of a cat to a large
mouse, with 23 species (this genus has been divided into a number of
sub-genera, Didelphys, Metachirus, Philander, Micoureus, Peramys).
Chironectes 111., water opossum, hind toes webbed to their extremities,
about the size of a rat, Guatalema to S. Brazil, 1 species. Amphipcratherium
Filhol., from the Oligocene and Miocene of Europe and Peratherium
from the Eocene and Miocene of Europe and America, and from the
Pliocene and Pleistocene of America, belong to this family.
A number of fossil forms known by little more than their lower jaw^s
and teeth and found in Mesozoic rocks, are associated in current classifica-
tions with the polyprotodont marsupials. These include the celebrated
lower jaws of the Stonesfield Slate (Lower Jurassic) of Oxfordshire and
of the Middle Purbeck Beds (U. Jurassic) of Dorsetshire. Apparently
similar remains are found in N. America in the U. Jurassic and U. Creta-
ceous formations, and two forms, viz. Dromatherium and Micronodon
are known by lower jaws in the Upper Trias of Carolina. The reasons
for associating these remains, which belonged to quite small animals no
larger than a rat, with the marsupials are indeed slender, based as they
are only upon the dentition of the lower jaw and upon the fact that in
some of them the angle of the mandible is slightly inflected. The den-
tition resembles that of Myrmecobius, and consists of at least three lower
incisors, well-developed canines and cuspidate molars and premolars.
These forms have been grouped in families which are here tabulated
as an appendix to the Polyprotodontia, for convenience of reference and
not because any real importance can be attached to the grouping.
Fam. 5. Dromatheriidae. Premolars styliform, molars triconodont,
with main cusp and several anterior and posterior smaller accessory
cusps all in the same line ; dentition of mandible i3clp3ml;
from the U. Trias of Carolina ; by many regarded as reptiles. Micro-
conodon Osborn, Dromatherium Emmons.
Fam. 6. Triconodontidae. With 4 premolars and 4 — 8 molars ; canines
* Stirling, Trans. Roy. Soc. S. Australia, 1891, p. 154 ; Gadow, P.Z.S.,
1892, p. 361.
540 MARSUPIALIA.
often with bifid root ; premolars and molars with 3 cusps in a row (tri-
conodont), with a strong cingulum and with bifid roots ; angle of mandible
inflected. Jurassic of England and N. America. Triconodon Owen,
Middle Purbeck Beds of Dorsetshire and U. Jurassic of Wyoming. Am-
philestes * Owen, Stonesfield Slate. Phascolotherium Owen, Stonesfield
Slate. Spalacotherium Owen, Purbeck, Dorsetshire, lower molars with
.one large outer cusp and two small inner cusps (tritubercular), resem-
bling those of some Insectivora ; dentition of mandible i3cl p 4 m 6.
Priacodon, Marsh, etc. IJ. Jurassic, Wyoming.
Fam. 7. Amphitheriidae.t With numerous two- or three-rooted tritu-
berculated lower molars with a heel (so-called tubercular-sectorial, Fig.
283), resembling those of the opossums, bandicoots, some insectivores,
and the lower carnassial teeth of Carnivora ; the main cusp (inner in the
upper jaw, outer in the lower) is connected with the two other cusps
by crests ; premolars with three cusps in a row and with cingulum ; canines,
usually two-rooted ; angle of mandible often slightly inflected. Jurassic
and Cretaceous. Amphitherium Blv., Stonesfield Slate ; the lower jaw
upon which this genus is based was together with that of Phascolotherium,
the first of the remains of Mesozoic Mammalia discovered. The specimens
a.Lc.
FIG. 283.— a Inner face of a molar of the right raraus of the lower jaw of Amphitherium pre-
voslii. b Hypothetical representation of the outer face of the corresponding tooth of the
left ramus (after Goodrich), a.i.c. anterior internal cusp (paracoue), ex.c external cusp
(protocone), h heel, m.i.c. median internal cusp (metacone).
were brought to Mr. W. J. Broderip of Oxford about the year 1814,
and one of them was acquired by Professor Buckland and placed in the
Ashmolean Museum ; it is now in the Oxford University Museum ;
dentition of lower jaw i 4 c 1 p 5 m 6 ; angle of mandible slightly
inflected ; mylohyoid groove conspicuous. Peramus Owen, U. Jurassic of
England. Amblotherium Owen, Purbeck, Dryolestes Marsh, Upper Jurassic
and Upper Cretaceous of N. America.
The Sparassodontidae (Borhyaenidae) present resemblances to the
carnivorous marsupials of Australia, and may be placed near the Dasyu-
ridae, which they resemble in their dentition. They are of considerable
or moderate size with a dentition of i j-^| c \ p j-jjj-j m £ ; the
canines (well-developed) and two premolars only are known to have
been replaced ; the upper molars are tritubercular, the lower cutting ;
there are no marsupial bones and the characteristic marsupial palatal
vacuities are absent ; the angle of the mandible is strongly inflected. By
* Goodrich, Q.J.M.S., 35, 1894, p. 407.
t Goodrich, op. cit.
ALLOTHERIA. 54 1
some observers they are placed with the Creodonta, to which they are
probably allied. All extinct, in the older Tertiaries of Patagonia. Bor
hyaena, Prothylacinus, Amphiproviverra, etc., Ameghino.
Sub-order 3. Allotheria.
The Allotheria (Multituberculata) are sometimes treated as a separate
order of the Mammalia, sometimes as a sub-order of the Marsupialia, and
sometimes as a sub-order of the Monotremata. The group is known to
us by very fragmentary remains, consisting of little more than teeth,
sometimes the lower jaw, and in a few cases of parts of the skull and
small portions of other parts of the skeleton. They possess multituber-
culate molars with the tubercles arranged in two or three rows, and the
premolars are either similar or provided with a secant obliquely grooved
edge, not unlike those of certain Macropodidae. An important feature
of the dentition, and one which also recalls the diprotodont marsupials,
is the presence of a pair of large rodent -like incisors in the lower jaw
and of a pair of large incisors and sometimes of one or two pairs of smaller
incisors in the upper jaw. Canines are absent ; the lower jaw is without
the mylohyoid furrow, and its angle is inflected. In one form remains
of the scapula have been found which suggest the presence of a distinct
coracoid. They have been found in a bed of marl a few inches thick in the
Middle Purbeck (U. Jurassic) of Swanage, in the Jurassic of Wyoming,
U.S.A., and in the Laramie beds of the Upper Cretaceous of the same
country. Tritylodon, if it be a mammal, is from the Trias of Stuttgart
and of S. Africa, and Microlestes from the Trias of Bavaria. They also
extend into the lower Eocene of N. America and France. In the Laramie
formation limb-bones have been found which have been ascribed to this
group — pelvic bones not united, and a scapula with two facets, one of
which is supposed to have been for a coracoid (Camptomus).
Fam. 1. Tritylodontidae. Premaxilla with a strong canine-like incisor
and a smaller incisor behind, upper and lower premolars alike, the latter
with three rows of tubercles. Trias of S. Africa and Europe ; by many
regarded as reptiles. Tritylodon Ow., Karoo formation ; Triglyphus
Fraas, Trias of Stuttgart.
Fam. 2. Bolodontidae. With two or three pairs of incisors in the
upper jaw ; upper premolars with three or four cusps. Jurassic, Creta-
ceous, Tertiaries. Bolodon Ow., Purbeck ; Allodon Marsh, Upper Jurassic
Wyoming ; Allacodon Marsh, Upper Cretaceous.
Fam. 3. Plagiaulacidae. Lower jaw with one pair of large rodent-
like incisors and inflected angle ; three or four cutting premolars marked
with oblique ridges on the outer face, and two small molars with tuber -
culated (crenulated) edges. Trias to Eocene. Microlestes Plieninger
(Hypsiprymnopais Dawkins), Upper Trias of Somerset and Wurtemburg.
Plagiaulax Falconer, Purbeck of Dorsetshire. Ctenacodon Marsh, U.
Jurassic, Wyoming and several genera from the Laramie beds (U. Creta-
ceous) of N. America. Ptilodus Cope, L. Eocene of New Mexico and
Neoplagiaulax Lemoine, Lower Eocene of France.
Fam. 4. Polymastodontidae. Rather larger animals with a pair of
rodent-like incisors in the lower jaw, and tuberculated premolars and
molars. Lower Eocene of N. America, and teeth in the Laramie beds.
Polymastodon Cope.
542 EDENTATA.
MONODELPHIA.
(Sometimes called Euiheria.)
This group includes the remaining orders of the Mammalia.
The urinogenital organs almost always open independently of
the rectum, and the vagina is single, though occasionally it is
partly divided into two by a median septum. There is no
marsupial pouch nor epipubic bones. The embryo is always
provided with an allantoic placenta and born at an advanced
stage of development. The corpus callosum of the brain is
well-developed. The testes usually pass into a scrotal sac,
which is always placed at the sides of or behind the penis.
Order 3. EDENTATA * (BRUTA).
Mammals with incomplete dentition, usually with numerous
grinders without roots, and with scratching or curved claws on the
extremities. Teeth are always absent from the anterior part of
the mouth, and they are without enamel.
This order, which includes but few genera (sloths, anteaters,
armadillos), is characterised by the relatively low grade of
development of all the organs, and especially by the incom-
pleteness of the dentition, teeth being in exceptional cases
absent altogether. Except in the case of a single dasypod,
incisors are always absent. When canines' are present they are
small, blunt and conical. All the teeth are devoid of enamel,
consisting of soft dentine covered externally by hard dentine
and sometimes cement, and they grow from persistent pulps
(rootless). With the exception of some armadillos (Tatusia,
etc.) and Orycteropus, milk teeth are not formed, and there is no
replacement (monophyodont). The ischium is almost always
united to the sacrum. The brain is variable ; the cerebrum
may be smooth and the corpus callosum small, or it may be
convoluted and possess a large corpus callosum. The repro-
ductive organs are also variable. The vestibule (urinogenital
canal) of the female is long, and the testes almost always remain
in the body. There are two superior venae-cavae, and retia
mirabilia are often present in the extremities.
* W. v. Rapp, Anatomische Unters. uber die Edentaten, Tubingen, 1852.
Fl. Ameghino, Sur les Edentes Fossiles de 1' Argentine, Revista del Jard.
Zool. de Buenos-Aires, iii, 1895, p. 113. R. Lydekker, Ann. Mus. La
Plata, Palaeont. Argentina, iii, 1893. For Bibliography, see Flower
and Lydekker' s Mammals Living and Extinct, 1891.
XENARTHRA. 543
Most of them are insectivorous (anteaters and armadillos),
a few are phytophagous (sloths). Many of them are burrowing
animals, but a few are arboreal. At the present day they are
confined to Africa, Asia and America. They are first found
fossil in the U. Cretaceous of Patagonia (Ameghino), and are
supposed to have relations through the Ganodonta and Tillo-
dontia (see below), with the early Carnivora and Rodentia, but
this is a highly speculative view.
The Edentata may be divided into two main divisions — the
Xenarthra and the Nomarthra. The Xenarthra comprise all
the American forms, viz., the anteaters (Vermilinguia), the
sloths (Tardigrada) and the armadillos (Loricata) with the
extinct Glyptodontidae. The Nomarthra are the Old-World
forms, Orycteropus and Manis. The New-World forms (Xenar-
thra) undoubtedly constitute a natural group, inasmuch as the
extinct ground sloths connect the apparently diverse sloths and
anteaters. This cannot be said of the Old- World genera Manis
and Orycteropus. It is difficult to see in what fundamental
points these show special affinity either to each other or to
the Xenarthra. There is an immense number of extinct forms
belonging to the Xenarthra, some of them very remarkable,
e.g. the Megatheriidae or ground sloths, and the Glyptodontidae
or extinct armadillos. These are all, like their living allies,
confined to the New-World.* They date from the Eocene or
U. Cretaceous of S. America.
Xenarthra.
With additional articulating processes on the posterior dorsal
and on the lumbar vertebrae ; the scapula has a second spine ;
the ischia are united to the part of the sacrum formed by the
anterior caudal vertebrae ; the testes are in the abdomen between
the rectum and the bladder, the penis is small, the uterus simple,
and the placenta dome-shaped (the chorion being complete).
They are exclusively American and mainly S. American, one or
two forms extending into the southern part of N. America.
Necrodasypus Filhol, from the Eocene of France, has been as-
signed to the Xenarthra, but the remains are too incomplete for
certainty as to their systematic position.
* Grandidier (Bull. Mus. Paris, 1901, p. 54) has described the re-
mains of a ground sloth, which he calls Bradytherium, from Madagascar.
544 EDENTATA.
Fain. 1. Myrmecophagidae. Anteaters, hairy, edentulous, without
tooth-germs ; with long snouts, long protrusible tongues, and enor-
mous submaxillary salivary glands. The clavicles are reduced. The
anterior margin of the scapula is produced over the coraco-scapula notch
to meet the coracoid. In the manus the third digit is greatly developed
and provided with a strong claw ; the other digits are reduced or suppressed.
The pes has four or five subequal digits with claws. The cerebrum
is convoluted and has a large corpus callosum and anterior commissure.
Uterus simple. Confined to the neotropical region. Myrmecophaga L.,
skull elongated with rostrum composed of mesethmoid, vomer, max-
illae, nasals ; prem axillae small and confined to the margin of the terminal
nares ; zygomatic arch incomplete ; pterygoid with palatal plates ; mandible
slender without coronoid. Vertebrae, C7, D15-16, L 2-3, S6, C31.
Sternal articulation of the ribs double. Manus and pes with 5 digits.
The animal walks on the end of digit 5 and on the dorsal sides of digits
3 and 4 of its manus and on the sole of its pes. Stomach with thin-walled
cardiac portion, and a thick-walled gizzard-like pyloric ; ilio-colic valve
absent, caecum short. Two pectoral mammae ; produces one at a birth.
One species, M. jubata L. the great anteater, ant-bear, body 4 feet in
length and 2 feet in height at shoulder ; with long fur ; eats termites
which it obtains with its long tongue, having broken into the ant-heap
with its strong claws ; terrestrial ; trop. S. and C. Amer. Tamandua
Gray, like the last, but smaller, with shorter fur, and tail tapering and
scaly at the end ; head less elongated, pterygoid with palatal plates.
Vertebrae, C7, D17, L2, S5, C37. Manus with 5 digits, the fifth being
concealed in the skin, pes with 5 digits ; arboreal, forests of S. and C.
Amer., 3 species. Cycloturus Gray, smaller than the last, about the
size of a rat, head short, pterygoid without palatal plates ; vertebrae
G7, DIG, L2, S4, C40. Manus with two complete digits (2 and 3), digit
4 with one nailless phalanx, digits 1 and 5 with metacarpal only ; in the
pes, the hallux is concealed and has one phalanx, digits 2-5 are sub-
equal ; ribs broad, overlapping ; clavicle complete ; stomach without
gizzard-like portion, colon with 2 small caeca ; arboreal, one
species S. and C. Amer.
Fam. 2. Bradypodidae (Tardigrada). Sloths, vegetable -feeders and
arboreal, with long coarse hair, coloured green by a parasitic alga ; with
rounded head, anteriorly directed eyes, long anterior limbs, short tail,
and pectoral mammae. With 5 pairs of teeth in the upper and 4 pairs
in the lower jaw, consisting of vaso-dentine covered with cement ; without
succession. Long bones without medullary cavities. Zygomatic arch
incomplete with downwardly directed process (Fig. 284) ; lower jaw with
coronoid ; cervical vertebrae unusual in number, dorsals often very
numerous. The anterior border of the scapula coalesces with the cora-
coid, and the acromion is united by cartilage with the coracoid ; clavicles
present ; scaphoid and trapezium united ; digits never more than 3, with
long curved claws. Stomach complicated, with several chambers ;
caecum absent ; uterus simple and globular, divided by longitudinal
partition ; testes placed as in Myrmecophagidae ; penis minute, crura
not directly attached to ischia. The sloths are exclusively arboreal ,
they use the curved claws at the end of the two or three closely connected
digits for hanging on to branches during their slow movements ; on the
ground they move very awkwardly ; forests of S. Amer. Brady pus L.
Three-toed sloths, the ai ; no tooth projecting beyond the rest ; vertebrae
XEXARTHRA. 545
C9, D15-17, Lo-3, SO, Cll ; manus and pes with 3 digits (2, 3, and 4) ;
with trapezoid and os magnum united ; 2 pectoral mammae ; trachea
folded on itself ; several species, but number uncertain, Guiana, Brazil,
Peru, Isthmus of Panama. Choloepus 111., two-toed sloths ; anterior
tooth in each jaw caniniform and separated by diastema from the others ;
vertebrae C6 or 7, D23-24, L3, S7 or 8, C4-6 ; manus with 2 digits
(2 and 3), pes with 3 digits (2, 3, 4) ; 2 species ; Ch. didactylus L., unau.
Extinct genera are Entelops and Trematherium Amegh., Eocene of Pata-
gonia.
A number of extinct families, intermediate between the sloths and
anteaters, are united Tinder the heading of Gravigrada (ground -sloths).
They are for the most part of considerable size, and are found in the
Tertiaries of N. and S. America. They date from the Eocene. In their
skull and dentition they resemble the sloths, in the vertebral column,
limbs and tail the anteaters. The teeth are usually f , and consist of
dentine and cement. The anterior border of the scapula is joined to the
coracoid process as in the two preceding families, and there is a well-
developed clavicle. In some, small bony nodules were present in the
skin. The jugal is very strong and has a downwardly directed process.
Tail well developed.
Fam. 3. Megatheriidae. With very deeply-rooted prismatic teeth,
quadrate in section and set in close
series. Megatherium Cuv., enormous
animals with a small head, a body
as large as that of an elephant but
with shorter limbs ; skull sloth-like,
zygoma complete with descending
process ; complete skeletons are
known ; Pleistocene of S. and C.
Amer. and of the southern United
States. Inter -odon Amegh., Oligo-
cene, Pliocene of Argentina ;
Promegatherium Amegh., Oligocene,
Argentina, with bands of enamel on FlG- 284.— Skull of Bradypus torquatus
(from Claus).
the teeth ; and other genera.
Fam. 4. Mylodontidae. With prismatic teeth, sloth-like skull, and
jugal reaching back to squamosal but not united to it ; skin often with
ossifications. Mylodon Owen, as large as a rhinoceros, dermal bony
plates not fused together ; Pliocene and Pleistocene of S. Amer. and
United States. Glossotherium Ow., Pliocene and Pleistocene of Argen-
tina. A portion of the skin of this animal with the hair perfectly pre-
served was discovered by Moreno in Patagonia in 1897 (Proc. Zool. Soc.
1899). A number of scattered small ossicles were embedded in it, and it
was assigned to a new genus Neomylodon. Later another piece of skin
was found by Hauthal in a cave in S. Patagonia in association with some
bones of an extinct ground sloth which has since been identified as Glosso-
therium (Grypotherium) (Proc. Zool. Soc., 1900, p. 64). A quantity of
cut hay and a thick deposit of the excrement of a large herbivore, pre-
sumably Glossotherium, were also found in the cavern, and Hauthal formed
the conclusion that the animal had been kept and fed by man. The
bones are in a very fresh state of preservation, retaining their gelatine
and showing traces of the dried periosteum and ligaments. There can be
little doubt that the skin and bones belonged to the same species of animal
z — ii. N N
54f) EDENTATA.
and that the latter was contemporaneous with man, whose remains were
also found in the cavern, together with those of an extinct horse and
portions of a large feline carnivore. There were also traces of fire in the
cavern. Scelidotherium Ow., Miocene and Pliocene of Argentina ; Nothro-
Iherium Lydekker, Pleistocene of Brazil and Argentina Promylodon
Amegh., Oligocene of Argentina, with bands of enamel on the teeth ;
and many other genera.
Fam. 5. Megalonichidae with several genera, for the most part
smaller in size, including Hapalops, etc., from the Eocene of. S. America;
Nothropus, from the Pleistocene of Argentina ; Megalonyx, from the
Pleistocene of N. America, and the Antilles.
Fam. 6. Dasypodidae.* Armadilloes. The back and sides of the
body are covered by an armour of suturally united bony scutes, over
which lie horny epidermal scales. These scutes are usually united into
four shields. There is a cephalic shield on the head, a scapular shield
on the shoulders, a pelvic shield attached to the ilia and ischia and arching
over the rump, and on the trunk a thoraco-abdominal shield, which fre-
quently consists of a number of moveable transverse zones, which are
connected by soft skin and permit of the body being rolled into a ball.
There may also be a nuchal shield on the neck. The scapular and pelvic
shields overhang the sides of the body and form chambers into which the
limbs can be withdrawn. The tail also is more or less completely encased
in bony rings, and the outer surfaces of the limbs are protected by irregular
scutes. The ventral surface of the body is soft and hairy, and hairs may
project between the scales on the back. In Chlamydophorus the bony
scutes are strongly developed in the pelvic region only. The dentition
is monophyodont except in Tatusia ; the teeth are numerous and not
found in the fore part of the mouth except in one or two forms in which
there is one tooth in each premaxilla. Premaxillae well developed ;
zygoma complete. The atlas is free, but more or fewer of the other
cervical vertebrae are ankylosed by their centra and arches as in Cetacea.
Lumbar and hinder dorsal vertebrae with accessory articulating processes.
The first rib is broad and flattened. The scapula has a second spine in
the postscapular fossa. Clavicles well developed. The femur has a
third trochaiiter and the tibia and fibula are joined distally. Manus
with 4 or 5 digits and strong curved claws ; pes plantigrade with o digits.
Tongue long and extensile. Submaxillary glands large. Stomach and
uterus simple. Caeca paired or absent. Placenta discoidal. Penis
large without glans ; the testes are abdominal. Brain smooth, with
large olfactory lobes. With one pair of pectoral mammae and an ad-
ditional inguinal pair in Tatusia ; they produce one or two young at a
birth except Tatusia. They are all burrowing nocturnal animals, of
small or moderate size, and omnivorous in their diet, eating roots, insects,
worms, lizards and carrion. They are somewhat pig-like, harmless animals,
usually with large external ears, and they can can run and burrow
with great rapidity. They inhabit the plains and forests of tropical and
temperate S. America and one species (Tatusia novem-cincta) ranges
into Texas. Chlamydophorus Harlan, the pichyciego. Small animals
with long silky hair differing from other dasypods in their dermal armour,
and with small external ears. The body is covered with four-sided horny
* L. J. Fitzinger, Die nattirliche Familie der Gtirtelthiere, Sitzb. Akad.
Wiss. Wien, 64, 1871. Lahille. Contrib. Etud. Edentes a bandes mobile
de la Rep. Argentine, Ann. Mus. La Plata, Zool., 2, p. 1-30.
XEXARTHRA. 547
plates, not divided into shields and moveable bands. The bony scutes
in front are very thin, but behind they form a strong shield attached to
the pelvis. Vertebrae, C7, Dll, L3, S10, C15. Limbs short, manus with
5 digits ; with bifid caecum ; 2 species. C. truncatus Harlan, about
5 inches long, in W. Argentina near Mendoza. Dasypus L., dentition
j'j or | , of which one tooth on each side is in the premaxilla ; auditory
bulla complete; vertebrae C7, Dll-12, L3, S8, C17-19 ; carapace with
6 or 7 moveable bands ; tail short ; manus with 5 digits ; 7 species, of which
3 are found in the Pleistocene ; D. sexcinctus L.,the 6-banded armadillo
Xenurus Wagl. (Lysiurus Am.), dentition f or f ; vertebrae, C7, D12-13,
L3, S10, CIS ; carapace with 12-13 moveable bands; manus with 5 digits,
of which 1 and 2 are slender and 3 has very large claw ; 5 species. X. uni-
cinctus L., the tatouay or cabassou. Priodontes Cuv. (Priodori), dentition
variable, differing on the two sides, |j=|- ; vertebrae, 07, D12, L3, S10.
C23 ; tail long ; carapace with 12-13 moveable bands, manus with 5 digit8'
claw of third very large ; 1 species. P. giganteus Geoff, (gigas) (Fig. 285)
the largest species of the family, body 3 feet long, eats termites and insects
FIG. 285.— Priodontes
and is said to uproot newly-made graves. Tolypeutes 111., dentition 9-y-^ ;
vertebrae C7, Dll, L3, S12, C13 ; carapace with 3 moveable bands ; tail
short ; manus as in preceding ; can roll up into a ball ; they run quickly on
the tips of their toes ; 3 species. T. tricinctus L., apar. Tatusia Cuv.
(Praopus) dentition |^-|, except the last with 2-rooted predecessors,
which are not changed till the full size has been nearly reached ; verte-
brae C7, D9-11, L5, S8, C20-27 ; carapace with 7-9 moveable bands;
manus with 4 visible toes, the 5th being small and concealed ; with 2
inguinal mammae in addition to the pectoral pair, produce 4 to 10 young
at a birth, about 12 species ; T. novemcincta L., peba. Vetelia Am.,
Eocene, Patagonia ; Propraoptis Am., Pliocene, Argentina, are extinct
genera allied here. Scelopleura A. M. Edw. Brazil, plates on the back
deficient. Extinct genera are Chlamydotherium Lund., Oligocene to
Pleistocene, as large as a rhinoceros ; Eutatus P. Gervais, Pliocene ; Dasy-
potherium, etc.
Fam. 7. Glyptodontidae. Extinct, sometimes gigantic, armadillo-
like animals with a rigid carapace formed of a great number of bony
scutes joined together and not divided into shields and bands; dentition f,
teeth with two deep flutings on each side ; zygoma with descending process
from the maxilla ; dorsal vertebrae ankylosed and some of the cervical ;
548 EDENTATA.
lumbars fused with sacrum ; the atlas is free ; the last cervical is separate
from the preceding and united with the dorsal, forming a peculiar joint
allowing of the retraction of the head. Tertiaries and Pleistocene of
Amer. as far as Mexico and Texas. Glyptodon Ow., 16-17 feet, ptery-
goids enter into formation of bony palate, manus with 5, pes with 4 digits ;
metatarsals as broad as long, several species, Pliocene of S. Amer., Plio-
cene and Pleistocene of Mexico, Texas and Florida. Palaeopeltis Am.,
U. Cretaceous, Patagonia ; Propalaeoplophorus Am., about 2 feet, with
premolars and molars and probably an incisor, dorsal vertebrae not
fused ; Eocene, Patagonia ; Palaehoplophorus Am., Oligocene of Pata-
gonia ; Plohophorus, Miocene, Patagonia ; Hoplophorus Lund., medium
size, Pleistocene, Argentina and Brazil ; Panochtus Burm., very large
forms, manus and pes 5-toed, Pliocene and Miocene, Argentina ; Doedi-
curus Burm., manus with 3, pes with 4 digits, about 12 feet, Pliocene
and Pleistocene. Peltephilus Am., U. Cretaceous and Eocene of Pata-
gonia ; intermediate between Glyptodontidae and armadillos ; the glenoid
part of the squamosal separated by suture from the rest (? quadrate) ;
plates of carapace moveable ; pterygoids enter hard palate ; teeth in the
anterior part of the jaws.
Nomarthra (Effodientia).
The vertebrae are without accessory articulations ; the ischia
are not united to the sacrum. The testes lie in the inguinal
canal, the penis is external ; the uterus is two-horned, the
vagina undivided, and the placenta diffuse or broadly zonary.
They are confined to the Oriental and Ethiopian regions with
fossil remains in Europe. It is extremely doubtful whether
the two Old-World families which constitute this group are
specially allied either to each other or to the New- World
forms.
Fam. 1. Manidae.* Pangolins. Edentulous, covered with large
overlapping epidermal scales which can be erected, and with hairs between
the scales. The tongue is long and extensile and there are large sub-
maxillary glands. The limbs are short and carry 5 digits. They walk
on the dorsal surfaces of the long claws of their fore-feet and on the soles
of the pes. Skull smooth, without distinction between orbit and tem-
poral fossa ; zygoma usually incomplete ; pterygoids elongated but not
contributing to palate, tympanic bones bullate and united to surrounding
bones, mandible without coronoid process, with flat condyle. Without
clavicle ; xiphoid process of sternum produced into long processes reaching
as far back as the pelvis. Femur without third trochanter. Stomach
with thick lining and muscular walls, and a large gland. Caecum absent.
Testes inguinal, penis well developed, placenta diffuse. Terrestrial
and burrowing animals one to five feet in length, can roll themselves into
a ball, and some of them can climb. They feed mainly on termites.
* Jentink, Revision of the Manidae in the Leyden Museum, Notes
Ley den Museum, 4, 1882, p. 193. Matschie, Die nattirl. Verwandschaft
etc. der Manisarten, S.-B. Ges. Naturf. Freund. Berlin, 1894, p. 1.
NOMARTHRA. SIREXIA. 549
Manis L., with 7 species, in Burmah, Malacca, Java, Borneo, China,
Formosa, Ceylon, India, Africa. Two extinct genera from the Eocene
of France, Necromanis, Leptomanis Filhol.
Fam. 2. Orycteropodidae (Tubulidentata). Hairy body with thoracic
and inguinal mammae, and long ears. Dentition diphyodont, the milk
teeth not cutting the gums, ^-°, not all in place at same time, the 3
posterior are without predecessors ; the teeth contain parallel tubular
prolongations of the central pulp-cavity. Skull with complete zygoma
and well developed premaxillae, annular tympanic not ankylosed, large
lacrymal ; mandible . slender with coronoid. Vertebrae C7, D13, L8, S6,
C27. Clavicles present. Manus without pollex, pes pentadactyle ;
femur with a third trochanter. Tongue vermiform, submaxillary gland
much developed. Stomach in two portions, a cardiac with thick lining
and a muscular pyloric with thin lining. A caecum is present. Testes
inguinal, descending temporarily into a scrotum ; penis small. Uterus
double, placenta broadly zonary. Burrowing animals, living near ant-
hills ; Africa. Orycteropus Gm., aardvark, or Cape anteaters, two
species, O. capensis Gm., the aardvark of S. Africa ; 0. aeihiopicus Sundev.
N. E. Afr., extending into Egypt ; an extinct species gaudryi, from Mio-
cene of Samos and Persia. The extinct Palaeorycteropus Filhol, from the
Eocene of France.
Order 4. SIRENIA.* (Sea-cows.)
Short-necked, thick -skinned, aquatic herbivorous animals, naked
or with very sparse hairy covering, with separate anteriorly
directed external nares, two pectoral mammae, fin-like anterior
limbs and horizontally flattened caudal fin. The posterior limbs
are absent.
The Sirenia are aquatic animals, living in the sea near the
coast, in estuaries and in rivers. They are herbivorous and
feed on seaweed or freshwater grasses. Their bones are heavy
in consequence of which they are able the more easily to lie
on the bottom when they are feeding. They have small eyes
with a third eyelid, the nostrils are separate from one another
and placed on the front of the head, and the ears are without
pinnae. The fore-limb is paddle-like and very moveable at all
its joints. The digits — five in number — are enclosed in a
* J. F. Brandt, Sirenae Sirenologicae, St. Petersburg, 1846, 61 and 68.
Owen, Proc. Zool. Soc., 1838, p. 29. W. Turner, Placenta of Dugong ;
Trans. Roy. Soc. Edinburgh, 35, 1889, p. 641. J. Murie, On the form and
structure of the manatee, Trans. Zool. Soc., 8, 1872, p. 127, and 11, 1880,
p. 19. A. Crane, Notes on the habits of manatees in captivity in the
Brighton Aquarium, Proc. Zool. Soc., 1881, p. 456. Hartlaub, Beitrage
z. Kenntnis der Manatus-arten, Zool. Jahrb., 1886, p. 1. Kiikenthal,
Vergl. anat. u. entwick. Unters. an Sirenen, Denlcschr. Med. Nat. Ges.
Jena, 7, 1897, p. 1, and Ent. der Sirenen, Verh. D.Z. Ges., 7, 1897, p. 140.
R. Lydekker, Catalogue of fossil mammalia in the British Museum. H.
Woodward, On the fossil and living Sirenia, GeoL Mag., 2, 1885, p. 12.
550 SIRENIA.
common cutaneous covering, and may or may not have traces
of nails. They possess the usual number of phalanges found in
mammals. There are no hind limbs. The tail is horizontally
expanded into a caudal fin, and there is no dorsal fin. The
mammae are pectoral in position close behind the anterior
limbs. The skin is thick, naked or with fine hairs scattered
over it, and in the deeper layers there is a considerable quantity
of blubber for which and for the skin these animals are much
sought after. The neck is extremely short, and is hardly
marked externally.
As already hinted, the skeleton is remarkable for its density.
In the skull the anterior narial apertures are placed far back
and look upwards, and the nasal bones are usually absent in
living forms, though present in some extinct species, but there
the resemblance to the skull of the Cetacea ends. The parietals
meet in the roof ; the tympanic is annular and ankylosed with
the periotic, and readily comes away with the latter ; the cranial
cavity is small and elongated ; the zygoma is -very stout ; the
orbit is small and nearly enclosed in bone ; the maxillae and
premaxillae are prolonged in front of the nares as a narrow
snout, which carries on its under surface a horned plate
working against a similar horny plate on the mandibular sym-
physis ; there is a large coronoid process. The dentition is
variable. In Rhytina there are no teeth ; in Halicore the molars
(HH) are rootless and without enamel, and there are two
tusk-like incisors in the male ; in Manatus, there are no visible
incisors and the molars are more numerous (TJ) and provided
with enamel and roots. The molars are never all visible at the
same time, the posterior coming up as the anterior are worn
away. There are milk predecessors in Halitherium, and in living
forms there appear to be milk teeth in the foetus (see Kiiken-
thal, op. cit.}. The centra of the vertebrae are without epi-
physes (in living forms) ; the cervical vertebrae (six only in
Manatus} are compressed antero-posteriorly, but except the
second and third in Manatus are not united. All the vertebrae
have articulating processes, though these are imperfect in the
caudal region, thus conferring considerable flexibility on the
tail. None of them are united to form a sacrum. The ribs are
mostly two-headed and the sternum is much reduced. Clavicles
are absent. The scapula is normal and not like that of Cetacea.
AFFINITIES. HABITS. 551
There is a pair of bones representing the pelvis and connected
with the transverse processes of the last precaudal vertebra, but
in no living species is there a trace of a femur. The lips are
tumid and provided with stiff bristles. Salivary glands are
well developed. The stomach is divided into two portions, of
which the cardiac is provided with a gland and the pyloric
usually with two caeca. The large intestine has a caecum.
The apex of the ventricle is cleft, and there are two superior
venae cavae. Extensive retia mirabilia are formed. The
diaphragm is extended very obliquely far back into the ab-
domen, so that the pleural cavities are ' prolonged dorsally
to the viscera, but the heart lies in the sternal region. The
brain is small and but little convoluted. The testes are
abdominal ; the uterus bicornuate and the placenta zonary (in
Halicore).
As will be gathered from this account, the Sirenia present no
important resemblance to whales. They differ in almost all
the cranial features and in the dentition ; in the structure of
the well- jointed anterior limb ; in the absence of a prolongation
of the epiglottis and arytenoid cartilages into the nasal pas-
sage ; in the small size and slight convolution of the brain.
The whale-like features are the reduction of the nasal bones,
the short neck, the form of the tail, and the absence of posterior
limbs. By some they have been supposed to be allied to the
Ungulata, but save in the form of the molar teeth in Manatus,
it is difficult to point to any resemblance. The affinities to
the Proboscidea are explained on p. 571.
There are two living genera, but a third genus Rhytina only
became extinct in the eighteenth century, and we have des-
criptions of its appearance and soft part. They are pure y
aquatic and never come on to the land. They inhabit shallow
seas near the coast, estuaries, and rivers which they ascend
sometimes almost to their source. They feed on sea-weeds
and aquatic plants. They are gregarious, slow, inoffensive,
gentle creatures, qualities which render them an easy prey to
the hunter, and which brought about the entire destruction of
the Khytina. They are sought after for their flesh as food,
for the oil derived from the fat beneath their skins and for
their hides. They use their limbs as hands for conveying food
to the mouth, and they are said to carry their young pressed
552 SIREXIA.
to the breast with their flipper. This fact (if true) together
with the pectoral position of the mammae, and the habit they
have of raising their head out of the water, may have given
origin to the legend of mermaids.
Numerous remains of Sirenians are known in the Miocene
and Pliocene of Europe and N. America.
Manatus Storr (Trichechus), manatee ; to 8 feet ; dentition * i f , m |j,
the incisors lie beneath the horny plates on the jaws and disappear before
maturity, the molars are rooted (3 roots in the upper and 2 in the lower
jaw), and have enamelled crowns with two tuberculated transverse ridges,
they come into use gradually, there never being more than £ functional
at the same time ; rostrum not bent downwards ; upper lip bifid and
used in feeding ; vertebrae C6, D17, L2, C23 to 35 ; tail entire and rounded ;
manus with vestiges of two or three nails ; caecum bifid. Mainly fluvia-
tile, but also marine ; shores of and the great rivers emptying into the
Atlantic Ocean within the tropics ; 3 species on the American side and
1 on the African.^Allied extinct genera are Manatherium Hartlaub,
Oligocene, Europe ; Ribodon Am., Oligocene, PatagoniaJ Halicore Illig.,
dugong, to 8 feet, i £ m |^-J ; the anterior upper incisor is tusk-like
and projects in the male, but is not cut in the female, the posterior upper
incisor is found only in the young ; the lower incisors lie beneath the horny
plate and are soon absorbed, the molars are without roots and enamel
and have tuberculated crowns which wear down to flat surfaces. The
rostrum of the skull is bent downwards. Vertebrae C7, D18-19, L and
C30. Tail notched and whale-like. Manus without nails. Caecum
single. Mainly marine, shores of the Red Sea, Indian Ocean, Australia,
3 species have been distinguished. RTiytina 111., Steller's sea-cow, 20-25
feet, recently extinct, about 1768, Behring and Copper Islands in Behring
Straits, discovered by Behring and Steller, who were wrecked upon Beh-
ring Island in 1741. Its flesh and fat were exceedingly delicious, and it
was used as food by them and later mariners. Owing to its gentleness
and fearlessness of man, it was easily slaughtered and soon became extinct.
It was edentulous, had the horny pads on the jaws, was without nails
but had bristles on its manus. Its vertebrae had epiphyses. Hali-
therium Kaup, Oligocene of Europe, Eocene of America ; with large tusk-
like incisors in the upper jaw, f or £ molars, well enamelled and tuber-
culated ridged crowns ; there appear to have been milk teeth ; sometimes
with normal but small nasal bones ; pelvis better developed with short
femur. A number of other genera are known from the Miocene and
Pliocene of Europe and America. Prorastomus Ow., Eocene of Jamaica
and Europe is the oldest form knowrn, -with dentition i -f- c i P and m £,
incisors not tusk-like.
* According to Kukenthal (loc. cit.} there are calcified rudiments of
canines in the lower jaw of the embryo, and of milk predecessors of some
of the teeth.
CETACEA. 553
Order 5. CETACEA.*
Aquatic, fish-like, naked forms without hind limbs. The head
passes continuously into the body and the nasal apertures are on
the top of the head.
The Cetacea are entirely aquatic animals. Though fish-like
in appearance, they are mammalian in structure, but they stand
far apart from other mammals, and it is impossible to guess at
their origin. Some species attain a colossal size, and are among
the largest, if not the largest, of all known animals, whether living
or extinct. The cervical region of the vertebral column is
extremely short, and there is apparently no neck, the head
passing directly into the trunk. There is a horizontally-ex-
panded caudal fin (the lateral expansions of which are called
flukes), and often a fatty dorsal fin. Hairs are almost entirely
absent, being represented only by a few bristles on the upper
lip, which are present during the whole of life or only during
the foetal period, and are without sebaceous glands. On the
other hand there is developed beneath the thick skin in the
subdermal cellular tissue a considerable layer of fat (blubber),
which to a certain extent takes the place of fur and serves both
to prevent the loss of heat and to diminish the specific gravity.
It does not, however, necessarily follow that the absence of hair
is caused by the presence of blubber, for in the seals both hair
and blubber are present. The absence of hair is a property
of the whale, and cannot be accounted for. The same remark
applies to the scanty hairy covering found in some other
mammals. The head is large, and the opening of the
external ear is very minute and without a pianna. The eyes are
* Hunter, Observations on the structure end oeconomy of whales,
Phil. Trans., 1787. F. Cuvier, Histoire naturellc des Cetaces, Paris, 1836.
D. F. Eschricht. Unters. uber die nordischen Walthiere, Leipzig, 1849.
D. F. Eschricht og J. Reinhardt, Om Nordhvalen, Copenhagen, 1861.
van Beneden and Gervais, Osteographie des Cetaces viv. et foss., 1868-1880,
1 vol. and atlas 64 plates, van Beneden, Histoire Nat. des Cetaces des
mers d* Europe, 1 vol. Svo, 1889. C. M. Scammon, Marine Animals of
the N.W. coast of N. America, 1874. J. F. Brandt, Unters. lib. die foss.
u. subfoss. Cetaceen Europa's, Mem. Acad. Petersbourg, (7), 20, and 21 r
1873-4. W. H. Flower, On the characters and divisions of the families
of the DelpTiinidae. Proc. Zool. Soc., 1883, p. 466. F. W. True, Review
of the Family Delphinidae, Bull. U. S. Nat. Mus., 1889. R. Lydekkery
Cetacea of the Suffolk Crag, Quart. Journ. Geol. Soc., 42, 1887, p. 7, and
Catalogue of the fossil mammalia in the British Museum, 1887. F. E,
Beddard, A Book of Whales, London, 1900.
554
CETACEA.
^
^i=-:
^
5-.^ —^. K, O P 3 ?
iSS-fi^gi^M
02"°.? 2.P-W oo
«» 0-t<5 g.rt'O MS?. 0»
; ^B- 3 III i
g>-s.^g.s-aii
;iil|^lis
sPFlI^li
lf» -e?f«
o
strikingly small and are often
placed near the angle of the
mouth. They are without a
third eyelid. The upper and
lower eyelids have usually but
little motion ; the lacrymal
gland is small or absent, and
there is no lacrymal duct.
The nasal apertures (spiracles)
are on the forehead, as the
single or double blow-hole.
The anterior limbs are repre-
sented by short, externally un-
jointed flippers, which can only
be moved as a whole, and are
without or with but the faint-
est traces of nails. The digits
are entire and enclosed in the
common integument, and the
number of phalanges tends to
exceed that normally found
in mammals. There are no
external hind limbs, though it
appears that vestiges of them
are present in the foetus. The
bones are spongy in texture
and contain oil. The brain
case is large, though small as
compared with the large facial
part of the head ; it is spher-
oidal in form, and often asym-
metrical, the right side being
the larger. Its bones are sep-
arated by sutures and loosely
connected. The supraoccipital
(Fig. 286) is large and extends
by its interparietal portion as
far as the frontal, pushing aside
the small parletals, which early
fuse with the interparietal.
SKELETON. TEETH. 555
The hard and dense petrous bone is loosely united with
the squamosal, and may or may not be ankylosed to the
tympanic ; it readily falls out in the dry skull. The
tympanic bones are thick and scroll- like. These bones are of
great importance to the palaeontologist, for they are found
wherever fossil remains of Cetacea occur, and were dredged
up from the ocean bed in considerable numbers by the Chal-
lenger. The frontal bones are prolonged into a plate on each
side which covers the orbit. The squamosal sends forward a
strong process which meets this supraorbital part of the frontal.
The jugal is usually a slender bone, underlying the orbit and
extending from the maxilla to the strong zygomatic process
of the squamosal. The maxillae are prolonged forwards almost
to the front of the snout, and with them, on their median sides,
extend the long premaxillae from the nasal aperture to the
end of the snout, where they contribute for a small area to the
margin of the mouth. The premaxillae do not bear teeth except
in Squalodon and Zeuglodon. The snout is composed of these
two bones, and of the vomer and mesethmoid cartilage. The
nasals are short and united to the frontal bones immediately
behind the nares ; they are often asymmetrical. Distinct •
lacrymals are present in some whalebone whales, and in the
Physeteridae. The nasal passages are almost vertical and the
turbinals are vestigial. The pterygoids frequently meet and
take part in forming the hard palate. The mandible has a
very small coronoid process. The hyoid is a broad plate of bone,
and has two pairs of cornua.
Teeth are sometimes absent. They have conical or com-
pressed crowns, are homodont (except Zeuglodon and Squalo-
don) and monophyodont, and are often very numerous.
In the whalebone whales, which have no teeth in the adult, there is
in the foetus a set of minute calcified * teeth, some of which are provided
with two or even three cusps. Kiikenthal maintains that these are
rudiments of the milk dentition, and that he has detected traces of a
successional series. Kiikenthal also maintains that he has detected
traces of successional teeth in some of the toothed whales, and that the
persistent teeth in these belong in reality to the milk dentition.
The vertebral column is distinguished by the thin disc-like
character of the cervical vertebrae which are usually more or
less fused together (especially in Balaena) ; by the relatively
* Julin, Arch. de. Biologie, 1, 1880.
556 CETACEA.
large number of lumbar and caudal vertebrae, the latter having
chevron bones ; by the absence of sacral vertebrae and by the
thick fibrous inter vertebral discs and the absence of articulating
processes on the posterior dorsal and hinder vertebrae. The
epiphyses of the vertebrae and of other bones remain distinct
for some time. The number of vertebrae is C7, D9-16, L3-24,
C18-30. The sternum tends to be short and but few ribs join
it. The ribs are distinguished by their loose articulation both
with sternum and vertebral column. There are no clavicles.
The scapula is remarkable for the position of the spine close to
the anterior border. The humerus is short and freely moveable
upon the scapula, but the other joints of the fore-limb are im-
perfect. The radius and ulna are flattened and short. The
carpal bones are more or less normal and embedded in fibrous
tissue, but they vary considerably. In the whalebone whales
many of the elements of the manus (including the phalanges)
remain cartilaginous. There are generally five digits, but
in most of the whalebone whales there are only four.* There
are more than three phalanges in some of the digits : this always
happens in digits Nos. 2 and 3, in which the number may mount
to fourteen or more. The phalanges have epiphyses at both
ends.
The pelvis is represented by a pair of bones placed longitu-
dinally at some distance from the vertebral column, and pro-
bably representing the ischia. The crura penis are attached to
them, and in the whalebone whales there may also be a trace
of the femur in the form of a short bony rod attached to their
outer sides, to which may be added the trace of a tibia.
The brain is very large and its surface richly convoluted.
It is the largest and most convoluted brain found beneath the
Primates. The lateral ventricle shows a trace of a posterior
cornu. The olfactory lobes and nerves are absent or small.
The soft palate is long and muscular. The glottis is funnel-
shaped, owing to the prolongation of the epiglottis and arytenoid
cartilages, which project into the narial passage. When this
spout-like structure is embraced by the soft palate there is a
* In such cases it has been said that it is digit No. 3 which has dropped
out ; vide Kiikenthal (Denksckr. Med. Nat. Ges. Jena, ?, 1889, p. 1, and
3, 1893, p. 221) who maintains that in a foetal Balaenoptera there is a trace
of a digit, which does not reach the carpus, between digits No5?. 2 and 3,
and that in the pentadactyle Balaena the first digit is a prepollex.
LUNGS. ALIMENTARY CANAL.
557
continuous passage between the narial passage and the larynx.
The trachea is very short, and gives off a third bronchus to the
right lung just before it divides. The lungs are very spacious
and not lobed ; they extend, like the swimming bladder of fishes,
far backward, and play an essential part in the maintenance of
the horizontal position in water. The diaphragm also has a
corresponding horizontal extension, as it has in the Sirenia.
The stomach is complicated and divided into three or more
chambers. In Phocaeni (Fig. 287) the oesophagus opens into
a large elongated blind sac lined by a thick epithelium ; near the
oesophageal end
of this is the
opening into the
second chamber,
the lining of
which is soft and
vascular and pro-
jects in longitu-
dinal folds into
the cavit}'. The
third chamber is
tubular, and pos-
sesses a small
globular dilata-
tion at its com-
mencement ; it
opens into the
duodenum, the
commencement
of which is dilated and receives the conjoined bile and pan-
creatic ducts. In Ziphioids * the first chamber is absent, or
combined with the second, and the pyloric chamber is divided
up into seven or eight chambers by successive constrictions.
There are saccular dilatations on the aorta and pulmonary
arteries, and retia mirabilia on the arteries, particularly those
under the pleura and between the ribs, and on the veins. The
use of these is not understood, but they are supposed to be
connected in some way with the power these animals have of
FIG. 287. — Diagrammatic section of the stomach of a porpoise
(from Flower and Lydekker). a oesophagus b cardiac cham-
ber, c middle chamber, d and e two divisions of the third or
pyloric chamber, / pylorus, g duodenum, h bile-duct.
* Jungklaus, Jen. Zeitschr., 3:2, 1898, p.
558 CETACEA.
remaining for a long time under water. The aorta in the sperm-
whale is a foot in diameter, and the heart sends out at each
stroke probably ten or fifteen gallons of blood. The kidneys
are lobulated. The testes are abdominal and in contact with
the ventral body wall, at about the level of the anterior end of
the bladder, and there are no vesiculae seminales. The penis
is large and there is no os penis. The uterus is bicoanuate and
the placenta diffuse. The females bear a single (the smaller
species rarely two) young at a birth. There are two mammae,
inguinal in position ; the teats lying in depressions on each side
of the vulva.
The Cetacea usually live together in herds (schools). The
smaller species frequent the coasts and some of them ascend
rivers ; others are mainly fluviatile. The larger species prefer
the open sea. They swim with great strength and speed, usually
keeping near the surface,to which they have frequently to ascend
for respiration. They can stay under the surface for a long time.
Some of the larger whales can remain submerged for more than an
hour, certainly for two hours and possibly for more. The spout-
ing or blowing of whales is not a spout of water ejected from
the nostrils, but is due to the condensation in the cold atmo-
sphere of the aqueous vapour of the column of warm and com-
pressed expired air, which issues with great force when the animal
reaches the surface.
The Cetacea are carnivorous predaceous animals. Most of
them feed on small marine organisms and on fish andcephalopods.
The gigantic whalebone whales, which are without teeth, but
possess whalebone on the palate, feed on small floating marine
animals, nudibranchiate molluscs and jelly fish, etc. They
are animals of great intelligence and generally of a mild disposi-
tion. The cows display great affection for their calves, and it
is this feature which is often taken advantage of by whalers
in their pursuit of them, for the mother will rarely desert her
weaker offspring. If the latter is wounded or killed, the mother
will turn upon her pursuers with fury, and deal destruction
to the boats and death to the men. But it is rarely that whales
will attack men if unprovoked. The sperm-whale is apparently
an exception to this, for there appear to be several authentic
instances of a cachalot having attacked a ship and done it
severe damage, even sinking it. But in these cases it is pro-
HABITS. 559
bable that the monster was provoked by the ship having acci-
dentally come into contact with it. Whaling is the finest
sport known to man. It requires great skill and knowledge,
and all the strongest qualities of human nature. Indeed, other
sports may be called child's play as compared with it. It is
generally carried on in the wildest and most terrible places of
the earth, and the quarry is by far the largest and most powerful
of animals now living, and the most profitable to capture. A
fine whale of the " right " kind will yield upwards of three
hundred barrels of oil and considerably over a ton of whalebone.*
So inveterately have some of these animals been pursued that
they appear to be on the verge of extinction. The Atlantic
right -whale has entirely forsaken its former grounds, the black
whales of the southern temperate ocean have been almost entirely
exterminated ; and Captain Scammon says of the Californian
grey whale that " ere long it may be questioned whether this
mammal will not be numbered among the extinct species of the
Pacific." As an illustration of the same fact, it may be men-
tioned that between the years 1788 and 1879, 4,195 Greenland
whales were brought into Peterhead, while in 1891 only 17
whales were captured, and a few years ago the catch by Dundee
whalers was only six.
The period of gestation is not certainly known, but in the
case of the larger species it is stated by Scammon to be from
nine to twelve months. Coition is probably effected with the
animals lying breast to breast, either horizontally on the sur-
face of the sea or in a vertical position. Their amatory antics,
which have sometimes been observed, are highly entertaining.
" Their caresses are of the most amusing and novel character.
When lying by the side of each other, the megapteras frequently
administer alternate blows with their long fins, which love-pats
may, on a still day, be heard at a distance of miles. They also
rub each other with these same huge and flexible arms, rolling
occasionally from side to side and indulging in other gambols,
which can easier be imagined than described." | They are
found in all seas, and their fossils occur in the Tertiary
* The price of whalebone varies considerably. At the beginning of
the fifteenth century it was about £150 a ton ; in 1891 whalebone of good
quality brought £2300 a ton.
f Scammon, op. cit., p. 45. The same authority has estimated their
duration of life at from thirty to a hundred years.
560 CETACEA.
deposits. The earliest known form is Zeuglodon from the
Eocene.
Sub-order 1. MYSTACOCETI (BALAENOIDEA.)
The whalebone whales, with large head, without teeth in the
jaws, with whalebone (baleen) hanging from the palate. The
oesophagus is narrow, there are two spiracles (external narial
openings), and the nasal passages are without saccular dilata-
tions. Manus tetradactyle except in Balaena.
Fam. 1. Balaenidae. Teeth are absent in the adult state, but numer-
ous minute calcified teeth are present in both jaws in the foetus. The
whalebone or baleen consists of a number of horny triangular plates
which are arranged in a row on each side of the palate and hang down
into the mouth. The outer edge of the plate is smooth, its base is attached
to a transverse ridge of the palate, and its inner edge is frayed out into
FIG. 288. — Skull of Balaena mysticetus, with the whalebone (R£gne animal).
numerous filamentous processes. A vascular lamella extends from the
palate into the base of each plate. From this there projects a number
of vascular papillae which extend into the free bristle-like fibres. The
epithelium round these papillae is cornified, and in the proximal region
gives rise to a connecting substance (" enamel ") which forms the smooth
outer substance of the plate, and with the contained fibres constitutes
the plate. Peripherally this connecting substance breaks down and the
fibres become free. The "gum" (intermediate substance) is a mass of
thickened epithelium between the bases of the plates. In feeding, the
animal opens its mouth so that the baleen plates hang vertically down-
wards. In Balaena, in which the plates are very long, their lower ends rest
on the base of the mouth within the lower lips which prevent their bending
outwards when the mouth is closed. The animal then closes its mouth
and the water is driven out through the strainer formed by the plates
and their fibres. It then swallows by the help of its tongue the organ-
isms which are retained by the strainer. The ends of the plates and their
fibres fold backwards when the mouth is closed.
; The skull is symmetrical, and the nasal bones are larger than in other
ODOXTOCETI. 561
Cetacea. The maxilla is produced in front of, but not over, the orbital pro-
cess of the frontal. The lacrymal bone is distinct and the tympanic is anky-
losed with the periotic. The rami of the mandible are convex outwards, and
the space between them is greater than the width of the rostrum ; they
are connected by ligament at the symphysis. The ribs articulate with
the ends of the transverse processes, the capitular part being imperfect
and not reaching the centrum. The sternum is short and articulates
with only one pair of ribs. Olfactory nerves and a small olfactory organ
are present.
The family includes the right -whales and the rorquals or fin-whales.
Balaena L., right-whales, skin of throat smooth, no dorsal fin. B.
tnifftticetus L., Greenland or Arctic right -whale ; Arctic Ocean ; from
45 to 50 feet ; 380 baleen plates or more, the longest 10 to 12 feet.
B. australis Desmoul., the southern right-whale, temperate seas of both
hemispheres ; smaller head and shorter baleen ; has been so much pursued
that it is now very scarce. Several extinct species in the Pliocene of
Europe and America. Neobalaena Gray, skin of throat smooth, a small
dorsal fin, to 20 feet, baleen very long and white, 1 species, N. marginata
Gray, New Zealand and Australian seas. Rhachianectes Cope, 1 species,
R. glaucus, the grey whale of the X. Pacific. Megaptera Gray, with
dorsal fin, skin of throat plicated and long pectoral fins. M. boops L.,
hump-back whale, 45 to 50 feet, Atlantic and Pacific ; several Pliocene
species. Balaenoptera * Lacep, rorquals, head small, skin of throat
plicated, dorsal fin present, body long and slender, cervical vertebrae
free ; in all seas ; whalebone inferior and blubber scanty. B. sibbaldi
Gray, blue whale, the largest known, to 85 feet ; Atlantic, Arctic Oceans.
B. musculus L., common rorqual, 65 to 70 feet, Atlantic and Arctic ; and
many other species ; many extinct species from the Pliocene. Several
extinct genera from the Miocene onwards, e.g. Cetotherium Brandt, Herpe-
tocetus v. Ben., Plesiocetus v. Ben., etc.
Sub-order 2. ODONTOCETI (DELPHINOIDEA).
In the toothed-whales, conical calcified teeth, often in great
number, are always present after birth. The external nares are
united to a single semilunar opening, and saccular dilations
lying between the skin and the skull are developed in the passage
which connects the opening with the narial passages. The upper
surface of the skull is more or less asymmetrical, and the superior
maxillary bone is posteriorly expanded and spread out over the
supraorbital process of the frontal. The nasal bones are reduced
to mere nodules, and take no part in roofing over the narial
passage. Lacrymal absent except in the Physeteridae. Tym-
panic not ankylosed to the periotic. Rami of the mandible
straight and meeting in a symphysis. Anterior ribs two-headed.
Sternum usually composed of several pieces and connected with
several ribs. Manus always pentadactyle. Caecum absent.
* v. Beneden, Les Balenopteres, etc., Mem, Cour. Ac. Belg., 41, 1888.
Z.— II. O O
-562 CETACEA.
Fam. 2. Physeteridae. With functional teeth in the lower jaw only ;
asymmetry of skull strongly marked. The maxillary and frontal bones
are spread out and produced so as to form on the upper and anterior
surface of the skull a basin, which is loaded with fat. The pterygoids
have palatal plates, and the mandibular symphysis is elongated. The
lacrymals are large and usually distinct. Most of the cervical vertebrae
are ankylosed. The posterior ribs lose their tubercular attachment,
but retain the capitular, a process arising on the centrum to meet the
latter. Fossil forms are known from the Eocene onwards in Europe,
America and Australia.
Sub-fam. 1. Physeterinae. Sperm-whales. With an enormous
head, swollen to the extremity by the accumulation of fat (sperma-
ceti) ; upper jaw without functional teeth, though functionless teeth
embedded in the gums are present ; mandibular teeth set in a groove,
not in sockets. Lacrymal bone not distinct. Cranial basin filled
with spermaceti. Physeter L., cachalot or sperm whale; one species,
P. macrocephalus L., from 55 to 60 feet, the female being smaller ;
zygomatic process of the jugal thick ; in all tropical and sub-tropical
seas ; food consists principally of cephalopods ; it has a large throat ;
ambergris, a concretionary substance, is a product of and found in
the alimentary canal of the cachalot, and has great commercial value ;
spermaceti and sperm oil are obtained from this whale ; the sperma-
ceti is found mixed with the fat all over the body where fat occurs,
but the principal accumulation is in the cranial basin. Kogia (Cogia)
Gray, with smaller head, slender jugal, teeth in upper jaw absent
or only two ; length 10 feet ; rare form, Southern Ocean, Madras,
and N. Pacific. Extinct genera, Diaphorocetus Am., U. Eocene,
America, Physodon Gerv., Hoplocetus Gerv., and other genera from
the Miocene onwards.
Sub-fam. 2. Ziphiinae. With only one or two pairs of fully
formed teeth in the mandible, the rest concealed in the gums ; anterior
part of mesethmoid usually ossified ; lacrymal distinct ; feed on
cephalopods. Hyperoodon Lacep., bottlenose, skull with largely
developed maxillary crests in the male, with spermaceti in upper
part of head, length 30 feet ; N. Atlantic ; tb<*y dive deep for food,
remain under some time; jump out of tru; water and return head
first; fossil in the Red Crag. Ziphius Cuv., Mtsoplodon Gervais,
Seas of N. and S. Hemispheres and in Red Crag. Berardius Duver-
noy, N. Zealand seas. Extinct genera from the Miocene onwards.
Fam. 3. Squalodontidae. Extinct forms from the Eocene, Miocene*,
Pliocene and possibly Pleistocene, known by their teeth and skulls ;
with teeth in the premaxillae and heterodont dentition, i $, c }, p %, m^;
the premolars conical and one-rooted ; the molars compressed, ser-
rated, especially posteriorly, and two-rooted. The skull like that of
other Odontoceti with reduced nasals, and posteriorly placed nostrils.
Squalodon Grat., Miocene and onwards ; Prosqualodon Lyd., Eocene,
Patagonia ; Phococetus Gerv., Eocene, France.
Fam. 4. Platanistidae. Fluviatile or estuarine, in the Ganges and
rivers of S. America. Rostrum much elongated and narrow, upper and
lower jaws with numerous conical one-rooted teeth, premaxillae without
teeth, mandibular symphysis very long, orbit very small, lacrymal distinct,
cervical vertebrae all separate ; the tubercula and capitula of the ribs
ODOXTOCETI. 563
blend posteriorly in the normal mammalian fashion ; Platanista Wagl.,
the maxillae are much expanded posteriorly and arched upwards so as
nearly to inset above the narial openings, blind eyes vestigial without
lens ; 8 feet, feeds on small fish and Crustacea, Ganges, Brahmaputra,
a7i<l Indus. Inia D'Orb., 1 feet, Upper Amazon. Pontoporia Gray,
5 feet, mouth of the Rio de la Plata. Extinct genera, Argyrocetus Lyd.,
Eocene, Patagonia ; Pontistes Burm., and Pontivaga Am., U. Eocene,
Argentina ; and other genera from the Miocene and Pliocene of Europe
and America.
Fam. 5. Delphinidae. The teeth are numerous in both jaws except
in the narwhal ; the rostrum is of moderate length and the symphysis
of the mandibles does not extend for more than one-third the length of
the lower jaw ; the maxillae and f rentals are not markedly produced
upwards at their edges ; lacrymals not distinct ; pterygoids frequently
meet. Anterior ribs two-headed, posteriorly they lose their capitula
and remain articulated to the transverse processes only. Sternal ribs
ossified. A large group of living forms, found in all seas, many will ascend
rivers in search of food ; about 19 genera and 50 to 100 species ; extinct
species of existing genera from the Miocene onwards.
FIG. 289.—Delphinus del-phis (Rdgne animal).
A. Head rounded, without distinct beak ; rostrum about as long as cranium.
MonodonL,., the narwhal, the entire dentition (save for some irregular
vestiges) is suppressed except two large teeth in the front of the maxilla ;
one (the left) of these, and sometimes both, project in the male as long
(7 to 8 feet), spirally grooved tusks ; in the female they both remain in
the alveolus ; a second pair of small teeth has been detected behind the
tusks in the foetus ; pterygoids wide apart ; cervical vertebrae mostly
distinct; with distinct neck and no dorsal fin ; 1 species. M. monoceros L.,
the use of the tusk is unknown, Arctic Ocean ; there is a Pliocene species.
Delphinapterus Lacep., like the last, but without tusks, dentition — °:
8 to 10
the only species, D. leucas Pall, the white-whale or beluga, 12 feet,
Arctic seas ; Miocene and Pliocene species are known. Neomeris Gray,
Indian Ocean. Phocaena Cuv., porpoise, dentition f|, teeth with com-
pressed crowns ; both this and the previous genus sometimes possess a
patch of small horny tubercles on the back * ; three species ; Ph. corn-
munis Cuv., feeds on fish, Atlantic and Pacific, not Mediterranean. Cepha-
lorhynchus Gray, about 3 species. Orcella Gray, Indian Ocean and Irra-
waddy, 1 species. Orca Gray, the killer, white and yellow on black, to
They are also found on the head and front of the flipper, and dermal
calcifications are found in connection with them. Kiikenthal, Anal.
Anz. 5, 1890, p. 237.
564 . CETACEA.
30 feet ; distinguished from all other cetaceans by preying upon fish,,
seals, and other cetaceans, with high dorsal fin, dentition about yf, 2
species, all seas from Greenland to Tasmania ; a Pliocene species known.
Pseudorca Reinhardt, all seas, 1 species. Globicephalus Less., nearly all
seas ; 6 species ; G. melas Traill, the pilot whale, ca'ing whale, 20 feet,
very gregarious and easily destroyed, dentition —^ Grampus Gray,
Atlantic, Pacific, Mediterranean ; teeth absent in lower jaw, in the mandible
3-7 on each side near the symphysis ; 1 species. Feresa Gray. Lage-
norhynchus Gray, teeth small, ^ *° ^, 9 species.
B. Head with beak ; rostrum of skull longer than the cranium ; atlas and
axis united, other cervicals separate. Porpoises and dolphins.
Delphinus L., teeth ^~|[J, small, close set ; pterygoids meeting in the
palate ; digits 2 and 3 weill developed, rest rudimentary ; 4 species. D.
delphis L., in all seas, common dolphin of the Mediterranean ; 7 feet.
Tursiops Gervais, 5 species. Tursio Wagl., 2 species. Prodelphinus
Gervais ; 9 species. Steno Gray ; 2 species. Sotalia Gray, 8 species,
mostly fluviatile or estuarine ; S. teuszii, Cameroon river, fresh-water
and apparently herbivorous. S. sinensis Flower, Chinese white dolphin ;
S. tucuxi Gray, from the Amazon.
Sub-Order 3. ZEUGLODONTA* (ARCHAEOCETI).
Eocene forms of doubtful affinity. The remains upon which the group
is based being imperfect it is impossible to arrive at certainty as to whether
they should be regarded as primitive Cetacea or as being allied to the
pinnipede Carnivora. They were animals of considerable size, attaining
a length of over 60 feet. They are said to have had an armour of dermal
plates, f The head is elongated and depressed, the nasal bones being long
and the external nares in front on the upper side of the snout. The
parietals meet in the sagittal suture, and the sagittal crest is well de-
veloped. The frontal roofs over the orbit, and is not overlaid by the
maxilla. The cranial cavity is small. These are all non-cetacean char-
acters, and it is difficult to see on what grounds such a head as this can
be regarded as belonging to that order. To these points of unlikeness
we may add the following. The premaxillae bear teeth and take part in
forming the edge of the upper jaw*. The dentition is heterodont,
P T c T P and ni 3, the posterior molars being laterally compressed
with two roots and serrated edges like the molars of seals. The cervical
vertebrae are separate and not compressed. The ribs are two-headed
and the sternum is composed of several pieces. The lumbar vertebrae
have elongated bodies. The limbs with the exception of a mutilated
humerus are unknown. Although the four last-named characters are not
inconsistent with cetacean affinity, the}'- cannot be regarded as proofs
of it, when due weight is allowed to the non-cetacean features of the
skull. We have however followed the usual practice of assigning the
single genus Zeuglodon Owen to the Cetacea ; Eocene of N. America,
Europe, Egypt, and N. Zealand.
* D'A. W. Thompson, On the systematic position of Zeuglodon, Studies
from the Museum of Zoology of Dundee, 1890. W. Dames, LTeb. Zeuglo-
donten aus Aegypten etc., Pal. Abh. 5, heft 5, 1894, p. 1. R. Lydekkerr
Proc. Zool. Soe., 1892, p. 560.
f Abel, Mem. Mus. Belgique, 1, 1901.
HYRACOIDEA. ObO
Order 6. HYRACOIDEA.*
Rodent-like plantigrade creatures of small size, with tetradactyl
manus and tridactyl pes, short ears and reduced tail. The grinders
are rhinocerotine, and there is a centrale in the carpus.
The affinities of this order are difficult to understand. They
have been associated with the Rodentia and with the Ungulata.
They are certainly not rodents, and except in the back-teeth it
is difficult to see any ungulate features. We have therefore,
following Huxley, given them the rank of an order.
They have close set fur, small ears, and a split snout. The
digits have nails, except digit No. 2 of the pes which has a curved
claw.
The dentition is i |-, c i, p J, m §. The upper incisors have
persistent pulps, enamel on the anterior side only and are
curved as in rodents ; they differ from the corresponding teeth
of rodents in being pointed. The lower incisors have den-
ticulated crowns and bite behind the upper. There is a diastema
and the grinders are lophodont and like those of the rhinoceros.
The milk dentition is i f , c •}, m J, the upper incisors being
rooted.
The jugal extends forwards to the lacrymal and takes part in
forming the glenoid cavity which is transversely placed. The
postorbital process of the skull (mainly from the parietal) is con-
siderable and nearly meets the jugal. There is an alisphenoid
canal. The premaxillae are large. In the vertebral column there
are from 28 to 30 dorso-lumbar vertebrae, of which twenty-one
or twenty-two are dorsal. There are no clavicles, and the spine
of the scapula is without an acromion. The ulna and fibula are
complete, and there is a vestige of the pollex. The carpus
(Fig. 290) has a centrale and the bones of the two rows do not
alternate. The 'femur has a small third trochanter. In the pes
(Fig. 290) digits 1 and 2 are entirely absent, and the ungual
phalanx of digit 2 is cleft. The astragalus presents a shelf on
* J. F. Brandt, Unters. lib. d. Gattung Hyrax, Mem. Ac. imp. Sci.
Pctersbourg, 1869, (6), 14. O. Thomas, On the species of Hyracoidea,
Proc. Zool. fioc. 1892, p. 50. M. Woodward, On the milk dentition of
Procavia, Proc. Zool. Soc. 1892, p. 38. George, Ann. Sci. Nat., (6), 1,
Is74. Ameghino, Mammiferes Cretaces de 1' Argentine, BoL Inst. Geogr.
Arg., 18, 1897. Fischer, Ban u. Entw. des Carpus u. Tarsus vom Hyrax,
Jen. Zeitftchr., 37, 1903, p. 691.
566
HYRACOIDEA.
its inner side for the articulation of a^process of the tibia.- The
fibula articulates with the' astragalus, not with the calcaneum.
The stomach is simple There is the usual caecum at the
FIG. 290. — Procavia arborea Smith, Cape of Good Hope. A skull. B upper jaw from below.
C manus. D pes (from Zittel). R radius, U ulna, s scaphoid, I lunar, c cuneiform, p pisi-
form, ce centrale, tm trapezium, td trapezoid, m magnum, v unoiform, c calcaneum, a astra-
galus, n navicular, c2, c3 meso- and ecto-cuneiform, cb cuboid, i-v digits numbered.
beginning of the large intestine, and a pair of smaller caeca
placed lower down on the colon. There is no gall bladder. The
testes remain in the abdomen and there is no scrotum. The
vulva and anus are enclosed in a common fold of skin. There
are six mammae, four of
which are inguinal and
two axillary. The uterus
is bicornuate and the
placenta zonary. Most
of the species live on
rocky ground, but a few
(the Dendrohyrax division)
live in trees.
FIG. 291.— Procavia syriaca (from Claus).
There is one living genus, Procavia Storr (Hyrax Herm. ), represented
by about 18 species in Africa ; one of these, P. syriaca Schreb., extends
into Syria ; it is the coney of the Bible. P. capensis Pall, rock-rabbit,
daman, dassy. The earliest remains of these animals hitherto found are
from the Upper Eocene of the Fayum in Egypt. These are Megalohyrax
PROBOSCIDEA. 567
Andrews,* about the size of a tapir, with a third incisor and premolari-
forni canine, and Saghatherium Andrews and Beadnell. t These forms
are similar to those now existing, and present all the peculiar features
of specialisation of the order. The skull of a fossil species, Pliohyrax
(Procavia) kruppii, is known from the Miocene of Samos, and recently
Amsghino has described remains from the Cretaceous and Lower Eocene
of Patagonia under the names of Archaeohyrax, Argyrohyrax, Plagiarthrus,
Order 7. PROBOSCIDEA. %
Large pachyderms with long proboscis which is used as a pre-
hensile organ ; with large lophodont grinding teeth, and tuslcs in
the premaxillae or mandible.
The peculiar gait of elephants is due to the fact that the legs
are not bent at the elbow and knee as is the case in most quad-
rupeds but as in Dinoceras and Titanotheirium depend vertically
from the body. They walk with the tips of their toes on the
ground, but the weight is mainly carried by a great cushion on
the posterior surface of the digits, so that they may be described
as semiplantigrade. The toes are not separate externally but
their termination is marked by nails, which are not, however,
always as numerous as the digits.
The body is covered by a thick skin which in the living forms
is only sparsely covered with hairs. The head is enormous,
being short and deep, and the skull is swollen by air-chambers
in the frontal, parietal, premaxillary, maxillary, nasal, palatal,
and other bones. All these air-spaces communicate with the
nasal passages. The apertures of the external nostrils are
placed at the end of a long trunk, which is extremely mobile and
* Andrews, Geological Magazine, 4, 10, 1903, p. 341.
f Andrews and Beadnell, A preliminary note on some new mammals
from the Upper Eocene of Egypt, Cairo, 1902.
J Kaup, Description tfossem. de foss. Mammi/eres, 1832-35, Cah. i. and
iv. ; Acten der Urwelt, 1841, 1. Lartet, Sur la dentition des Prob. foss.
etc.. Bull. Soc. Geol. France, 1859, 16. Falconer and Cautley, Fauna
antiqua sivalensis, 1846. Falconer, On the species of Mastodon and
Elephant, fossil in Gt. Britain; Pt. 1, Mastodon, Pt. 2, Elephant, Quart.
Journ. Geol. Soc., 13, 1857, p. 308; and 21, 1865, p. 253. Falconer,
Palaeontologies^, Memoirs, 2, 1868. H. v. Meyer, Studien lib. d. Genus
Mastodon, Palaeontographica, 1867, 17. Weinsheimer, Ueber Dinotherium
giganteum, Palaeont. Abh. 1, 1883, p. 207. Forbes, Viscera, P.Z.S.,
1879, p. 420. Adams, Monograph of the British Fossil Elephants, 3
pts., Palaeontographical Soc., 1877-8. Cope, The Proboscidea, Amer.
Nat., 23, 1889. Amcghino, Pyrotherium, Bol. Inst. Geograf. Argentina,
15, 1895, 18, 1897. Lydekker, Cat. Foss. Mam. B. M., 1-5, 1885-7.
Andrews, C. W., Evolution of the Proboscidea, Phil. Trans., 196, 1904,
p. 99.
568 PROBOSCIDEA.
is used as a prehensile organ ; by means of it the animal conveys
food to its mouth, uproots trees, and sucks up fluid, which it may
transfer to its mouth or squirt over its body. The ears are large
and there is a moderate tail. The tusks are enormously enlarged
rootless incisor teeth (i 2) and in living forms are only present
in the premaxillae. In the mastodon there are also two incisor
teeth in the lower jaw which soon fall out in the female, but in
the male are retained as tusks. Incisor teeth are also present
in the lower jaw of Dinotherium where they have the form of
tusks, and of Tetrabelodon, Palaeomastodon and Moeritherium,
etc. (see below).
The tusks consist mainly of dentine, being only tipped with
enamel in Elephas and ridged with the same substance in some
extinct species. They are preceded by milk teeth. There are
no canines in recent forms. The grinders are highly peculiar.
They are enormous elongated teeth with very numerous rows
of transversely elongated tubercles forming plates and com-
posed of enamel and dentine. The spaces between these tubercles
are in living forms filled with cement, and the grinding surface
presents in the worn tooth a number of transverse rhombic marks
consisting of dentine with an outer coating of enamel. In the
mastodon the cement is sparse, and the dental papillae are short
having the form of mammillary prominences (Fig. 294). In
Dinotherium, Palaeomastodon, Moeritherium, etc., in which there
is the ordinary succession, the molar teeth are bilophodont and
tapir-like, and there is no cement on the crowns.* In Stegodon
there are six to twelve transverse ridges, the valleys being partly
filled with cement. In Elephas (Fig. 293) the number of ridges
is much greater, increasing in the posterior teeth, so that the
last may have as many as twenty-seven. With this increase in
complexity, the crowns become longer, so that the brachydont
condition of the molars of Mastodon, Dinotherium and other
early forms gives place to a marked hypsodont structure. There
are altogether six grinding teeth in modern elephants on each
side of each jaw. Of these, three are either premolars which
have no predecessors, or deciduous molars which have no suc-
cessors ; the other three are molars. There are never more than
three rarely more than two above the gum at the same time,
* See pp. 572, 573.
DENTITION. SKULL.
569
for the posterior teeth, which are larger and have more lamellae
than the anterior, only make their appearance after the anterior
have been worn down and have fallen out. At first each half of
the jaw has only one grinder ; behind this a second is soon
developed, and so on. The whole series gradually moves for-
wards in the jaw and, as those in front are worn down and cast
off, the posterior
teeth are de-
veloped and
moved forwards
into position.
In Dinotherium,
etc., the ordin-
ary succession
is found ; the
milk molars are
vertically dis-
placed by pre-
molars and all
the grinding
teeth are in use
at the same
time.
The principal
peculiarities of
the skull (Fig.
292), in addition
to the enormous
thickness of
some of the
bones owing to
the presence of
the air-spaces,
are the large size
of the premaxillae which carry the tusks, the shortness
of the nasals, in consequence of which the bony narial
passage opens upwards as in whales ; the comparatively
slender jugal arch, the middle of which only is formed
by the jugal, contrary to the arrangement usually found in
Ungulates. The mandibles have a high vertical portion and
FIG. 292.— Skull of Ele-pkas indicus in longitudinal
section (from Zittel). So supraoccipital, co occ. con-
dyle, Pa parietal, Fr frontal, MX maxilla, Pmx pre-
maxilla, ME mesethmoid, ce cranial cavity, n narial
passage, i tusk, ml, m2 first and second grinders.
570 PROBOSCIDEA.
are extensively ankylosed at the symphysis which forms a kind
of spout. In the young the air-cells are but slightly developed,
and the great increase in the size of the skull which takes place
during growth is mainly due to their development . The lacrymal
is small and interorbital. The f rentals are produced into supra -
orbital processes which give off small postorbital processes. The
orbit is not separated from the temporal fossa. There is a broad
post -tympanic process which meets the posterior boundary of
the glenoid fossa beneath the external auditory meat us. The
tympanic is united with the periotic and forms a large rounded
bulla. There are no paroccipital or postglenoid processes.
The vertebrae (in Elephas) are C 7, D 19-21, L 3-4, S 4, C 26-
33. The centra are flattened from before backwards especially in
the neck, and the epiphyses remain separate for some time. The
scapula has a long backward process from about the middle of
the spine (as in some Rodents) and there are no clavicles. The
ulna and fibula are complete and separate. The radius is fixed
in the prone position, crossing the ulna. The carpal ia are suc-
cessional, and the metacarpals and phalanges are short and
thick. The femur is without a third trochanter, the tibia i&
short, arid the fibula articulates with the calcaneum. The
astragalus articulates distally with the navicular only, and is
remarkable for the flatness of both its surfaces.
The stomach is simple, and the large intestine very long, half
the length of the small. The apex of the ventricle is bifid.
There is a large caecum and no gall bladder. Primitive features
are shown by the presence of two superior venae cavae and by the
fact that the cerebellum is left entirely uncovered by the cerebrum.
The cerebrum, however, is large and very richly convoluted.
The testes remain in the abdomen close to the kidneys, to which
they are attached. The vulva is placed on the abdominal
surface at some distance in front of the pubis. The uterus is
bicornuate and the two mammae are thoracic. The placenta
is zonary and the period of gestation is about twenty months,
but the time may be variable.*
Elephants love dark and shady forests. They are purely
vegetable feeders, living mainly on the leaves of trees, which they
* Dr. Chalmers Mitchell informs me that in] the case of an Indian
elephant in the Zoological Gardens of London, the time appears to have
been 28 months, during 23 of which the animal was in the gardens.
DISTRIBUTION. AFFINITIES. 571
frequently uproot for the purpose of getting at the upper leaves.
They live to a great age (100 to 120 years, perhaps longer) and
are said not to attain maturity till the fortieth year. They are
remarkably intelligent and possess a good memory. The two
living species are confined to Africa and India (including Ceylon,
Burma, Malay Peninsula, Sumatra, Cochin China). Both species
have been domesticated, the African more rarely than the Indian.
They will rarely breed in captivity.
The Proboscidea constitute a distinct and on the whole isolated
order. They are commonly united with the Ungulata. They
present features of resemblance to the Rodentia (scapula, etc.)
and Sirenia (succession of teeth, etc.), and in many parts of their
anatomy are very primitive, e.g. structure of manus and pes,
presence of two superior venae cavae, uncovered cerebellumr
abdominal testes.
The sirenian affinities have been recently emphasized by Andrews.*
The following characters are common to the two groups : (1) The non-
deciduate and zonary placenta, (2) the pectoral mammae, (3) the abdominal
testes, (4) the bifid apex of the ventricle, (5) the absence of the cohdylar
foramen always in the Proboscidea and generally in the Sirenia, (6) the
bilophodont character of the molars with a tendency to the formation
of an additional lobe from the posterior part of the cingulum (talon),
(7) the fact that in both groups the molar series move forward in the jaws
throughout life, the anterior worn teeth being shed, while fresh teeth
come into use behind. There is however no evidence of this last character
in the earliest Proboscidea, Moeritherium and Palaeomastodon.
The Proboscidea are first found fossil in the Middle
Eocene of Egypt and a fairly complete series of forms are known
connecting the highly specialised modern Elephas with the
earliest of these remains. Their fossil remains are found in
both the Old and the New World.
Elephas L. (Euelephas), i £ c g p or dm f m f ; the incisors are
curved and tipped with enamel ; they are usually larger in the male ;
grinders with numerous laminae. Fossil species are known from the TJ.
Miocene of India, Pliocene and Pleistocene of Eur., Afr., Asia, N. and S.
Amer. E. indicus L. (distribution, see above), average dental ridge
formula 4, 8, 12, 16, 24, laminae of the worn plates nearly parallel, female
without tusks, manus with 5, pes with 4 nails, height of full grown male
at the shoulder from 8-11 feet. E. africanus Blumenb. (Loxodon), average
ridge formula of molars 3, 6, 7, 7, 8, 10 ; laminae thicker in the middle
than at the edges (Fig. 293), manus with 4 nails, pes with 3, tusks in both
sexes, but smaller in female ; larger than the Indian species, a full grown
male may measure 12 feet to the shoulder. There are many extinct
species, of which may be mentioned the mammoth E. primigenius Blu-
* Op. cit.
572
PROBOSCIDEA.
d
FIG. 293. — Upper molar of Elephas africcinus. d dentine,
e enamel, ; cement (from Owen).
menb., in the Pleistocene of Eur., As., and Amer. The skin had a thick
woolly covering, as is shown by the frozen carcases occasionally met
with in X. Siberia, where the tusks (somstimss from 10-12 feet in length)
are found in considerable numbers, affording ivory for export, and also by
contemporary drawings scratched on mammoth ivory. The cause
of the comparatively recent extinction of the mammoth is doubtful ;
it may have been due to the decay of the forests in which it lived. E. meli-
tensis Falcon., a pigmy species found in caves in Malta.
Extinct
genera, Stego-
don Falc.,
tusksinupper
jaw, with en-
amel band ;
grinders com-
posed of 6-12
1 o w cusped
ridges, with
cement i n the
v a 1 1 e y s ,
Miocene and
Pliocene of Asia. Dinotherium Kaup, i y c £ p ^ m £, the grinders
being bilophodont (except ml, which has 3 ridges), and all in function at
once, the premolars have milk predecessors ; the extremity of the mandible
is deflected and the tusks (lower incisors) project downwards (Fig. 295);
cranium depressed with but few air-cells : in size it surpassed living ele-
phants ; M. and U. Miocene of Eur. and As. Mastodon Cuv., i —
1 or 0
c Jj p f m I ; u. incisors as large tusks with bands of enamel, 1. incisors
variable, never large, sometimes absent ; grinders with mammillated
ridges and scanty cement (Fig. 294), the anterior three grinders some-
times replaced, Miocene and Pliocene of Old World, in the Xew World
it survived until the
Pleistocene. Tetrabelodon
Cope, dentition, i \ c %
p | m f , the upper in-
cisors are tusks and the
lower are procumbent
teeth in close contact ;
there appear to have
been 3 deciduous molars,
the last two of which
were replaced ; the pre-
molars were shed early ;
the premolars and molars
are brachyodont and bi-
or tri - lophodont, the
ridges being tuberculated, and m3 has a tuberculated talon ; the sym-
physial region of the mandible is much elongated. Miocene and Pliocene
of Eur. Asia, Afr., X. Amer., extending into the Pleistocene in Amer.
Palaeomastodon Andrews, from the Upper Eocene of Fayum, Egypt ;
dentition i \ c fj p f m |, the upper incisors are tusks, the lower pro-
cumbent and spatulate ; the premolars and molars very similar to those
of Tetrabelodon except that all were in use at once in the usual way,
FIG. 294.— Oblique side and crown view of the last
upper molar of Mastodon arvernensis (from Flower and
Lydekker).
IXi.L'LATA.
573
ml being most worn ; the mandibular symphysis was elongated but not
so long as in the last genus, and the basis cranii and facial region of the
maxilla longer.
Moeritherium Andrews, Middle and Upper Eocene of Fay urn ; den-
tition tfc£pj-m$; i 2 in the upper jaw is tusk-like though not
so large as in the other genera, il and iS are small as is the canine ; in the
lower jaw i'2
is larger than
il, i3 being
absent ; the
premolars are
cuspidate and
the molars
bilophodont
(quadri tuber-
cular). This is
the ordinary
dentition, save
for the absence
of pi in the
upper jaw and
of i3, c and pi
in the lower.
The mandibu-
lar symphysis
is but slightly
elongated.
Barytherium
Andrews, M.
Eocene.
Pyrotherium
Am., from the
Cretaceous
(Eocene) of
Patagonia has
been claimed FIG. 295. — Skull of Dinotherium giganteum, from the Lower Pliocene
(after Kaup, from Flower and Lvdekker). 7)3, 4 premolars ;
as a member lf 2, 3 molars.
of this order.
Order 8. UNGULATA.
Usually hoofed, digitigrade animals in which the digits of the
pes never exceed four and the carpal and tar sal bones interlock.
There is no os centrale in the carpus and no entepicondylar
foramen in the humerus, and clavicles are always absent. The
scapula is usually devoid of an acromion. The placenta is
diffuse or cotyledonary , the mammae inguinal or abdominal, and
the testes always descend into a scrotum.
The Ungulata as thus defined includes the Perissodactyla, and
Artiodactyla and excludes absolutely the Proboscidea and
574 UNGULATA.
Hyracoidea. This is as it should be, for there are no specially
Ungulate features about either of the two latter, and when care-
fully surveying the facts, it is difficult to understand upon what
grounds they have been and are classed with the hoofed animals.
But the definition if strictly applied goes further than this and
excludes from the Ungulates a certain number of extinct forms,
which ought perhaps to be placed with them. Such are the
Lipoterna (e.g. Macrauchenia) which appear to have all the
Ungulate characters mentioned except the interlocking carpals
and tarsals and the universal absence of digit No. 5 on the pes.
It is true that this group has some remarkable characters of its
own, but in the present state of knowledge it may fairly be left
with the Ungulata. A case might also be made out for including
the Toxodontia and the Amblypoda, but after careful considera-
tion they must, we think, be excluded. It is true that both these
groups present some of the ungulate features, but they are
without the others, and they both present remarkable features
of their own, which, we feel convinced, would exclude them from
the group were they alive at the present day so that we could
study their soft parts. We refer especially to the structure of
the brain as revealed by casts of their skulls.
There remain the Typotheria, Ancylopoda and the Condy-
lartha. These are dealt with fully below. Here it is only
necessary to say that the two latter, though showing some
ungulate features depart far too widely from that type to be
included with it in classification ; and that the Typotheria differ
from the Ungulata in all their characters.
In maintaining these opinions as to the limitations of the order
Ungulata, we are in opposition to the views of many eminent
zoologists, men who have devoted much thought, labour and
research to the study of these obscure remains. We therefore
urge our views with much diffidence and have only decided to
give expression to them after considerable hesitation. But we
feel that we cannot evade the matter in a treatise of this kind.
We are obliged to look into the facts and in forming a judgment
upon them we must exclude from our minds as far as is possible
all that bias which comes so readily from theoretical predilec-
tions.
Dentition.* The back teeth are nearly always rooted and may
* See pp. 499-508.
DENTITION. MANUS. PES. O<O
be either bunodont (p. 504), or lophodont (p. 504). Selenodont
teeth are a variety of the lophodont type in which the tubercles
have a crescentic form ; they are found mainly in the ruminant
division of the Artiodactyla. As a general rule the teeth have
short crowns and the neck of the tooth, i.e. the junction of the
crown and root lies at the top of the alveolus (brachyodont) ; but
in Equidae and some ruminant artiodactyls the crowns are much
lengthened and the neck of the tooth lies for some time in the
socket (hypsodont or hypselodont, p. 505). The hypsodont tooth
is clearly more adapted for prolonged use ; there is more
wear in it and its possessor is able to eat habitually drier and
harder food than creatures possessing brachyodont grinders.
The layers of hard enamel traversing the softer dentine and cement
give rise to a slight roughness of the surface which is of advantage
for trituration of the food.
There is considerable modification of the manus and pes
within the group, more so than perhaps in any other organ ; and
as these modifications are combined with the ungulate characters
and are continuous or nearly so, i.e. the extreme modifications
are connected by intermediate gradations throughout the
group, there is comparatively little difficulty in fixing the sys-
tematic position of their possessors. To begin with, we may
describe a constant character which is found in all ungulates and
which is mentioned in the definition. The bones of the two
rows of the carpus and tarsus are not placed vertically below one
another, are not serial or successional as it is called, as they are
in most mammals, e.g. the elephant or Hyrax (Fig. 290), but the
bones of the distal row have been shifted towards the inner side,
so that in the carpus the os magnum is partly under the scaphoid
as well as under the lunar, and the uncif orm articulates not only
with the cuneiform but also with the lunar (Fig. 298). In the
pes the astragalus no longer articulates solely with the navicular
but it also has a surface of articulation for the cuboid (Fig. 299).
In this condition which is, as we have stated, characteristic of
ungulates, the two rows of carpal and tarsal bones are said to
interlock, and the interlocking gives greater strength to the
carpal and tarsal joints.
The modifications in the manus and pes relate to the number
of digits present. In the manus the greatest number of complete
digits is four with occasionally a trace of the pollex, in the pes
57P> UXGULATA.
four with never a trace of the hallux. The absence of digit No. I
may be therefore taken as a characteristic of the group. In the
Suidae and Hippopotamidae, there are four digits in each foot,
but digits Nos. 2 and 5 are weaker than the others and may not
reach the ground. This change is accompanied by an elongation
of the metacarpals and metatarsals, metapodia as they are
called. In the Ruminantio the outer digits are very small and
functionless as in the deer (Fig. 308) or entirely absent as in
Camelidae and some Bovidae, and the metapodia of the persisting
large digits (Nos. 3 and 4) are united into the so-called cannon bone.
In the Perissodactyla the modifications are slightly different.
Here in the tapir the manus has four complete digits (No. 1 being
absent), the pes three (Nos. 1 and 5 being absent) ; the rhinoceros
has three in both limbs, while the horse has only one complete
digit (No. 3) with traces of the metacarpals of digits 2 and 4.
In this sub-order digit No. 3 is larger than the others even in the
tetradactyle tapir (Fig. 309). The gradual elongation of the
metapodia is also manifest in this series as may be gathered from
an inspection of the figures (Fig. 316). The Ungulata are found
all over the world except the Australasian region. They are
almost all herbivorous and none purely carnivorous. The forms
with broad tetradactyle feet frequent places where the ground
is soft (rhinoceros, hippopotamus) ; they may be described as
almost semiplantigrade, for although they stand on their digits
the weight is partly borne by a large pad on the hinder side of
the foot. The majority, however, are purely digit igrade, and
walk on the tips of their reduced toes which are encased in hoofs.
These creatures inhabit hard ground, grassy plains and mountain
sides and are swift and active runners.
There are three suborders, the Artiodactyla, the Perissodactyla r
and the Lipoterna.
Sub-order 1. ARTIODACTYLA.*
Digitigrade forms in which the axis of the limbs passes between
digits Nos. 3 and 4, these digits being symmetrical with each
other and their metapodia closely applied together or united into
a cannon bone. The premolars and molars are not alike and the
last lower molar is three-lobed. The first milk molar is not
* W. Kowalevsky, Palaeontographica, 22, 1873-4. E. D. Cope, The-
Artiodactyla, Amer. Naturalist, 22 and 23, 1888-9.
ARTIODACTYLA.
577
c | p I ra f ,
replaced ; it may persist for some time. There is no
alisphenoid canal and the nasals are not expanded posteriorly.
The number of dorso-lumbar vertebrae is always nineteen.
The femur is without a third trochanter, the fibula articulates
with the calcaneurn, and the facets upon the distal face of
the astragalus for the navicular and cuboid are sub-equal,
and both its distal and proximal surface are pulley-like.
These are the differential characters of the living members of
the sub- order, and it is upon their application to the imperfectly
known extinct forms that the systematic position of these must
depend. The digits are very commonly reduced in number ; the
limit* of the reduction being found in the more specialised Rumin-
ants in which digits 3 and 4 alone persist, all trace of the others
having disappeared.
The dentition consists typically of 44 teeth, i
but there is a tendency A
towards the suppression
of the upper incisors, and,
as already stated, the first
tooth of the premolar
series is probably the
long -persistent first milk
molar. The premolars
are usually simpler than
the molars (Fig. 296).
In the so-called primitive forms the grinding teeth are low-
crowned (brachyodont) and the tubercles are conical (bunodont) ;
the latter being in two pairs (Fig. 296) with a tendency to the
intercalation of an accessory tubercle in the upper molars between
the tubercles of either the anterior or the posterior pair. There
is almost always a heel (talon) on the last molar of the lower jaw
(Fig. 296 B). In many forms the tubercles become V7-shaped or
semilunar and are connected by basal ridges ; in this way the
teeth pass through a stage which may be called buno-lophodont
or buno-selenodont to selenodont, the form which is eminently
characteristic of the Ruminantia (Fig. 297). In selenodont forms
the concavity of the semilunar tubercles are directed outwards
in the upper and inwards in the lower jaw ; and in the upper jaw
the two outer tubercles are usually united, forming the outer wall
of the tooth, and there is a projecting ridge along the wall at the
FIG. 296. — Homacodon vagans. A right upper pre-
molars 2-4, molars 1-3 ; B right lower premolais
3 & 4, molars 1-3 (after Marsh, from Woodward).
Z — II
P P
578
UNGULATA.
point of union. In the lower molars the inner tubercles usually
unite to form an inner wall. The lower molars are usually
narrower than the upper.
The tubercles are generally short (brachyodont) but in the
higher forms they lengthen and the spaces between them become
filled in with cement. In some of the ruminants (Bovidae) the
crowns become as long as in the Perissodactyla : this is the hyp-
sodont condition.
The skull in the primitive extinct forms recalls that of the
Carnivora. In the higher forms the face becomes lengthened.
The lacrymals extend on to the face.
In the more primitive forms the odontoid process is conical ;
with increased specialisation it tends to become spout-shaped.
But this as in the
case of Agriochoerus
(p. 585) does not
always hold. In the
hinder dorsal and in
the lumbar vertebrae
the prezygapophysis
frequently bends
round the postzyga-
pophysis of the pre-
ceding vertebra, so as
to overlap and articu-
late with its dorsal
surface. The scapula is generally without an acromion.
The ulna and fibula are complete and distinct in some forms,
but there is a tendency to their reduction and fusion with the
radius and fibula. In the ruminants the fibula is only represented
by its lower end (malleolar bone), \vhich articulates with the
calcaneum. As already stated the digits tend to diminish in
number. There are five metacarpals in the Oreodontidae (Fig.
297 bis, A) and Anoplotheridae, but No. 1 is reduced. In all
others this digit has completely gone, but digits 2 and 5 generally
persist though reduced. Digits 3 and 4 always persist and in the
higher forms their metapodia are united into a cannon bone which
is generally grooved in front or slightly cleft below and always
contains two medullary cavities.
In the artiodactyl manus with five metacarpals metacarpal 1
FIG. 297. — Selenodont dentition of an Oreodont Agrio-
choerus latifrons. The upper teeth are above in the
figure (after Scott from Zittel). m first molar.
ARTIODACTYLA.
579
articulates with the trapezium, me. 2 with the trapezium, trape-
zoid, and magnum, me. 3 with the magnum and unciform,
me. 4 and 5 with the unciform (Fig. 297 bis, A). If this arrange-
ment is maintained with reduction in the digits, the reduction is
spcken of as inadaptive reduction (297 bis, B) ; inadaptive
reduction is characteristic of the ancient forms. In adaptive
reduction the upper articulating surfaces of me. 3 and 4
broaden out and push the lateral metapodia outwards, so
FIG. 297 bis. — Manus A of Oreodon, B of Xiphodon, showing inadaptive reduction ; C of Sus,
D of Tragulus, showing adaptive reduction (from Zittel). c cuneiform ; I lunar ; m mag.
num ; R radius ; « scaphoid ; td trapezoid ; tz trapezium ; U ulna ; u unciform ; i-v digits
numbered.
that me. 2 ceases to articulate with the magnum (Fig 297 bis, C,
D). The pes is always ahead of the manus in reduction and in
the fusion of the metapodia. It never possesses even the meta-
tarsal of digit 1.
It is said that the metapodia when fused in the adult retain
their distinctness in the embryo, thus corresponding with the
older forms. But it must not be forgotten (1) that this distinct-
ness is confined to the stage of cartilage, (2) that the metapodia,
however close the coalescence may be, always show distinct
traces of their double origin in the adult (separate medullary
cavities, and grooved surface), and (3) that no traces of the
580
UNGULATA.
skeletal parts of digits which are totally missing in the adult
have so far been discovered in the embryo.
The stomach is generally complex, the caecum small, the
placenta diffused or cotyledonary. The mammae are few and
inguinal or numerous and abdominal.
The Artiodactyla constitute by far the largest group of living
Ungulates. They are rich in genera and species and they are
found all over the world except in Australia and New Zealand.
The living forms are divisible into quite well defined groups, but
there are a large number
of extinct forms, which
tend to fill up the gaps
between existing families
and to obliterate the divid-
ing lines. The earliest of
these are found in the
Eocene.
Fam. 1. Suidae.* Skin hairy;
with tuberculated brachyodont
molars ; with incisors and
canines in both jaws ; the last
molar in both jaws with an
additional hinder lobe, the
premolars with a simple cutt-
ing edge ; the first deciduous
molar is not replaced. Four
completely developed digits in
both limbs, digit 1 being ab-
sent ; digits 3 and 4 are larger
than the others, are closely
applied together and the
adjacent surfaces of their
hoofs are flattened ; digits 2
and 5 do not reach the ground in walking. The metacarpals and
metatarsals are generally separate and never completely fused together.
The axis of the face is bent upon the basi-cranial axis ; the orbit
is not closed behind, the postorbital processes of the frontal and jugal
not meeting ; the openings of the lacrymal canal are on the face ;
the nasals are long and the premaxillae unite with them for some
distance ; there is often a prenasal bone ; the bulla is large, the bony
auditory meatus is long ; the post-glenoid and post-tympanic processes
of the squamosal are united beneath the meatus, and there is a long par-
occipital process. The centra of the cervical vertebrae are short. The
* H. v. Nathusius, Die Racen des Schweines, I860, and Vorstudien
fur Oeschichte u. Zucht der Hausthiere, Berlin, 1864. Marsh, Homacodon,
Amer. Journ. Sci. (3), 48, 1894, p. 261. Filhol, Listriodon, Bibl. Ecol'e
Haute* Etudes, 37, 1890, t>. 205.
• JV T-
FlG. 298.
FIG. 298.— Bones of the maims of the pig (Sus
scrofa) x £ (from Flower), digits numbered,
bones with initial letters.
FlG. 299.— Right tarsus of pig x %,
ARTIODACTYLA, SUIDAE.
581
FIG. 300. — Skull of Susscrofa ferus.
ulna and fibula are complete and separate from the radius and tibia.
There is a single precava. The stomach is fairly simple, with a cardiac
pouch and a groove leading towards the pylorus from the oesophageal
opening. There is a caecum. The placenta is diffuse, the teats are
abdominal and the testes descend into a scrotum. Living forms
are confined to the Old
World. Fossil remains
are firs found in the
Eocene of Europe and
N. America. Sus L.,
milk dentition i f c \
m % ; permanent denti-
tion i | c \ p $ m|;
the canines have per-
sistent roots and project
as tusks, less developed
in the female ; gestation
16-20 weeks; palaearctic
and oriental regions, in
other regions introduced by man ; S, scrofa L., wild boar, with many
varieties ; the source of the various breeds of domestic pig is unknown ;
S. salvanius Hodg., no larger than a hare, India ; 13 other species are
distinguished and many extinct from the Miocene onwards. Potamo-
chaerus Gray, river-hogs, Africa and Madagascar. Babirussa Less., * |
c i P I m S»
enormous can-
ines in the male,
the upper pierc-
ing the skin, al-
most hairless, 1
species, Celebes
and B uru.
Phacochoerus G.
Cuv., wart-hogs,
with large cuta-
neous lobes on
each side of the
face, i$ c } p f
m f ; teeth tend
to disappear
with age except
the canines and
posterior mol-
ars, which latter
attain an enor-
mous develop-
ment, owing to
the great number and elongation of the tubercles ; the form of the
last molars and the fact that the anterior grinders are gradually
worn down and disappear, leaving the last only, constitutes an
approximation to the condition in elephants ; 2 sp., Africa. The following
extinct genera, many tending to connect the Suidae and Dicotylidae, are
placed with the Suidae ; some of them show affinities outside these
FIG. 301. Left side view of dentition of the boar (Sus scrofa), showing
roots exposed (from Flower and Lydekker). t incisors, c canines,
pm premolars, m molars.
582
UNGULATA.
Co.
families : Achaenodon Cope ; Homacodon Marsh (Pantolestes), Middle
Eocene, N. Amer., Bridger Beds. ; Choeropotamus Cuv. ; Palaeochoerus
Pomel ; Listriodon Meyer, the cusps of the upper and lower molars fuse
into complete transverse ridges,
Middle Miocene. Elotherium *
Pomel, Eocene and Miocene of
Europe and America, with com-
pletely enclosed orbit, with two
complete toes, digits 2 and 5
being represented only by their
metapodia, last molar without a
supplementary lobe.
Fam. 2. Dicotylidae. Peccaries
* f c | p f ra |, upper canines
directed outwards, the last pre-
molar nearly as complex as the
Fio. 302. — Grinding surface of a worn molar of molars, only three toes on pes ;
*o»ach 3-chambered with oeso-
phageal groove ; the metacarpals
and metatarsals of digits 2 arid 3 coalesce into a cannon bone, on the
back is an oleaginous musk gland ; only 2 young at a birth ; 2 species, New
World, from Texas to Patagonia. Many extinct species Pliocene and
Pleistocene of Amer.
Fam. 3. Hippopotamidae.f Skin
almost hairless ; with huge head and
large heavy unwieldy body with a thick
skin, with short tetradactyle limbs all
the digits of which rest on the ground
and have nail-like hoofs ; milk denti-
tion i f c T m %, permanent, i £ c }
p f m f, premolars simpler than
molars ; molars with four tubercles
which wear down so as to present a
double trefoil pattern (Fig. 302) ; last
lower molar trilobed. Incisors tusk-
like, rootless ; canines large, curved,
rootless. The orbits are tubular and
nearly completely enclosed ; tympanic
large and ankylosed with the approxi-
mated post-tympanic and postglenoid
processes of the squamosal. Scapula
with a short acromion, ulna and fibula
complete. Brain not richly convoluted.
Stomach very large, with three com-
partments. No caecum. Kidneys lobu-
lated. Mammae inguinal. Scrotum
absent. Herbivorous, semiaquatic ;
confined to Africa. H. amphibius at-
tains a weight of four tons, Africa ; H.
* Kowalevsky, Palaeontographica, 22, 1876. Marsh, Amer. Journ. of
Science (3), 48/1894, p. 407.
•f Falconer, Palaeontological Memoirs, 1 and 2, London, 1868. Lydekker,.
Indian Tertiary and Post Tertiary Vertebrata, Palacont. Indica, ser. 10,.
1-4, 1874-87. Filhol, Ann. Sci. Nat. (7), 16, 1893, p. 151.
FIG. 303.—Hyopotamus (Ancodus) vdau-
nus Cuv., Oligocene. A anterior, B
posterior foot x i. digits numbered,
carpals and tends marked by initial
letters (after Kowalevsky, from Zittel).
ARTIODACTLAY, HIPPOPOTAMIDAE.
583
liberienaia is a small species with only two incisors in the lower jaw, Liberia
(formerly called choeropsis} ; extinct species from all over the Old World,
including Madagascar (not in Australia), Pliocene and Pleistocene.
All the above families
have tuberculated mo-
lars.
We now come to
a number of extinct
forms in which the
tubercles of the molars
are connected by low
ridges, so that they
may be called buno-
lophodont. They are
intermediate forms
leading to the Rumi-
nantia. The Caeno-
theridae and Xiphodon-
tidae show affinities to
living groups. The
others though inter-
mediate between Suidae
and Ruminantia show
no special affinity to
any living group
Fam. 4. Anthracoth-
eriidae. * Extinct forms,
Eocene and Miocene.
i f c \ p i ra | ; u.
molars with 4 tubercles
and an intermediate
tubercle in the anterior
half of the tooth, molars tending to selenodonty ; tetradactyle limbs,
inner and outer toes rather smaller than the middle, metacarpals and
•/?" r m* B
FIG. 304. — Hyopotamus velaumts Cuv. Skull, A from below.
B from the side {after Kowalevsky, from Zittel).
FIG. 304 bis. — Anoplotherium latipes Gerv., Upper Eocene. A the two hinder upper pre-
molars and the anterior molar. B the two hinder lower molars. The cusps are lettered
as follows : a antero-external, b antero-internal, 61 antero-intermediate, c postero-
external, d postero-internal ; a antero-internal, p antero-external, y postero-external ;
/3', £*, y1 the three inner tubercles (nat. size, from Zittel).
metatarsals not fused (Fig. 303) ; ungual phalanges pointed. Anthra-
coiherium Cuv., Hyopotamus Ow. (Ancodus Pomel), Merycopotamus
Falconer, u. molars with 4 tubercles only.
Fam. 5. Anoplotheriidae.f Extinct, Eocene and Miocene ; i f c 1
p | m f ; teeth in a continuous row, without gaps as in man ; molars
seleno-bunodont, u. molars with an intermediate tubercle (Fig. 304 bis, A, b)
* W. Kowalevsky, On the Osteology of the Hyopotamidae, Phil. Trans.,
1873. t Cuvior," Ossem. Foss., 3, 1812.
584
UNGULATA.
sometimes between the anterior and sometimes between the posterior
tubercles ; anterior premolars elongated and cutting (Fig. 305) ; feet with
4, 3, or 2 digits, reduction inadaptive (Fig. 305, D), metacarpals and meta-
tarsals not united ; ungual phalanges pointed. Anoplotherium Cuv., with
u
FIG. 305. — A Upper grinders, B right lower jaw frcm the side, C the same from below, D
manus, E pes of Diplobune quercyi Filhol (from Zittel).
long tail, with three complete digits (probably webbed) ; Eocene of
Europe. Diplobune Rut.
ARTIODACTYLA. 585
Fam. 6. Caenotheriidae.* Small animals with selenodont dentition,
with 4 complete digits, outer digits not reaching ground, radius and ulna
separate ; they are supposed to show affinities to the Tylopoda ; Miocene,
France. Caenotherium Brav., Plesiomeryx Gervais. Dichobune Cuv.,
U. Eocene, Europe, with tubercular molars is allied here.
Fam. 7. Xiphodontidae.f With selenodont molars, feet slender,
didactyle, the lateral metacarpals and metatarsals much reduced, reduction
madaptive. Teeth continuous, without gap, canine not enlarged ; last
premolars like the molars ; appear to be related to the Tragulidae and
Cervidae, U. Eocene, Europe. Xiphodon Cuv., Dichodon Ow., Amphi-
meryx Pomel.
Fam. 8 Oreodontidae.J Teeth in closed series or with diastema,
molars selenodont, u. molars with 4 rarely with 5 crescents, lower canine
incisor-like, and anterior premolar assuming its function ; metacarpals
and metatarsals separate. Feet tetradactyle, manus sometimes penta-
dactyle. U. Eocene to L. Pliocene of N. America. They are closely
allied to the Anthracotheriidae and Anoplotheriidae, but not to any
living forms. Protoreodon Scott and Osb., Oreodon Leidy, dentition
complete, without diastema, orbit complete, odontoid spoutshaped, said
to have had a clavicle. Agriochoerus Leidy, premaxillae toothless,
diastema in both jaws, manus with 5, pes with 4 digits, apparently
ending in claws, § pollex, which is small and functionless, apparently
occupies an opposable position.
RuminantiaJI
Living selenodont Artiodactyls with complicated stomach; usually with-
out incisors in the upper jaw, or with only one pair ; three pairs of incisors
in lower jaw with an incisiform canine applied to them ; p f m f ; meta-
podia 3 and 4 always united to a cannon bone (metacarpals remain long
separate in Hyomoschus). Digits 2 and 5 always reduced and frequently
absent ; horns provided with a bony core generally present. The
stomach of a typical ruminant (Fig. 306) is divided into four chambers, of
which two — the rumen and reticulum — may be regarded as belonging to
the cardiac, and two — the psalterium and abomasum — to the pyloric
division. The rumen or paunch is a large sac on the cardiac side with a
papillated lining. It opens by a wide aperture into the smaller reticulum
the lining of which is raised into a number of folds which bound small
hexagonal cells. The reticulum opens into the psalterium which is part
of the pyloric division ; it is tubular and its lining is produced into a number
of longitudinal lammelliform folds, which bear some resemblance to the
leaves of a book (hence the name). The fourth chamber is the abomasum
or rennet-stomach ; it has a vascular glandular lining and is the digestive
chamber of the stomach. The oesophagus opens at the junction of the
paunch and the reticulum and there is a groove bounded by muscular
* Filhol, Ann. Sci. Geol., 8, 1877 and 10, 1879. Owen, Palaeontology,
1860. Lydekker, Cat. of the Fo#s. Mam. in the B.M. 1885-7.
t Cuvier, Ossem. Foss., 3, 1812.
{ Scott, Morph. Jahrb., 16, 1S90, p. 319.
§ Wortman, Bull. Amcr. Mus. N. Hist , 7, 1895, p. 145. In spite of
this remarkable feature, the animal appears to have been digitigfade.
|| Rlitimeyer, Fauna der P/ahlbauten. Id., Versuch einer natiirlichen
Oeschichte des Rindes, Dentech. der Schweizer Naturf. Gesellschaft, 22
and 23. Sundevall Methodwche Ubers. ub. d. wiederkauenden Thiere, 2
Theale, 1847.
586
UNGULATA.
folds leading from it to the psalterium. The lips of these folds can be
approximated so as to convert the groove into a canal leading from the
oesophagus to the psalterium. The food when first swallowed passes into the
rumen and reticulum and remains there, mixed with swallowed saliva
until the animal has eaten what it requires. It then lies down to chew the
cud or ruminate. The first part of this process is akin to vomiting,
portions of the swallowed food being successively regurgitated into the
mouth, by a contraction of the diaphragm and abdominal muscles and a
reversed peristalsis of the oesophageal muscles. Tn the mouth it is
thoroughly mas-
ticated and then
again swal-
lowed. But now
the finely tri-
turated food
does not stay in
the paunch but
passing along
the groove, the
lips of which
may be approxi-
mated, it enters
the psalteri\im
through which it
passes into the
abomasum,
where it is sub-
mitted to the
action of the
gastric juices.
In the Tragu-
lidae and the
Camelidae the
stomach is very
similar in its
main features,
but the psalter-
ium is reduced
or absent. The
placenta is
generally coty-
ledonary, i.e. the villi of the chorion are concentrated into a number
of bunches or cotyledons, the intermediate portions being devoid of
papillae.
The Ruminantia comprise the Camelidae, Tragulidae, and Pecora.
Fam. 9. Camelidae (Tylopo da). Witho ut horns • i'±^± c} p |^fw|;
the dentition is complete in some of the extinct, but reduced in the liv-
ing ; grinders selenodont, hypsodont. Arches of the cervical vertebrae
perforated by the vertebrarterial canal as in Macrauchenidae ; orbit
enclosed, tympanic bullae filled with spongy bone. Ulna reduced and
ankylosed to radius, fibula represented only by its distal end, the malleolar
bone, which is articulated to the lower end of the tibia and to the cal-
caneum. Trapezoid and magnum, cuboid and navicular distinct, cunei-
forms 2 and 3 fused ; feet tetra- or didactyle, outer toes absent in recent
FIG. 306. — A stomach of a sheep, B of Tragulus. oe oesophagus,
Ru rumen, Ret reticulum, Ps psalterium, A, Ab abomasum, Du
duodenum, Py pylorus (from Huxley).
ARTIODACTYLA, RUMIXANTIA. 587
forms ; metacarpals and metatarsals 2 and 3 fused except in the oldest
forms ; cannon bone cleft below, digits with nails not hoofs, digitigrade on
cushion-like pads. Stomach 3-chambered, psalterium absent, riynen
smooth, with a number of diverticula with narrow openings which can be
shut off by a sphincter muscle from the stomach : these are the water-
cells and into them can pass the fluid of the stomach. The blood corpuscles
are elliptical. Placenta diffuse. Two living genera, Camelus L., camels
and dromedaries, dentition i ^ c \ p f m f , three incisors in upper jaw
in the young ; lower incisors procumbent; with one or two dorsal adipose
humps ; hairy not woolly, 2 species, Asia ; C dromedaries L., arabian
camel, one hump ; unknown in the wild state ; C. bactrianus L., 2 humps,
also domesticated but wild in Turkestan. Fossil species in U. Miocene
of India. Lama (Auchenia) G. Cuv., dentition i | c } p ,rjri m f ;
without hump, hair woolly, smaller than Camelus, they kick, bite, and
spit, and in their stomach are found bezoar stones ; 4 species usually dis-
tinguished, L. glama, the lama (not known in the wild state) ; L, pacos,
the alpaca ; L. huanacus, the guanaco, L. vicugna, the vicugna ; all in
S. America, the two first domesticated. Extinct species from Pliocene
and Pleistocene of Arner. Extinct genera from the Miocene onwards of
Amer. In Leptotragulus Scott and Osb., from the Eocene of Amer. with
3 premolars only in the lower jaw, there are 4 toes and the metapodia are
separate. Protylopus Wortm.,* Eocene, N. Amer., dentition complete,
orbit not enclosed, pes with digits 2 and 5 vestigial, about the size of a
rabbit. Poebrotherium t Leidy, Miocene of N. Amer., in form and size
resembling a small gazelle, has brachyodont, complete dentition, i f c \
p $ m |, metapodials separate and remnants of metapodials 2 and 5.
Protolabis, Miocene, dentition as in the last. Procamelus Leidy, Miocene
and L. Pliocene of N. Amer. i ± c \ p $ m f , metapodia united and no
trace of lateral digits. No fossils of the Camelidae except those of the
genus Camelus have been found in the Old World. It has been held that
the extinct genera show less and less specialisation as Camelidae, the
older they are ; but this statement is only a rough approximation to the
facts. Leptotragulus 1 (Parameryx) which is found in the same beds as
Protylopus and has more complete outer digits, has a dentition more special-
ised not only than that of Protylopus but even than that of the later Protola-
bis, in the fact that there are only 3 lower premolars. Wort man (op. cit.) in
his account of the phylogeny of the Camelidae gets over this fact by
describing Leptotragulus as a " precociously specialised side branch
which died out at the close of the Eocene." Moreover Protylopus, which
by its small size and other features might be regarded as a primitive type,
possesses unfortunately hardly any trace of the outer digits in the pes.
This difficulty is got over by supposing that the manus, which is unknown,
possessed four digits (Wortman, op. cit., p. 137).
Fam. 10. Tragulidae.§ Chevrotains. Hornless small animals, with
conical odontoid process, four complete toes (outer toes reduced), metapodia
of 3 and 4 uniting late, complete fibula ankylosed at its lower end with
the tibia, well developed canines, secant premolars, three-chambered
stomach and diffuse placenta. The premaxillae are edentulous, the lower
* J. L. Wortman, The Extinct Camelidae of N. America, etc., Bull.
Amer. Mus., 10, 1898, p. 93-142.
t Scott, Journ. Morpt., 5, 1891, p. 1.
J Scott, Trans. Amer. Phil. Soc., N.S., 16, 1896, p. 479.
§ Thomas, P.Z.S., 1891, p. 385.
588 UNGULATA.
canines are incisiform, p ± w f » the premolars secant ; molars seleno-
dont ; the navicular, cuboid and ectocuneiform bones are united. The
psalterium of the stomach is reduced to a tube. Blood corpuscles To<5oo in.
in diameter. 2 living genera, S. Asia and Africa ; an ancient family,
known since the Eocene. They are in many respects intermediate between
the Ruminants and the other Artiodactyls, the stomach, placenta and feet
recalling the latter. Tragulus Pall., smallest living Ungulate, 3 species
from the Malay Peninsula, 1 from Ceylon and India, 1 species in the
Pliocene. Hyomoschus Gray (Dorcatherium}, 1 species, the water-chevro-
tain, from W. Africa. Extinct genera, Lophiomeryx Pomel, Eocene,
France ;. Gelocus Aymard, Miocene, France, sometimes placed with the
Xiphodontidae ; Dorcatherium Kaup, Miocene, Europe and Asia.
Peeora (Cotylophora).*
Skull usually with horns containing a bony core i g c —^ p f ra -J ;
lower canines as incisors ; premolars simpler than molars ; odontoid
process crescent-shaped ; molars brachydont or hypsodont ; with closed
orbit ; a vacuity between the nasal, lacrymal, frontal and maxilla (absent
in sheep and oxen) ;
large lacrymals,
often with a depres-
sion, the suborbital
or lacrymal fossa ;
tympanic not fused
to periotic ; bulla
small without can-
cellous tissue ; large
paroccipital process.
FIG. m.^knU o< Cbw *NM*fMif. Ulna reduced, fixed
behind the radius ;
fibula reduced to the malleolar bone which articulates with the lower
end of the oibia ; metapodia of digits 3 and 4 aiikylosed into a
cannon bone, those of 2 and 5 never complete and often absent
together with the reduced digits ; navicular and cuboid coalesced.
The stomach has four complete chambers. The placenta is cotyledonary.
The Peeora are entirely absent from the Australian region, and there are
comparatively few living forms in the New World. Bovidae are entirely
absent from the Neotropical region and there are only four genera in the
Nearctic. Living Cervidae are entirely absent from the Ethiopian region.
Fam 11. Cervidae.f Deer. Horns when present have the form of
antlers. They consist of bony processes of the frontal bones covered
during their growth by a soft vascular velvety skin. They are found in
the male only, but in the reindeer they occur in both sexes. They are
absent altogether only in Moschus and Hydropotes. They are shed each
year after the rutting season and grow again with great rapidity in the
following year. When they have attained their full size a circular ridge
— the burr — is formed round the base at a short distance from the skull,
and the 'velvet' gradually dries up and is rubbed off. Later absorption of
bone takes place on the proximal side of the burr and the antler is shed.
* A. H. Garrocl, Proc. Zool. Soc. 1877, p. 2.
f Riitimeyer, Beitr. Nat. Geschichte d. Hirsche, Abh. Schweiz. paldonl.
Ges. 7, 1880 ; 8, 1881 ; 10, 1883. Lydekker, Deer and their Horns, 1808.
ARTIODACTYLA, RUMINANTIA.
589
gall-bladder
60 species,
There are no horns in the young, but they make their appearance in the
first year in a simple form, becoming, in the species which have branched
antlers, more complicated and branched at each subsequent year until
complete maturity is attained. The main stem of the antler beyond the
burr is called the beam ; the part below the burr is the pedicle ; the branches
of the beam are called the lines or snags. The teeth are brachyodont, the
neck being from the first on a level with the alveolar border. Upper
canines are usually present in both sexes. The magnum and trapezoid are
fused, as are usually cuneiform 2 and 3, cuneiform 1 remaining separate.
The outer digits of the feet are usually present though small, their meta-
podia being reduced, and either separate or fused with the cannon
bone. The placenta has few cotyledons, and there is no
(except in Moschus). There are 11 genera, and about
present all over the world except in the Australian
and Ethiopian regions. Moschus L., musk deer, without
horns, upper canines large, lateral hoofs of pes well de-
veloped ; musk gland on the abdomen of the male only,
opening in front of the prepuce ; highlands of C. and E.
As. Cervulus de Blainv., muntjacs, hoofs but not the
bones of the lateral digits present ; S. and E. Asia and
islands ; 53 species. Elaphodus M. Edw., China. Cervus
L., deer proper, 22 species, one species C. canadensis, the
wapiti, in the Neartic region, the rest Palaearctic and
Oriental ; C. elaphus the red-deer, C. dama the fallow
deer. C. giganteus, extinct Irish-elk ; the genus appears
in the Pliocene. Rangifer H. Smith (Tarandus Ogilby),
reindeer, both sexes with antlers, arctic, circumpolar.
Alces H. Smith, the elk or moose, arctic, circumpolar.
Cervalces Scott, extinct, Pleistocene of N. Amer. Cap-
reolus H. Smith, Eur. and C. Asia ; probably 1 species,
C. caprea the roe-deer. Hydropotes Swinhoe, water-deer,
without antlers, with large upper canines, China. Cariacus
Gray, N. and S. Amer., about 20 species. Pudua Gray,
Chilian Andes, and Patagonia, 2 species.
Several extinct genera are known in Europe frcm
the Lower Miocene onwards. In the oldest Miocene
forms horns are absent, e.g. Palaeomeryx v. Meyer, Amphi-
tragulus Pomel, and the earliest deer with horns is Dicro-
cerus Lartet from the Middle Miocene. In the later forms the horns~are
said to increase in complexity as the present time is approached. But this
statement, like so many others of the same kind will not bear close
examination, for the stag with the most elaborate antlers known (Cervus
Sedgwickii] is from the Pliocene. All we can at present affirm is that the
Miocene deer so far discovered are without horns or have only simple
horns.
Fam. 12. Giraflidae.* The living forms have long limbs (the anterior
being the longest), long necks, and are usually provided with horns, which
are covered by the ordinary skin and thus differ from the horns of all other
Artiodactyls. The horns have a bony core, usually placed over the suture
between the parietal and frontal bones, at first separate from the skull,
but later ankylosing with it. They are present in both sexes and in the
FIG. 80S.— Ma-
nus of red-
deer (Cervus
elaphus) x |.
* Falconer, op. cit., 186S, Forsyth Major, Proc. ZooL Soc., 1891, p. 315.
590 UNGULATA.
new-born young. In' addition there is a smaller median process of the
frontal, which increases with age. i £ c ^ p f m §, molars brachyodont
with rugose enamel. Lateral digits are entirely absent and the humerus
has a double bicipital groove. Gall-bladder present. Giraffa Zimm., two
living species confined to Africa ; G. camelopardalis L., the giraffe or
cameleopard, lives on foliage of trees, especially the mimosa, over which
its head towers to 16 feet in height, gregarious, Somaliland ; G. capensis
E. Geoff., S. Africa. The genus is found fossil in the Pliocene of Greece,
Persia, and India. A second genus, Okapia Lankester, has recently been
discovered in the Semliki forest, West Afr., it has a shorter neck, and the
horns are on the frontal bone.*
Extinct genera from the U. Miocene of S. Europe, Persia and India.
Helladotherium Gaudry, hornless, neck shorter than in Giraffa, limbs
nearly equal, U. Miocene of Greece and India. Palaeotragus Gaudry, with
long horns, U. Miocene of Greece. Samothsrium Fors. Maj., male skull
with a pair of short horns, neck shorter than in Giraffa, U. Miocene of
Samos and Persia. Sivatheritim Falc. and Cautl., two pairs of horns, the
posterior are the larger and palmated, neck short, limbs equal, Miocene
of India ; Hydaspitherium Lydekk., Bramatherium Falc., are similar to the
last.
Fam. 13. Antilocapridae. The horns are on the cavicorn type, but
are deciduous and branched ; they contain a bony core which is not
branched and not deciduous. Antilocapra Ord, the prong-buck, confined
to N. America, 1 species.
Fam. 14. Bovidae.t Antelopes, sheep, goats and oxen. The horns
consist of a bony core and an outer horny covering. The core is a process
of the skull and frequently contains prolongations of the frontal air
sinuses ; the horny covering is an epidermal product ; neither the core
nor the horn is shed. They are present in the males of all Bovidae and
in the females of many. Molars frequently hypsodont, the neck being
at first hidden in the socket. The cotyledons of the placenta are numerous.
Gall bladder generally present. Lateral digits usually present, represented
by hoofs with or without reduced skeleton. In other respects they resemble
the Cervidae. The Bovidae are the largest group of the Ungulata at the
present time, containing 45 genera and about 200 species, the bulk of
which are antelopes. J Found all over the Old World (not in Australia),
five genera in the Nearctic region, absent from the Neotropical.
Sub-fam. 1. Bubalinae. Large African antelopes, horns in both
sexes. Bubalis Cuv., 9 species, Afr., B. caama F. Cuv., the hartebeest.
Damaliscus Scl. and Th., 7 sp., includes the bontebok and blessbok,
Afr. Connochoetes Licht., 3 sp., includes the gnus, Afr.
Sub-fam. 2. Cephalophinae. Small or medium African and
Indian antelopes, horns in the males only. Cephalophus S. Smith,
with 20 sp., duikerboks, Afr. Tetraceros Hardw., with 1 sp., 2 pairs
of horns, India.
Sub-fam. 3. Neotraginae. Africa, horns in male. Oreotragus A.
Smith, with 1 sp. the klipspringer. Ourebia Laurillard, with 5 sp.
Eaphicerus H. Smith, with 4 sp., includes the grysbock and steinbock.
* Lankester, Trans. Zool. Soc., 16, 1902, p. 279.
f Rutimejrer, Kinder der Tertiaren-Epoche, Abh. Schv.'eiz. palaont.
Ges. 4, 1877.
J P. L. Sclater and O. Thomas, The Book of Antelopes, 1900, London.
ARTIODACTYLA, RUMINATIA. 591
Nesotragus v. Diib., with 2 sp. Neotragus H. Smith, with 1 sp. includes
the royal antelope, only 10 inches high. Madoqua Og., with 6 sp.
Sub-fam. 4. Cervicaprinae. Water-bucks and reedbucks. Afr. ;
horns in male only. Cobus A. Sm., with 13 sp., waterbucks. Cervi-
capra Blainv., with 5 sp., reedbucks. Pelea Gray, with 1 sp.
Sub-fam. 5. Antilopinae. Horns sometimes in both sexes, Palae-
arctic, Oriental and Ethiopian. A ntitope Pall., with 1 sp., black-buck,
India. Aepyceros Sundev., with 2 sp., includes the palla, Afr. Saiga
Gray, with 1 sp., E. Eur. and W. Asia. Pantholops Hodg., with 2 sp.
the chiru, Thibet. Antidorcas Sundev., with 1 sp., the springbok,
Afr. Gazella Blainv., with 25 sp., Palaearctic and Ethiopian. Am-
modorcas Thorn., with 1 sp., Somaliland. Lithocranius Kohl., with
1 sp., Afr. Dorcatragus Noack, with 1 sp., a pigmy form, Somaliland.
Sub-fam. 6. Hippotraginae. Large animals with long horns in
both sexes, u. molars like those of oxen; Afr. Hippotragus Sundev.,
with 5 sp., includes the sable antelope, blaubok, equine antelope,
Baker's antelope, Oryx Blainv., with 6 sp., Afr., extending into
Arabia and Syria, horns in both sexes, includes the leucoryx, gemsbok,
the beisa. Addax Rafin., 1 sp., N. Afr. and Arabia.
Sub-fam. 7. Tragelaphinae. Large bovine antelopes, Afr., with
one Oriental genus, horns usually in male only. Boselaphus Blainv.,
1 sp., the nilghai of India, female hornless. Tragelaphus Blainv., 6
sp., the harnessed antelopes, includes the guib, nakong, bushbuck.
Oreas Desmar., 2 sp., includes the eland, both sexes horned, the
largest antelope ; and Strepsiceros H. Sm., the kudu.
Sub-fam. 8. Rupicaprinae. Intermediate between the antelopes
and goats, Palaearctic and Oriental with one N. American genus.
Horns in both sexes. Rupicapra Blainv., 1 sp., the chamois. Nemor-
rhaedus H. Sm., 16 sp., Oriental, includes the goral,serow, cambing-
utan. Haplocerus H. Sm., 1 sp., the Rocky-mountain goat, California.
Budorcas Hodg., 1 sp., the takin of Assam.
Sub-fam. 9. Caprinae. Sheep and goats, both sexes with horns,
mainly Palaearctic, unknown before the Pliocene. Hemitragus Hodg.,
3 sp. Capra L., 13 sp., goats and ibex, both sexes horned, horns
flattened, males with strong odour, mountains of S. Eur., Abyssinia,
Persia, Himalayas, Thibet, N. China, the Nilgherries. Ovis L., 22 sp.,
sheep, male without odour and beard, mainly Palaearctic, also
Oriental and 1 sp., in N. America, essentially mountain animals.
Sheep are not known before the Pleistocene. The origin of the
domestic sheep is not known. Ovibos Blainv., 1 sp., the musk-ox,
Northern part of N. Amer.
Sub-fam. 10. Bovinae. Cxen. Horns in both sexes, muffle
naked, broad, moist ; not found in S. Amer. or Madagascar ; one
Nearctic species. Anoa H. Sm., 1 sp., Celebes. Buffelux Rut., 7 sp.,
buffaloes, India, Africa, B. caffer from the Cape. Bibos Hodgs.,
4 sp., the gaur, India, the gayal, Indo-China, the banteng, Indo-China
and the Islands. Poephagus Gray., 2 sp. Bison H. Sm., 2 sp., the
American bison, and the aurochs (B. bonasus) of Europe. Bos L.,
1 sp., now only known in the domestic state, including the varieties,
xcoticus, primigenius (extinct, Pleistocene), urus, etc. The Chillingham
cattle are supposed to be but little modified descendants of B. primi-
genius. Numerous extinct genera are known from the Miocene on-
wards of Europe. They first appear in the Middle Miocene.
592 UNGULATA.
Sub-order 2. PERISSODACTYLA.*
Unguligrade forms in which the axis of the limbs passes through
the middle of digit No. 3, which is symmetrical in itself, and the
toes of the hind foot are odd in number, never being more
than three. The premolars and molars are alike, and the last
lower molar is not larger than the others. The first milk
molar is generally replaced. There is an alisphenoid canal
and the nasals are expanded posteriorly. The number of
dorso-lumbar vertebrae is always more than twenty- two.
The femur has a third trochanter, the fibula does not articu-
late with the calcaneum, and the facets upon the distal face
of the astragalus for the navicular and cuboid are very un-
equal and its distal surface is flattened.
These are the differential characters of the living members of
the sub- order. They may need some slight qualification in
dealing with the extinct members.
The dentition is frequently complete, i | c -f p ¥ m |,
especially in the Eocene forms ; with increased specialisation
there is a tendency to the reduction of the incisors, and a loss
of the upper canine and first premolar ; the posterior premolars
very commonly resemble the molars (except in some older forms).
The grinding teeth are brachyodont in the primitive forms, and
generally lophodont ; but occasionally they tend to be bunodont.
In the higher forms they are hypsodont, the tubercles being very
long, and folded, and the valleys filled in with cement. The last
lower molar is commonly without a third lobe.
The tympanic is small. The orbits are generally open
behind (closed only in the Equidae). The dorso-lumbar
vertebrae are never fewer than 22 (except in Tilano-
therium). The scapula is generally without an acromion.
The ulna and fibula are complete and free in the less
specialised forms, but they become slender distally and
incomplete in the higher. The carpus consists of eight bones,
the bones of the two rows alternate ; the pollex is always absent.
In the tarsus fusion of the cuneiforms may occur, otherwise the
bones remain separate ; there is never a trace of digits 1 and 5.
The stomach is simple, the caecum large, and the gall bladder
* G. Cuvier, Becherches, sur les oss. foss., 3rd ed., Paris, 1846. Cope,
The Perissodactyla, Amer. Nat., 1887, pp. 985, 1060. Osborn, The evo-
lution of the Ungutatft foot, Trans. Amer Phil. Soc., n. s , 16, 1889, p. 531.
PERISSODACTYLA.
593
is always absent. The cerebrum is well convoluted. The
mammae are inguinal, and the testes generally descend into a
scrotum or project from the inguinal canal. The placenta is
diffused.
There are only three living genera ; Tapir, Equus and Rhino-
ceros, but the number of extinct forms known is very great. The
earliest of these are from the Eocene.
Fam. 1. Tapiridae.* Short-haired forms of medium size with mobile
proboscis, i f c \ p ^ m | ; all grinding teeth brachyodont, with two
transverse ridges (bilophodont) ; p 1 of the u. jaw
• with a milk predecessor ; posterior premolars like
the molars except in the oldest fossil forms ; last
lower molar without a posterior lobe. Manus
with 4 digits, the ulnar digit not reaching the
ground, pes with 3 digits, each digit hoofed.
The orbits are not enclosed by bone, the
frontals being devoid of a postorbital process ;
the premaxillae are small and the nasals widely
separated from them ; the postglenoid and par-
occipital processes are large ; the tympanic is
reduced. Ulna and fibula well developed and
separate from the radius and tibia. They are
first found fossil in the Lower Eocene of Europe
and N. America and endure there until the
Pliocene.
Tapirua Cuv. Vertebrae, C 7, D 18, C 5, S 6,
C 12 ; dentition i | c | p £ m f ; the third upper
incisor is larger than the upper canine but the
lower canine is larger than the third incisor and
bites between the third incisor and canine of the
upper jaw ; considerable diastema between the
canines and premolar ; the premolars except the
first resemble the molars*. There is no distinct
scrotum. The two mammae are inguinal. The
placentation is diffuse. They are nocturnal,
inoffensive herbivorous animals frequenting forests
and the neighbourhood of water. There are 5 species, four of which are
neotropical, the other being oriental in the Malay Peninsula and Sumatra.
The genus is firsf met with in the Miocene. It is found in the Miocene
and Pliocene of Europe and Asia and in the Pleistocene of America.
There is a number of extinct genera. These vary from the size of a
rabbit to that of a rhinoceros. Some of them are united with the tapir
and some in a sub-family the Lophiodontinae, which show affinities to the
extinct Palaeotheridae.
Extinct genera. Lophiodon f Cuv. ^fcjpfmf; Eocene of
* Wortman and Earle, Bull Amer. Mus. N. Hist., 5, 1893, p 159
Gaudry, Bull. Soc. Geol. France (3), 25, 1897, p. 315.
t Osborn and Wortman, Perissodactyls of Lower Miocene Beds, Bull.
Amer. Mus., 7, 1895, p. 358. Osborn, Amer. Nat., 1892, p. 673.
FlQ. 309. — Tapirus
americanus L.
Left manus, x 4.
(from Flower).
Z— II.
Q Q
594 UNGULATA.
Europe, premolars simpler than molars, last lower molar with talon ;
Heptodon Cope and Helatetes Marse, Eocene of N. Amer. ; Colodon Marsh,
Eocene of N. Amer., Miocene of Europe. Protapirus Filhol, Oligocene of
Europe ; Systemodon Cope, Eocene of Amer. ; Palaeotapirus Filhol, Eocene,
Eur ; Insectolophus Sc. and Os., Eocene of Eur. and Amer., etc.
Fam. 2. Equidae.* Horses, asses, and zebras. Orbit closed. Grind-
ing teeth hypsodont, with much elongated tubercles or cusps and the
valleys filled in with cement ; i$c\p$m%, the first premolar being
small, without successor and early falling out. Upper molars with two
crescentic intermediate tubercles (six cusps in all) ; lower with a large
grooved pillar (anterior inner tubercle) at the junction of the two crescents
(see p. 595). Incisors chisel-shaped, the enamel being invaginated into
the crown to form the lining of a pit (the mark). Radius and ulna fused,
the latter being very slender distally. Manus and pes three- or one-toed,
the lateral digits being either complete but functionless, or reduced to
their metapodia (splint bones).
Fossil remains are found in the U. Miocene, Pliocene and Pleistocene
FIG. 310.— Skull of Equus cabaUus.
of Europe, Asia, N. Africa and America ; at the present day represented
solely by the genus Equus which is indigenous in Europe, Asia and Africa.
Equus L., the only living genus. In the upper molars both inner tubercles
(pillars) are connected with their respective intermediate crescentic
tubercles (Fig. 312, A). Manus and pes with a single complete digit, and
the proximal portions of metapodia 2 and 4 (splint bones). A callosity on
the inner side of the fore-limb above the carpus. The genus first appears in
theU. Miocene (? Pliocene) of India (Siwalik Hills) ; it is also found in the
Pliocene and Pleistocene of Europe, N. Asia, N. Africa and America.
Digit No. 3 alone is functional, digits 1 and 5 are entirely absent, and
digits 2 and 4 represented only by the proximal ends of their metapodia
(splint bones). The milk dentition is i f c \ m |, the permanent
* Marsh, Amer. Journ. Sci. (3), 43, 1892. Huxley, Annual Address,
Ceol. Soc., Quart. J. Geol. Soc., 1870, 26. W. Kowalevsky, op. cit. For-
syth Major, Beitrage zur Geschichte der foss. Pferde, Abh. Schweiz. pal.
Ges., 4 and 7, 1877-86. Scott, Osteology of Mesohippus, etc., Journ.
Morph., 3, 1891. A. Ecker, Das europaische Wildenpferd, etc., Globus,
34, Brunswick, 1878. J. M. M'Fadyean, Anatomy cf the Horse, 1884.
F. H. Huth, Bibliographical Record of Hippology, 1887.
PERISSODACTYLA.
595
Fia. ' 311.— Un-
worn, upper molar
of horse. The an-
terior side of the
crown is to the
right and the
outer side is up-
wards (from
Flower and Ly-
dekker).
i 4 c \ p i m f , the first premolar has no successor and falls out early (wolf
tooth), and the others are similar to the molars ; the last molar is not
more complex than the others, nor the last milk molar than the premolar
which succeeds it. The incisors are chisel-shaped and their crowns possess
a deep cavity (the mark) which is formed by a fold of the enamel and
eventually disappears as the tooth wears down by mastication ; the first
molar comes into place long before the milk-nrolars
are shed, and the canines (tusks) are small and do
not always appear in the female ; there is a con-
siderable diastema. The grinding teeth are hypso-
dont and grow for some time, eventually forming
roots. The upper molars possess four main tuber-
cles and two intermediate, the latter being placed
between the tubercles of the anterior pair and those
of the posterior pair. The two exterior tuber-
cles are semilunar in form with their concavities
outwards (Fig. 311) and are connected together,
forming the doubly-concave outer wall of the
tooth. The outer wall is marked by a vertical ridge
formed at the concrescence of the two tubercles.
The outer wall possesses therefore two concavities
and is W-shaped (in the worn tooth, Fig. 312,
a, c). The intermediate tubercles are also crescentic with their concavities
outwards. The anterior intermediate tubercle is connected with the anterior
part of the outer wall and the posterior intermediate with the middle part.
These in part longitudinally and in part transversely directed crescents
of the intermediate tubercles form in the worn tooth the laminae of the crown
(Fig. 312, 61, d1) ; the spaces between them and the outer wall are filled
with cement. The two inner tubercles (vertical pillar) remain tubercular,
but both are connected by ridges with their respective intermediate
tubercles. The anter-
ior inner tubercle (Fig.
312, 6) is the larger.
All these tubercles are
formed of enamel sur-
rounding dentine and
the valleys between
them are filled up with
cement which also
covers the whole
crown of the tooth.
As a result of masti-
cation these tubercles
are worn down and
islands of dentine are
exposed surrounded by their enamel. In consequence of this the
crown of the worn tooth is traversed by double bands of enamel
containing dentine between the two laminae of each band and em-
bedded in the cement which covers over the whole crown and fills in
the valleys (Fig. 312). The enamel on the concave side of the intermediate
tubercles is slightly plaited. In the lower molars there are only the four
main tubercles, the intermediate tubercles being absent. The two outer
tubercles are crescentic and joined to form the outer wall, but the crescents
FIG. 312. — A upper, B lower molar of Equus caballus (from
Zittel). a antero-external, b antero-internal, 61 antero-
intermediate, c postero-external, d postero-internal, rf1
postero-intermediate tubercle, y posterior internal, /3' /3"
anterior internal, a anterior part of anterior outer tubercle
of the lower molar.
596 UNGULATA.
are convex externally, thus differing from the corresponding tubercles of
the upper molars. The outer wall, therefore, presents two convex surfaces
separated by a depression (Fig. 312, B). The inner tubercles (vertical
pillars) are grooved longitudinally on their inner faces, so that in the worn
tooth the enamel bounding them presents an hour glass -shaped form.
The anterior of these inner tubercles is attached to the junction of the
two outer crescentic tubercles, the inner and smaller being joined to the
posterior part of the posterior outer tubercle. The orbit is enclosed by
bone and the aperture of the lacrymal canal is intraorbital. The tym-
panic is prolonged into a tubular meatus, the post-tympanic and post-
glenoidal processes of the squamosal do not approach below the latter ;
there is a long paroccipital. Vertebrae, C 7, D 18, L 6, S 5, C 15 to 18, the
centra of the cervical vertebrae are opisthocoelous. The scapula is without
an acromion. The ulna and fibula are reduced and ankylosed with the
radius and ulna. The carpus has seven bones, the trapezium being absent.
There are two sesamoids behind the metacarpo-phalangeal articulation
and one at the joint between the second arid third phalanx. The femur
has a third trochanter. The tarsus has six bones, the ento- and meso-
cuneiform being generally fused. The horse stands on the termina
phalanx of the middle digit which is covered with a horny hoof. The
so-called " knee " is really the wrist, and the " hock " is the heel. The
fetlock is the metacarpo-phalangeal joint, the pastern is the joint between
the first and second phalanges, and the coffin- joint that between the
second and third phalanges. The first phalanx is the large pastern, the
second and small pastern, and the last is the coffin bone. There is a large
caecum, but no gall-bladder. The interventricular septum has a cartilage
and there is one precava. The cerebral hemispheres are well convoluted
and the sulci are deep. There is a scrotum, and the female has a hymen,
two inguinal mammae and a bicornuate uterus. The placenta is diffuse
and pregnancy lasts eleven months. E. caballus L., the horse, the long
hairs of the tail grow from the base of their organ ; with a small callosity
(the chestnut) on the inner side of the leg just above the hock ; in Europe
and Asia wild horses were formerly abundant and they have persisted in
the domesticated state to the present day, but it is doubtful if there are
any primitively wild horses now living ; in other words the horse appears
to be extinct as an originally wild animal all over the world. Horses have
escaped from domestication and become feral in many parts of the world,
even in America and Australia, which were without horses when they were
discovered. The species is found fossil in the Pleistocene of Europe,
N. Asia, N. Africa and America. E. przewalskii Poliakoff, C. Asia, with
callosities on both limbs, but the long hairs beginning halfway down the
tail. Sub-genus Asinus,* asses, with the species hemionus, kiang, onager,
hemippus, all from Asia, and asinus the domestic ass, which probably arose
in Africa and was derived from the species E. africanus N. Africa. Sub-genus
Hippotigris H. Smith, striped, Africa, with the species grevyi, quagga
(probably now extinct), zebra, 'burchelli. Extinct genera Protohippus f
Leidy (Merychippus, U. Miocene of N. Amer. , anterior inner tubercle of the
upper molars connected with its intermediate 'tubercle, three-toed, the
outer digits not reaching the ground. Pliohippus Marsh, Hippidion Ow.,
* Landkavel, Die wilden Einhufer Asiens., Zool. Jahrb, x, 1897. Prazak,
Wild Horses, I, 1898.
f Cope, Prelim. Report Vert. Pal. Llano Estacodo, Ann. Eep. Geol.
Survey Texas, 1892, p. 20.
PERISSODACTYLA.
597
FIG. 313. — A half worn upper molar of
Palaeotherium magnum (after Owen,
from Flower and Lydekker). //con-
cavities of outer wall, a postero-exter-
nal tubercle (metacone), ft antero-
external tubercle (paracone), cpostero-
internal tubercle (hypocone), forming
with the intermediate tubercle which
is not distinct the posterior transverse
ridge, d antero-internal tubercle
(protocone) forming with the not
distinct antero-intermediate tubercle
i (protoconule) the anterior transverse
ridge, e median valley, g posterior
valley.
Pliocene of Amer. Hipparion * Christol., grinding teeth less hypsodont
than in Equus (half the length), anterior inner tubercle of upper molar
isolated and laminae of enamel
more plicated than in Equus ; foot
tridactyle, outer digits not reaching
ground, ulna rather better de-
veloped than in the horse, about
the size of a donkey ; U. Miocene
and Pliocene of Eur., N. Amer.,
and Asia.
Fam. 3. Palaeotheriidae. Orbits
not closed, grinding teeth brachy-
odont, rooted, valleys not filled
with cement ; hinder premolars
usually like the molars, rarely
simpler ; last lower molar with or
without a third lobe ; u. grinders
with W-shaped outer wall ; 1.
grinders with two crescents which
at their point of union form one or
two small cusps ; radius and ulna
separate ; feet tridactyle, metapodia
relatively short, the lateral digits
reaching the ground ; U. Eocene and
Miocene of Eur. and N". Amer.
Palaeotherium G. Cuv., u. grinders
with W-shaped outer wall and two
oblique transverse ridges (Fig. 313), the intermediate and inner tubercles
forming the transverse ridges and not distinct from each other ; in the
lower molars the outer tubercles are crescentic and convex outwards (Fig.
314), but the inner tubercles (pillars of the horse) are not distinct ; the
three cuneiforms of the tarsus (Fig. 316, E} are separate ;
the skull is rather tapir like, and the neck shorter than
in Equidae ; they attain to the size of a rhinoceros ;
U. Eocene of Europe. Paloplotherium Ow., the inter-
mediate tubercles are distinct in the u. grinders, with
cement; pes (Fig. 316, D) as in the last, U. Eocene
of Europe. Mesohippus f Marsh, u. grinders with
W-shaped outer wall formed of the two V-shaped
outer cusps, there are four other cusps not united,
viz. two intermediate and two internal ; a splint like
metacarpal 5, in possessing which it approximates to
the next family ; Oligocene of N. Amer. Anchitherium £
H. v. Meyer (Figs. 315, C, 316, (7), more horse-like than
the other genera of this family, incisors slightly pitted,
u. grinders with W-shaped outer wall ; inner tubercles
connected with the outer wall by the semilunar inter-
mediate tubercles (the distinction between the inter-
mediate tubercles and the inner is not clear, as in
* Cope, Review of X. Amer. sp. of Hippotherium, Proc. Amer. Phil.
Soc., 1889.
f Osborn and Wortman, Bull. Amer. Mus. N. Hist., 1, 1895, p. 352.
% W. Kowalevsky, Mem. Akad. Imp. Sci., Petersbourg, (7), 20, 1873. ;
FIG. 314. — Palaeo-
therium crassum,
Cuv., anterior
lower molar (from
Zittel). ft antero-
external tubercle.
a antero-internal
tubercle not dis-
tinct from ft ; y
postero - external ,
•y1 postero-inter-
nal tubercle, ft}
cusp formed
where the cres-
cents meet.
598
UNGULATA.
Palaeotherium), with accessory tubercle behind. Odontoid process gpout-
like. Ulna and fibula complete, weak, fused with radius and tibia ; outer
digits complete but weak, U. & L. Miocene of Eur. and N. Amer.
Anchilophus Gerv., U. Eocene, Europe. Miohippus Marsh, L. Miocene of
B
D
M JT
FIG. 315.— Carpus and metacarpus of A Equus, B Hipparion, C Anchitherium, D Palaeo-
thenum. c cuneiform, I lunar, s scaphoid, u unciform, m magnum, td trapezoid, ii-v meta-
carpals (from Zittel).
Amer. ; \Desmaihippu8 Scott, U. Miocene, Amer., with brachyodont
grinders, valleys with thin cement, very similar to preceding, but if
anything nearer to Protohippus in its digits. In this series of genera
Anchitherium is perhaps the most equine, but its grinders depart
D
E
FIG. 316.— Bight pes of A Equus, B Hipparion, C AnchitJicrium, D PaloplotJierium, E Palato-
therium. ca calcaneum,. a astragalus, n navicular, cb cuboid, c 1-3 three cuteiforms, ii-iv
second to fourth toes (from Zittel).
PERISSODACTYLA.
considerably from the equine type of pattern and resemble thosa of
Paheotherium which is the most tapir-like.
Fam. 4. Hyracotheriidae.* * | c i p $ m | ; grinders low and
tubercular, premolars (usually tritubercular) simpler than the molars ;
upper molars (Fig. 317, A) with six cusps, lower (Fig. 317, B) with four ;
tubercles conical or V-shaped, ridges low ; orbit not closed, but post-
orbital process of frontal present ; odontoid conical ; radius and ulna
subequal, separate ; scapula with a well-marked coracoid process ; manus
with four (without trace of No. 1), pes with three digits. They are the
oldest Perissodactyls and are confined to the Eocene of Eur. and N.
Amer. Their grinders are practically bunodont. at any rate in the upper
jaw where there are hardly any outer wall or ridges. Hyracotherium Ow. ,
a smallish animal, about 3 feet long, Lower Eocene of Eur., and N. Amer. ;
Eohippus Marsh, and Protorohippus Wort., Eocene, N. Amer. ; Orohippus
(Epihippus) Marsh, and Pachynolophus Pomel, Eocene of Eur. and Amer.
teeth more equine with ridges connecting the tubercles; Propalaeo-
therium Gerv., M. Eocene, Eur., etc.
Much has been written on the ancestry
of the horse. It has been maintained by
many authors that a continuous series of
forms connecting it with the four -toed,
brachyodont, bunodont Hyracotheridae
of the Eocene has been discovered and
that here if anywhere a demonstrative
historical proof has been obtained of the
truth of the doctrine of organic evolution.
Without desiring in the smallest degree to
impugn that doctrine, it may be permitted
us here to examine rather closely the
view that the series of forms which recent
palaeontologies! research has undoubtedly
brought to light constitute that historical
proof which has been claimed for them.
The forms which are utilised for this series are : Pliohippus, Protohippus,
Desmathippus, Miohippus, Mesohippus, Orohippus and Hyracotherium.
The characters which are chiefly pointed to as showing the gradation are
those of the limbs, and the teeth, and to a certain extent of the skull.
Beginning at the lower end of the series, we find in Hyracotheriidae, brachy-
odont molars which are practically bunodont, a complete dentition, pre-
molars simpler than the molars, a well marked coracoid process on the
scapula, a conical odontoid process, an orbit not closed in by bone
though the frontal has a postorbital process, four complete digits on the
manus and three on the pes, radius and ulna nearly equal in size and
separate. In the stage next succeeding in the ascending order— Palaeo-
theriidae — we find these characters modified as follows : the teeth are still
brachyodont with little cement, low ridges connect the tubercles, the
hinder premolars are usually like the molars, a complete dentition ; the
orbit is still open ; the radius and ulna are still separate and about equally
developed, but the manus is tridactyle, digit No. 5 having become reduced
* Wortman, Species of Hyracotherium, etc., Bull Amer. Mus. Nat.
Hist., 8, 1896, p. 81. Earle, Comparison of the American and European
forms Hvracotherium, Amer. Nat. 1896, p. 131.
FIG. 317. — Hyracotherium lepor-
inum Ow. A second upper, B
first lower molar. The tubercles
are : a antero-external, a1 acces-
sory, 6 postero-external. ft1 an-
tero-intermediate, V postero-in-
termediate, c postero-external,
d postero-internal ; ft antero-
external, ft1 antero-internal, y
postero-external, y1 postero-in-
ternal (from Zittel, after Owen).
'600 UNGULATA.
to the merest vestige of its metacarpal, the pes is very similar to that of
the preceding family. The changes here, as compared with the previous
family, are the presence of ridges connecting the tooth-cusps, the reduction
of digit No. 5 of the manus.
We now come to the Equidae, where we find Protohippus with hypsodont
molars, about half the length of those of Equus, and valleys filled in with
cement, the anterior inner tubercle of the tipper molars is connected with
the intermediate tubercle, orbit closed, manus and pes tridactyle, the
outer digits not reaching the ground, no trace of any other digits, ulna
slender distally and fused with radius. Lastly we have Pliohippus with
rather longer grinders, very similar to Equus in pattern, without lateral
digits, the metacarpals only being represented ; ulna and fibula still more
approximating to the condition found in Equus.
So far as the characters mentioned are concerned, we have here a
very remarkable series of forms which at first sight appear to constitute a
linear series with no cross-connections. Whether, however, they really do
this is a difficult point to decide. There are flaws in the chain of evidence,
wh'ch require careful and detailed consideration. For instance, the genus
Equus ape ears in the Upper Siwalik beds, which have been ascribed to
the Miocene age. It has, however, been maintained that these beds are
really Lower Pliocene or even Upper Pliocene. It is clear that the decision
of this question is of the utmost importance. If Equus really existed
in the Upper Miocene, it was antecedent to some of its supposed ancestors.
Asain in the series of equine forms, Mesohippus, Miohippus, Des-
mathippus, Protohippus, which are generally regarded as coming into
the direct line of equine descent, Scott * points out that each genus is, in
some respect or other, less modernised than its predecessor. In other
words it would appear that in this succession of North American forms
the earlier genera show, in some points, closer resemblances to the modern
Equus than to their immedate successors. It is possible that these
difficulties and others of the same kind will be overcome with the growth
of knowledge, but it is necessary to take note of them, for in the search
after truth nothing is gained by ignoring such apparent discrepancies
between theory and fact.
Fam. 5. Rhinocerotidae.f Large unwieldy pachyderms, usually with
one or two epidermal horns on the strongly arched nasal and frontal
bones ; i ~~ c \~^ P 4^| m f , complete only in the oldest types ;
incisors and canines frequently absent ; premolars like the molars but
simpler in the older forms ; last lower molar without third lobe ; u. grinders,
with thick outer wall, nearly flat with obliquely transverse laminae, lower
grinders with two semilunar ridges joining to form the outer wall. The
orbit is widely open behind and the frontal is without a postorbital process ;
the nasals are extensive ; the postglenoid processes very large and may or
may not unite with the post-tympanic process of the squamosal to form a
false external auditory meatus ; the tympanic is annular. Ulna and
radius, tibia and fibula complete. Manus with 3 or 4, pes with 3 digits ;
digit No. 3 is larger than the others and symmetrical in itself, digit No. 1
is not present, and digit No. 5 when present in the manus is smaller than
* Trans. American Philosophical Society (N.S.) 18, 1896, pp. 119, 120.
f Lydekker, Notes on Rhinoceroses ancient and modern, Field, 79,
p. 903,' and 80, p. 38, 1892. Pavlow, Les Rhinoceridae de la Russie, etc.,
Bull. Nat. Moscow, 1892, p. 147.
PERISSODACTYLA. 601
the others ; it is never present in the pes. They have short necks and legs
and a very thick skin with scanty hair, and often folded so as to give them
the appearance of being armoured. The horns are purely epidermal
structures without bony core ; they have been compared to a mass ol
agglutinated hairs. The anterior horn is on the nasal bones, the posterior,
which is absent when there is only one, on the frontals. The stomach is
simple, the villi of the small intestine long, there is no gall bladder. The
testes hardly project, the uterus is bicornuate and the two mammae
inguinal.
They are stupid timid animals, but ferocious when attacked. They
often inhabit swampy regions and like wallowing in water or mud. At
the present day they are found in Africa, the Malay Islands, and tropical
India. They are known fossil from the U. Eocene onwards in the Old and
New Worlds, but they become extinct in America at the end of the Pliocene.
There is but one living genus, Rhinoceros L. (including the genera Cera-
torhinus Gray and Atelodus Pom. ), the incisors are variable and often fall
out early, there are no upper canines, the peculiar cutting teeth of the
front of the lower jaw are probably canines, p % m | ; the first milk
molar is smaller than the others and not always replaced ; the grinders
form roots early and the valleys are not filled in with cement. Vertebrae
C 7, D 19-20, L 3, S 4, C about 22. Manus and pes with three hoofed
digits ; in the manus there is a rudiment only of metacarpal 5.
The living species are R. unicornis L., India, with one horn ; R. son-
daicus Desm., with one horn, Java, India, etc. ; R. sumatrensis Cuv.,
Malacca, Sumatra, Borneo, two horns ; R. simus Burchell, the white
rhinoceros, Africa, two horns ; R. bicornis L., Africa, two horns. Many
extinct species from, the Miocene of the Old World onwards. It is there-
fore like the tapir a very ancient type. R. antiquitatis Blumenb. (ticho-
rhinus Cuv.) is the woolly rhinoceros of the Pleistocene of Europe — a huge
animal with two horns, the carcases of which with those of the mammoth
have been discovered in N. Siberia.
A large number of fossil genera, which have been arranged in sub-families,
are known from the earlier tertiary strata of the Old and New Worlds from
the U. Eocene onwards. Many of the older of these forms are charac-
terised by having a complete dentition, premolars simpler than the molars,
and a fully developed, though slender digit No. 5 on the manus. It is
impossible to deal with these here, but one or two may be mentioned.
Hyrachinus Leidy, U. Eocene of N. Amer. with 4 toes on manus. Hyra*
codon Leidy, with 3 toes in manus, L. Miocene of N. Amer., both with
complete dentition, without horns and with longer limbs and neck, and in
their general build more resembling Anchitherium than modern rhino-
ceroses. Aceratherium Kaup., hornless, with i \ c % p % m %, and 4 toes
on the manus, from the U. Eocene of France and Pliocene of India ;
Diceratherium Marsh, with two horns, U. Miocene, N. Amer. Elas-
motherium Fisch., Pleistocene of Siberia, a huge beast with 2 horns, with
p '4 m $, enamel much plicated, very hypsodont and valleys filled with
cement ; Amynodon Marsh, is the type of an ancient and primitive group
from the U. Eocene of N. Amer.
Here maybe placed provisionally the Titanotheriidae,* which depart in
* Earle, A memoir upon the genus Palaeosyops Leidy and its allies,
Journ. A cad. Philadelphia, 9, 1892, p. 267. Osborn, Revision of the
genus Tdmatotherium, Bull. Amer. Mus. N. Hist., 1, 1895, p. 82, and 346.
602 UNGULATA.
some important respects from the perissodactyl type, e.g. the fore-foot is
artiodactyl-like, and the number of dorso -lumbar vertebrae is less than 22.
They are huge extinct beasts from the Eocene and Miocene of N. America
and probably of Europe. They possessed two bony horn-like prominences
on the nasal bones. cj^|* T P ^Tvm f » grinding teeth brachyodont
with a W-shaped outer wall and two inner tubercles with low connecting
ridges. Manus with 4 digits, artiodactyl-like, axis passing between digits
3 and 4, pes perissodactyl with 3 digits. The bones of the two
carpal rows alternate. Premolars like the molars in the later forms,
simpler in the older ; femur with a small third trochanter, and the fibula
articulates with the calcaneum. The orbits were open behind. The
brain cavity was small and there was a small, much convoluted cerebrum.
There appear to have been only 19 or 20 dorso-lumbar vertebrae, a
character which also recalls the artiodactyls ; probably omnivorous.
Lambdotherium Cope, Palaeosyops Leidy, Titanotherium Leidy, Bronto-
therium and Brontops Marsh.
Sub-order 3. LIPOTERNA.*
They are remarkable extinct American digitigrade ungulates, f which
in the structure and reduction of their digits (the axis of the limb passing
through the third digit) and in the structure of their lophodont grinding
teeth resemble the Perissodactyla ; but they differ from them in the
carpal and tarsal bones not alternating, and in the fact that the fibula
articulates with the calcaneum as in Artiodactyls. The humerus is without
an entepicondylar foramen. The digits vary in number from five to one. The
astragalus is flattened below, the carpus has no centrale, the orbit is usually
closed, there is a third trochanter on the femur, and there is no clavicle.
The brain case is small and the dentition complete or slightly reduced.
The group is not well known, but the digits and the teeth show variations
not unlike those presented by the same organs in the Perissodactyls. For
instance the digits vary from five to one, the teeth show a tendency to
reduction in some genera, but these variations do not form a continuous
series as in the Perissodactyls. The oldest forms, e.g. Thoatherium f rom
the Eocene of Patagonia show a reduction in the teeth and of the digits
to the equine condition, and a diastema between the incisors and grinders,
whereas in the comparatively recent form Macrauchenia from the Pliocene,
the dentition is complete, the feet have three digits, and there is no gap
in the tooth series. A remarkable feature of the Macrauchenidae is the
presence of a mark in the incisors as in the Equidae, and in the same
family the vertebrarterial canal pierces the neural arches of the cervical
vertebrae as in the camels and My.mecophaga. It can hardly be sup-
posed that the sub-order is related to the Perissodactyls, but the resem-
blances are certainly remarkable.
Fam. 1. Maerauchenidae. Dentition i f c ± p \m f in a closed row ;
incisors with a "mark," anterior premolars simpler than the molars, grinders
rhinocerotine ; nasal openings far back, nasal bones reduced or aborted ;
* Ameghino. Contrib. al conocim de los Mammiferos foss. d. 1. Bepubl.
Argent., Actas Ac. nac. Cordoba, 1889, 6, p. 523, and Revista Argentina,
1, '1891. Cope, The Lipoterna, Amer. Sat., 25, 1881. Gervais, Mem.
JSoc. Geol. France, (2), 9, 1873.
•j- The reasons for placing this sub-order among the ungulates are stated
on p. 574.
AMBLYPODA. 603
feet 3- or 5-toed ; vertebrarterial canal perforating neural arches of cervical
vertebrae. Tertiaries of S. America. Theosodon Am., orbit open behind,
manus and pes with 5 digits, the outer being much reduced ; Eocene,
Patagonia. Macrauchenia Ow., manus and pes with three digits, orbit
closed ; femur with third trochanter ; Miocene and Pliocene S. Amer.
Fam. 2. Proterotheriidae. Nasal bones elongated, orbit closed, dentition
t $ C § p £ m $, with short diastema, grinders resembling those of
Anchitherium. Limbs 3- to 1-toed, the lateral metapodia weak. Tertiaries
of S. America. Proterotherium Amegh., Eocene, Miocene, S. Amer., with
3 toes. Thoatherium Am., with one toe, Eocene, Patagonia.
Order 9. AMBLYPODA.*
Extinct semiplantigrade animals with pentadactyle hoofed
limbs, interlocking carpals and tarsals, and very small brain.
There is no clavicle. A centrale is sometimes present in the carpus
and an entepicondylar foramen in the humerus. The grinders are
lophodont, and usually brachyodont.
We separate this order very doubtfully from the Ungulata. It
presents most of the ungulate features, and the grinders are
ungulate-like. The most remarkable character of the group is
the minute size of the brain which seems to separate it from all
other mammals (Fig. 319, A).
They are extinct, usually large, semiplantigrade animals with short,
hoofed, pentadactyle feet and broad terminal phalanges (Fig. 319). The
dentition is usually complete, and the grinders are brachyodont and
lophodont. The brain is very small and smooth, smaller and simpler than
in any other known mammal. The orbit is open behind. The ulna and
fibula are free and well developed. The carpalia alternate slightly and
a centrale is sometimes present, the astragalus is flattened and articulates
largely with the cuboid and with the tibia and fibula, and the femur has
a third trochanter only in the earlier forms. There appears to be no
clavicle, but the scapula has a large acromion. There is an entepicondylar
foramen in Pantolambda, but not in the more recent forms. The Amblypoda
present a certain resemblance to the elephants in their size, feet and
the general structure of their limbs ; but the resemblance is only super-
ficial. The head and dentition of the two groups differ totally, and the
resemblance in the limbs is quite superficial. For instance there is no
interlocking of the carpal and tarsal bones in the elephant, and the astraga-
lus is quite different in shape in the two groups. Moreover the elephant
has no third trochanter. They are found in Europe and America and are
confined to the Eocene. The earliest forms are from the Lower Eocene.
Pantolambda Cope, L. Eocene, New Mexico, of moderate size, dentition
complete, grinders tritubercular, skull without horns, femur with third
* Cope, The Amblypoda, Amer. Nat., 1884 and 5. Earle, Revision
of the species of Coryphodon, Bull. Amer. Mns. N. Hist., 4, 1892. Marsh,
Monograph of the Dinocerata, U. S. Geol. Surv., 10, 1884. Osborn, Bull.
Amer. Mus. N. Hist., 10, 1898.
G04
AMBLYPODA.
FIG. 318.— Tinoceras ingens, skeleton x -3\T, restored (after Marsh, from Woodward).
JH 8
Jj'iu. ^19. — Dinoceras mirauue. A outline of dorsal aspect of skull, shovung size and form
of brain cavity, x \. B left manus, and C left pes, x -|- (after Marsh, from Woodward).
TOXODONTIA. 605
trochanter ; scapular and neural spines as in the next, carpus with centrale,
humerus with entepicondylar foramen. Coryphodon Ow., dentition com-
plete, canines large, grinders ridged, neural spines weak, skull smooth,
without horns ; scapula characteristic, narrow above, shaped like a leaf ;
tibia articulates with the calcaneum and astragalus ; femur with third
trochanter ; about the size of a tapir, probably omnivorous ; this genus
was first made known by a fragment of a jaw dredged in the sea off the
coast of Essex. Lower Eocene of Europe and America. Dinoceras Marsh
( Uintatherium Leidy), approaching the elephants in size, with three pairs
of bony horn-like prominences on the skull, formed by prolongations of
the parietals, maxillaries, and nasals. Dentition i § c \ p 3-^ m f ,
canines as large tusks ; neural spines short ; scapula broad above ; limbs
elephantine, carpus without centrale (Fig. 319, B) and femur without
third trochanter, fibula articulating with the astragalus only ; M. and U.
Eocene, X. Amer. Tinoceras Marsh (Loxolophodon), contains the largest
forms (Fig. 318). The genus Arsinoitherium, Beadnell * from the Upper
Eocene of the Fayum of Egypt may be placed provisionally in this order.
It was a large animal with a massive skull bearing two pairs of horns,
the larger of which were furnished by the great nasal bone, and the smaller
by the frontals. The squamosal is large and there are large post-tympanic
and postglenoid processes, which approach one another below the auditory
meatus. The dentition is^fcyp^mf, the tooth series is closed, and
there is no clear distinction between the incisors, canines, and premolars.
The premolars and molars are hypsodont and lophodont and easily dis-
tinguishable. The scapula resembles that of Dinoceras. as do the tibia and
tarsus. The femur is without a distinct third trochanter.
Order 10. TOXODONTIA. +
Extinct semi plantigrade or plantigrade animals with tridactyle
limbs, hypsodont, rodent-like grinders, without clavicles and
entepicondylar foramen in the humerus. There is a centrale in
the carpus. The carpal bones interlock but the tarsals are
serial.
They are all extinct, South American forms and were herbiv-
orous and plantigrade. The dentition is usually complete, but
the canines tend to be weak or aborted. The grinders are
prismatic and somewhat rodent-like, resembling those of the
Typotheria. The fibula articulates with the calcaneum.
* Beadnell, A preliminary note on Arsinoitherium zitteli, Beadn., from
the Upper Eocene strata of Egypt, Survey Department Public Works
Ministry, Cairo, 1902. Andrews, Geological Mag., n. s., 5,' 1, p. 109 and
157.
f Burmcister, Ann. Mus. Buenos Ayres, 1, 1867, and 3, 1869. Cope,
On Toxodon, Proc. Amer. Phil. Soc., 1881, Owen. Toxodon in the Zoology
of the Voyage of the Beagle, 1840, and Nesodon, Phil. Trans., 1853.
Lydekker, op. cit., under Typotheria. Roth, Revista Mus. La Plata* 6,
1895, p. 333.
GOG TOXODOXTTA. TYPOTHERIA.
The earliest forms are from the Cretaceous of Patagonia, but the bulk
are from the Eocene. They extend through the Miocene into the Pliocene
where the first of them, Toxodon, was found by Darwin in the Pampas
Formation.
The dentition though often complete and continuous is very highly
specialised. The grinders are peculiar and can hardly be said to be
ungulate -like. The skull is massive, and high behind ; the nasals project
freely and are sometimes short and suggest a proboscis ; the lacrymals
are small -and the orbits open behind. It is difficult to say what affinities
the skull suggests. The structure of the fore-limbs in the form of the
scapula, the absence of a clavicle and the tridactyle manus, recalls the
rhinoceros. The same may be said of the hind limb, but the third tro-
chanter is small or absent, and the tarsalia are successional. These points
militate against perissodactyl affinities, as does the presence of a centrale
in the carpus. On the whole it is difficult to see why these animals
should have been placed with the Ungulata, unless it be because they
cannot be related to any other group.
Nesodon Ow., of small or moderate size, with nasal opening directed
forwards ; cerebrum large and much convoluted ; *£c-^p£mfiii
almost continuous series and most of the teeth rooted ; femur with small
third trochanter, and feet tridactyle and digitigrade ; Eocene, Santa
Cruz Formation. Toxodon Ow., large animals with nasal openings further
back, dentition reduced i f c ^ p ^ m f , all rootless, scapula without
acromion, radius crossing the ulna as in Proboscidea, carpalia alternating,
femur without third trochanter, extremities tridactyle and plantigrade,
Miocene, Pliocene.
Order 11. TYPOTHERIA.*
Extinct pentadactyle plantigrade animals, with a clavicle,
an entepicondylar foramen in the humerus, serial or interlocking
carpus, and an opposable hallux. A centrale is present in the
older forms, and the grinders are rodent-like.
If it was difficult to settle the position of Hyrax in the
mammalian series, it must be still more difficult to settle
that of the present group for all its members are extinct and
there is no living form to assist us with its soft parts. They
are generally placed with the Ungulata, though it is difficult
to see their ungulate affinities. They show some resemblances
to Hyrax, and to rodents.
Hitherto the Typotheria have only been found in South
America. They are first met with in the Cretaceous, but the
* Ameghino, Contrih. al Conoc. de los Mammi/eros de la Pepubl. Argen-
tina, Buenos Aires, 1889, and Revista Argentina de Hist. Nat., 1, 1891.
Gervais, Remarques sur le Typotherium, ZooL et Paleont. generales, 1 .
Lydekker, A study of extinct Argentine ungulates, Ann. Mus. La Plata,
Palaeont. Argentina, 2, 1893, 1894.
TILLODOXTIA. 607
bulk of them are found in the Eocene, though they extend
through the Miocene into the Pliocene.
Their general characters may be described as follows. They were small
animals, about the size of Hyrax. The brain cavity is small and the brain
was smooth ; the orbit is not closed though the frontal has a well
marked postorbital process. The skull on the whole recalls that of Hyrax,
and in certain features that of rodents and of the Toxodontians. The
dentition is in the oldest forms complete and almost in a closed series. It
is in many respects like that of the Toxodontia. The grinders are hypso-
dont and rodent like. In the older forms the teeth seem to have been
rooted, but in the more recent they were rootless. The scapula has a
coracoid process and its spine has an acromion and a peculiar backwardly
directed process as in elephants and some rodents, and there is a clavicle.
The humerus has an entepicondylar foramen. The ulna and radius are
separate and capable of rotation. The fibula articulates with the cal-
caneum and is separate from the tibia. The femur has a third trochanter.
The carpus has a cent-rale in the older forms, and the arrangement of the
two rows of bones is successional in the other, alternating in the more recent
forms. The manus possesses five digits, and the distal phalanges are
either broadened and hoof-like or split, like that of digit No. 2 of the foot
of Hyrax. The pollex appears in some cases at any rate to have been
opposable. In the foot the distal phalanges are broadened and the hallux
was opposable. The sacrum was composed of seven vertebrae as in some
edentates. Protypotherium Am., i -g c \ p $ raf in a nearly closed series ;
carpalia serial, with centrale, the pes has 5 digits, the fibula articulate
with the calcaneum, Eocene and Miocene. Icochilus Am., Eocene. Typo-
Iherium Bravard, i i c § \ p '\ m |, with wide diastema, grinders rootless ;
carpalia alternating, without centrale ; fibula articulating with astragalus ;
pes tetradactyle ; attains the size of a pig ; Miocene, Pliocene.
Order 12. TILLODONTIA.*
This is a group of extinct forms from the Lower and Middle Eocene of
N. America and according to Ameghino from the Cretaceous of Patagonia,
and there are fragmentary remains (Platychaerops Charlesw.) from the
Eocene of England. The group is not well known but the characters,
so far as ascertained, are as follows. Plantigrade, pentadactyle, with
clawed digits ; and rodent-like incisors growing from continuous or long-
persistent pulps, and with enamel only on their anterior face ; the u.
grinders are tritubercular, the lower tubercular-sectorial. The premaxillae
are large ; there is no postorbital process on the frontal ; the humerus has
an entepicondylar foramen, and the femur a third trochanter. The skeleton
presents resemblances to the Carnivora. The dentition when complete is
* I c T P :' m %> but the first and third incisors are smaller than the second
large rodent-like pair and may be absent. The canines also tend to be
reduced. The brain was small and weakly furrowed. The Tillodontia
were large and medium-sized land animals with likenesses to the Carnivora
and Rodentia and are often associated with the latter in classification,
* Marsh, Tillotherium, Amer. Journ. Sci. (3), 0, 1875, p. 221, and 11,
1S76, p. 249. Cope, Vertebrata of the Tertiary Form, of the West, 1877.
Wortman, Ganodonta, Bull. Amer. Mus. N. Hist., 9. 1897, p. 59.
TILLODONTIA.
Esthonyx Cope, Lower and Middle Eocene (Wasatch and Bridger), Anchip-
podus Leidy, Bridger Eocene ; Tillotherium Marsh, Bridgor Eocene, the
most specialised with dentition i'i c } p% m f, incisors very rodent-like,
but lower jaw with transverse condyle.
Here may be mentioned the Taeniodonta Cope (Stylinodonta Marsh)
lately^renamed Ganodonta,* known by fragmentary remains. The dental
series' is continuous or nearly so ; there is a tendency to reduction of
incisors, and the canines are large and sometimes resemble rodent incisors ;
the grinders are bilophodont or quadrituberculate (or tritubercular) and
there appears to
,„ -,, ^ . be a deficiency
" — if - A CA vi of enamel ; in
some species
there is hypso-
dontyand growth
from persistent
pulps; the radius
and ulna appear
to have admitted
of pronation and
supinationof the
manus, a clavicle
is present, and
the digits had
curved claws ;
there was a weak
third trochanter.
A fragmentary
manus seems to
resemble that of
a ground -sloth,
and on this evid-
ence together
with the poverty
of enamel in the
molars and cer-
tain features of
the pelvis and
vertebrae has
been evolved the
certainty that
these animals are
the Eocene fore-
runners of the Edentata. All are from the Lower Eocene (Puerco,
Wasatch and Bridger Beds) of N. America. Hemiganus Cope, Puerco
Beds. Psittacoiherium Cope, Upper Puerco, this is the genus of which the
ground sloth-like manus is known, canines and grinders rooted. Gala-
modon Cope, Wasatch Beds, and Eocene of England, with large rootless
canines like a rodent incisor, grinders with roots. Stylinodon Marsh,
Wind River, and Bridger Eocene, canines and all lower teeth rootless. It
is quite possible that the Ganodonta are allied to the Edentata, but there
FIG. 320,j — Homalodont other ium segoviae, A right manus, B third digit
in side view, x | (after Ameghino, from Woodward), en cunei-
form, In lunar, m magnum, me metacarpal, p pisiform, sc scaphoid,
id trapezoid, tm trapezum, un unciform, i-v digits, 1-3 phalanges.
* Wortman, op. cit.
ANCYLOPODA. COXDYLARTHRA. 609
is a large step from the admission of that possibility to the definite asser-
tion that they are the ancestors of that order.
The Conoryctidae with Conoryctes and Onychodectes Cope, from the
Puerco Eocene, are possibly allied here.
Order 13. ANCYLOPODA.*
Plantigrade forms with 3 or 5 digits apparently ending in claws. They
appear to have possessed characters common to a number of groups.
When first discovered they were placed with the Edentata, but their
grinders are perissodactyl-like, On the other hand they may be without
a third trochanter on the femur and the axis of the limb does not pass
through the third digit. The bones of the two carpal rows alternate, but
the tarsals are serial. They are found in the Cretaceous and Eocene of
Patagonia, in the Eocene of Europe, the Miocene of Europe, America and
Asia and a few in the Pliocene. Homalodontotherium Huxley, penta-
dactyle (Fig. 320), complete dentition, Eocene, Patagonia ; Chalicotherium
Kaup., tridactyle, without incisors, Miocene, Europe ; Macrotherium
Lartet, Miocene, Europe.
Order 14. CONDYLARTHRA.f
Extinct, plantigrade or digitigrade animals with pentadactyle
limbs, without hoofs ; without a clavicle. Carpalia and tarsalia
sometimes serial, sometimes interlocking. The carpus
usually with a centrale. Dentition complete ; grinding teeth
brachyodont and bunodont. The humerus has an entepicondylar
foramen and the femur a third trochanter. From the Eocene
of America, and a few remains in the Eocene of Europe.
They had a very small brain with an uncovered cerebellum
and a smooth cerebrum. The skull is elongated with orbits
widely open behind, the frontals and jugals being devoid of
postorbital processes. The canine teeth are not much
enlarged and the premolars are simpler than the trituber-
cular or quadritubercular molars. There is no clavicle. The
humerus has an entepicondylar foramen, therein differing
from that of Ungulata. They are commonly described as
* Ameghino, Enum. Synopt. des Mammif. tert. de Patagonie, 1894.
Flower, Homalodontotheriu^i, Phil. Trans., 1874. Huxley, Quart. J.
Geol. Soc., 1870. Filhol, Etudes sur les Mammif. de Sansan, Ann. Sci.
geol., 1891, 21. Osborn, Amer. Nat. 22, 25, 26, 27, 1889-93. Cope,
Amer. Nat., 1889, p. 658.
f Cope, Synopsis of the Vert. Fauna of the Puerco Series, Amer. Phil.
Soc., 16, 1888. Osborn and Earle, Fossil Mam. of the Puerco Beds., Bull.
Amer. Mus. N. Hist., 7, 1895. Matthew, A Revision of the Puerco Fauna,
ibid,, 9, 1897, p. 259. Osborn, Phenacodus, ibid., 10, 1898. Marsh,
Hyracops, Amer. Journ. Sci. (3), 43 1892.
Z— ir. E 1.
610
CONDYLARTHKA.
plantigrade, but Phenacodus was digitigrade. The carpus and
tarsus (Fig. 321) are very similar to those of Procavia (Fig.
290) ; the bones of the two rows are usually serially arranged
and the navicular articulates laterally with the cuboid. The
astragalus has a neck and convex distal surface, and resem-
bles that of
A "R
theCreodonta.
The three mid-
dle digits are
longer than the
outer, and the
axis of the limb
traverses digit
No. 3 as in Pe-
rissodactyla.
The terminal
phalanges are
expanded and
pointed and
musthave car-
ried hoof-like
nails. The
femur has a
third trochan-
ter — another
v perissodactyl
feature. Ulna
and fibula are
separate and
complete, and
KG. 321—Hyracops socialis Marsh. Lower Eocene, Wasatch. the fibula ends
A left manus, B left peg (after Marsh, from Woodward). R frpplv oo j^
radius, [7 ulna, s scaphoid, I lunar, p pisiform, ce centrale, tm trape- * "*J
zium, td trapezoid, m magnum, u unciform, ca calcaneum, a astra* (•* Q rr, i AT /-> r a
galus, n navicular, cb cuboid, 1, 2, 3 cuneiforms, x epicuneiform.
The tail ap-
pears to have been of some length. They were probably
omnivorous animals and they varied from the size of a tapir
to that of a fox.
This appears to be a central group with affinities to the
Creodonta, Perissodactyla, and to the Hyracoidea. Affinities
to the Insectivora and Primates have also been claimed by
CREODOXTA 611
Cope, so that, as it can hardly be supposed that we have
found remains showing all the variations of structure charac-
teristic of this order, it seems not unreasonable to conclude
that the Condylarthra constituted a group combining charac-
ters now belonging to many mammalian groups and totally
unlike any order now existing. If this view conveys a correct
appreciation of the facts, it would seem unwise to pick out
those of its features which show a faint resemblance to the
Ungulata, and allow them to fix the position of the group in
the system. We have therefore ventured to confer upon
the Condylarthra ordinal rank.
Periptychus Cope, basal beds (Puerco Formation) of the Eocene of New
Mexico, tarsal bones interlock. Euprotogonia Cope, L. Eocene of Xew
Mexico, with interlocking carpalia, the tarsus appears to be serial. Mio-
claenus Cope, L. Eocene of Xew Mexico, Protoselene Matthew, L. Eocene,
X. Mexico. Meniscotherium Cops, L. Eocene of Mexico, carpus and
tarsus serial. Hyracops Marsh, upper molars quadritubercular with
W-shaped outer wall, and two ridge-like intermediate tubercles. Pleuras-
pidotherium Lemoine, L. Eocene, France. Phenacodus Cope, of which
complete skeletons have been obtained from the Wasatch Formation of
X. America ; digitigrade with 15 dorsal vertebrae ; upper molars with
four principal and two intermediate tubercles ; the two anterior premolars
with one cusp, the two posterior with main cusp and one or two inner
cusps.
The Astrapotheridae may provisionally he placed here. They are
extinct forms from the Cretaceous and Eocene of Patagonia.
Order 15. CREODONTA.*
Extinct, digitigrade or semiplantigrade, carnivorous animals
with penta- or tetra-dactyle, clawed limbs. The canines are
large, the dentition complete and the brain small and weakly
furrowed. The carpus has a centrale, the femur a third tro-
chanter, and the humerus usually an entepicondylar foramen.
Eocene to the L. Miocene of Europe and North America.
The Creodonta are frequently placed as a suborder of the
Carnivora to which they present many resemblances, especially
in the dentition ; but they differ from them in the small size
of the brain, the absence of carnassial teeth, and in the
* Cope, The Creodonta, Amer. Nat., 1885. Schlosser, Die Affen, Le-
muren, Chiropteren, Insectivoren, Marsupialier, Creodonten und Carni-
vorcn des Europ. Tertiars, Beitr. zur Palaeont. Oesterr-Ung., 6, 1887, and
9, 1889. Osborn and Earle, Bull. Amer. Mus. Nat. Hist., 7, 1895. Scott,
Revision of the X. Amer. Creodonta, Proc. Acad. Nat. Sc. Philadelphia,
1892. Wortman, Studies of Eocene Mammalia, 1-4, American Journal
of Science, 13 and 14, 1902.
612 CREODONTA. CARNIVORA.
separation of the scaphoid and lunar bones of the carpus.
They also approximate closely to the Condylarthra, and show
some resemblance to the Insectivora, and to the carnivorous
Marsupials (through the Sparassodontidae, p. 540), but they
differ from the latter in having a complete succession of
teeth, and in being without the inflected angle of the lower
and the palatal vacuities characteristic of that group. It is
clear, therefore, that like the Condylarthra they are a central
group with affinities in several directions, and that it is safest
in the present state of knowledge to accord them independent
ordinal rank.
In addition to the important characters already referred to, the following
may be mentioned. The skull is carnivora-like and the muzzle usually
elongated. The dentition is normal, i^c\p^m^or slightly reduced.
The canines are powerful and sometimes two-rooted. The back-teeth are
inclined to be trenchant, but the carnassial modification, so characteristic
of Carnivora, is not found. The ulna and radius are separate, the carpus
has a centrale and the scaphoid and lunar are not united. The terminal
phalanges are often split and flattened at the ends. The lumbar region of
the vertebral column is rigid owing to the form' of the zygapophyses.
They appear to have been, in some cases at least, semiaquatic. The prin-
cipal genera are : Arctocyon Blv., a bear-like omnivorous form ; Mesonyx
Cope, a thylacine-like form ; Proviverra Rut. ; Sinopa Leidy (Stypolophus] ;
Patriofelis Leidy, a seal-like form ; Miacis Cope ; and Hyaenodon Luizer
and Parieu, the most specialised and best known of the group.
Order 16. CARNIVORA * (FISSIPEDIA).
Carnivorous, sometimes omnivorous mammals with large
projecting canine teeth, almost invariably three incisors on each
side in each jaw, cutting premolars, and tuberculate molars.
The last upper premolar and the first lower molar are always
modified as carnassial teeth. The clavicles are absent or
reduced, the scaphoid and lunar bones are fused, the limbs have
never fewer than four digits and are unguiculate. The placenta-
tion is zonary.
The Carnivora are by no means all exclusively carnivorous ;
a considerable number are omnivorous and some chiefly
* Gray, Carn., Pachyderm., and Edentate Mamm., Brit. Mus. Cat.
1869. C. Greve, Die geograph. Distrib. de jetzt lebenden Raubthiere,
Nov. Act. k. Leop-Carol Deutsch. Akad. Naturf. zu Halle, 63, 1.893. Lydek-
ker, Carnivora (Felidae and Viverridae) in Allen's Libraiy, 1895. H.
Winge, Jordfunde (Carnivora) fra Brasilien, cum appendice de class,
etc., E Museo Lundii, 1895. See also Cope, Amer. Nat. 1880, p. 833,
and 1883, p. 235. Flower, P.Z.S., 1869, p. 5. Mivart, P.Z.S., 1882,
1885.
CARNIVORA.
GIB
vegetable feeders. The dentition though essentially similar
throughout the group shows some variation which is generally
correlated with the mode of nutrition, though in the case of
the bears it would be difficult to distinguish the carnivorous
forms from the frugivorous by this character alone.
The essential features are as follows : six incisors (very
rarely fewer) in each jaw, conical or chisel-shaped, set nearly
in a straight line across the jaw and usually increasing in size
from within outwards ; two powerful pointed canines pro-
jecting beyond the other teeth ; a variable number of grinders
divided as
usual into ^ ^~~* x
premolars .
which have
predeces-
sors in the
milk denti-
tion, and
molars.
The lower
canines
bite in
front of
the upper,
which are
separated
from the
incisors by a small gap. One of the grinding teeth on each side
in each jaw is different from the rest and called the carnassial
or sector ial tooth. In the upper jaw the tooth so modified
is p 4, in the lower jaw m 1. The teeth in front of the
carnassial are sharp and compressed, those behind it as a
rule are broad and tuberculated. The former consist of a
main cusp to which is frequently added a small anterior and
posterior cusp. The carnassial tooth of the upper jaw (p 4)
has when typically developed, an elongated trituberculate
crown and three roots (Fig. 322, //). Two of these tubercles
(2, 3), of which the anterior (2) is the longer, may be said to
•constitute the outer blade of the tooth, while the third is
low (4) and forms a talon-like process at the anterior end of
FIG. 322.— Left upper carnassial teeth / of Felis, II of Canis, III of
Ursus, seen from the outer side and from below (from Flower
and Lydekker). 1 anterior, 2 middle, 3 posterior cusp of the
blade, 4 inner cusp of the upper carnassial, supported on distinct
root, 5 inner cusp posterpr in position and without distinct root,
characteristic of the Ursidae.
614
CARXIVORA.
the tooth ; the outer blade is supported on two roots and the
inner cusp on one root. In the Felidae (Fig. 322, /), Hyae-
nidae, and some Viverridae there is an additional anterior
outer tubercle (1), so that the blade is 3-cusped. In the
Ursidae (Fig. 322, ///) the inner tubercle and the correspond-
ing root are absent, but there is often a small posterior inner
cusp without root (5). The lower carnassial (ra 1) has two
roots and consists of an outer cutting blade with two cusps of
which the pos-
4 i "| W,4 terior is the
larger (Fig.
323, //, 1, 2),
an inner tu-
bercle (3) and
a talon (4).
In theFelidae
the talon is
not developed
(Fig. 323, /),
and the tooth
is entirely a
cutting tooth.
In the omni-
vorous forms,
e.g. U r s u s
(IV.), the
talon is much
developed
and tuberculated. The teeth behind the carnassial
(molars) have broad crowns and are trituberculate in the
purely carnivorous forms, tetra- or multi-tuberculate in the
omnivorous forms. The more exclusively carnivorous the
diet, the fewer and weaker are these teeth : in the Felidae
there are none of them in the lower jaw and only one pair in
the upper. From this account it will be gathered that in the
purely carnivorous forms the cheek teeth are practically
all sharp trenchant teeth, adapted for cutting the flesh off
the bones of the animals on which they prey, whereas in the
omnivorous or mainly vegetable-feeding species the posterior
cheek teeth have broad and tuberculate crushing crowns.
FIG. 323.- Left lower carnassial teeth 7 of Felis, II of Canis, III of
Herpestes, IV of Lutra, V of Meles, VI of \l'rstts (from Flovser
and Lydekker). 1 anterior, 2 posterior cusp of the blade ; 3 inner
cusp ; 4 talon.
CARNTVORA. 615
The milk dentition is i ij- c | m f (except in the Felidae
in which the deciduous molars are -i|). The first deciduous
molar dm 1 is displaced by p 2 of the permanent dentition,
dm 2 is displaced by p 3 but resembles p 4 (carnassial in the
upper jaw), dm 3 is displaced by p 4 but resembles m 1 of
the permanent dentition.* P 1 of the permanent dentition
which has no deciduous predecessor and the anterior molar
appear before any of the deciduous molars are shed.
The paroccipital process of the exoccipital projects either
behind the bulla (Ursidae) or is closely applied to its hinder
surface (Felidae, Viverridae). The mastoid process of the
periotic is usually rather weakly developed. The opening
for the carotid canal is either at the front end of the foramen
lacerum posterius, or a little way in front of this on the inner
side of the bulla. The condylar foramen for the hypoglossal
may either be behind the foramen lacerum posterius or within
its lips (Felidae). There is a postglenoid foramen for a vein
just behind the glenoid cavity except in the Viverridae and
living Felidae. The alisphenoid canal is present in Ursidae,
and Canidae, and Viverridae, but absent in Mustelidae,
Felidae, and Hyaenidae. In the older extinct Felidae, how-
ever, both alisphenoid canal and postglenoid foramen are
present, and the condylar foramen opens behind the foramen
lacerum posterius.
The orbit is not closed behind but the frontals carry post-
orbital processes. The nasals are well developed. There is
often a well-marked sagittal crest at the union of the parietals.
The jugal is strong and the palate is completely ossified. The
tympanic forms a flat or inflated bulla and may or may not be
prolonged below the external auditory meatus. The mandible
has a coronoid process, and the glenoid articulation of the
lower jaw is transversely directed, thus restricting the motion
of the jaw to the vertical plane.
The dorso-lumbar vertebrae are usually twenty in num-
ber. The clavicles are always reduced and sometimes absent.
The humerus may or may not have an entepicondylar fora-
men, and the ulna and fibula are distinct. The scaphoid
* It has been suggested that we have to do here with an overlapping
of the premolar and molar series, similar to that suggested for the Marsu-
pials (p. 530).
616 CARNIVORA.
and lunar are fused in the carpus, and there is no centrale.
The femur is without a third trochanter. The pollex and
hallux are not opposable, and the digits are nearly always
provided with sharp claws. The bears are plantigrade ; the
others either digitigrade or semidigitigrade (sub-plantigrade).
In some forms, particularly the Felidae, the claws are
retractile. The retraction consists in the folding back of the
ungual phalanx into an integumentary sheath, placed in the
manus on. the outer or ulnar side of the middle phalanx of the
digit, in the pes on the dorsal surface* of the corresponding
phalanx ; it is effected by an elastic ligament connecting the
two phalanges. The straightening out of the phalanges and
consequent protrusion of the claws is caused by the contrac-
tion of the flexor profundus digitorum muscle.
The cerebrum is fairly large and usually well convoluted,
but it never completely covers the cerebellum.
The stomach is simple and the large intestine is generally
provided with a caecum (absent in Ursidae) which is however
short.
The testes descend into a scrotum, and there is generally
an os penis. The glans penis, which is frequently covered
with recurved hooks, swells in some forms (e.g. Canidae)
during the act of copulation so that it cannot be withdrawn.
Vesiculae seminales are always absent, and Cowper's glands
are present or absent.
The ovaries are contained in peritoneal sacs ,and the
uterus is bicornuate. The mammae are abdominal or thoracic
and the placenta is always zonary.
The living Carnivora may be classified in three sections,
the cat-like or Aeluroidea, the dog-like or Cynoidea and the
bear-like or Arctoidea. The characters utilised are taken
from certain features of the base of the skull around the
tympanic region and agree fairly well with the characters
afforded by the dentition and other parts of the body.
The Aeluroidea including the Felidae, Viverridae, Hyaenidae
and Protelidae present the following features. The auditory
bulla is dilated and nearly divided into two chambers by a
septum ; the lower lip of the bony auditory meatus is very
short ; the paroccipital process is closely applied to the
* And to a certain extent on the fibular side.
CLASSIFICATION. 617
bulla, and the mastoid process is inconspicuous or absent ;
the condylar foramen opens within the margin of the foramen
lacerum posterius and the postglenoid foramen is absent ;
the alisphenoid canal is absent. The opening of the carotid
canal in the Felidae looks into the foramen lacerum posterius,
but it and the foramen lacerum medium are very minute in
accordance with the small size of the internal carotid artery.
In other Aeluroidea the carotid canal is a groove at the side
of the bulla, and the foramen lacerum medium is better
marked. The molars are reduced ; there is a short caecum ;
the os penis is small or absent. Cowper's glands are present.
The Cynoidea include the Canidae. The bulla is inflated,
but the internal septum is very incomplete. The lower lip
of the external auditory meatus is longer than in the cats.
The paroccipital process is applied to the back of the bulla,
but its end is free. The condylar foramen is distinct from
the foramen lacerum posterius and there is a postglenoid
foramen. The alisphenoid canal is present and the posterior
opening of the carotid canal looks into the foramen lacerum
posterius. The molars are less reduced, and the blade of the
upper carnassial has two cusps. The caecum is folded, the
os penis is present and grooved, and the male is devoid of
Cowper's glands.
The Arctoidea include the IJrsidae, Procyonidae and
Mustelidae. The bulla is without a septum and usually
flattened ; there is a considerable lower lip to the bony
auditory meatus. The paroccipital process stands behind
and clear of the bulla ; the mastoid process is prominent.
The condylar foramen is distinct from the foramen lacerum
posterius and there is a postglenoid foramen. The ali-
sphenoid canal is absent except in Ursus, Melursus and
Aelurus, and the posterior opening of the carotid canal is
placed on the inner margin of the bulla behind the foramen
lacerum posterius. The molars are as in the dogs but the
crowns are broad and tuberculated, and the carnassial teeth
dift'er (except in Mustelidae) from those of the other two
sections ; there is no caecum ; the os penis is large and not
grooved ; Cowper's glands are absent and the prostate is
small ; there are always five completely developed toes on
each foot.
618
CARNTVORA.
These divisions, though very convenient when applied to living forms,
break down when the extinct species are considered. Thus, as already
mentioned, in the older extinct Felidae the alisphenoid canal and post-
glenoid foramen are both present, the condylar foramen opens behind the
foramen lacerum posterius, and the molars are more numerous. More-
over some of the older Viverridae seem to approach so close to the Mustelidae
both in their cranial and dental characters that it is difficult to separate the
two families. The inference has been drawn from these facts that the
Arctoidae are not a natural group and that the resemblances between the
living Mustelidae and Ursidae have been independently acquired. This
conclusion is not in our opinion justified. To say that features of resem-
blance which undoubtedly exist between two families A and B, have
been independently acquired simply because A is found to present features
of resemblance to a third family C, which B does not resemble so closely,
seems to us an unsatisfactory position for a systematic zoologist to hold.
We should prefer to leave out all speculations as to descent and to place the
matter in this way. Certain extinct animals (e.g. Stenoplesictis, etc.) must
be placed with the living Felidae and Viverridae because of certain charac-
ters, but they differ from these living forms in also possessing characters
which belong to Mustelidae. These however are not strong enough to
separate them from the living Felines, but are only sufficient to show a
closer affinity of Felines to Mustelidae than was at first thought possible.
In the same way the Mustelidae have certain Ursine features which induce
us to class them with bears. These are on the whole more important than
the resemblances to the extinct Felines, so we leave the Mustelidae with
the Ursidae, merely noting the fact that they have affinities to the extinct
Felines. What we have here is merely an example of the principle, to
which we have often before called attention in this work, that the more
closely any given group of animals is studied, the more complex are the
mutual relations between its different members found to be. For an
example of this we may refer the reader to vol. 1, p, 410. We have there
given a rough diagram showing the interconnections existing between
different groups of the Nudibranchiata. A similar diagram might be
constructed in the present case.
AELUROIDEA.
Fam. 1. Feliiae.* Dentition i f c \ p ±-f m -^ ; canines very strong ;
upper carnassial with three lobes on the blade and an inner cusp (Fig. 322),
lower with two outer cusps (Fig. 323), a weak or absent inner cusp, and a
weak cutting or absent talon. U. molar very small and transverse.
Premolars reduced in number. Auditory bulla inflated, with an internal
septum and short bony auditory meatus, the paroccipital processes
flattened against the bulla ; without alisphenoid canal | ; carotid canal
minute ; condylar foramen opens within foramen lacerum posterius. The
humerus has an entipecondylar foramen. Digitigrade, manus with 5, pes
usually with 4 digits. Os penis small, Cowper's glands present, prostate
* Elliott, Monograph of the Felidae, London, 1878-83. Mivarfc, The
Cat, London, 1881. Cope, The extinct cats of America, Amer. Nat:,
1880, p. 833. Adams, Extinct Felidae of N. America, Amer. Journ.
Sci., 1, 189fj, p. 419.
iv Present in some extinct forms.
AELUROIDEA. 61 £
lobed. The Felidae are distributed over the whole world save in Australasia
and Madagascar. Their fossil remains first appear in the Upper Eocene,
and give us no clue to the origin of the family. Felis L., i § c \- p f m 7,
lower carnassial without talon and inner cusp, upper molar small, the first
upper premolar (p 2) may be absent ; clavicles better developed than in
other Carnivora, claws very retractile, tongue writh sharp horny papillae ;
50 living species, Neotr. 13, Ethiopian 8, Oriental 15, Nearct, 1, Pal. 20 ;
fossil in the M. Miocene onwards. F. leo, lion, Afr., India, W. Asia.
F. tigris, tiger, nasal bones reach back beyond the frontal processes of the
maxillae, Asia, Sumatra, Java, not Ceylon. F. pardus, leopard, pard.
Afr. and Asia, Ceylon, Java, Sumatra, Borneo. F. uncia, ounce, highlands
of C. Asia. F. nebulosa, clouded leopard, S.E. Asia, Sumatra, Java,
Borneo, Formosa. F. serval, serval, S. Afr. F. catus, wild cat of Eur.,
British. F. caffra, caff re cat, Afr. and S. Asia, the domestic cat is probably
derived from this species. F. caracal, caracal, India, Persia, Arabia,
Africa. F. lynx, lynx, stumpy tail, lower carnassial with trace of talon
Scandinavia, Russia, N. Asia. F. concolor, puma, Amer. from Canada to
Patagonia. F. onca, jaguar, Amer. from Texas nearly to California. F.
pardalis, ocelot, tiger-cat, trop. Amer. Cynaelurus Wagler, with 1 sp.,
Cynaelurus jubatus, the cheeta or hunting leopard, same distribution as the
lion, claws less retractile, talon of upper carnassial without cusp. Several
fossil genera are allied here, some placed in separate families ; Proaelurus,
Aelurictis, Dinictis, Pogonodon, Hoplophoneus, etc. ; Machaerodus, the
sabre-toothed tiger with enormous upper canines, upper Eocene to Pleisto-
cene of Europe and Miocene of India, Smilodon, a similar form from Pleis-
tocene of America. It is remarkable to find these large and highly special-
ised carnivora suddenly appearing and flourishing as far back as the Eocene.
Fam. 2. Viverridae. Civets, genets ; comparatively small animals
with long bodies and heads ; p f or £ m r or £ '•> uPPer carnassial usually
with two, sometimes with three outer cusps, and an inner cusp at the
front end ; lower carnassial with two outer and an inner cusp and
a well-developed, cusped talon ; upper molars tritubercular. Audi-
tory bulla with septum. Usually an alisphenoid canal. Carotid
canal has a groove on the side of the bulla. Humerus usually with
an entepicondylar foramen. Plantigrade or digitigrade ; usually penta-
dactyle, but pollex and hallux may be absent ; usually with well-developed
perineal scent glands. They are found in the Old World including Mada-
gascar, but not in Australasia. They are not found either living or
extinct in the New World. There are about 26 genera and 69 species.
They are known fossil from the Upper Eocene onwards. The denti-
tion is primitive in the large number of premolars. The upper car-
nassial essentially resembles that of the Canidae and Mustelidae, and
the upper molars resemble those of the Canidae. The lower carnassial
resembles that of the older extinct Canidae and Mustelidae, and were it
not for the third lower molar of the Canidae it would be impossible to
distinguish the lower jaw of the older Canidae and Viverridae. In the
elongation of the skull and its construction behind the orbits the two
families are alike and are supposed to be primitive. In fact it seems clear
that the Viverridae of the present day resemble in some important features
the older Canidae and Mustelidae.
Cryptoprocta Bennett, sometimes placed with the Felidae on account_of
its denition, which is feline ; i -f c } p % m } ; p 1 is minute and tran-
sient, the upper carnassial has a small inner cusp ; molar small and placed
620 CARNIVORA.
transversely as in Felidae ; lower carnassial without inner cusp, with a
minute talon ; subplantigrade, pentadactyle ; Madagascar 1 sp., C. ferox ;
shows some affinity to the extinct Felines, Proaelurus. and Pseudaelurus
Viverra L., civets, include the largest species, preineal glands well developed
and yielding the civet used in perfumery, Ethiopian 1 sp., Oriental 4 sp.,
V. civetta, African civet ; V. zibetha, Indian civet. The genus Viverra is
known from the Eocene. Viverricula Hodgs., rasse, 1 sp. Oriental and
Madagascar ; Fossa Gray, Madagascar 1 sp., without scent pouch ; Geneta
G. Cuv., genets, Ethiop. 4 sp., Pal. 1 sp., O. vulgaris in France s. of the
Loire, also Asia and Afr. ; Prionodon Horsf., linsangs, 3 sp., Oriental,
without the second upper molar ; Poiana Gray, 1 sp., Ethiop. ; Para-
doxurus F. Cuv., palm-civets, 10 sp., Oriental, some of the species vary
their diet with fruit; Arctogale Gray, Oriental 2 sp., Hemigale Jourd.
Orient. 2 sp. ; Arctictis Temm., binturong, arboreal, partly vegetable
feeders, 1 sp. Orient. ; Nandinia Gray, 2 sp. Ethiop., without caecum and
hinder part of bulla unossified ; Cynogale Gray, 1 sp. Orient., semiaquatic
and arboreal, feeding on fish, small mammals, birds and fruit. Herpestes
111., ichneumons, mongooses, p $ or f , ra f ; pentadactyle, plantigrade,
post orbital process of frontal and jugal generally meeting, feed on small
mammals, birds, reptiles, eggs of birds and reptiles, insects, famous as
snake destroyers, 9 sp. Orient., 10 sp. Ethiop., 1 sp. Pal., H. ichneumon is
found in Europe, H. mungo the common Indian mongoose ; Helogale
Gray, Afr. 2 sp. ; Bdeogale Pet., Afr. 2 sp. ; Cynictis Ogilv., Afr. 2 sp.,
with long caecum ; Rhinogale Gray., Afr. 1 sp. ; Crossarchus F. Cuv.,
Afr. 5 sp. ; Suricata Desm., meerkat, Afr. 1 sp. The three next genera
are from Madagascar and are distinguished by the absence of alisphenoid
•canal and entepicondylar foramen. Galidictis Geoffr., 2 sp., Galidea Geoff.,
1 sp., Hemigalidea Doyere, 2 sp. Eupleres Jourd., 1 sp. Madagascar, with
weak jaws and small teeth ; on account of these it was included among
Insectivora ; with entepicondylar foramen, without alisphenoid canal.
Extinct genera : Amphictis, Upper Eocene (with Viverra), Ictitherium,
Upper Miocene.
Fam. 3. Protelidae. Without alisphenoid canal, auditory bulla
•divided into two chambers, pes with 4, manus with 5 toes ; premolars and
molars 3*r4 , small, placed far apart and simple ; feed on insects and
carrion. Proteles Geoffr., 1 sp., P. cristatus, aard wolf of S. Africa ; a
burrowing nocturnal animal. This family is sometimes united with the
next.
Fam. 4. Hyaenidae.* i f c \ p -~- m - '— ; upper cornassial
elongated, with three outer cusps and an inner cusp at the front end, lower
carnassial with two cusps and weak talon ; upper molar small, placed
transversely within the line cf the other grinders ; bulla without septum,
alisphenoid canal absent ; humerus without entepicondylar foramen ;
digitigrade, manus usually, pes always with 4 toes ; hind limbs shorter
than fore. They are apparently related to the Viverridae through Icti-
therium of the Upper Miocene of Eur., and India. There is one living genus
confined to the Old World, 3 sp. Ethiop., 1 sp. Afr., and 1 sp. Pal. ; fossil
genera (Hyaenictis, etc.) from the Mionene onwards of Eur., N. Afr, S.
Asia. Hyaena Zimm., p $, m \, mainly carrion eaters; H. crocuta the
spotted hyaena, Afr., S. of Sahara ; H. striata the striped hyaena of N.
Afr., and S. Asia.
* Watson, P.Z.S., 1877, 78, 79, and 81, on visceral anatoir^ of hyaenas.
CYNOIDEA.
621
CYNOIDEA.
Fam. Canidae * i f c \ p $ in —• ; upper carnassial elongated
with two outer cusps and inner cusp at the front end ; upper molars three-
cusped, transversely elongated, often with intermediate cusps; lower carnas-
sial (m 1) with two outer cusps and a small inner cusp placed just behind
the posterior of the two outer, and a broad tuberculated talon ; m 2
smaller, m 3 very small. The bulla is inflated and undivided, the septum
being incomplete and small, the tympanic is prolonged a short distance as
the floor of the external auditory meatus ; the paroccipital process in
contact with bulla, but long. The condylar foramen is outside the foramen
lacerum posterius and the caro-
tid canal is present. There is an
alisphenoid canal. Entepicon-
dylar foramen absent in living
species, but present in the old-
er fossil forms. Digitigrade.
manus 4- or 5-toed, pes usually
4-toed, claws not retractile ; a
considerable os penis. Caecum
small, but always present, and
generally folded. The Canidae
are found in all the great
regions excepting New Zeal and
and Madagascar. They are
supposed by some to be the
most primitive of existing
Carnivora. The occasional
presence of traces of epipubic
bones and of an inflection of
the angle of the lower jaw
(Otocyon) may be mentioned
in connection with this view.
They first make their appear-
ance in the Upper Eocene of
Europe, and their remains are
found in the Miocene, Pliocene,
and Pleistocene of Europe,
Asia and N. America, in the
Pliocene and Pleistocene of lower jaw
S. America and in the Pleisto-
cene of Australia. Canis L., if c \ p\ m f, but the dentition is slightly
variable, m 3 in the upper jaw is occasionally present, and m 3 in the
lower is occasionally absent ; milk dentition, i f c \ m f , the first per-
manent premolar has no predecessor. Vertebrae C7, D13, L7, S3, C17-22.
Clavicles reduced, manus with 5 toss, pollex very short, pes with 4 toes
and the metacarpal of the hallux (occasionally with loose small phalanges
and claws in domestic dog). They generally hunt in packs. Some burrow.
All are carnivorous, but soma species may eat insects and vegetables.
FIG. 324.— Canis lupus. A right upper jaw, B right
f (from Zittel).
* Huxley, Dsntal and cranial characters of the Canidae, P.Z.S., 1880,
p. 238. Mivart, Monograph of the Canidae, 1890.
622 CARXIVORA.
The distribution is that of the family. The genus dates from the Miocene,*
or possibly even from the Eocene. t There are 35 species which maybe
divided into the fox-like and the wolf -like, Aust., 1 sp. (C. dingo), Neotrop.
9 sp., Ethiopian 7 sp., Oriental 3 sp., Nearct. 9 sp., Pal. 13 sp. C. lupus,
wolf, Pal. and Nearct., extinct in England since 1660, in Ireland since 1770 ;
C. aureus, jackal, Pal. and Orient. ; C. rutilans, dukhunensis, javaanicus,
wild dogs of S.E. Asia ; C. cancrivorus, brasiliensis, etc., wild dogs of S.
Amer. ; C. latrans, the prairie wolf ; C. dingo, the Australian dingo, sup-
posed by some on no particular grounds to have been introduced by man ;
C. vulpes, common fox, with other species ; C. lagopus the arctic fox,
changing colour to white. The origin of the domestic dogs is unknown.
Probably they have originated from several wild species in different parts
of the world. They have long been domesticated, and many primitive
peoples at the present time possess them. The mental qualities which fit
them to be the companion of man seem to be possessed in varying degrees
by more than one species of the genus. Lycaon Brookes, 1 sp. S. Afr.,
L. pictus the Cape hunting dog. Ic.tic.yon Lund, 1 sp., S. Amer., /. venati-
cus, bush dog, m ^. Otocyon Licht., p % m ~^, 1 sp. O. megalotis
S. Afr.
There are several extinct genera, Cynodiclis, Temnocyon, Qalecynus,
Amphicyon, Dinocyon, Simocyon. Some of these connect the Canidae
with the Viverridae and Ursidae.
In Cynodictis, U. Eocene, Europe, the dental formula is as in Canis, the
teeth like those of the Viverridae ; the auditory bulla is inflated and without
septum and there is an entepicondylar foramen. Amphicyon L. and M.,
Miocene, Europe, on the other hand is dog-like by its dentition but ap-
proaches the Ursidae by its limbs which are pentadactyle arid plantigrade.
ARCTOIDEA.
Fam. 1. Ursidae. Dantition with some slight variations is i f c |
p ^ m f ; the carnassial teeth differ from those of the dogs and cats ;
the upper carnassial (p 4) with two outer cusps and an inner posterior
cusp without a separate root ; the anterior premolars small transient and
sometimes absent ; upper molars quadratic or oblong with multituber-
culate crowns, the last is the largest ; in the lower jaw the three anterior
premolars are small and may fall out early as in the upper, the carnassial
(m 1) is elongated, the front part has three cusps and there is a large
tuberculated talon ; m 2 is multituberculate and larger than m 1, m 3 is
smaller than either. The milk teeth are small and shed early. The skull
is rather elongated. The tympanic bulla is depressed, and there is no
septum ; the tympanic is prolonged for a considerable distance on the
floor of the external auditory meatus, the paroccipital process is separate
from the mastoid process ; the condylar foramen is distinct from the
foramen lacerum posterius ; the carotid foramen is large and placed on
the inner margin of the bulla, the alisphenoid canal is present except in
Aeluropus. Plantigrade ; pentadactyle, with short tail and large os penis.
The humerus is without entepicondylar foramen. There is no caecum,
and the kidneys are lobate. They are large omnivorous carnivores which
feed on flesh, fruits, roots, honey, etc., and are distinguished from all other
* Scott, Trans. Am. Phil. Soc. 18, 1894, p. 75.
t Marsh, Amer. Journ. Sci., 1871, p. 123.1
ARCTOIDEA.
023
carnivores by their multituberculate molars and carnassial teeth. They
are found in all regions except the Ethiopian and Australasian, and
Madagascar. They make their appearance in the Miocene, and are closely
connected with the Canidae by the extinct genus Amphicyon, Ursus L.,
bears, animals of considerable bulk, p ^, m f, vertebrae, C7, D14, L6,
So, C8-10 ; claws curved and non retractile ; the three anterior premolars
in both jaws small and one-rooted, sometimes absent, p 1 of the lower
jaw is small, separated by a wide gap from p '2 and soon falls out ; 10 sp.,
viz. Xeotrop. 1, Orient. 2, Xearct. 4, Pal. 5. Omnivorous or herbivorous.
U. maritimus polar bear, circumpolar ; U. arctos brown bear, Pal. region,
is still found in Europe in the Pyrenees, Norway, Hungary and Russia ;
U. horribilis, grizzly bear of X. Amer. ; the genus is first found fossil in the
Pliocene. Melursus Meyer, sloth bear first upper incisors shed early or
absent, with small teeth, feeds on insects, fruit, honey; 1 sp., M. labiatus,
India, Ceylon. Aeluropus M. Edw., p | m f ; 1 sp. A. melanoleucus in
Thibet, a large herbivorous animal with large and multicuspid, two-rooted
(except the first) premolars. There are a few extinct genera, e.g. Arcto-
therium, Hyaenarctos.
Fam. 2. Proeyonidae. i $ G \ p %m % ; carnassial teeth not typically
developed, molars broad and tuberculate, upper p 4 quadrituberculate
and like the molars ; lower molars quadrangular with two-cusped talon.
Alisphenoid canal absent except in Aelurus. Tympanic bulla (sometimes
rather inflated) and adjacent parts as in the Ursidae. Tail long. Ente-
picondylar foramen present or absent. Feet pentadactyle, plantigrade.
Omnivorous. Confined to America save for the genus Adurus which is
Oriental. A few fossil species in the Pleistocene of America. Aelurus
F. Cuv., the panda, p f m f , p 1 of the lower jaw small and early decid-
uous, molars broad and tuberculate, mainly a vegetable feeder ; 1 sp.
A. jidgens, rather larger than a cat with thick fur, S.E. Himalaya. Procyon
Storr, racoons, p | m f , longish limbs, manus remarkable for handiness and
the great mobility of its digits, omnivorous, 2 sp., P. lotor, dips its food in
water before eating, X. Amer. ; P. cancrivorus, S. Amer. Bassariscus
Rhoads, 1 sp., U.S. and C. Amer. Bassaricyon Allen, 2 sp., S. Amer.
Nasua Storr, coati-mundis, arboreal, 2 sp. in X. and S. Amer. Cercoleptes
111., the kinkajou, arboreal, in forests, 1 sp., X. and S. Amer.
Fam. 3. Mustelidae. Weasels, badgers, otters. For the most part
bloodthirsty animals with elongated bodies ; i^c^p^m^; upper
carnassial (p 4) with two sharp outer cusps, and strong inner cusp ; lower
carnassial (m 1) large, with large often excavated talon ; upper molar
broad, tritubercular, m 2 in the lower jaw small, soon falling out. Tym-
panic bulla and adjacent parts as in Ursidae except that the bulla may be
swollen and the paroccipital process pressed against it ; alisphenoid canal
absent. Feet usually pentadactyle, plantigrade or digitigrade. Ente-
picondylar foramen present or absent. The kidneys are lobed in the otters.
They are universally distributed, being absent only in the Australian region
and in Madagascar. There are 17 living genera which may be divided into
the otter-like (Lutrinae) 9 the badger -like (Melinae)jand the weasel-like
(Mitstelincte). The family is known from the Upper Eocene of Europe
onwards. Some of the extinct genera show a close approximation to the
earlier Viverridae and can scarcely be separated from them. Stenoplesictis
with a dentition of i f c \ p £ m |, and a complete septum in its bulla
has even been placed with the Viverridae. Other genera are Palaeoprion-
odon, Haplogzle, Stenogale, Plesictis — all Upper Eocene, and (some of them)
624 CARNIVORA. PINNIPEDIA.
Lower Miocene. Mustela arid Lutra make their appearance in the Middle
Miocene.
Sub-fam. 1. Lutrinae. Otters. With webbed toes, and lobed
kidneys, aquatic. Lutra 111., i % c \ p * m ± ; 11 sp., Neotrop. 3,
Ethiop. 2, Orient. 3, Nearct. 2, Pal. 1 ; feed on fish ; L. vulgaris the
common British otter. Latax Gloyer (Enhydra), i 'i c \ p % m \,
the first lower incisor being absent ; pes fin-like, phalanges flattened,
1 sp., L. lutris the sea otter, Nearctic, on the shores of the N. Pacific
Ocean, feed on shell fish.
Sub-fam. 2. Melinae. Badgers, etc. Feet elongated, claws non-
retractile, terrestrial and fossorial. Mephitis Cuv., skunks, i f c -i-
p f m i ; with largely developed anal glands, the secretion of which
is extremely offensive, 5 sp. Nearctic, mainly insectivorous. Conepa-
tfwsGray, Neotrop. 3 sp.,Nearct. 1 sp. ArctonyxF. Cuv., Orient. 1 sp.>
Pal. 3 sp. ; Mydaus F. Cuv., Orient., 2 sp. ; Meles Storr, badgers, i f ,
c \ p \ m ± ; 4 sp., Pal. ; M. taxus, the common badger of England,
Europe and N. Asia, omnivorous. Taxidea Waterh., badgers of N.
America, Nearct. 2 sp. ; Mellivora Storr, the ratel, Ethiop. 1 sp.,
Orient. 1 sp. ; Helictis Gray, Orient. 5 sp. ; Ictonyx Kaup, 4 sp.,
Ethiop. 3, Pal. 2.
Sub-fam. 3. Mustelinae. Weasels, etc. Toes short, partially
webbed ; claws short, sharp, often semiretractile ; terrestrial and
arboreal. Galictis Bell, 2 sp., Neotrop. ; G. vittata, the grison ;
Mustela L., martens and sables, ifc|p|m^;10sp., Orient. 4,
Nearct. 3, Pal. 5 ; M. martes pine-marten, arboreal, British
N. Eur., Asia ; M. zibellina the sable, E. Siberia ; M. americana, the
North American sable. Putorius Cuv., about 47 sp., Neotrop. 9,
Orient. 15, Nearct. 16, Pal. 10 ; p f , includes the minks, weasels,
ermines, stoats, ferrets, polecats ; P. vison, mink of N. Amer. ; P.
putorius, the polecat, of which the ferret is a domesticated variety,
British and European ; P. vulgaris, the weasel, reddish-brown above,
white below, British, Eur., Asia, N. Amer. ; P, erminea, stoat or
ermine, reddish brown above, white below, in some localities chang-
ing to white in winter except black tip of tail, larger than the weasel,
British Eur., Asia, N. Amer; P. hibernicus, the Irish stoat, confined
to Ireland. Poecilogale Thos., S. Afr. 1 sp. ; Lyncodon Gervais,
1 sp., Patagonia ; Gulo Storr, the glutton or wolverine, 1 sp., circum-
polar, Nearct. and Pal., has a habit of secreting articles which are of
no use to it, mainly feeds on carcasses.
Order 17. PINNIPEDIA.*
Aquatic Carnivora with pentadactyle fin-like limbs, the digits
of which are united by a membrane. The brain is large and
the cerebrum complexly convoluted.
These animals are closely related to the Carnivora, from
* Allen, History of Nprth American Pinnipeds, 1880. Mivart, Notes
on the Pinnipedia, P.Z.S., 1885, p. 484. van Beneden, Ossem. fossiles
d'Anvers. Mem. Acad. Roy. Belgique, 1, 1877. Turner, Report on the
Seals of the " Challenger," Chall. Reports, 20, 1887. Balkwill, Geograph.
Dist. of Seals, Zoologist, 12, 1888, p. 401.
PINNIPEDIA. 625
which they differ mainly in their dentition, aquatic habits
and the structure of their limbs. The limbs are short and penta-
dactyle, the proximal portions being more or less imbedded
in the common integument of the body. All the digits are
united by a membrane which may or may not project beyond
their extremities. Xails are occasionally well developed but
generally small or even absent. They are all' covered with
hair, and there is sometimes a fine soft under-fur, which in the
fur seal is much developed. The incisors vary in number
and are conical ; they are never less than -|. The canines
project though not as much* as in the Carnivora. The
premolars and molars are all alike, and may be conical and
one-rooted, or laterally compressed with three cusps and two
roots ; their number varies from five to six. The milk teeth
are i f- , c y, m -| and are shed early, either before or shortly
after birth. The cranium is generally rounded and capacious.
The orbits are open behind and there is no lacrymal bone or
canal. The tympanic bulla is large and is prolonged beneath
the meatus auditorius ; the paroccipital and mastoid processes
are inconspicuous. The condylar foramen is distinct from
the foramen lacerum posterius, and an alisphenoid canal is
present or absent. The mandible has a coronoid process.
The tail is short. Clavicles are absent ; the scapula is
large, the spine being nearer the hinder edge. The humerus
is short and without entepicondylar foramen. Ulna and
radius are separate, and the scaphoid and lunar are fused.
The calcaneum has a short tuber calcis. There is always a
considerable os penis. The brain is large and well convoluted,
the olfactory nerves and anterior commissure small. The
colon has a short caecum. The kidneys are lobulated, and
Cowper's glands are absent. The mammae, two or four in
number, are abdominal. A scrotum may be present or absent.
They are all aquatic, but come to the land, on which they
move clumsily, to breed. They are mainly marine, but some
species ascend rivers, or inhabit inland seas and lakes. Their
fossil remains are found in Europe and North America from
the Miocene onwards.
There can be no doubt that the Pinnipedia are allied to
* Except in the walrus.
Z-li s s
G2 ) PINNIPEDIA.
the Carnivora, and affinities especially with the Ursidae
have been claimed through the Otariidae.
Fam. Otariidae. Eared seals. This family is characterised by
possessing a small pinna, and by the fact that the hind limbs are capable
of supporting the body in locomotion, being turned forwards beneath it.
They have tolerably long necks, and the nostrils are placed at the end of
the snout. The skin of the feet is extended beyond the nails, which are
small, being best developed on the three middle digits of the pes. The
skull has large post-orbital processes, and an alisphenoid canal. The
angle of the lower jaw is markedly inflected. Vertebrae, C7, D15, L5, S4,
C9-14. Dentition, i f c \ p % m ll°- of which p 2, 3 and 4 are
preceded by milk teeth, which are shed a few days after birth. The
testicles descend into an external scrotum. They pair and bring forth
their young on land, upon which they can move with considerable
freedom. They are gregarious and polygamous. Otaria P6r., 9 species,
principally Antarctic, but extending to the north in the Pacific ; 0, stelleri,
the northern sea-lion, N. Pacific, about 10 feet in length. O. jubata, the
Patagonian sea-lion from Patagonia and the Falkland Islands. O. cali-
forniana from California. O. ursina, the fur seal of commerce or sea-
bear, with a dense soft under-fur, N. Pacific. 0. pusilla, Cape of Good
Hope. O. forsteri, Australia.
Fam. Trichechidae. Walrus or morse, with one genus Trichechus L.
They are without external ears, but resemble Otaria in the position of
their hind limbs and mode of walking. They are exceedingly bulky
animals, and attain to a length of from 10 to 11 feet. The upper canines
are modified into projecting tusks. They are covered with short hair,
which tends to fall off in old age, and there is a tuft of long bristles on each
side of the muzzle. The tail is reduced. The manus has sub-equal digits
and small flattened nails ; in the pes the nails of digits 1 and 5 are minute ;
those of the others large, compressed and pointed. The soles of the feet
are devoid of hair and provided with a rough warty pad. The functional
dentition is i <y c \ p and m f ; the molars are conical but wear down
to flat crowns ; in the young the teeth are i f c \ m f , some of which
are lost early or remain through life concealed beneath the gums. Verte-
brae 07, D14, L6, S4, C12. The skull is round with an alisphenoid canal
but without postorbital processes. There is a third bronchus on the right
side, as in bears, ruminants and cetaceans. The cerebrum is large and
richly convoluted, and there is a trace of a posterior cornu. They are
gregarious and live on various shell fish, which they dig up with their
tusks. They are much hunted for their skins, oil and ivory, and are rapidly
diminishing in number and range. The distribution is circumpolar and
there are two species, T. obesus in the N. Pacific, and T. rosmarus in the
N. Atlantic.
Fam. Phocidae. Seals. More modified for an aquatic life than the
preceding families. The nostrils are dorsal and there is no pinna, and
the hind limbs are stretched out backwards on each side of the tail with
which they are connected ; they cannot be used in locomotion on land.
The fore-limbs are buried to the elbow in the skin but can be used for
supporting the body. The outer digits of the pes are longer than the
middle. The under side of both manus and pes is hairy. There is no
woolly under-fur. Both postorbital processes and alisphenoid canal
PINXIPEDIA. RODEXTIA. 627
are absent, and the angle of the mandible is not inflected. The tympanic
bullae and mastoid processes are large. The skull in many of its fea-
tures recalls the cetacean type. Dentition, i ^— - c \ p and ra f ; the
canines are well developed ; the milk molars appear to be f , and are some-
times shed during foetal life. There is no scrotum, and the testes are
abdominal or just outside the inguinal canal. *|
Locomotion on the land is effected by a wriggling of the trunk, with
or without the assistance of the forelimbs. They are inoffensive crea-
tures and mostly gregarious and polygamous. They are exceedingly
intelligent and docile, and in captivity attach themselves to man. It is
said that in some species the young do not readily take to water, and
have to be taught to swim. When born they have a thick soft fur, which
falls off before they enter the water. They are much hunted for their
skins and oil.
There are 9 genera and about 15 species, principally confined to the
Arctic and Antarctic seas, but found in intermediate areas. Most of
them are marine, but a few ascend rivers and are found in inland seas and
lakes, as the Caspian and Lake Baikal. Their remains, not numerous,
are known fossil from the Miocene onwards in Europe and N. America.
Sub-fam. 1. Phocinae. * f, feet with well-developed claws,
digits of pes sub-equal with membrane not extending beyond the
toes. Halichoerus Nils., 1 sp. H. grypus, the grey-seal of the
British Isles, attains to 8 feet in length, Atlantic. Phoca L., 6 species,
N. Hemisphere ; P. vitulina, the common seal, British Isles, 4 to 5
feet in length, ascends rivers, Arctic Ocean, N. Atlantic and Pacific ;
P. caspica, Caspian and Aral Seas ; P. sibirica, Lake Baikal ; P.
groeenlandica.
Sub-fam. 2. Monachinae. i f , the outer digits of the pes exceed
the others in length, with small or absent nails. Monachus Flem.,
1 sp. M. albiventer, monk-seal of the Mediterranean and Atlantic.
Ogmorhimis Pet., 1 sp. O. leptonyx, the sea-leopard, Antarctic and
southern temperate seas ; Lobodon Gray, 1 sp., Antarctic Ocean.
Leptonychotes Gill., 1 sp., Ant. Ocean; Ommatophoca Gray, 1 sp.,
Ant. Ocean.
Sub-fam. 3. Cystophorinae. i t, outer digits of pes longer than
the others, nails small or absent. Cystophora Nils., 1 sp. C. cris-
tata, hooded or bladder-nosed seal of the N. Atlantic, occasionally
visits the British coasts ; with a dilatable sac upon the face. Macro-
rhinus F. Cuv., the elephant seal ; nose produced into a short pro-
boscis capable of dilatation, 1 sp., M. leoninus, the sea-elephant,
attaining a length of nearly 20 feet, Antarctic Ocean and N. Pacific
(California).
Order 18. RODENTIA* (GLIRES).
Usually plantigrade animals ivith a pair of large sharp
chisel-shaped rootless incisors in each jaw and without canines.
The grinding teeth are either lophodont or bunodont; the articular
surface for the lower jaw is nearly always longitudinally elon-
* Waterliouse, Natural History of the Mammalia, vol. 2, 1843. Brandt,
Die craniologischen Entwickelungs-stufen u. Class, der Nager der Jet/
628 RODENTIA.
gated and the angular process of the jaw is well developed.
There are never more than three papillae circumvallatae on the
tongue.
The rodents are usually small animals, though in a few
cases, e.g. the capybara, they may attain to some size. They
have fur which is often fine, but in some it may be modified
into spines on the back. The limbs are usually pentadactyle.
They are plantigrade or semiplantigrade and the nails on
the digits are usually claw-like, but in a few cases they have
the form of hoofs.
The dentition is their most characteristic feature. Canines
are always absent and the lower jaw has never more than one
pair of incisors. The upper jaw also has only two incisors
except in the Duplicidentata (hares, rabbits and pikas), in
which there is a second pair of small incisors behind the large
pair. There is always a wide diastema behind the incisors.
The grinding teeth vary from f in the Hydromys to -| in the
rabbit. Three pairs of these are molars, the rest premolars.
If there are only three pairs of grinders or less than three
there are no premolars. In the majority the grinding teeth
are four pairs, p J- m -|. The premolars usually displace
milk molars. The milk dentition is varied. In some forms
with three pairs (e.g. Muridae] or less than three pairs
(Hydromys} of grinders, there appear to be no milk teeth at
all, and the dentition is monophyodont. In some forms
(e.g. Cavia) milk grinders are present in the embryo, but
absorbed before birth ; in some (e.g. Castor) the milk grinders
persist until the animal is half-grown ; and there are condi-
tions intermediate between these two. Milk incisors seem
generally to be absent. They have however been detected in a
few forms ; e.g. three pairs have been detected in the squirrel
as vestiges, while in the rabbit there appear to be two pairs
of deciduous incisors in the upper jaw. and one pair in the
welt, Mem. Acad. Imp. Petersbourg, 1855. Forsyth Major, Nageriiber-
reste aus Suddeutschland u. der Schweiz, Palaeontographica, 22, 1873,
p. 75. Alston, Class, of the order Glires,P.Z.S., 1876, p. 61. Cowes and
Allen, Monograph of N. American Rodentia, U. S. Geol. Surv. Territ.,
11, 1877. Schlosser, Die Nager der Europ. Tert., Palaeontographica,
31, 1884-5. Winge, Rodentia fra Lagos Santa, Brazil, Mus. Lund.
3, 1887. Thomas, Genera of Rodents, P.Z.S., 1896, p. 1012. Tullberg,
Das System d. Nagerthiere, Act. Ak. Upsala, 1890.
TEETH. SKULL.
lower jaw. Of the former the anterior pair does not appear
above the gum and is absorbed before birth, while the pos-
terior is shed in the third week after birth ; the milk incisors
of the lower jaw are absorbed before birth. The large incisors
appear always to be rootless and to grow throughout life.
They extend far back into the jaws and are much curved.
They have enamel only on their anterior faces except in the
Duplicidentata, in which it extends on to their inner sides.
The small incisors of the latter are also rootless and have
enamel on both faces. By continuous wear they are kept to
a sharp edge of enamel. In many rodents the enamel of
the incisors is stained a yellow colour. The milk molars have
roots, and are brachyodont. The permanent grinders are
either brachyodont and rooted, or hypsodont and rootless,
growing throughout life. In the latter case they are curved
as in Toxodon, so as to take the pressure off the growing
pulp. There is considerable variety in the surface of the
crown according to the food (vide Tullberg, op. cit.}. In
omnivorous forms they are brachyodont and bunodont, the
enamel of the crown not being much folded and wearing
through with use, so that the surface comes to consist of
dentine surrounded by an enamel ring. In the herbivorous
forms, however, in which the wear is greater, they are hypso-
dont and continue to grow throughout life or through part
of life, and the enamel is deeply folded into transverse ridges,
the valleys between which may be filled in with cement. As
a rule there are two or three ridges, but in the capybara, the
last of the four grinders has a great number of these transverse
enamel folds and appears to consist of many laminae embedded
in cement. In these cases of lophodont molars the unworn
tooth is tuberculated, the laminated pattern becoming
apparent when the tubercles are worn off. The enamel
varies in the arrangement of the prisms in different families,
and in some cases dentinal tubes extend into it.
The long axis of the articular condyle of the lower jaw is
directed longitudinally and the squamosal has no postglenoid
process. There is a large tympanic bulla, and the tympanic is
generally prolonged into a tubular nieatus ; it often remains
distinct from the squamosal and periotic. The paroccipital
processes of the exoccipital are long. The jugal occupies the
630 RODENTIA.
middle of the zygomatic arch, but is occasionally prolonged
back to the glenoid cavity. The orbit is not closed behind
and the frontal is without postorbital processes except in a
few genera. The lacrymal foramen is intraorbital, and the
infraorbital foramen is often very large, sometimes as large
as the or it (Hystricidae, etc.), transmitting part of the
masseter muscle.
The nasals extend far forward and the premaxillae are
large. There is usually an interparietal bone. The palate
is narrow and the anterior palatal foramina extensive. The
angular part of the mandible is considerable and the coronoid
process low.
The dorsolumbar vertebrae are usually nineteen.
Clavicles are usually well developed but they may be feeble
or absent. The scapula is narrow, and has an acromion
usually with a metacromion. The humerus is without an
entepicondylar foramen, and the femur often has a third
trochanter. The radius and
ulna are distinct and some-
times capable of rotation, but
the tibia and fibula are often
united. The carpus has a cen-
trale and the scaphoid and
lunar are generally fused.
°' Cricetm "*"* There are usually five digits
in the manus but the pollex
may be reduced or absent. In the pes the digits vary from
five to three and in the Dipodidae the metatarsals are much
elongated and may be ankylosed.
The brain is small and the cerebellum is left uncovered by
the cerebrum, the surface of which is usually but slightly
convoluted. In the larger forms the convolutions are better
developed and in the smaller they are absent, the surface
being quite smooth.
The hairy integument of the face is often prolonged into
the mouth behind the incisors, and there is thus a kind of
antechamber to the mouth in which gnawed matter not
intended for food may be intercepted. The hairy lining
may extend even into the cheek pouches if these are present.
In the Geomyidae the cheek pouches open externally on the
VISCERA. HABITS. 631
cheeks. The stomach is generally simple, but there may be
complications. It may be constricted between the cardiac
and pyloric portions with a groove leading from the oesophagus
to the pyloric end and occasionally (e.g. Castor) there are
cardiac glands. In Myoxus the oesophagus has a glandular
dilatation at its lower end. There is always a large caecum
except in Myoxus and the gall bladder is generally present.
The colon is occasionally spirally twisted. There are two
superior venae cavae. In some genera the ureters open into
the fundus of the bladder. Vesiculae seminales are present
except in the Duplicidentata and the penis usually has a bone.
The testes are in most cases abdominal, descending into the
inguinal region in the breeding season. In the Duplicidentata
they may be said to descend into a scrotum in which they
remain permanently. A prostate is present. The uterus is
bicornuate, or may be quite double. They usually produce
numerous young at a birth and have a considerable number
of thoracic and abdominal mammae. The young are born
naked and helpless in the burrowing forms. The placenta
and the chorion are both discoidal.
Odoriferous glands are very generally present ; they open
into the prepuce or into the rectum or near the anus.
The Rodentia are the largest mammalian order. There
are about 1,400 species and 160 genera. They are cos-
mopolitan. They are most numerous in South America,
which has been termed their home, and least so in Australia
and Madagascar, where they are represented by only a few
genera of Muridae.
They present great diversity of life. They all gnaw and
are herbivorous. A few are omnivorous. It is possible that
one or two may be carnivorous. Some are arboreal, and in
the flying squirrels provided with a parachute-like membrane
for floating in the air. Others are aquatic, as the water-vole,
while yet others live on the earth and are strong runners, as
the hares. Many of them build nests, dig out complicated
burrows, and lay up stores for the winter. The latter usually
possess cheek pouches. Some fall into a winter sleep at the
cold season of the year.
Typical rodents are first found fossil in the Upper or
possibly in the Lower Eocene, most of the remains belonging
632 RODENTIA.
to existing families and genera, and they seem to have under-
gone but little change since that period. There is no sugges-
tion as to their origin, but similarities have been pointed out
between them and the Proboscidea and Typotheria, the
latter resembling them in their jaws, teeth, nasal bones and
paroccipital processes of the skull.
Sub-order 1. SIMPLICIDENTATA.
With one pair of upper incisors, without vesiculae seminales.
testes abdominal, descending into a temporary scrotum.
The fibula does not articulate with the calcaneum.
Tribe 1. Sciuromorpha.
Skull with slender zygomatic arch, clavicles well developed, fibula free,
infraorbital foramen small except in Anomaluridae.
Fam. 1. Anomaluridae. Arboreal forms, with their limbs connected
by a patagium, supported by a cartilaginous fascia arising from the ole-
cranon ; tail long, hairy, with large scales on its ventral surface near the
root ; p \ ; molars with transverse enamel loops ; Ethiopian. Anoma-
lurus Wat., 9 sp. Idiurus Matsch., 1 sp. Zenkeretla Matsch., 1 sp.
Fam. 2. Seiuridae. Squirrels. Arboreal or terrestrial, with cylin-
drical hairy tails, often brilliantly coloured ; skull with postorbital pro-
cesses, p y> molars rooted, tubercular ; cosmopolitan, excluding Austral-
asian region and Madagascar. Bheithrosciurus Gray, 1 sp., Borneo, with
grooved incisors. Xerus H. and E., spiny squirrels, Afr. (Ethiopian and
Palaearctic), 5 sp., terrestrial, burrowers. Sciurus L., cosmopol., except
Austr. and Madgr., 106 sp. ; manus 4 digits and reduced pollex, pes 5
digits, first upper p. minute, soon lost ; no cheek pouches ; >SV vulgaris,
common English squirrel, ranges to Japan. Tamias 111., ground squirrels,
chipmunk, Nearctic, 30 sp., Palaearctic, 1 sp., with cheek pouches. Sper-
mophilus F. Cuv., pouched marmots, sousliks, burrowers, Nearct., Palae-
arct., 40 sp. Cynomys Raf., prairie dogs, burrowers, live in com-
munities, often with a burrowing owl and a rattlesnake, Nearct., 4 sp.
Arctomys Schr., marmots, burrowers, Nearct., Palaearct., 10 sp. ; A.
marmotta, the alpine marmot. Eupetaurus Thos., flying squirrel, Ori-
ental, 1 sp., patagium as in the next, with hypsodont grinders. Petau-
rista Link. (Pteromys G. Cuv.), flying squirrels, Oriental, 13 sp., limbs
united by an expansion, the support of which articulates with the carpus.
Sciuropterus F. Cuv., flying squirrels, Oriental 17 sp., Nearct. 5 sp.,
Palaearct. 2 sp., patagium as in the last. Nannosciurus Trouess., Ethiop.
1 sp., Oriental 2 sp. Extinct genera from the U. Eocene onwards.
Fam. 3. Castoridae. Beavers, p \, molars rootless, without post-
orbital process, stomach with a large glandular appendage, anus and
urinogenital duct open into a common cloaca, pes webbed. Castor L.,
burrowers on the banks of rivers, 2 sp. ; C. fiber, European, formerly
British, do not as a rule make dams ; C. canadensis, N. Amer., construct
dams. Extinct sp. and genera from the Miocene onwards.
Fam. 4. Haplodontidae. Haplodon (Aplodontia) Rich., 2 sp., Nearct.
DORMICE. RATS, MICE. 633
Tribe 2. Myomorpha.
Skull with slender zygomatic arch, clavicles well-developed, except in
Lophiomys, tibia and fibula united, infraorbital foramen variable.
Fam. 5. Gliridae (Myoxidae). Dormice, small, arboreal, with long
hairy tails, intestine without caecum, p }, molars rooted, lophodont.
Palaearctic, Ethiopian, Oriental. Glis Briss. (Myoxus), Palaearctic, 1 sp.
Muscardinus Kaup., Palaearct., 1 sp. M. avellanarius, common dormouse,
Brit, and Eur. Eliomys Wagn., Palaearct., 2 sp. Graphiurus F. Cuv.
Ethiopian, 13 sp. Platacanthomys Big., Oriental, 1 sp. Typhlomys M.
Edw., Oriental, 1 sp.
Fam. 6. Muridae. Rats, mice, Australian water rat, hamster, etc.
Without premolars ; molars rooted or rootless, bunodont or lophodont ;
f rentals contracted ; pollex reduced, often with a small nail ; tail rarely
densely-haired, sometimes scaly. There are about 86 genera and 724
species. Cosmopolitan, being found in Australasia (Hydromys, Xeromys,
-Mug, Pogonomys, Craurothrix, Mastacomys, Uromys, Conilurus), and in
Madagascar (Brachytarsomys, Nesomys, Hallomys, Brachyuromys, Hypo-
geomys, Gymnuromys, Eliurus). The following may be mentioned ;
Hydromys Geoff., Australian water-rats, molars £, Australia, Tasmania,
N. Guinea, 4 sp. Xeromys Thos., m f Queensland, 1 sp. Celaenomys Thos.,
Chrotomys Thos., Crunomys, RTiynchomys Thos., Phlaeomys Wat., all
Oriental with 1 sp. Gerbillus Desm., Ethiop. 20 sp.. Orient. 2 sp., Palaearct.
16 sp., burrowers, with tufted tails, jerboa-like. Mus L., rats
and mice, largest genus of mammals, Aust. 30 sp., Eth. 30 sp., Orient.
50 sp., Palaearct. 20 sp., absent from the New World, 5 British species.
M. minutus, harvest mouse, 2^ in. ; M. sylvaticus, wood-mouse ; longer
ears than M. musculus, the common house mouse, probably a native
of Asia ; M. rattus, the black rat ; M. decunutnus, the Hanoverian rat
or brown or Norway rat. Lophiomys M.-Edw., Eth., 1 sp., hallux,
opposable, temporal fossa covered by a bony plate from the parietal to
the jugal, as in turtles. Cricetus G. Cuv. (Hamster), hamsters, Palae-
arct., 12 sp., with large cheek pouches, 8-9 inches, with short tails.
Microtus Schrank (Arvicola), voles, Xearct. 40 sp., Palaearct. 40 sp.,
short ears, short hairy tail, molars composed of triangular prisms placed
alternately, 3 British species, M . amphibiua, water-rat, feet not webbed ;
M. agrestis, field-vole, occasionally appearing in immense mimbers and
doing much damage ; M. glarevhts, bank-vole. Lemmus Link. (Myodes
Pall.), lemming, Nearct. 1 sp., Palaearct. 3 sp. ; L. lemmus, the Scandi-
navian lemming, 5 inches, at indefinite intervals it multiplies exces-
sively, and migrates in a straight line in enormous herds, crossing all
obstacles till it reaches the sea into which it plunges in the continuance
of its wandering and is drowned ; during the migration, which may last
1-3 years, it continues to multiply abnormally and is attacked by all
animals en route and destroyed in large numbers ; many perish from
disease, due to over-crowding, none appear to return ; the instinct
is a good instance of a useless character. Siphneus Bts.. Palaearct., 5 sp.,
mole-like, subterranean creatures. Fiber G. Cuv., musk-rat, musquash,
Nearct., 3 sp., F. osoyoozennis, builds nests on bulrushes above water,
carnivorous. Pachyuromys, Ethiop. 1 sp., Palaearct. 1 sp. Meriones,
Ethiop. 2 sp., Orient. 1 sp., Palaearct. 10 sp. Psammomys, Palaearct., 2
sp. Rhombomy*, Palaearct., 1 sp. Otomys, Eth., 4 sp. Oreinomys,
634
RODENTIA.
Eth., 1 sp. Deomys, Eth., 1 sp. Dendromys, Eth., 6 sp. Limacomys,
Eth., 1 sp. Steatomys, Eth., 4 sp. Malacothrix, Eth., 1 sp. Nesokia, Orient.
8 sp., Palaearct., 4 sp. Cricetomys, Eth., 1 sp. Malacomys, Eth., 3 sp.
Lophuromys, Eth., 4 sp. Saccostomus, Eth., 3 sp. Acomys, Eth., 7 sp.,
Palaearct. 3 sp. Arvicanthis, Eth. 9 sp., Palaearct. 2 sp. Dasymys,
Eth., 4 sp. Golunda, Eth. 2 sp., Orient. 1 sp. Vandeleuria, Orient., 1 sp.
Chiropodomys, Orient., 3 sp. Batomys, Orient., 1 sp. Carpomys, Orient.,
2 sp. Pogonomys, Aust., 8 sp. Hapalomys, Orient., 1 sp. Pithecocheirus,
Orient., 1 sp. Lenomys, Orient., 1 sp. Crateromys, Orient., 1 sp. Mal-
lomys, Orient., 1 sp. Craurothrix, Aust., 1 sp. Mastacomys, Aust., 1 sp.
Uromys, Aust., 8 sp. Conilurus, Aust., 16 sp. Megalomys, Neotrop., 1
sp. Sigmodon, Nearct., 7 sp. Oryzomys Neotrop. 60 sp., Nearct. 6 sp.
Chilomys, Neotrop., 1 sp. Eeithrodontomys, Neotrop. 3 sp., Nearct.
0 sp. Eligmodontia, Neotrop. 6 sp. Nectomys, Neotrop., 7 sp.
Neotomys, Neotrop., 1 sp. Reithrodon, Neotrop., 5 sp. Phyllotis, Neo-
trop., 5 sp. Scapteromys. Neotrop., 2 sp. Ichthyomys, Neotrop., 4 sp.
Akodon, Neotrop., 40 sp. Mystromys, Eth., 1 sp. Brachytarsomys
Madagascar, 1 sp. Nesomys, Madagascar, 1 sp. Hallomys, Madagascar,
1 sp. Brachyuromys, Madagascar, 2 sp. Hypogeomys, Madagascar,
1 sp. Gymnuromys, Madagascar, 1 sp. Eliurus, Madagascar, 4 sp.
Onychomys, Nearct., 8 sp. Peromyscus, Nearct., 30 sp. Rhipidomys,
Neotrop., 12 sp. Tylomys, Neotrop., 3 sp. Holochilus, Neotrop., 4 sp.
Oxymycterus, Neotrop., 8 sp. Blarinomys, Neotrop., 1 sp. Notiomys,
Neotrop., 1 sp. Neotoma, Neotrop. 1 sp., Nearct. 33 sp. Nelsonia,
Nearct., 1 sp. Xenomys, Nearct., 1 sp. Hodomys, Nearct., 1 sp
Phenacomys, Nearct., 6 sp. Evotomys, Nearct. 14 sp. Palaearct. 5 sp.
Synaptomys, Nearct., 7 sp. Dicrostonyx, Nearct. 1 sp., Pala'earct. 1 sp.
Ellobius, Palaearct., 4 sp.
Fam. 7. Spalacidae. Mole-like forms, with very small sometimes
vestigial eyes and pinna, and short tail ; molars rooted, lophodont. Spalax
Giild., Palaearct., 8 sp. Rhizomys Gray, bamboo-rats, Orient., 5 sp.
Tachyoryctes Rupp. Ethiop., 3 sp.
Fam. 8. Geomyidae. Pouched rats. Fossorial with large cheek
pouches opening on the cheeks outside the mouth, p ±. Geomys Raf.,
pocket-gopher, Nearct., 8 sp. Thomomys Max., Nearct., 1 sp.
Fam. 9. Heteromyidae. Burrowing, with long hind limbs and tail ;
all confined to Nearctic except Heteromys. Dipodomys Gray, kangaroo-
rat, jerboa-like, with 4 or 5 toes on pes, 12 sp. Perodipus Fitz., 10 sp.
Microdipodops Murr., 1 sp. Perognathus Wied., 38 sp. Heteromys Desm.,
Nearct. 12 sp., Eth. 30 sp.
Fam. 10. Bathyergidae. Subterranean, mole-like, with small eyes
and pinna, short legs and tail, hairs reduced, the upper incisors stand out
in front of the closed lips, premolars present or absent, all Ethiopian.
Bathyergus 111., Cape mole-rat, 1 sp. Georychus 111., 10 sp. Myoscalops
Thos., 3 sp. Heterocephalus Riipp, 2 sp., Somaliland, with nearly naked
skin.
Fam. 11. Dipodidae. Jerboas, terrestrial usually with 4 u. grinders,
rooted, lophodont ; infraorbital foramen large ; metatarsals greatly elon-
gated, often fused into a cannon bone, pes from 3 to 5 digits, all Palae-
arctic except Zapus. Sminthus Keys, and Bias., 4 sp. Zapus Coues, Nearct.
6 sp., Palaearct. 1 sp. Dipus Gmel., 10 sp., pes 3-toed, metatarsals anky-
losed, cervical vertebrae except atlas ankylosed ; leap and burrow. Alac-
taga F. Cuv., 10 sp. Platycer corny s Brandt., 1 sp. Euchoreutes W. Scl. 1 sp.
PORCUPINES. CAVIES. 635
Tribe 3. Hystrieomorpha.
With stout zygomatic arch, clavicles perfect or imperfect, fibula distinct,
infraorbital foramen large, p \.
Fain. 12. Pedetitae. With rooted molars, cervical vertebrae free,
hind limbs elongate, metatarsals free, pes tetradactyle, Ethiopian. Pe-
detes 111., 1 sp. ; P. kaffer, the Cape jumping-hare.
Fam. 13. Octodontidae. Clavicles complete, grinders with external
and internal enamel folds, anterior palatal foramina long extending into
maxillae, maniis and pes usually with 5 digits, teats high up on the flanks,
tail with short hairs or scales, usually terrestrial, occasionally fossorial
or aquatic, all Neotropical unless otherwise mentioned, 21 genera. Lou-
che) es 111., porcupine-rats, with small spines in the fur, 18 sp. Thrynomys
Fitz. (Aulacodus), ground rat of S. Afr., 4 sp., Eth. Myocastor Kerr
(Myopotamus), 1 sp. ; M. coypu, the coypu, a large S. American water-
rat, to 2 feet. Ctenodactylus, 1 sp., Eth. Massoutiera, 1 sp. Eth., 1 sp.
Palaearct. Pectinc'tor, 1 sp., Eth. Petromys, 1 sp., Eth. Ctenomys,
9 sp. Aconaemys (Schizodon), 1 sp. Spalacopus, 1 sp. O.'todon, 4 sp.
Abrocoma, 2 sp. Dactylomys, 1 sp. Thrinacodus, 1 sp. Kannabateomys,
1 sp. Thrichomys, 4 sp. Cercomys, 1 sp. Carterodon, 1 sp. Mesomys
4 sp. Echinomys, 13 sp. Capromys, 5 sp. Plagiodontia, 1 sp.
Fam. 14. Hystricidae. Porcupines. Fur more or less modified
into spines and hollow quills, tail not prehensile, soles of feet smooth,
grinding teeth with external and internal folds ; skull bones often inflated
by air-sinuses, clavicle incomplete, limbs sub-equal. Hystrix L., Ethiop.
3 sp., Orient. 7 sp., Palaearct. 2 sp ; H. cristata, the common porcupine,
S. Eur., N. and W. Afr. Atherura G. Cuv., Ethiop. 3 sp , Oriental 1 sp
Trichys Gunth., Orient., 1 sp.
Fam. 15. Erethizontidae. Hair as in last, clavicles complete, soles
tuberculated, tail usually prehensile, Neotropical except Erethizon F. Cuv.,
Nearctic, 2 sp ; Coendu Lac. (Cercolabes and Synetheres, Sphingurus), tree
porcupines, arboreal, Neotrop. 9 sp. Chaetomys Gray, Neotrop., 1 sp.
Fam. 16. Chinchillidae. Terrestrial, with long hind limbs, bushy
tails, soft fur, and complete clavicles, grinders lophodont, all Neotropical.
Chinchilla Benn., 1 sp., squirrel-like, fur grey, valuable; Andes. Lagidium
Mey., 3 sp. Lagostomus Brooks, 1 sp. L. trichodactylus, viscacha, live in
burrows.
Fam. 17. Dasyproctidas. With long incisors, sub-equal limbs, hoofs
like claws, short tail, Neotropical. Dasyprozta 111., agoutis, pes with
3 digits, C. and S. Amer. and W. Ind. Islands, 12 sp. ; Coelogenys F. Cuv.,
paca, pes with 5 digits, jugal arch very broad, enclosing on each side a
cavity communicating with the mouth, body attains a length of 2 feet.
Fam. 18. Dinomyidae. Cleft upper lip, long bushy tail, limbs tetra-
dactyle, 1 genus and sp. and only 1 specimen found, Peru. Dinomys Pet.
Fam. 19. Caviidae. Terrestrial or aquatic with short incisors, lopho-
dont grinders, milk teeth shed in foetal life, paroccipital processes long and
curved, clavicles imperfect, tail short, manus with 4, pes with 3 digits,
Neotropical. Cavia Pall., cavies, 11 sp. ; C. porcellus, guinea pig. Doli-
chotis Desm., 2 sp., Patagonian cavy. Hydrochoerus Briss., 1 sp., H.
capybara, capybara, aquatic, the largest rodent, length 4 to 5 feet, without
tail, manus tetra-, pes tri-dactyle, digits webbed, hoof-like nails, last u.
molar very large with 14 laminae.
636 RODENTIA. INSECTIVORA.
Sub-order 2. DUPLICIDENTATA.
Incisors at birth f-, the outer upper soon lost, the next pair
small and placed behind the large third pair (p. 628). Skull with
optic foramina confluent, without alisphenoid canal. Fibula
ankylosed to tibia and articulating with calcaneum. Testes
permanently external ; without vesiculae seminales.
Fam. 20. Lagomyidae. Picas, p ± or f, grinders rootless lopho-
dont, skull depressed, clavicles complete, ears short, no external tail.
Lagomys G. Cuv. (Ochotona Link.), pica, tailless hare, mountainous parts
of N. Asia, S. E. Eur. and Rocky Mountains, 16 sp.
Fam. 21. Leporidae. Hares and rabbits, p |, skull compressed,
frontals with large wing-like postorbital processes, facial portion of maxillae
reticulated, clavicles imperfect, ears and hind limbs long, tail short;
cosmopolitan except Australasia and Madagascar. Romerolagus Merr.,
1 sp., Neotrop. Lepus L., hares and rabbits ; manus 5, pes 4 toes, about
20 sp. L. timidus (europaeus), hare ; L. cuniculus, rabbit, produces naked
young and lives in burrows. The common hare, lives on its " form,"
produces active young, extends all over Europe, not known in Ireland.
L, variabilis, the mountain hare, often changes colour in winter, but does
not change in Ireland.
Order 19. INSECTIVORA.*
Terrestrial, rarely arboreal or natatorial mammals of small
size, with plantigrade or semiplantigrade, generally pentadactyle,
unguiculate feet ; with clavicles (except in Potamogale) ;. with
more than two incisors in the mandible, and with enamelled, tuber-
culated rooted molars.
The Insectivora are small animals covered with fur and some-
times on the dorsal and lateral surfaces with spines. The
limbs are usually pentadactyle, and the digits are armed with
claws. They are plantigrade or semi-plantigrade, and digit
No. 1 is not opposable in either foot. The extremity of the
muzzle projects beyond the end of the mandible.
The dentition contains all kinds of teeth, but in many
cases the incisors, canines and premolars are not clearly dif-
ferentiated from one another ; it sometimes attains the lull
* Peters, Die Classification der Insectivoren, Monatsb. Akad. Wissensch.
Berlin, 1865. Mivart, Osteology of Insectivora, P.Z.S., 1871. Gill,
Synopsis of Insectivorous Mammals, Bull. GeoL and Geog. Survey, U.S.A.,
1875. Dobson, Monograph of the Insectivora, London, 1882-90. Id.,
Synopsis of the Soricidae, P.Z.S., 1890, p. 49, 1891, p. 349. Id., Insecti-
vora in Blanford's Fauna of British India. Schlosser, op. cit., see Carni-
vora.
INSECTIVORA. 637
mammalian number of teeth, i^c\p^m^ (e.g., Talpa,
Myogale], but there are usually reductions. The incisors are
primitively conical, and are occasionally enlarged in a rodent-
like manner. The posterior incisor sometimes has two roots
(Erinaceus, Galeopithecus). The canines are not usually strongly
developed and may have two roots (Erinaceus, Talpa, Galeo-
pithecus). The premolars are usually sharp and pointed, but
the last may be like the molars. The upper molars are three-
or four-cusped, the cusps being isolated or connected by ridges.
The last molar is frequently smaller than the others. The
lower molars have three cusps in front and a talon which is often
two-cusped behind. There is a milk dentition, which however
is frequently absorbed in utero.
The skull is elongated and depressed, and has a small cranial
cavity. The orbit is not closed by bone except in the Tupaii-
dae. The palate is very generally incompletely ossified, and
the angle of the mandible may be inflected as in marsupials ;
and as in that order the alisphenoid contributes to the anterior
wall of the tympanic cavity. The tympanic bulla is rarely
completely ossified and frequently falls off in the dry skull.
The mastoid process is often marked and sometimes joins the
postglenoid process of the squamosal below the external auditory
meatus. The jugal is often weak and sometimes absent, in
which case the zygomatic arch is incomplete.
The vertebral column presents considerable variations, both
in number and character of vertebrae, even in different species of
the same genus. The lumbar region often presents intercentra.
The scapula has a well developed spine with an acromion and
often a metacromion. A clavicle is present in all except Pota-
mogale. The humerus usually has an entepicondylar foramen,
and the radius and ulna are generally separate. The scaphoid
and lunar are fused in some genera (e.g. Galeopithecus, Tupaia,
Erinaceus, etc.), and there is usually a centrale in the carpus.
The manus has typically five digits, but the pollex may be
aborted. The femur often has a third trochanter. The fibula
is usually united with the tibia, but in a few genera it is free.
The digits of the pes are five, but the hallux may be absent.
The pelvis presents considerable variations ; the pubic sym-
physis being long, short or absent (e.g. Talpa).
The brain is small. The cerebrum never projects back over
638 INSECTIVORA,
the cerebellum, and often leaves the optic lobes uncovered ;
its surface is smooth, except for one shallow longitudinal sulcus
on each side. The corpus callosum is small and the anterior
commissure large. The stomach is simple (except in Galeo-
pithecus). A caecum is present or absent. There are two
superior venae cavae.
The testes are inguinal or abdominal and never descend into
a scrotum. The penis is usually pendent, and in some forms is
retractile within the fold of integument surrounding the anus.
The uterus is bicornuate, and often without a distinct os uteri,
the placenta discoidal, and the mammae which are generally
numerous are variable in position. They frequently extend
along the ventral surface from the axilla to the inguinal region,
but occasionally they are axillary (Galeopithecus) or even post-
inguinal (Solenodon). Odoriferous glands are present in many
species. They may be just behind the axilla, as in the shrews,
or near the anus.
The Insectivora are, with the exception of the Tupaiidae,
nocturnal animals. Most of them are cursorial, but a few are
burro wers (the moles), and some are aquatic (Potamogale, Myo-
gale). Others again are arboreal (Tupaiidae) &nd Galeopithecus
flits about from tree to tree by means of a patagium as do the
flying squirrels. They live on insects and worms. ,
They are generally regarded as the most primitive of placental
mammals, and perhaps their nearest allies are the polyproto-
dont marsupials. In their dentition and in the structure of the
skull and brain they recall the Chiroptera, and by their fossil
forms they approximate to the Creodonta and Lemuroidea.
• The primitive characters are the small and smooth brain,
the frequent occurrence of trituberculate molars, the absence
of a scrotum, and the frequent abdominal position of the testes ;
moreover the palate is often fenestrated and the angle of the
mandible inflected, and sometimes the anus and urinogenital
apeHvres are surrounded by a common fold of integument,
so that there is a kind of cloaca.
They are widely distributed over the earth's surface, but
are entirely absent from the Australian region, and in South
America are only found in the northern Andes.
They make their appearance in the Lower Eocene of Europe
and North America. Many of the older forms are not referable
SHREWS. HEDGEHOGS. 639
to existing families and present greater resemblance to marsu-
pials, creodonts and lemuroids than do the more modern types.
Fam. 1. Tupaiidae. Arboreal diurnal forms with large brain case,
closed orbit and well-developed zygomatic arch, perforated jugal, a tym-
panic bulla, and a long symphysis pubis. Upper molars broad, multi-
cuspidate, with cusps arranged in a W ; usually with a short caecum ;
Oriental region. Tupaia Raffles, tree-shrews, i f c *. ^ p |- m -|, about
14 species, squirrel-like. Ptilocercus Gray, pen-tailed tree-shrew, 1 sp.,
Borneo. Extinct genera from the M. Miocene ; Lantanotherium, Plesio*
sorex, Galarix.
Fam. 2. Macroscelididae. Nocturnal saltatorial forms with large
brain case, well-developed zygomatic arch, imperforate jugal, orbit not
surrounded by bone, a tympanic bulla and a long symphysis pubis. The
metatarsus is greatly elongated, the tibia and fibula are united, and the
caecum is large. The penis is anterior and suspended from the abdo-
minal wall. The molars are broad and have four cusps arranged in a W.
Africa. Macroscelides A. Smith, jumping or elephant-shrews, 10 sp. ;
Petrodromus Pet., 3 sp. ; Rhyncttocyon Pet., fossorial, 4 sp.
Fam. 3. Erinaceidae. Hedgehogs. Terrestrial forms with planti-
grade feet, small brain case, slender zygomatic arch, an annular tympanic
hot forming a bulla ; without postorbital process ; with slender clavicles'
and bifid acromion ; radius and ulna free, tibia and fibula ankylosed ;
caecum absent. The spinal chord is much thickened in the cervical
region and is continued as a slender filament, the filum terminate. The
penis is anterior and suspended from the abdominal wall, m 1 and 2
of upper jaw with 5 cusps, the central cusp being minute and united by
a ridge on each side to the two internal cusps ; Palaearctic, Ethiopian
(except Madagascar), and Oriental regions. Gymnura Horsf. and Vig.,
i ^ c i p | m -|, without spines, Malayasia. Erinaceus, L hedgehogs ;
* f c T P I m f » witn spines ; about 20 species, Palaearctic, Ethiopian
and Oriental regions ; E. europaeus I ., the common hedgehog, hibernates
during the winter, young born in July or August. Extinct genera from
the Miocene and Eocene.
Fam. 4. Soricidae. Shrews. Terrestrial, rarely aquatic, rat-like or
mouse-like forms, with long and pointed muzzle ; without zygomatic
arch, postorbital process, and pubic symphysis ; the tympanic is annular,
the tibia and fibula are united, and the cusps of the u. molars are arranged
in a W ; widely distributed. The dentition is not fully understood,
owing to the early obliteration of the maxillo-premaxillary suture. The
ordinary statement is that there are four incisors, one canine, a variable
number of premolars and three molars in the upper jaw, but it is possible
that the fourth incisor may be the canine, and the canine the first pre-
molar. There are always three molars. In the lower jaw there are always
six teeth (possibly seven in Myosorex] on each side. There is no caecum
or symphysis pubis, and the penis is retractile within the fold of the
integument surrounding the anus. This family includes the majority
of species of the order.
Sub-fam. 1. Soricinae. Teeth tipped with red. Sorex L.,
' ' £ c 77 P f m t ' milk dentition functionless ; terrestrial ; urino-
genital opening separated from the anus, ears well-developed, tail
Jong ; Palaearctic and Nearctic ; two British species, S. vulgar is,
640 INSECTIVORA.
the common shrew, and S. minutus, which is rarer ; in the former
there is a gland opening on each side of the body and emitting an
odoriferous fluid. Soriculua Blyth, Oriental. Notiosorex Coues, C.
Amer., Mexico. Blarina Gray, N. American short-tailed shrew.
Crossopus Wag., i ^ c ± p f m |, urinogenital opening and anus
enclosed in a common ring, ears small, tail long, aquatic ; C. fodiens,
the water-shrew, of Britain (not Ireland), Europe, Asia ; is con-
siderably larger than the common shrew.
Sub-fam. 2. Crocidurinae. Teeth white. Myosorex Gray,
* i c ?i P T«r 2 m !> terrestrial, Africa. Crocidura Wag., terres-
trial, with cloaca, about 70 species, Eur., Afr., Asia. Diplomesodon
Brandt, terrestrial, 1 sp., Asia. Anurosorex M.-Edw., mole-like,
terrestrial, 2 sp., Asia. Chimarrogale Anderson, aquatic Asia, 2 sp.
Nectogale M.-Edw., aquatic 1 sp., Thibet. Fossil forms as far back
as the Eocene.
Fam. 5. Talpidae. Fossorial, rarely natatorial or cursorial forms,
with fore-limbs generally modified for digging and anteriorly placed ;
humerus short, articulating with scapula and clavicle ; tibia and fibula
united ; without symphysis pubis ; with elongated skull, slender zygoma,
and tympanic bulla ; without postorbital process ; without caecum ;
i forf c yoro P ffto| ™> f ; *'» c and p vary much in form, in with
W-shaped cusps. Eyes small and sometimes covered by the skin. Ears
short and concealed by the fur. Penis pendent in front of the anus.
Clitoris like the penis and traversed by urethra. The moles possess an
elongated radial sesamoid (os falciforme), articulating with the scaphoid.
Nearctic, Palaearctic, and N. parts of Oriental.
Sub-fam. 1. Myogalinae. Without os falciforme. Myoqale Cuv.,
with webbed feet, aquatic, 2 sp., Eur., Asia. M. mosckata, the
desman, S.-E. Russia, 16 in. in length ; M. pyrenaica, Pyrenees.
Urotrichus Tern., mole-shrews, fossorial, Japan and N. Amer., 2 sp.
Sub-fam. Talpinae. Manus with os falciforme. Scalops Cuv.,
N. Amer., 3 sp. Scapanus Pomel., 3 sp., N. Amer. Condylura 111.,
1 sp., N. Amer. The above are New World moles. The following
are Old World moles. Scaptonyx M.-Edw., 1 sp., Thibet. Talpa
L., moles, usual dentition, i \ c | p ± m f , 5 sp. ; T. europaea
the common mole, eye small, but uncovered, tail long and hairy ;
the sternum is keeled, the humerus and clavicle short and powerful,
a very powerful burrower, voracious, hunting earthworms, Palae-
arctic.
Fam. »i. Adapisorieidae. Extinct, L. Eocene.
Fam. 7. Potamogalidae. Without clavicles, zygomatic arches, and
postorbital processes ; tympanic annular. The male and female organs
and anus open within the same fold of integument, and the penis can be
wholly retracted. Ethiopian. Potamogale Du Chaillu, a long animal,
nearly 2 feet in length, inhabiting the banks of streams; W. Afr.
Geogale M.-Edw., Madagascar.
Fam. 8. Solenodontidae. Without zygomatic arches and postorbital
processes ; tympanic annular. Penis pendent and anterior, testes re-
ceived into perineal pouches ; upper molars tritubercular ; mammae
two, placed on the buttocks ; single genus. Solenodon Brandt, Cuba
and Hayti.
Fam. 9. Centetidae. Without zygomatic arch and postorbital pro-
INSECTIVORA. CHIROPTERA. 641
casses ; tympanic annular. Upper molars tritubercular. Penis pendent
and retractile within the fold of integument surrounding the anus. In
the female the urinogenital organs and anus open together. The testes
are near the kidneys. Caecum absent. Madagascar. Centetes 111., 1 sp.
C. ecaudatus, the terirec, 12-16 in. in length without a tail. Hemicentetes
Miv, Ericulus I. Geoff. Microgale Thos. Oryzoryctes Grandidier.
Fam. 10. Chrysochloridae. Without postorbital process, with zygo-
matic arch and tympanic bulla, with stout fossorial fore-limbs, without
symphysis pubis. The eyes are covered with skin and the ears without
pinnae. Mammae thoracic and inguinal. Dentition i |- c \ p f m f °,f »
upper molars tritubercular. Generative organs as in Centetidae. S.
Africa. Chrysochloris Lac., Cape golden moles, 7 or 8 sp.
Fam. 11. Galeopithecidae.* The single genus, Galeopithecus Pall.,
of this family has been placed amongst the bats and amongst the primates.
It is now, however, generally regarded as an aberrant insectivore.f The
essential peculiarity of the genus is the possession of a parachute -like
flying membrane, the patagium, which enables its purely arboreal pos-
sessor to float from tree to tree in the forests which it inhabits. The
patagium is a muscular membrane, extending between the neck and the
fore-limbs, between the fore- and hind-limbs, and between the hind-limbs
and the tail. It is covered with hair on both sides, and, though it ex-
tends as a kind of web between the digits of both manus and pes, the
fingers are not elongated, as they are in the bats, to support the anterior
part of it. The dentition ist£0^-p£m£; the upper and lower
incisors are compressed and multicuspidate, the lower pectinated, and
the second upper incisor and the canines of both jaws have two roots.
The orbit is nearly enclosed by bone, the posterior margin of the palate
is thickened, the tympanic forms a bulla, and the postglenoid process of
the squamosal unites with the mastoid beneath the external auditory
meatus. The fore-limbs are slightly larger than the hind-limbs, and
there are five clawed fingers and toes. There is a large sacculated caecum,
and the large intestine is longer than the small. There are two pairs of
axillary mammae, the penis is pendent, and the testes descend into in-
guinal pouches. The optic lobes are uncovered and the upper surface
of the cerebrum is marked by two longitudinal furrows on each side.
Galeopithecus differs entirely from the bats in the structure of the fore-
limb, and in the position of the hind-limb. It resembles the insectivores
in the structure of the skull, in the double-rooted canines (found also in
Erinaceus and Talpa). There are two species, which inhabit the forests
of Malayasia and the Philippine Islands. They are nocturnal, phyto-
phagous animals, and when at rest hang by their posterior limbs with
the head downwards, after the manner of bats.
Order 20. CHIROPTERA.!
Flying mammals with the fore-limbs specially modified for flight.
With one (or two) pairs of thoracic, usually postaxillary, mammae.
* Leche, Ueber Galeopithecus, K. Svensk. Akad. Handl, 1886.
f It is sometimes placed in a special sub-order of the Insectivora, the
Dermoptera, and opposed to the rest of the order which are termed Insec-
tivora vera.
J G. E. Dobson, Catalogue of the Chiroptera in the British Museum,
1878. Id., New accessions to the Chiroptera ; Report of the British Associa-
Z — II. T T
642
CHIROPTERA.
Among the marsupials (Petaurus), the rodents (Pteromys)
and the insectivores (Galeopithecus), there is a number of forms
which are assisted in jumping by a kind of parachute, which
consists of a cutaneous expansion, the patagium, stretched be-
tween the limbs on each side. The patagium is much more
completely developed in the bats ; in these animals it is con-
tinued over the extraordinarily elongated fingers of the hand,
and in virtue of its great size and elasticity constitutes a true
organ of flight. The tail, when present, is included in the pata-
gium, but the thumb and the foot are separate from it (Fig. 326).
FIG. 326.— Skeleton of Pteropus (after Owen, slightly altered). Cl clavicle ; D thumb ; F
fibula ; -Fe^femur ; Jl ilium ; Js ischium ; H humerus ; P pubis ; R radius ; Sc scapula ;
St sternum ; T^tibia ; U ulna.
Both fore- and hind-limbs are pentadactyle. The thumb has
two phalanges and is armed with a claw, as are also the five
digits of the foot (Fig. 326). The second digit of the, manus
is also, in some forms, provided with a claw.
Peculiar outgrowths Jof the skin surrounding the nasal aper-
tures (nose-leaf) are often present and give the face a very
strange appearance (Fig. 327). Except upon these appendages
and upon the thin elastic patagia, both of which have a large
tion, 1880. Allen, A Monograph of the Bats of North America, Bull.
U.S. Nat. Mus., No. 43, 1893. H. Winge, Chiroptera (viv. et foss.) ex
Lagoa Santa, Minas Gerass, Brasil., E. Museo Lundii, 2, 1, 1892.
SKELETON. NERVOUS SYSTEM. VISCERA. 643
supply of nerves and a remarkably delicate sense of touch,
the surface of the body is closely covered with hair.
The skeleton (Fig. 326) is remarkably light, and the bones
of the limbs have large medullary cavities. It is distinguished
by the large size and rigidity of the thoracic framework, by the
possession of a keel on the presternum, by the length of the
strongly developed sacrum with which the ischia are united,
and by the fact that the anterior limbs are larger than the
posterior, and possess four greatly elongated digits (digits 2-5).
Moreover the hind-limb has been rotated outwards so that the
knee is directed backwards and the sole of the foot forwards,
the hallux being external. The calcaneum carries a bony or
cartilaginous process, the calcar, which projects backwards
and inwards supporting the interfemoral part of the patagium.
The cerebral hemispheres are smooth and do not extend over
the cerebellum. The spinal cord is reduced to a fine thread
in the lumbar-sacral region. The eyes are relatively small ,
but the senses of hearing and of touch, and probably of smell,
are enormously developed. Spallanzani has shown that bats
which have been made blind are able to avoid all obstacles,
such as strings stretched across a room, in their flight. The
pinna of the ear is always large, and often of great size ; it
probably not only intensifies the power of hearing, but also
acts as an organ of touch in the species in which the nose-leaf,
which is probably the tactile organ par excellence, is not
present.
The dentition never exceeds i § c \ p $ m jj, and is frequently
reduced from this. The alimentary canal is distinguished by
the narrowness of the oesophagus, the relatively short length
of the intestine and by the general absence of a caecum.
The heart and lungs are proportionately large. Both
superior venae cavae are present.
In the reproductive system, the penis is pendent and often
provided with a bone, the testes are abdominal, but descend
into the perinaeum in the breeding season, and the clitoris is
occasionally perforated by the urethra. The uterus may be
rounded or bicornuate, and the placenta is discoidal and deci-
duate. They bear one or two young at a birth, and carry them
about with them during their flight.
Bats are nocturnal animals. Some of them are insectivorous,
644 CHIROPTERA.
some frugivorous, and some (Desmodus, Diphylla) suck the
blood of other mammals. When at rest they hang suspended
by the claws of one or both legs, head downwards. On the
ground they rest with the knees directed upwards, and move
in a shuffling manner, pushing themselves along by their feet
which are rotated forwards and inwards, and hauling themselves
forwards by the claws on their thumbs. Many of them hiber-
nate, and in some at least the sexual season is separated by a
considerable interval from that of ovulation and conception
(see p. 517). The sexes appear frequently to live apart except
in the breeding season.
They are nearly cosmopolitan in distribution.* There are
about 520 species and 95 genera of living forms. The earliest
fossil Chiroptera, which are from the Upper Eocene, show all
the features of specialisation of the order. Remains of about
6 genera and 35 species have been discovered, all belonging to
existing families.
Such are the principal characters of the Chiroptera. It is
clear that they are a very sharply defined group with many
peculiar features, and the diversity of structure within the
group cannot be said to be very great. Formerly, on account
of the usual number of their upper incisors, the position of the
mammae, the pendent penis, the placental characters and the
form of the uterus they were included amongst the Primates ;
but there can be very little doubt that their real affinities are
with the Insectivora.
The following details may be added to the foregoing account.
The nose-leaves are found in the Rhinolophidae, the Nycteridae and the
Phyllostomidae. They are folds of the skin at the margins of the nostrils,
are richly supplied with nerves (mainly derived from the nasal branch
of the trigeminal), and contain many sweat and sebaceous glands, which
maintain their surfaces in a soft and highly sensitive condition. There
can be no doubt that they are highly developed organs of touch, and are
one of the principal means by which their possessors are able to feel objects
without touching them, as bats are undoubtedly able to do. But this
function must also be discharged by other organs ; for the power of
avoiding obstacles in the dark is, as was shown by Spallanzani's experi-
ments, possessed by bats without a nose-leaf. These organs are pro-
bably the patagium, and the pinna of the ear which is remarkably de-
veloped in bats. The pinna is always large, and in some species its length
* Dobson, op. cit., states that they have not been found in Iceland,
St. Helena, the Galapagos Archipelago, Kerguelen Island, and the Low
Archipelago.
CHIROPTERA. 645
nearly equals that of the head and body. Its form is very diverse. In
many species the tragus is greatly developed, and in the Rhinolophidae,
in which the tragus is absent, compensation is probably afforded by the
large bullae osseae and the largely developed nose-leaf.
The patagium consists of (1) the antebrachial portion which extends
from the point of the shoulder along the humerus and more or less of the
fore-arm to the base of the thumb, the metacarpal bone of which is partly
or wholly included in it, (2) the wing-membrane which is spread out
between the greatly elongated fingers, and extends along the sides of the
body to the posterior limbs, generally reaching to the feet, and (3) the
interfemoral membrane which is the most variable part and is supported
between the extremity of the body, the legs and the calcar. In most
species the wing-membrane arises from the sides of the body, but in a
few (Notopteris, Cephalotes, etc.) it springs from the middle line of the
back. The interfemoral membrane is best developed in the insectivorous
forms, and aids them in their rapid doubling movements. In the frugi-
vorous and blood-sucking species it is deeply cut out behind or forms a
narrow projection along the legs.
Odoriferous glands and pouches opening on the surface of the skin are
present in many species. The chief of them are the frontal pouches of
Phyllorhina, the gular glands and pouches of Taphozous, Molossus, Phyl-
lostoma, etc., the shoulder glands and pouches of Pteropus, etc., the pubic
and anal glands of Rhinolophidae, etc., and the wing-pouches of
Saccopteryx.
Skeleton. In addition to the points already noted, the following fea-
tures may be mentioned. The vertebral column is short and constant
in form. There are usually 12 thoracic and 5 lumbar vertebrae. With
the exception of the axis none of the cervical or thoracic vertebrae develop
spines. From the first thoracic to the last lumbar vertebra the spinal
column forms a single curve backwards.
The skull is the most variable part of the skeleton. The postorbita 1
processes of the frontal are absent or short in Microchiroptera, long and
traversed by a foramen in Megachiroptera, and in Pteropus leucopterus
the orbital ring is complete. The premaxillae are very variable, and
may be cartilaginous or almost absent. The zygomatic arches may be
strong, slender or absent. The tympanic bullae are without an external
canal, and are loosely connected with the adjacent bones.
The clavicle is always well developed, and the spine of the scapula has
a large acromion. The humerus has a large pectoral ridge, and is without
a supracondylar foramen. The ulna is small and ankylosed with the
radius. In the carpus the scaphoid, lunar and cuneiform are ankylosed
to form a single bone and the distal bones are normal. The pollex always
has a claw, as has the second digit in most Megachiroptera. The first,
fourth and fifth digits possess two phalanges ; in the second and third
the number of phalanges varies. In Megachiroptera the second digit
has three phalanges ; in most Microchiroptera it only has a single rudi-
mentary phalanx (absent in the Rhinolophidae). The third finger is the
longest, and except in the Phyllostomidae and one or two others in
which it has three, bears two phalanges only. The metacarpals and
phalanges of the second to the fifth digits are for the most part elongated.
The pelvic girdle is weak. The fibula is reduced except in the Molossinae.
Dentition. The molar teeth of the insectivorous forms are acutely
tubercular, with usually well-developed W-shaped cusps. In the frugi-
646 CHIROPTERA.
vorous Megachiroptera the molar teeth are longer than broad and their
crowns are traversed by a longitudinal groove. In the milk dentition
the teeth have pointed recurved cusps which assist the young to secure
a firm hold of the nipple of the mother during flight. They are shed
early.
Tribe 1. MEGACHIROPTERA.
Frugivorous bats, generally of large size. Crowns of the molar teeth
smooth, marked with a longitudinal furrow ; bony palate continued
behind the last molar, narrowing slowly backwards ; second finger gener-
ally terminating in a claw ; sides of the pinna forming a complete ring
at the base ; pyloric extremity of the stomach elongated. The tail is
short or absent, when present it is partly in the interfemoral membrane,
except in Epomophorus, in which it is free from this structure. Tropical
and sub-tropical regions of the Old World.
Fam. Pteropidae. With the characters of the tribe. Epomophorus
Bennett, 10 sp., Ethiopian except Madagascar. Pteropus Briss., flying
foxes, the largest known bats, with long pointed muzzle, without tail,
i^c^p^m f, about 50 sp., Madagascar and Mascarene Islands, Oriental
region, S. Japan, Australia and Polynesia (except Sandwich Islands,
Ellice's group, Gilbert's group, Tokelau, Low Arch., and N. Zealand) ;
P. edulis measures 5 feet across on the wing with a body-length of 12
inches. Pteralopex Thos., 1 sp., Solomon Islands. Cynonycteris Ptrs., 10
sp., Ethiop. and Orient. Boneia Jent., 2 sp., Malay Arch. Harpyonicteris
Thos.. 1 sp., Philippines. CynopterusF. Cuv., 11 sp., Oriental. Scotonyc-
teris Matschie, 1 sp., Cameroons. Harpyia 111., with external nostrils
prolonged as tubes, i ^ c \ p|wf, 2 sp., Austro-Malaya. Cephalotes
E. Geoff., 2 sp., Austro-Malaya. Hypsignathus Allen, 1 sp., Afr. Lei-
ponyx Jent., 1 sp., Afr. Eonycteris Dob., 1 sp., Burmah. Megaloglossus
Pag., 1 sp., Afr. Macroglossus F. Cuv., 3 sp., Oriental and Polynesia.
Melonycteris Dob., 1 sp., New Ireland. Callinycteris Jent., 1 sp., Celebes.
Netonycteris Thos., 1 sp., Solomon Is. Notopteris Gray, 1 sp., Fiji, New
Guinea.
Tribe 2. MICROCHIROPTERA.
Mainly insectivorous bats of small size. Crowns of the molar teeth
acutely tubercular, marked by transverse furrows ; bony palate narrow-
ing abruptly, not continued laterally behind the last molar ; second
finger not terminated by a claw and usually with one small phalanx
only ; outer and inner sides of the pinna commencing anteriorly from
separate points of origin ; stomach simple or with the cardiac extremity
more 'or less elongated. Tropical and temperate regions of both
hemispheres.
Fam. Rhinolophidae. With well developed foliaceous cutaneous
appendages surrounding the nasal apertures, which are placed in a depres-
sion on the upper surface of the muzzle ; with large, generally separated
ears, without a tragus ; first finger without phalanx, middle finger with
two phalanges ; with rudimentary premaxillae suspended from the nasal
cartilages, i \ c \ p f ™i m ~ ; the upper incisors are rudimentary,
the molars have acute W-shaped cusps. They possess complicated nasal
appendages, supported by the nasal bones which are much expanded.
Females with 2 nipple-shaped appendages in front of the pubis. Tail
distinct, reaching to the posterior margin of the interfemoral membrane.
CHIROPTERA. 647
They are the most highly organised of insectivorous bats. Temperate
and tropical parts of the Old World (not found in Polynesia). Rhino-
lophus E. Geoffr., with complicated nose-leaf, and ear with large anti
tragus, wings large, i * c y p f m 5 ; more than 20 sp. R. hippo-
siderus, the lesser horseshoe bat, Eur., South of England and Ireland ; R.
ferrum-equinum, the greater horse-shoe bat, England to Japan and Cape
of Good Hope. Triaenops Dob., with very remarkable nasal appendage
and ears, Persia, Afr., Madagascar, 3 sp. Rhinonycteris Gray, 1 sp., Aus-
tralia. Phyllorhina Bonap. 1831 (Hipposiderus Gray, 1834), i \ c \
p f m f , 25 sp., trop. and sub-trop. parts of Asia, Malayasia, Australia
and Afr. Anthops Thos., 1 sp., Solomon Is. Coelops Blyth, 1 sp.,
India.
Fam. Nycteridae. With distinct cutaneous appendages on the margins
of the apertures of the nostrils, with large united ears with well-developed
tragi ; the premaxillae are cartilaginous or small ; upper incisors
absent or small in the centre of the space between the canines ; Ethiopian,
Oriental. Megaderma E. Geoff., 2 sp. Asia, 2 sp. Afr., 1 sp. Australia ;
M. lyra, eat frogs and probably small mammals, India. Nycteris E.
Geoff., Afr. 6 sp., Java 1 sp.
Fam. Vespertilionidae. Simple terminal nostrils without cutaneous
appendages, ear with tragus, middle finger with 2 phalanges, with a long
tail contained and produced to the hinder margin of the large interfemoral
membrane ; i f °rri c -}- p |°'| m f , molars with W-shaped cusps,
upper incisors separated by a wide space and placed near the canines ;
10 genera, and over 190 sp., in all temp, and trop. regions. Anlrozous
Allen, 1 sp., California. Nyctophilus Leach, 3 sp., Australasia. Synolus
Keys, and Bias., » f C ^ p f m f , 2 sp.,S. barbastellus, the barbastelle,
Britain, Eur., and a Himalayan sp. Plecotus E. Geoff., i%c±p%m%;
3 sp., 2 of which are N. American ; P. auritus, the long-eared bat of this
country, ranging to India. Euderma Allen, 1 sp., California. Oto-
nycteris Ptrs., 1 sp. Africa and Asia. Vespemgo Keys, and Bias.,
i -°r- c y p |°Ji m ^, cosmopolitan, over 70 species, includes the
common bats of most countries ; the British species are V. serotinus,
the serotine bat ; V. noctula ; V. leisleri and V. pipistrellus, the pipis-
trelle. Chalinolobus Ptrs., 8 sp., Australian and Ethiopian. Scotophilus
Leach, 12 sp., Ethiop., Orient, and Austr. Regions. Nycticejus Baf.,
1 sp., Amer. Atalapha Raf., 9 sp., Amer., Sandwich and Galapagos
Islands. Harpiocephalus Gray, 1 sp. Japan, 8 sp. from the Himalayas
to the Malay Arch. Vespertilio Keys, and Bias., i f c \ p f m f,
cosmopolitan, 50 sp., 4 of which are British ; V. bechsteini, Bechstein's
bat ; V. nattereri, the reddish-grey bat ; V. daubentoni, Daubenton's
bat ; V. mystacinus, the whiskered bat. Kerivoula Gray, 15 sp., Oriental,
Ethiopian. Thryoptera Spix., 2 sp., S. Amer. Myxopoda A. M.-Edw.,
1 sp., Madagascar. The last two genera have hollow suctorial organs
on the base of the pollex and on the soles of the feet. Miniopterus Bon.,
throughout the Eastern Hemisphere, 5 sp.
Fam. Emballonuridae. With truncated muzzle; without nose -leaf,
with generally large, often united, ears ; with short, sometimes minute
tragi ; the tail is partially free, either perforating the interfemoral mem-
brane and appearing upon its upper surface or produced far beyond its
posterior margin ; the first phalanx of the middle finger is folded in
repose toward the upper surface of the metacarpal bone ; dentition
variable. Tropical and sub-tropical regions of both hemispheres.
648 CHIROPTERA.
Sub-fam. 1. Emballonurinae. Tail perforating the interfemoral
membrane and appearing on its upper surface or terminating in
it ; legs long ; upper incisors weak. Furia F. Cuv., 1 sp., Brazil.
Amorphochilus Ptrs., 1 sp., Peru. Emballonura Temm., 7 sp., Mada-
gascar, Malay Arch. Coleura Ptrs., 2 sp., S.-E. Air., Seychelles.
Rhynchonycteris Ptrs., 1 sp., Neotrop. Saccopteryx Ilh'g., 7 sp.,
Neotrop. Taphozous E. Geoff., 11 sp., Ethiop., Orient, and Aust.
Regions. Diclidurus Wied., 2 sp., Neotrop. Noctilio L., first upper
incisors close together, giving a rodent-like appearance, feed on
fish, 2 sp., C. and S. Amer. Rhinopoma E. Geoff., 1 sp., from Egypt
through Asia Minor to India and Burmah.
Sub-fam. 2. Molossinae. Tail thick, produced far beyond the
posterior margin of the interfemoral membrane (except in Mysta-
cina) ; legs short and strong, with large feet, of which the first toe
and often the fifth are much larger than the others, the feet are free
from the wing membrane ; of all bats the most fitted for terrestrial
progression. Molossus E. Geoff., 10 sp., neotrop. Nyctinomus
E. Geoff., 32 sp., trop. and warmer temp, zones of both hemispheres.
Mystacina Gray, 1 sp., N. Zealand.
Fam. Phyllostomidae. With cutaneous
processes either surrounding or close
to the nostrils ; with moderately large
ears and well-developed tragi ; with 3
phalanges in the middle and 1 phalanx in
the index finger ; and with generally well
developed united premaxillae ; dentition
variable. This family includes insecti-
vorous, frugivorous, and blood -suck ing
forms. Confined to the Neotropical
Region ; 36 genera.
Sub-fam. 1. Natalinae. Natalus Gray,
3 sp.
FIG. 327. — Head of Vampyrus Sub fam. 2. Mormopinae. Nostrils ter-
spectrum (Regne animal). rainal,. opening by simple apertures, not
margined by a distinct nose-leaf ; chin with expanded leaf -like append-
age. Chilonycteris Gray, 6 sp. Mormops Leach, 2 sp.
Sub-fam. 3. Phyllostominae. Nostrils opening on the upper
surface of the muzzle, and surrounded by a nose-leaf : chin with
warts. Lonchorhina Tomes, 1 sp. Macrotus Gray, 3 sp. Macro -
phyllum Gray, 1 sp. Vampyrus E. Geoff., insectivorous and frugi-
vorous, 2 sp. ; V. spectrum L. (Fig. 327), which was supposed to be
a blood-sucker, is mainly frugivorous. Other genera are, Lophos-
toma, Schizostoma, Olyphonycteris , Trachyops, Phylloderma, Phyl-
lostoma, Tylostoma, Mimon, Carollia, Rhinopkylla, Glossophaga,
Phyllonycteris, Monophylhis, Ischnoglossa, Lonchoglossa, Anura,
Choeronycteris, Lichonycteris, Artibeus, Vampyrops^ Chiroderma,
Stenoderma, Ectophylla, Ametrida, Pygoderma, Sturnira, Brachy-
phylla, Centurio.
The true blood-suckers or vampires belong to this sub-family. They
are Desmodus Wied. (2 sp.), without molar teeth and calcar, and
Diphylla Spix. (1 sp.), with a small molar in each jaw and small
calcar. The dentition is i i c y p f m \°0l%, the upper incisors
are large, canine-like and trenchant, the oesophagus very narrow, and
PROSIMIAE. 649
the cardiac end of the stomach produced into a long narrow caecum.
They are small bats and suck the blood of men, horses and cattle
and probably of other warm-blooded animals.
Order 21. PROSIMIAE.* (LEMUROIDEA).
Plantigrade, usually pentadactyle, arboreal animals with oppos-
able pollex and hallux. The orbit is closed behind by a bar of bone
formed by the union of the frontal and jugal, but is not completely
shut off from the temporal fossa by a wall. Digit No. 2 of the pes
always has a claw.
The lemurs are small or medium -sized, for the most part
nocturnal animals, covered with fur and usually provided with
a long tail which is never prehensile. They are generally quad-
ripedal, and the pollex and hallux are always well developed
and opposable.
The dentition varies in the different families so that no general
formula can be given for it, but except in Chiromys, which has
no canines, all kinds of teeth are present. In living species it
is usually i f c \ p |£J m 3, but in some of the extinct
forms attributed to this group from the Eocene and L. Miocene
it is i f orl c { p ^ m f, the teeth extending without a
break along the jaw. The molars are tri-or quadri-tubercular,
and the cusps are connected by low ridges. The third lower
molar usually has a small talon. The premolars are always
simpler than the molars, and have one sharp cusp, but the last
may be molar-like.
The brain case is small relatively to the size of the face, which
is generally elongated. The orbits, though completed behind
by the bony union of the jugal and frontal are not completely
shut off from the temporal fossa as in apes, nor does the lateral
plate of the ethmoid enter into the inner wall of the orbit but
is shut off by the maxilla. The lacrymal foramen is on the
* Mivart, Crania and Dentition of Lemuridae, P.Z.S., 1864 and 1867.
Mivart and Murie, Anatomy of Lemuroidea, Trans. Zool. Soc., 1, 1872.
Turner, Placentation of Lemurs, Phil. Trans., 166. A. Milne-Edwards,
L'embryol. d. Lemuriens et les affinites de ces animaux, Ann. Sci.Nat.,
1871, and Classification des Lemurieus, Revue Scientifique, 1871. A.
Milne-Edwards and Grandidier, Hist. Nat. de Madagascar, Mammiferes,
1 and 2, 1875-96. Winge, Primates, E. Museo Lundii, 1895. Schlosser,
op. cit, see under Carnivora. Wortman, Studies of Eocene Mammalia
in the Marsh Collection, American Journal of Science, 15, 1903, pp. 163,
399, 419. Hubrecht, The Descent of the Primates, New York, 1897.
050
PROSIMIAE.
face. It has been asserted that the Madagascar lemurs differ
from others by the fact that the tympanic bone is reduced to
a ring, and the bulla is formed by the periotic (F. Major, P.Z.S.
1899, p. 987).
The hind-legs are always longer than the fore. The humerus
has an entepicondylar foramen and the femur a small third
trochanter. The carpus usually has a centrale, and in some
living species the tarsus is extraordinarily elongated (Tarsius,
Galago, etc.), the elongation implicating the navicular and
FIG. 328. — Chiromys wadagascarensis
(from Vogt and Specht).
FIG. 329.— Galago (OtoHcnus] galago
(from Vogt and Specht).
calcaneum. In the pes, digit No. 2 often differs from the others
in size and always bears a claw-like nail ; while in the manus,
digit No. 2 may be vestigial (Potto).
The cerebral hemispheres* are relatively small and do not
completely cover the cerebellum (except in the Indrisinse)..
Their surface is only feebly convoluted, but the calcarine
sulcus is indicated.
* Flower, Trans. Zool Soc., 1863, p. 130. Beddard, P.Z.S. , 1895,.
p. 142. Oudemans, Verh. Ak. Amsterdam, 27, 1890.
LEMURIDAE. 651
There are no air-sacs or cheek-pouches. There is often a
sublingua. The stomach is simple, the caecum large but with-
out vermiform appendix. In many forms the arteries and
veins break up into retia mirabilia as in some edentates and
cetaceans.
The uterus is bicornuate and the placentation diffuse and
nondeciduate (except in Tarsius], There is a scrotum, and
the penis is pendent and usually has a bone. The urethra
traverses the clitoris. There are usually a pair of mammae
on the thorax, but there may be in addition one or two pairs
on the abdomen.
The lemurs are frugivorous or omnivorous animals and are
all arboreal. Most of them are nocturnal. There are about
50 living species, 35 of which are confined to Madagascar and to
neighbouring islands. The rest are found in Africa and the
Oriental region.
The sub-order dates from the Lower Eocene of Europe and
America, but no representatives of living families are known
earlier than the Pleistocene.
Fam. 1. Lemuridae. Dentition usually i | c -J- p |-~| m | ; upper
incisors two on each side, vertical, small and separated by an interval
in the middle line ; upper canines are canine-like and projecting ; lower
incisors close-set, laterally compressed, proclivous, and the canines are
closely applied to them and similar in form and direction. Premolars
sharp, usually with one cusp, but the last may be molar-like. P 1 on
the lower jaw is canine-like, but bites behind the upper canine'. Molars
with three or four sharp cusps, connected by low ridges. The orbit is
closed, but not shut off from the temporal fossa. The digits of both
rnanus and pes, except digit 2 of the pes which has a claw, have flat nails ;
both pollex and hallux are opposable.
Sub-fam. 1 Indrisinae. %'fc^p|m£; milk dentition
i \ c \- m |, dm 1 not being replaced ; digits 2-5 of the pes united
by a membrane as far as the end of the first phalanx ; tail variable,
pinna usually small. The hind-limbs are greatly developed, and
when on the ground they walk on their hind legs, holding their arms
above their heads. Colon spirally coiled, caecum large. Two
pectoral mammae. Herbivorous. Confined to Madagascar. Indris
Geoff., with moderate ears and reduced tail, carpus without centrale,
upper incisors sub-equal, upper canine larger than p 1, I sp. Pro-
pithecus Benn., short ears, long tail, a centrale in carpus, outer upper
incisor smaller than the inner, upper canine larger than pi, 4 sp.
Avahis Jourd., ears small, tail long, no centrale in carpus, outer
upper incisors larger than inner, upper canine and p 1 almost equal,
1 sp.
Sub-fam. 2. Lemurinae. Dentition usually i f c -j p f m j| ;
652 PROSIMIAE.
the lower canine and incisors are proclivous ; upper incisors some-
times absent or only one pair. With long tails ; toes of pes not
webbed ; tarsus only slightly elongated. Caecum moderate. Con-
fined to Madagascar and the Comoro Islands. Lemur L., face elon-
gated, large ears, long tail, two pectoral mammae, upper incisors
separated from each other and the canine ; omnivorous, they carry
their young ; 8-15 species. L. catta, the ring- tailed lemur, less
arboreal than other lemurs, often living among rocks and bushes.
Hapalemur Gray, upper incisors very small, with 4 mammae, 2 sp.
Lepidolemur Geoff r., upper incisors absent or reduced, 7 sp. Mixo-
cebus Pet., upper incisors one pair, 1 sp.
Sub-fam. 3. Galaginae. Dentition as in last ; the calcaneum
and navicular are elongated, with large ears, long tail ; with 4 mam-
mae, 2 pectoral and 2 abdominal ; Madagascar and Africa. Chiroyale
Geoffr., last upper premolar small, with only one external cusp,
Madagascar, 4 sp. Otolemur, Madagascar, 2 sp. ; both these genera
sleep during the dry season, consuming fat which has been deposited
at the root of the tail. Galago Geoffr., last upper premolar with
two external cusps, nearly as large as m 1, Africa, 6 sp. Microcebus
the smallest of lemurs, Madagascar.
Sub-fam. 4. Lorisinae. Slow lemurs ; nocturnal, sluggish, with
rounded head, large eyes, short ears, omnivorous. Dentition as in
Lemurinae ; digit No. 2 of the manus reduced and nailless ; limbs
nearly equal in length ; tarsus not elongated ; hallux directed back-
wards ; tail reduced ; two pectoral mammae ; the arteries of the
limbs form retia mirabilia as in sloths ; African Continent and Ori-
ental region. Nycticebus Geoffr. , digit No. 2 of the manus small but
complete, first upper incisor larger than the second, which often
falls out early, no tail, 1 sp., Oriental region ; AT. tardigradus. Loris
Geoffr., manus as in last, upper incisors small and equal, no tail,
slender body and limbs, 1 sp., Oriental. Perodicticus Bennett, digit
No. 2 of manus as a tubercle without nail, tail short, 1 sp., P. potto,
Africa. Arctocebus Gray, manus as in last, 1 sp., Old Calabar.
Megaladnpis F. Maj. (Phil. Trans. 1894) is a recently extinct gigantic
lemur from the Pleistocene of Madagascar, about 4 times the size of a
cat.
Fam. 2. Tarsiidae.* With large eyes and ears, long thin tail tufted
at the end, very long tarsus, fingers and toes ending in flattened discs,
feeds on insects and lizards, arboreal ; i \ c ^ p f ™> f ; inner upper
incisor large and in contact with its fellow ; molars with numerous pointed
cusps ; lower canine upright and diverging from the incisor. Orbit
largely separated by a partition from the temporal fossa. Fibula united
below with tibia ; digits 2 and 3 of the pes writh claws ; other digits with
nails. Calcaneum and navicular much elongated. Colon short, not
folded. Placenta metadiscoidal, deciduate. Indo-Malaya Archipelago
and Phillipines, 1 sp., Tarsius spectrum.
Fam. 3. Chiromyidae.t A squirrel-like animal with large ears, long
bushy tail, inguinal mammae, digit No. 3 of manus thin and long, all
digits with claws except the opposable thumb and hallux ; it appears to
* Tarsius is included by Hubrecht among the Primates, on account
of its placenta (Gegenbaur's Festschrift, 2, 1896, p. 147).
f Oudemans, Verh. Ak. Amsterdam, 27, 1890.
EXTINCT FORMS. 653
feed on the juices of the sugar-cane, etc., on fruit, and on wood-boring
caterpillars which it gets at with its rodent-like incisors, and then picks
out with its thin finger, but the use of the latter is not clear ; nocturnal
and difficult to observe, makes a nest in trees. Dentition i±c%p±ml;
incisors large, rodent-like, with enamel on front only, with persistent
pulps ; grinding teeth with flat, faintly tuberculated crowns ; milk
dentition i \ c £ m f . One genus and species, Chiromys madagascar-
ensis, the aye-aye, Madagascar.
A large number of extinct lemurs are known from the Eocene of Europe
and N. America, but their remains have not been found, with the excep-
tion of one or two species in the Lower Miocene, in the formations inter-
vening between the Eocene and the Pleistocene. The following may
be mentioned, Anaptomorphus Cope, Omomys Leidy, Mixodectes Cope,
Necrolemur Filhol, Microchoerus Wood, Adapis G. Cuv., Caenopithecus
Rut., Pelycodus Cope, Hyopsodus Leidy, Indrodon Cope, Plesiadapis
Gerv., Protoadapis Lemoine. The remains are not complete, but the
dentition appears to have been sometimes slightly reduced (i -^ c i
p |^ m f ), and sometimes normal and in closed series, e.g. Lemuravus,
Pelycodus (i f c i p £ m f ), or in Adapis i \ c i p ± m -f. Some
of them had an entepicondylar foramen in the humerus, and a third tro-
chanter on the femur. In Anaptomorphus and Necrolemur the cranial
cavity is known to have been capacious ; these two genera have been
referred to the Tarsiidae. Many of these forms while agreeing
with lemurs in their skull (orbit, lacrymal foramen in front of
orbit, etc.) resemble the apes more closely in the form of their dentition,
and in the case of some of them there has been considerable difficulty
in deciding whether they should be referred to the Insectivora, the
Rodentia, or to the Lemuroidea. Chriacus, which was at one time held
to be a lemur, is now placed with the creodonts, while Mixodectes,
Plesiadapis, and Protoadapis have been referred to the Rodentia. As
might be expected from the imperfection of the remains, the whole
subject is in considerable confusion, and we can draw no satisfactory
conclusions as to the nature and affinities of these early forms.
Order 2SL PRIMATES.*
Plantigrade, usually pentadactyle animals with complete den-
tition, i f, bunodont premolars and molars, and two thoracic
mammae. The orbit is completely separated from the temporal
fossa, the pollex when present is always opposable (except in the
Hapalidae). The cerebral hemispheres completely or almost
completely cover the cerebellum, the uterus is without horns and
the placentation is metadiscoidal.'f
* H. O. Forbes, Handbook to the Primates, 2 vols., 1894 (Allen's Natu-
ralist Library). Is. Geoffrey St. Hilaire, Catalogue methodique des Pri-
mates du Museum de Paris, 1851. Gray, Catalogue of Monkeys, etc., in
the Brit. Museum, 1870. Schlegel, Museum d'Histoire Nat. des Pays
Bas. L. 12, Simiae, 1876. Reichenbach, Die vollstandigste Naturges-
chichte der Affen, 1863. Wortman, Amer. Journal of Science, 16, 1903,
p. 345; 17, 1904, pp. 23, 133, 203.
t The placentation is at first diffuse ; it becomes secondarily discoidal
f)54 PRIMATES.
The Primates include the Monkeys, Apes and Man. With
the exception of the last named they are all well covered with
hair, inhabit for the most part the warmer regions of the Old
and New World, and are on the whole arboreal inhabit. The
baboons (Papio), however, inhabit rocky mountain regions.
The most important characters are stated in the definition.
In addition to those the following may be mentioned. The
incisors are never more than •§- ; the canines are -^ and gener-
ally project ; the upper molars have generally 4 cusps, but the
posterior inner cusp may be weak or, in the American monkeys,
absent ; the lower molars are tetracuspidate, but the last usually
has a talon (rarely present in the New- World forms). In the
Old- World monkeys the molars usually increase in size from
before backwards * ; in the New- World forms they dimmish,
the last being usually the smallest. The premolars have two
cusps. There is generally a small gap between the incisors and
canines particularly in the upper jaw.
The cranial cavity is spacious, and with the increase of the
brain the cranial capsule becomes rounder and the foramen
magnum gradually moves from the posterior part on to the
lower surface. The orbits look forward and are always com-
pletely shut off from the temporal fossa, by the backward and
inward extension of the postorbital processes of the frontal
and jugal to meet the alisphenoid ; the lacrymal foramen is
intraorbital. In most of them the two frontals meet ventrally
over the presphenoid between the ethmoid and orbit osphenoid,
but this does not happen in Homo, Simia, Anthropopithecus and
some Cebidae. The mastoid portion of the periotic appears on
the surface between the squamosal and exoccipital, but does not
form a process except in Homo. The stylohyal is never ossified
except in Homo and occasionally in Simia, and the tympano-
hyal is very small or absent.
The vertebrae are C7, Dll-14, L4-7, S2-6, and caudal vari-
able.
A clavicle is always present. The humerus never has an
by the restriction of the villi to a discoidal area. In the discoidal type
of placenta the placentation is discoidal from the beginning, and the
chorion does not surround the embryo, but is confined to a discoidal
patch.
* In Homo and some other genera of the Anthropomorphidse, the
last molar is smaller than the others.
SKELETON. VISCERA. 655
entepicondylar foramen, and the radius and ulna are separate
and capable of pronation and supination. The carpus generally
has a centrale (absent in Homo, Gorilla and Anthropopithecus),
and the thumb is always opposable when present ; it is occa-
sionally absent.
The femur has no third trochanter ; the tibia and fibula are
separate, and the astragalus has a convex tibial surface with a
lateral process for the fibula. The hallux is shorter than digit
No. 2, and is opposable, except in Homo. The digits always
have flat nails except in the Hapalidae.
The cerebrum is large and its surface is usually well convo-
luted (except in a few American monkeys) ; it completely or
nearly completely covers the cerebellum. The lateral ventricle
has a posterior 'cornu and hippocampus minor.
The uterus is without cornua. There is one pair of
pectora mammae, and the clitoris is not perforated by the
urethra.
As already stated, most apes are arboreal and inhabit the
forests of the warmer countries. Only a few lead a solitary life.
Most of them live together in large companies which are led by
the largest and strongest male. They feed chiefly on fruit
and seeds, but also on insects, eggs and birds. The female
produces only one young (rarely two or three) at a birth,
and they protect and tend their offspring with great affec-
tion. Intellectually the apes take with the dog and elephant
the highest place among mammals after man.
There are four families. Two of these, the Hapalidae and
Cebidae, are confined to the New World, and are sometimes
grouped together as the PlatyrrMna ; the other two, Cerco-
pithecidae and Anthropomorphidae, are, with the exception of
one genus (Homo), found exclusively in the Old World, and are
sometimes grouped together as Catarrhina. The only Euro-
pean monkey is the Barbary ape (Maczcus innuus], which is
found on the precipices of Gibraltar.
The Platyrrhina are distinguished by possessing a broad carti-
laginous internasal septum, by the absence of a bony external
auditory meatus, and by the fact that the alisphenoid usually
meets the parietal on the side of the skull, and the jugal joins
the parietal. They are without cheek pouches and ischial
callosities ; the last lower molar is usually without a talon and
656
PRIMATES.
the last molar in both jaws is smaller than the preceding molar.
In many of them the tail is prehensile.
In the Catarrhina the internasal septum is narrow, there
is a bony external auditory meatus, the frontal usually meets
the squamosal in the side wall of the skull (not in Simia), and
the jugal does not join the parietal. The tail is never pre-
hensile.
The Cebidae are found fossil in the Eocene. The other
families, including the Anthropomorphidae, are first found in
the Miocene.
Fam. 1. Hapalidae. Marmosets. Dentition i f c \ p f m | - ;
upper molars tritubercular, the inner cusp
being V-shaped ; upper premolars broader
than long with pointed inner and outer
cusp ; lower molars with four cusps, m 2 is
the largest in both jaws ; canines project-
ing. The skull is rounded and the brain
case capacious. The fore-limbs are shorter
than the hind-limbs. All the digits have
claws except the very small hallux, which
has a nail, and the pollex is not opposable.
The tail is longer than the rest of the body
and is not prehensile. Cheek pouches and
ischial callosities are absent ; the ears are
large and hairy. The cerebrum is large and
has a smooth surface ; there is a posterior
cornu, a hippocampus minor and a deep cal-
carine fissure. There are no cheek pouches.
They are frugivorous and insectivorous, and
arboreal ; and they give birth to three
young at a time. They are confined to the Neotropical Region. Hapale
111., the lower canines are approximated to the incisors and do not exceed
them in length ; about 7 species. Midas Geoff r., lower canines longer
than incisors, about 24 sp.
Fam. 2. Cebidae. These are also habitually quadripedal, but the
thumb is opposable as well as the hallux and the manus is a hand. All
the digits of both limbs have nails. Dentition ifcyjofmf; upper
and lower molars tetracuspidate, premolars bicuspidate. The brain
case is rounded and smooth ; there is no mastoid process and the styloid
process is not ossified. The skull varies considerably in the length of
the face and the position of the foramen magnum. In Mycetes which
represents one extreme the face is prominent and the plane of the fora-
men magnum posterior and almost vertical. In Chrysothrix, at the other
extreme, the face is less prominent, the brain case arched, and the foramen
magnum is on the under side of the skull, near its middle. There is a
centrale in the carpus ; the pollex is reduced to its metacarpal in Aides.
The tail is almost always long and prehensile ; the ears are rounded and
bare ; cheek pouches and ischial callosities are absent. The stomach is
simple, the caecum large, without vermiform appendix. The brain is
FlG. 330. — Skull of Pitkecia sata-
nas (from Claus).
CEBIDAE. 657
variable ; in Chrysothrix the cerebrum projects behind the cerebellum,
while in Mycetes it barely covers it ; in Cebus and Ateles its surface is
much convoluted, in others (e.g. Nyctipithecus} it is almost smooth.
They are arboreal animals and confined to the Neotropical region. A
few fossil remains of living forms have been found in the Pleistocene of
Brazil and a few genera (Homunculus, Anthropops, Pitheculus) have
been recorded by Ameghino from the Eocene of Patagonia, the family
being unrepresented in the intermediate strata.
Sub-fam. 1. Mycetinae. Lower incisors vertical, hyoid bones
inflated, tail long, prehensile and naked beneath at the end ; pollex
well developed. Alouata Lacep. (Mycetes 111.), howling monkeys,
face large with a low facial angle, the basicranial axis is as long as
the cerebral cavity and the foramen magnum is placed at the hind
end of the skull ; the cerebrum is well convoluted, but it hardly
covers the cerebellum ; the rami of the mandible are very deep
and protect the much swollen body of the hyoid in which is placed
a large air sac communicating with the larynx below the epiglottis ;
the ventricles of the larynx are also dilated and prolonged upwards.
They are in the habit of occasionally sitting on the topmost branches
of trees and howling, the resonating apparatus increasing the
power of the howls. The use of the howl is not known ; it has
been suggested that it is for the purpose of intimidating their
enemies ; 6 sp.
Sub-fam. 2. Pitheciinae. Lower incisors inclined forwards, tail
not prehensile, pollex well developed. Pithecia Geoff r., the sakis,
with long tail, 5 sp. Brachyurus Spix (Ouacaria Gray), short tail,
3 sp., which have a curious and local distribution in the forests on
the banks of the Amazon.
Sub-fam. 3. Nyctipithecinae. Lower incisors vertical, tail long,
not prehensile, pollex well developed. Callithrix Geoffr., teetees,
about 1 1 species. Chrysothrix Kaup ; squirrel monkey, face small
with high facial angle, plane of the foramen magnum horizontal,
cerebrum nearly smooth, projecting behind the cerebellum, 3 sp.
Nyctipithecus Spix, douroucoulis, nocturnal, with large eyes, with
owl-like face, head and brain as in the last ; 5 sp.
The extinct Eocene genera of Ameghino, Homunculus, Anthro-
popst Pitheculus, Homocentrus, Eudiastatus, are placed in this sub-
family.
Sub-fam. 4. Cebinae. Lower incisors vertical, tail long, pre-
hensile, pollex may be absent. Ateles E. Geoffr., spider-monkeys,
coaitas, slender, long limbed forms with non-woolly fur, and absent
pollex ; tail naked below at the end, very prehensile ; about 1 1 sp.
Brachyteles Spix (Eriodes E. Geoffr.), with woolly fur and reduced
pollex, tail naked below at the end, nails compressed and pointed ;
3 sp. Lagothrix E. Geoffr., barrigudos, woolly monkey, pollex well
developed, tail naked below at the end, fur woolly ; 2 sp. Cebus
Erxleb., sapajous or capuchins, monkey of organ grinders, not
woolly, pollex well developed, tail completely hairy ; about 17 species.
The extinct family Nesopithecidae from the Pleistocene of Mada-
gascar is placed here. It has also been assigned to the lemurs. The
lacrymal foramen is just inside the orbit, and the dentition is
* ' T c T P t m f ' *ne m°lars being pithecine, but the tympanic
bulla is formed by the periotic as in Madagascar lemurs.
Z. — II U r
658 PRIMATES.
Fam. 3. Cefcopitheeidae. These Old-World monkeys are essentially
quadrupedal, and the hind limbs are not much longer than the fore-limbs.
Both pollex (when present) and hallux are opposable, and they usually
have a tail which is never prehensile. Ischial callosities are present ;
cheek-pouches present or absent. All the digits of both limbs have nails.
Dentition *fcipfmf; molars elongated antero-posteriorly, usually
tretracuspidate, last lower molar often with a talon ; the outer and inner
pairs of cusps are sometimes separated by a longitudinal furrow and
sometimes connected by transverse ridges ; premolars bicuspidate. The
skull varies in shape, the frontal region being rounded and the facial
angle small, or the face is prolonged and dog-like and the facial angle is
large. The nasal septum is narrow. There is no distinct mastoid pro-
cess, and the stylo id process is not ossified ; the parietals do not unite with
the alisphenoid, being cut off by the union of the squamosal and frontal.
There is a bony external auditory meatus. The frontal bones usually
unite across the base of the skull in front of the union of the presphenoid
and ethmoid ; the basicranial axis is shorter than the length of the cerebral
cavity, and the foramen magnum looks obliquely backwards and down-
wards. The suture between the premaxillary and maxillary bones does
not disappear until the permanent dentition is complete. The carpus
has a centrale, and the pollex is complete except in Colobus. The pos-
terior ends of the ischia are everted and rough. The stomach is usually
simple, the caecum small and without a vermiform appendix. A median
air-sac is sometimes present opening into the larynx below the epiglottis ;
it may be large, extending down the neck and sending processes into the
axilla. The brain is large, the cerebrum projects behind the cerebellum,
and its surface is always complexly convoluted. The penis usually has
a bone. The phenomena of oestrus appear to approximate to those
found in the human female.* They are confined to the Old-World, being
found in the Ethiopian (absent from Madagascar), Oriental, and Palae-
arctic regions. The fossil remains are few, but representatives of living
genera are found as far back as the Pliocene ; and a few genera classed
with existing families are known from the Pliocene and Miocene of Europe.
Sub-fam. 1. Cereopitheeinae. Omnivorous, with cheek-pouches,
simple stomach ; fore- and hind-limbs sub-equal, nostrils terminal,
tail long, short or absent. Papio Erxl. (Cynocephalus Lacep.),
African baboons ; muzzle elongated, dog-like, and tail moderate,
ischial callosities large ; they usually inhabit rocky ground and are
frequently gregarious ; about 9 living species, Africa and Arabia,
and a few extinct from the Pliocene and Pleistocene of India and the
Pleistocene of Algeria ; P. maimon, mandrill, tropical W. Africa ;
P. porcarius, chaima, S. Afr. Theropithecus I. Geoff r., like the
last, but nostrils sub-terminal, 2 sp., Abyssinia. Cynopithecus
I. Geoff r., 1 sp., the black ape of Celebes. Macacus Lacep., muzzle
produced, nostrils not terminal, tail long, short or absent ; last lower
m. with talon ; generally gregarious ; about 20 sp., all Asiatic except
M . innuus, the Barbary ape of N. Afr. and Gibraltar, without tail ;
M . rhesus, the Bengal monkey ; M. speciosus, Japan, the most nor-
therly monkey and the only one found in Japan. Cercocebus E.
Geoff r., mangabeys, like Cercopithecus, but last lower molar with
talon ; long tail, upper eyelids white, 6 sp., W. Afr. Cercopithecus
* Heape, op. cit., p. 517.
ANTHROPOMORPHIDAE. 659
Erxl., guenons, muzzle shorter, ischial callosities moderate, tail
long, last lower m. without talon ; about 40 sp., Africa ; C. diana,
Diana monkey ; C. callitrichus , green monkey ; C. lalandi, the
vervet. Miopithecus T. Geoffr., talapoin, like the last, but the
lower molars have only 3 cusps.
The extinct Oreopithecus Gerv., from the Miocene of Italy, is in-
cluded here.
Sub-fam. 2. Semnopithecinae. More purely herbivorous, without
cheek pouches, with sacculated stomach, long tail ; the build is
slender and the hind limbs are longer than the fore. In the skull
the frontal region is more rounded and the facial angle smaller than
in the Cercopithecinae. The stomach is divided into 3 chambers, of
which the middle is sacculated. Semnopithecus F. Cuv., langurs,
with small pollex, and narial aperture extending upwards between the
orbits ; Asia, from the Himalayas (S. schistaceus) at 11,000 ft. to
Borneo and Sumatra ; about 29 sp. S. entellus, the sacred ape of
the Hindoos. Colobus Illig., guerezas, pollex absent or reduced
to a tubercle with or without a nail, arboreal, celebrated for their
skins, 11 sp., Afr. Nasalis E. Geoffr., proboscis monkeys, the nose
is produced into a proboscis in the adult, 1 sp., Borneo. Rhino -
pithecus A. M.-Edw., 1 sp., China.
The extinct Mesopithecus Wag., from the Miocene of Greece, and
Dolichopithecus Dep. from the pliocene of France are placed here.
Fam. 4. Anthropomorphidae * (Simiidae). Erect or semi-erect animals.
In the former case progression is effected entirely on the hind limbs ; in
the latter the anterior limbs, which are in this case longer than the pos-
terior, may be used to assist in locomotion, the tips of the fingers or the
knuckles being applied to the ground. The body is covered with hair,
but in one genus (Homo) it is much reduced, especially on the back. The
pollex is always and the hallux usually opposable, and all the digits,
except in Hylobates, have flat nails. A tail is always absent. Cheek
pouches are also absent, and ischial callosities except in Hylobates. Den-
tition i |- c y p \ m %, in closed series in Homo, but with a slight dias-
tema between the incisors and canine in the other genera ; the inner
upper and the outer lower incisors are larger than the others ; the canines
project except in Homo ; the molars have 4 cusps (except the 2nd lower
molar, which has 5), the inner and outer alternating, without transverse
ridges ; the last lower molar with or without weak talon ; upper pre-
molars broader than long, bicuspidate. The skull varies, but in all the
frontal region is well developed and the facial angle small. Supraorbital
and occipital ridges are present in all except Homo. In Hylobates and
Anthropo pithecus the sagittal crest is absent, and the occipital (lamb-
doidal) small. The alisphenoids usually meet the parietal in Hylobates,
Simia and Homo, but in Anthropopithecus and Gorilla they are cut off
by the union of the frontal and squamosal. There is a bony external
auditory meatus. The frontals meet in the base of the skull over the
ethmopresphenoidal suture in Hylobates and Gorilla, but not in
Anthropopithecus, Simia and Homo. The mastoid projects in Homo,
but not in the other genera. There is no ossified stylo id process,
* Hartmann, Anthropoid Apes, Internat. Sci. Series, London, 1885.
H. O. Forbes, op. cit. Huxley, Man's Place in Nature, London, 1894
(Collected Essays, vol. 7).
660
PRIMATES.
Flo. 331.— Skeleton of Gorilla (from Claus).^ A as-
tragalus, Ac acromion, C calcaneum, Cl clavicle ;
Fe femur, Fi fibula, H humerus, II ilium, Is
ischium, Os sacrum, P pubis, Pa patella, PC
coracoid process, R radius, Sc scapula, T tibia,
U ulna.
except in man and occa-
sionally the orang. The
suture between maxillary
and premaxillary bones dis-
appears in man before birth,
in the other genera it per-
sists until the completion
of the second dentition or
nearly to that period. In
Hylobates there are 18
dorsolumbar vertebrae, in
Simia 16, but in the other
genera the number is 17.
Homo and Simia have 12
pairs of ribs, Anthropopi-
thecus and Gorilla 13. The
sacrum contains at least 5
ankylosed vertebrae. The
carpus has a centrale in
Hylobates and Simia, but
not in Anthropopithecus,
Homo or Gorilla. The
hallux is opposable except
in Homo. The cerebrum is
always well convoluted and
large, projecting back be-
hind the cerebellum (except
in the Siamang). The
volume of the brain in
Simia and Anthropopithecus
is about half that of man ;
in Gorilla it is rather larger.
The stomach is simple, and
the caecum small with a
vermiform appendix. There
is an os penis except in
Homo, in which there may
sometimes be a trace of it.
All are omnivorous, and all
arboreal, except Homo.
A few fossil species be-
longing to existing genera
are known from the Pliocene
of India, and three fossil
genera, Pithecanthropus Du-
bois, from the Pliocene of
Java, Dryopithecus Lartet,
and Pliopithecus Gervais,
from the Miocene of Europe.
Dryopithecus seems to
have been allied to the
gorilla and Pliopithecus to
the chimpanzee. Pithecan-
AXTHROPOMORPHIDAE.
661
thropus * seems to have been nearer to Homo. The remains consist
of a skull cap, two teeth and a femur, which are supposed to have
belonged to the same individual. The cranial capacity was probably
about two-thirds that of man, the forehead low, and the supraorbital
ridges prominent. The femur indicates an upright gait.
Hylobates 111., the gibbons. Arboreal. Body and limbs slender, fore
limbs so long as to reach the ground when the animal is walking upright.
The carpus has a centrale, the nails of the pollex and hallux are alone
flat, and the hallux is well developed, and there are small ischial callosities.
There are 18 dorso-lumbar vertebrae and 13 pairs of ribs. In walking they
habitually go upright with the flat of the sole on the ground and without
the assistance of the arms. Smaller than the other genera, height not
exceeding 3 feet, S.E. Asia, 9 species ; omnivorous. H. syndactylus, sia-
mang, possesses a laryngeal sac, communicating with the larynx by two
openings in the thyrohyoid membrane.
Simia L., the orang-utan, 1 sp., S. satyrus in Borneo and Sumatra ;
arboreal. Body and limbs massive, the fore-limbs reach to the ankle,
the carpus has a centrale,
the pollex and hallux are
small, and the latter is
sometimes without a nail ;
16 dorsolumbar vertebrae
and 12 pairs of ribs. The
males attain a height of
a little over four feet,
and have a beard when
adult. They walk on the ,,™,^ ^ ^ >m ™ -.
outsides of their feet with
their knuckles on the
ground. There is a large
median vocal sac ventral
to the trachea which ex-
tends as far as the axilla ; Fm_ 332._skull of Simia , (from claus)>
it communicates with each
of the ventricles of the larynx. They build a nest on trees. Exclusively
herbivorous.
Gorilla I. Geoffr., 1 sp., G. gorilla in the forests of W. Africa ; arboreal,
but less so than the next genus ; mainly herbivorous. Body and limbs
massive, the fore-limbs reach to the middle of the lower leg, the carpus
is without centrale, hallux well developed, 17 dorsolumbar vertebrae
and 13 pairs of ribs. Male larger than female, with strongly developed
ridges on the gkull, and with larger canine teeth. The male may attain
a height of 5^ feet. Their air-sacs are very similar to those of Simia.
They walk like the chimpanzee on the soles of their feet with the backs
of their hands on the ground. The heel is better developed than in Simia,
and they can stand and walk without the assistance of their arms. They
have a ferocious and gloomy disposition and are untameable.
Anthropopithecus de Blainville (Troglodytes E. Geoffr.) the chimpanzee,
arboreal ; 2 sp., A. troglodytes L., and A. tchego Duv., W. Africa. Very
* Dubois, Pithecanthropus erectus, Eine menschendhnliche Uebergangs-
form aus Java, Batavia, 1894, and Proceedings of the Zoological Congress
at Leyden, 1895.
662
PRIMATES.
similar to Gorilla, but the mandibular symphysis is shorter, the skull
is without the sagittal crest and the males and females are very similar,
the former having larger canine teeth. Height does not exceed 5 feet.
Vocal sacs as in Gorilla. Arms reach but a slight distance below the
knee. They walk with the flat of their soles upon the ground, either
with or without the support of their arms. They have a lively and com-
paratively gentle disposition and are tameable.
FIG. 333.— Gorilla gorilla (from Vogt and Specht).
Homo * L., 1 sp., H. sapiens L., world wide in distribution. Fore-limbs
shorter than the hind-limbs, the fore-limbs reaching a little below the
middle of the thigh. The carpus is without a centrale. The hallux is
* Darwin, Descent of Man, 2nd ed., London, 1885. Lyell, The An-
tiquity of Man, 4th ed., London, 1873. Huxley, Evidence as to Man's
Place in Nature, op. cit. Quatrefages, Hist. gen. des races humaine, Paris,
1887-89. Flower, On the classification of the varieties of the human
species, Journ. Anthrop. Inst. Gt. Brit, and Ireland, 1885. Fraipont and
Lohest, La race humaine de Neanderthal ou de Canstadt, Arch. Biol., 7,
1887, p. 587. Wiedersheim, The Structure of Man, etc., London, 1895.
Schwalbe, Die Vorgeschichte des Menschen, 1904. W. L. H. Duckworth,
Morphology and Anthropology. Pitt Press, 1904.
MAX. 663
large but not opposable. There are seventeen dorso-lumbar vertebrae and
twelve pairs of ribs. The canine teeth scarcely project in either sex ; there
is no diastema ; and, as in Simla, the posterior molar is smaller than the
others. The males usually have a beard. The legs are relatively longer
than in the other genera. The hairy covering is much reduced, especially
on the back. There are no vocal sacs. The brain is at least twice the size
of the brain of Simia and Anthropopithecus and rather less than twice the
size of Gorilla, but the convolutions though more complex are very similar.
They walk erect on the soles of the feet,
The skull is without the sagittal and occipital crests and the supraorbital
ridges are less strongly developed than in other Anthropomorphidae. The
frontal development and the preponderance of the cranial over the facial
part of the skull is more marked than in any other genus of the family,
or indeed in any other Old-World Primate, but curiously enough some
of the new-world forms, e.g. Chrysothrix, approach Homo in these points.
The early disappearance of the suture between the maxilla and premaxilla,
the projection of the nasal bones, the slight projection of the canines and
the absence of a diastema in the tooth series are also distinctive human
features. The foramen magnum looks almost directly downwards. The
symphysis of the lower jaw has a mental prominence, an indication of which
is seen also in Hylobates. They are omnivorous gregarious animals, being
chiefly distinguished from the other genera of the family by the feebleness
of the hairy covering, the non-opposable hallux and completely erect
attitude, and by their larger brain. The latter feature is associated with
the greater mental development, which is the especial characteristic of the
genus. This shows itself in their speech, their more effective powers of
reasoning, and in the intellectual qualities of sympathy and imagination,
in virtue of which they have at last been able to dominate all other animals,
to accommodate themselves to every climate, and to spread to every quarter
of the globe.
Living men, though forming one species, fall into a considerable number
of varieties or races. These pass imperceptibly into one another and it is
impossible to construct a satisfactory classification of them. They are
all, so far as is known, fertile with one another, and there can be no question
that the intermingling which is thus rendered possible has been in the
past a potent factor in giving rise to new races, and that it is taking place
at the present day. It is a striking commentary on the attempts of
modern naturalists to discover the pedigrees of different species of animals
that, with our relatively full knowledge of man, historical, anatomical and
ethnological, we are unable to agree upon a zoological classification of
him which shall show the consanguinity of 'the different races. It has
usually been the habit of anthropologists to establish certain primary groups
or types of men presenting some variations within themselves and therefore
divisible into sub-groups, and connected with each other by intermediate
forms which have been produced by crossing. These primary groups are
regarded as primitive or ancestral types from which all the extant races of
men have been derived by descent with modification. It is therefore of
the first importance to determine them. This however cannot be done
for there is no agreement and apparently no possibility of agreement
among naturalists ; and even if we give our adherence to any particular
scheme, the difficulty remains of assigning to their proper places the
intermediate races, which often present equally important resemblances
to more than one of our primary types.
664 PRIMATES.
We therefore relinquish the attempt to ascertain the primary races,
and we relinquish it without regret, for we doubt if any such natural groups
exist or ever have existed in nature. They are useful groups for the
student and as such have considerable value. But too much importance
must not, in our opinion, be attached to them, for it cannot be shown
that at any previous epoch in the history of man an interdigitation of
races which is so characteristic of the present time did not exist.
The primary groups * into which the human race may be divided are
three in number: (1) the Negroid races, (2) the Mongolian, and (3) the
Caucasian.
(1) The Negroid races are characterised by frizzly hair, dark skin, a
broad flat nose, thick lips, prominent eyes, large teeth, a narrow pelvis,
and dolichocephalic skulls. The typical example of this group is the
African Negro. The following varieties may be mentioned : (a) the
Bushmen of S. Africa ; they have a yellowish skin and in certain other
features approach the Mongolian type. (6) The Pigmy races of the Central
African Forests, of the Andaman Islands, Malay Peninsula and the Philip-
pines ; they depart from the type in having brachycephalic skulls,
(c) The Melanesians or Oceanic Negroes of the Western Pacific and the
Tasmanians ; they depart in many features from the type and are probably
largely mixed with other races, (d) The Australians who differ in many
respects from the type, notably in not possessing the frizzly hair.
(2) The Mongolian races have a yellowish skin, black straight hair, a
broad face with prominent cheek bones, small nose, sunken narrow eyes,
teeth of moderate size, and a variable skull. The typical examples of
this group are the inhabitants of Northern and Central Asia (China,
Thibet, Japan, Burmah and Siam). In Europe they are represented in
a much modified form by the Lapps, the Finns, the Magyars and the
Turks. The other representatives of this group are the Esquimaux, the
Malay (including the inhabitants of Madagascar), the brown Polynesians
(Samoan, Tongan, Eastern Polynesian Islands and New Zealand) who
present in some respects affinities to the Caucasian group, and lastly the
original inhabitants of the continent of America who differ in some im-
portant respects from the type.
(3) The Caucasian or White races, which present two main varieties,
(a) the Xanthochroi with fair and white skin found in Northern Europe
extending into North Africa and West Asia, (&) the Melanochroi with black
hair and skins varying in colour from white to black. The Melanochroi com-
prise the inhabitants of S. Europe, N. Africa, and S.W. Asia. The
Caucasians have soft, straight hair, well developed beard, variable cranium,
retreating cheek-bones, narrow and prominent nose, small teeth, and
broad pelvis.
Man is not known fossil till the Pleistocene. He is there represented
by H. sapiens, and by an extinct species, H. primigenius Schwalbe (nean-
derthalensis) from the Neanderthal (1856), from Spy (1885), and from
Krapina in Croatia (about 1899), and possibly from other localities. This
extinct species is not thoroughly known, but it clearly belongs to a lower
grade of organisation than H. sapiens.
* In the following account the classification adopted by Flower and
Lydekker (op. cit, ) has been mainly followed.
UNIVERSITY
or
MAN. 665
The mental qualities which are so characteristic of the genus
Homo have led many naturalists to create a special family
(Anthropidae) or even order (Bimana] for its reception. But
in this work we are concerned with man from the standpoint
of morphology, and, in assigning him his position in the
system, we can only take into consideration the facts of his
bodily structure, as we have done in the case of other animals.
If psychical characters were taken into account in Zoology,
the whole of classification would be thrown into confusion,
and in the case of man how should we define the position to
be assigned to him ? For
What a piece of work is a man ! How noble in reason /
how infinite in faculty ! in form and moving how express
and admirable ' in action how like an angel ! in appre-
hension how like a god !
and again
Thou hast made him a little lower than the angels and
hast crowned him with glory and honour.
END OF VOL. II.
INDEX.
Every reference is to the page. In some cases the upper and lower half of
the page is indicated by a small number, ] or 2, placed above the number of the
page. Figures in black type refer to the systematic position. Figures in
italics refer to an illustration.
Aardvark, 5491.
Abastor, 3672.
Abderitidae, 5381.
Abdimia, 4612.
Abdominal fin, 185.
Abdominal pores, Chel-
onia, 410 ; Crocodilia,
379 ; Dipnoi, 249 ;
Elasmobranchii, 120 ;
fishes, 90 ; Marsipo-
branchii, 112; Tele-
ostei, 208.
Ablabes, 3672.
Ablabophis, 3662.
Ablepharus, 3541.
Abrarais, 2202.
Abrocoma, 6351.
Abrostomus, 2192.
Acalyptophis, 370 l.
Acanthaphritis, 2432.
Acantharchus, 2341.
Acanthias, 126. 1521.
Acanthicus, 222 1.
Acanthistius, 2351.
Acanthobrama, 2202.
Acanthocybium, 2382.
Acanthodactylus, 3531.
Acanthodes, 146, 147.
Acanthodii, 146.
Acantholabrus, 2372.
Acanthonus, 2442.
Acanthophis, 370 l.
Acanthophthalmus,
221i.
Acanthopsis, 22V.
Acanthopterygian, 185.
Acanthopterygii, 233.
Acanthorhodeus, 220 '.
Acanthosaura, 3501.
Acanthurus, 237 i.
Acanthyllis, 473'.
Acara, 2372.
Ace. = accessory.
Accentor, 4752.
Accipiter, 4632.
Accipitres, 4831.
Acentrophorus, 176,
179.
Accra therium, 601 2.
Acerina, 2342.
Aceros, 471 2.
Acestra, 222 '.
Achaenodon, 5821.
Achalinus, 3662.
Achilognathus, 2201.
Achirus, 2402.
Acipenser, 168, 169,
170 ; pericardium, 85.
Acomus, 4652.
Acomys, 6341.
Aconaemys, 6351.
Acontias, 3541.
Acrania, 11.
Acris, 311 1.
Acrobates, 5362.
Acrochilus, 2201.
Acrochordonichthvs,
2212.
Acrochordus, 3662.
Acrodont, 343.
Acrodus, 151 *.
Acronurus, 2371.
Acropoma, 2342.
Acrosaurus, 334.
Acrotus, 231 2.
Acryllium, 4651.
Actinotrichia, 54.
Actitis, 467'.
Acustico-lateralis, 75,
76.
Adapis, 6531.
Adapisoricidae, 6402.
Adaptive reduction,
579.
Addax, 591 1.
Adeciduata, 520.
Adipose fin, 185.
Adjutant, 46 12.
Adrenals, 442.
Aegaeonichthys, 246 *.
Aegialitis, 467 *.
Aegithalus, 4771.
Aegithognathous, 430.
Aegotheles, 4722.
Aelurichthys, 221 2.
Aelurictis, 6191.
Aeluroidea, 6162, 618.
Aeluronyx, 3491.
Aeluropus, 6231.
Aelurosaurus, 349 *,
4002.
Aelurus, 6231.
Aepyceros, 591 *.
Aepyornis, 4582.
Aepyprymnus, 5352.
Aesculap-snake, 3672.
Aesopia, 2402.
Aetobatis, 1542.
Aetosaurus, 382 *.
Aex, 4631.
Affinities, of Marsipo-
branchii, 115 ; of
Rhynchocephalia,
332.
Afr. = African.
Aftershaft, 421.
Agalychnis, 311 l.
Agama, 3501.
Agamodon, 3531.
Agamura, 349 *.
Agapornis, 4702.
Age, Carp, 2191 ; ele-
phant, 571.
Ageniosus, 221 2.
Aglossa, 309.
Aglypha, 3661.
668
INDEX.
Agnus, 2432.
Agoniates, 2172.
Agonomalus, 2422.
Agonopsis, 2422.
Agonostomus, 2312.
Agonus, 2422.
Agoutis, 6352.
Agrammus, 2421.
Agriochoerus, 578, 5851.
Agriopus, 2421.
Ahlia, 2251.
Ai, 5442.
Ailia, 221 2.
Aipichthys, 2391.
Aipysurus, 370 1.
Air-bladder, occurrence
and function of in
• Teleostei, 200, 204.
Air-sacs, Balaena, 513 ;
birds, 444.
Aistopoda, 3151.
Akodon, 6341.
Akysis, 2212.
Alactaga, 6342.
Alauda, 4752.
Alausa, 2142.
Albacore, 2382.
Albatross, 461 1.
Albula, 206, 2142.
Albulichthys, 2192.
Alburnus, 2202.
Alca, 468i.
Alcedo, 4711.
Alces, 5892.
Alcidea, 2421.
Alcyone, 4711.
Aldrovandia, 2272.
Alectis, 2392.
Alepidosaurus, 2261.
Alepisaurus, 2261.
Alepocephalus, 2142.
Aleposomus, 2142.
Alestes, 2172.
Algiroides,.3531.
Allacodon, 541 2.
Allantoio artery and
vein, 521.
Allice-shad, 2142.
Alligator, 3832.
Alligatorellus, 3822.
Alligatorium, 3822.
Allodon, 541 2.
Allosaurus, 3851.
Allotheria, 541.
Allulandina, 3682.
Alopecias, 125, 1521.
Alopias, 1521.
Alopoglossus, 3522.
Alosa, 208, 2142.
Alouata, 6571.
Alpaca, 5871.
Alsophylax, 349 *.
Al trices, 451.
Alula, 424.
Alutera, 247J.
Alytes, 264, 293, 295,
296, 3101.
Amastridium, 3681 .
Ambassis, 2342.
Ambergris, 562 1.
Ambliceps, 221 2.
Ambloplites, 2341.
Amblotherium, 5402.
Amblycephalus, 371 J.
Amblyodipas, 3682.
Amblyopsis, 2271 ;
habits, 92.
Amblyopus, 2411.
Amblyornis, 4771.
Amblypharyngodon,
2192.
Amblypoda, 603.
Amblyrhynchichthys,
2192.
Amblyrhynchus, 3502.
Amblystoma, 266, 278,
280, 306i.
Ameiurus, 221 2.
Ameiva, 345, 3522.
Ametrida, 6482.
Amia, 160, 161, 162,
164, 166, 182 ; con-
nection of testis to
kidney, 89.
Amiichthys, 2342.
Amioidei, 180.
Amitra, 2422.
Amiurus, 221 2.
Ammocoetes, 96, 113,
114.
Ammocrypta, 2342.
Ammodorcas, 5911.
Ammodytes, 2311.
Ammopleurops, 2402.
Amnion, false, 518.
Amorphochilus, 6481.
Ampelis, 4762.
Amphiardis, 3662.
Amphibamus, 3151.
Amphibia, 263.
Amphibolurus, 3501.
Amphicoelous, 59.
Amphictis, 6202.
Amphicyon, 6221.
Amphignathodon,
3111.
Amphilestes, 54Qi.
Amphimeryx, 5851.
Amphioxus, 10, 13, 31 ;
connective tissue of,
15 ; fin-rays of, 16 ;
development of, 31 ;
habits, 11 ; oral cirri,
1 1 ; metapleural folds,
12 ; atrial pore, 12.
Amphiperatherium,
5391.
Amphipnous, 200, 206,
2222.
Amphiprion, 2372.
Amphiproviverra, 5411.
Amphisbaena, 335, 3531,
355.
Amphisile, 2291.
Amphistium, 2391.
Amphistylic, 63.
Amphitherium, 540,
5401.
Amphitragulus, 5892.
Amphiuma, 269, 280,
290, 305.
Amphodus, 31 12.
Amplorhinus, 3682.
Ampullary canals, 79.
Amynodon, 601 2.
Anabas, 183, 2321 ;
breathing, 92.
Anableps, 196, 2271.
Anacanthini, 232.
Anaconda, 3652.
Anacrytus, 2172.
Anadia, 3522.
Anadromous, 91.
Anaides, 306].
Anampses, 2381.
Anapterus, 2261.
Anaptomorphus, 6531.
Anarhynchus, 467 x.
Anarosaurus, 3972.
Anarrhichas, 2441.
Anarrhichthys, 2441.
Anas, 4631.
Anastomus, 2171.
Anchilophus, 5981.
Anchippodus, 60S1.
Anchisaurus, 384, 365.
Anchitherium, 5972, 598.
Anchovia, 2141.
Anchovy, 2141.
Ancient living genera,
150, 234, 258, 4132,
563, 571, 5811, 5932,
6011,6201, 622i, 6241.
Ancistrodon, 371 2.
Ancodus, 5832.
Ancylodon, 2352.
Ancylopoda, 609.
INDEX.
669
Anelytropsis, 3542.
Anema, 2432.
Angel-fish, 153.
Angler, 24o2, 2461.
Anguilla, 223 ', 2242.
Anguilliformes, 223.
Angola, 335, 336, 35 12,
352i.
Anhyperodon, 2351.
Anisolepis, 3502.
Anisotremus, 2361.
Anniella, 352 1.
Anoa, 591 2.
Anodontohyla, 3122.
Anolis, 3502.
Anomalepis, 3651.
Anomalochilus, 3661 .
Anomalops, 239 2.
Anomalurus, 6321.
Anomodontia, 398 ;
mammalian charac-
ters of, 398.
Anoplogaster, 2341.
Anoplophallus, 3681.
Anoplopoma, 2421.
Anoplotherium, 583,
584.
Anops, 353i.
Anorhinus, 471 2.
Anous, 4681.
Anser, 4631.
Anseranas, 4631.
Anseriformes, 4621.
Anteater, 5441; Cape,
5491.
Antechinomys, 539 l.
Antelope, 5901 ; sable,
equine, Baker's, 59 11 ;
harnessed, 591 1.
Antennarius, 92, 210,
Anterior abdominal
vein, birds, 441 ;
Chelonia, 411; lizards,
347 ; snakes, 363 ;
Reptilia, 325.
Anthias, 235i.
Anthops, 6471.
Anthracotherium, 5832.
Anthropidae, 665.
Anthropoides, 4661 .
Anthropomorphidae,
659 1.
Anthropopithecus, 661 2.
Anthropops, 6572.
Anthus, 4752.
Antiarcha, 261.
Anticitharus, 2402.
Antidorcas, 591 l.
Antigonia, 2362.
Antilocapra, 5901.
Antilope, 591 *.
Antimora, 2331.
Antrozous, 6472.
Anura, 307, 6482.
Anurosorex, 640 l.
Anus, derivation of, 4.
Aodon, 1542.
Apar, 5472.
Aparallactus, 3682.
Ape, black Barbary,
6582 ; Sacred, 6591.
Apedodus, 175.
Apeltes, 2291.
Aphanapteryx, 4661.
Aphaniotis, 350 J.
Aphanopus, 2391.
Aphia, 241 1.
Aphoristia, 2402.
Aphredoderus, 2341 .
Aphritis, 2432.
Aphyocharax, 21 72.
Aphyocypris, 2192.
Aphyonus, 2442.
Apionichthys, 2402.
Apistus, 2421.
Aplacentalia, 520.
Aploactis, 2421.
Aplodontia, 6322.
Apocryptes, 241 !.
Apoda, 300.
Apodes, 223.
Apodichthys, 2441.
Apogon, 2342.
Apogonichthys, 2342.
Apomotis, 2341.
Aporophis, 3672.
Aporosaura, 3531.
Aporoscelis, 3501.
Apostolepis, 3682.
Aprasia, 3501.
Aprionodon, 151 1.
Apsilus, 2352.
Aptenodytes, 4602, 461.
Apteria, 422.
Apteryx, 419, 433, 434,
457, 4582.
Aptornis, 4661.
Apua, 2211.
Aqueductus sylvii, 67.
Aqueductus vestibuli,
121, 323.
Aquila, 4632.
Aquintocubital, 423.
Ara, 4702.
Aracana, 2471.
Aramus, 4661.
Arapaima, 2151.
Arbaciosa, 2432.
Arch. = Archipelago.
Archaeoceti, 564.
Archaeohyrax, 5671.
Archaeomenidae, 213.
Archaeopteryx, 418
433, 438, 454, 455.
Archaeornithes, 454.
Archaeus, 2391.
Archegosaurus, 3151.
Archibuteo, 4632.
Archinephric duct, 87.
Archipterygium, 57, 251.
Archistes, 2422.
Archizonurus, 5371.
Archoplites, 234 ^
Archosargus, 2361.
Arcicentrous, 60.
Arcifera, 3101.
Arciferous, 271.
Arctictis, 6201.
Arctocebus, 6522.
Arctocyon, 6121.
Arctogale, 620 l.
Arctoidea, 6172, 622.
Arctomys, 6322.
Arctonyx, 6241.
Arctoscopus, 2362.
Arctotherium, 6231.
Arcualia, 98.
Ardea, 461 2.
Ardeosaurus, 344.
Argalia, 3522.
Argentea of eye, 196.
Argentina, 2162.
Arges, 2221.
'Argus- pheasant, 4652.
Argusianus, 4652.
Argyriosus, 239 *.
Argyrocetus, 5631.
Argyrohyrax, 5671.
Argyrosomus, 2162.
Aristelliger, 349 *.
Aristodesmus, 4001.
Aristotle on Eels, 223.
Arius, 201, 210, 2212.
Armadillo, 490, 5461 ;
6-banded, 547.
Arnoglossus, 2402.
Arran-turtle, 4142.
Arrhamphus, 231 *.
Arrhyton, 3672.
Arsinoitherium, 60S1.
Artamidae, 4762.
ArtedieUus, 2422.
Artedius, 2421.
Arterial arches, Am-
phibia, 288 ; reptilia,
327.
670
INDEX.
Arthrodira, 260.
Attagis, 4672.
Arthroleptis, 296, 3131.
Atypichthys, 2371.
Arthrosaura, 3522.
Auchenia, 5871.
Artibeus, 6482.
Auchenipterus, 221 2.
Artiodactyla, 5762.
Auchenoglanis, 2212.
Arvicanthis, 6341.
Auditory organ of fishes,
Arvicola, 6332.
77, 78.
As. = Asia.
Auditory ossides, mam-
Ascalabota, 3491.
malia
,498.
Asima, 2361.
Auk, great, little, 4681.
Asinus, 5962.
Aulacocephalus, 2351.
Asio, 4721.
Aulacodus, 6351.
Aspidelaps, 3701.
Aulacorhamphus, 4741 .
Aspidites, 3652.
Auliscops, 2291.
Aspidoparia, 2201.
Aulopus, 2262.
Aspidophoroides, 2422.
Aulopyge, 2192.
Aspidorhynchus, 180.
Aulorhynchus, 229 1.
Aspidura, 3662.
Aulostoma, 229 1.
Aspis, 3702.
Auricular nerve, 275.
Aspius, 2202.
Aurochs, 59 12.
Aspredo, 210, 2221.
Ausonia, 2392.
Aspro, 2342.
Austr. = Australia.
Ass, 5962.
Autodax, 3061.
Asterodermus, 1541.
Auto sauri, 335.
Asterolepis, 262.
Autostylic, 63.
Asterophrys, 3102.
Auxis, 2382.
Asterospondylons, 124,
Avahis,
6512.
125.
Averruncus, 2422.
Astrape, 1541.
Aves, 416.
Astrapotheridae, 611 2.
Avocet,
4671.
Astrolytes, 2422.
Avocettina, 2242.
Astronesthes, 92, 2162.
Axolotl,
306^.
Astrophysus, 2221.
Axonost, 54.
Astroplebus, 2221.
Axyrias, 2422. |
Astroscopus, 2432.
Aye -aye
, 6531.
Astur, 4632.
Azemiops, 371 2.
Atalapha, 6472.
Azygos vein, 290.
Ateles, 516, 6562.
Atelodus, 601 *.
B. M. = British Museum.
Athecae, 412.
Babirussa, 581 *.
Atherina, 212, 2311.
Baboon,
6582.
Atherinella, 2312.
Back-teeth, 499.
Atherimchthys, 2312.
Badger,
6241.
Atherinops, 231 2.
Bagarius, 221 2.
Atherinopsis, 2312.
Bagrichthys, 221 2.
Atheris, 371 2.
Bagroides, 221 2.
Atherura, 6352.
Bagropsis, 221 2.
Athlennes, 231 *.
Bagrus, 221 2.
Atl.= Atlantic.
Bairdiella, 2352.
Atlantosaurus, 3852.
Balaena, 513, 561.
Atopochilus, 2212.
Balaeniceps, 461 2.
Atoposaurus, 3822.
Balaenoidea, 560.
Atractaspis, 3712.
Balaenoptera, 561.
Atractus, 3672.
Balearica, 4661.
Atrial chamber, 14, 26.
Baleen, 560.
Atrial pore, 12.
Balfour,
F. M., on
Atrichornis, 4751.
Ganoids, 160.
Atriocoelomic funnels,
Balistes,
247 i.
26, 23.
Ballan wrasse, 2372.
Band-fish, 2352.
Bandicoots, 5381.
Banteng, 591 2.
Baptanodon, 3951.
Baptornis, 4592.
Barb, 420.
Barbastelle, 647 2.
Barbatula, 4732.
Barbel, 184.
Barbels, 2191.
Barbet, 4732.
Barbicels, 421.
Barbichthys, 2192.
Barbules, 420.
Barbus, 2191.
Barilius, 2201.
Barracudas, 23 12.
Barramunda, 259.
Barrigudo, 6572.
Bartholin, glands of,
516.
Barynotus, 2192.
Barytherium, 5732.
Basalia, 56.
Bascanichthys, 2251.
Baseost, 54.
Basilar plate, 60.
Basiliscus, 3502.
Basisphenoidal rostrum,
318.
Basitemporals, lizards,
340.
Basking shark, 1521.
Bass, 2351, black, 2341 ;
sea, 2342 ; stone, 2351.
Bassaricyon, 6232.
Bassariscus, 6232.
Bastard wig, 424.
Bat, Bechstein's, Dau-
benton's, reddish-
grey, whiskered,lesser
horse-shoe, greater
horse-shoe, long-ear-
ed, serotine, 647.
Bat, ovulation of, 518.
Batagur, 4131.
Bateson on teeth, 502.
Batodon, 5381.
Batomys, 6341.
Bathyagonus, 2422.
Bathyclupea, 2341.
Bathydraco, 2432.
Bathyergus, 6342.
Bathygadus, 2322.
Bathylaco, 2162.
Bathylagus, 2162.
Bathymaster, 2352.
Bathynectes, 2442.
Bathyophis, 2162.
INDEX.
671
Bathyphasma, 2422.
Bathypterois, 2262.
Bathysaurus, 226 '.
Bathythrissa, 2142.
Bathytroctes, 2142.
Batrachia, 307.
Batrachocephalus, 221 2
Batrachoides, 2441.
Batrachophrynus, 276,
3121.
Batrachopsis, 3102.
Batrachoseps, 293, 3061.
Batrachus, 187, 203,
2441.
Batrachylodes, 3131.
Batrachyperus, 3061.
Batrochostomus, 4722.
Bdellophis, 304.
Bdellostoma, 95, 117.
Bdeogale, 6201.
Beak, birds, 438.
Bear, ant, 5441 ; native,
5371.
Bears, 6231.
Beaumaris shark, 15 12.
Beaver, 6322.
Bee-eater, 47 12.
Beisa, 59 11.
Belemnobatis, 1541.
Bellia, 413i.
Bellows-fish, 229 1.
Belodon, 381.
Belodontichthys, 221 2.
Belone, 231 1.
Belonesox, 2271.
Belonorhynchidae, 170.
Belonostomus, 180.
Beluga, 5632.
Bembras, 2421.
Bembrops, 2432.
Benedenius, 170.
Benthodesmus, 2391.
Benthophilus, 241 1.
Benthosaurus, 2262.
Berardius, 5622.
Bernissartia, 3822.
Beryx, 2332, 234*.
Betta, 2371.
Bettongia, 5352, 535.
Bezoar stone, 587 1.
Bib, 2322.
Bibos, 591 2.
Bidder's organ, 295.
Bilophodont, 5931.
Bimana, 665.
Binturong, 6201.
Biot on air-bladder, 204.
Bipinnula, 2382.
Bird of Paradise, 4771.
Bison, 591 2.
Bitis, 371 2.
Bitterling, 2201.
Bittern, 46 12.
Black bass, 2341.
Black-bird, 4752.
Blackhead, 2192.
Black-sea bream, 2361.
Black-snake, 3681, 3702.
Black witch, 4701.
Bladder, Amphibia, 291;
Chelonia, 410; Rep-
tilia, 324.
Blanus, 3531.
Blarina, 6401.
Blarinomys, 6341.
Blastopore, Amphibia,
297 ; Amphioxus, 33 ; i
Blastopore relation of
to mouth and anus, 3.
Blastosphere of Am-
phioxus, 32, 33.
Blaubok, 591 1.
Bleak, 2202.
Blenniiformes, 2431,
Blenniops, 2441.
Blennius, 208, 2 12,244!.
Blennophis, 2441.
Blenny, 2432 ; butterfly, I
2441.
Blepsias, 2421.
Blessbok, 5902.
Blind fish, 2271.
Blind-worm, 3521.
Blubber, 553.
Blue-shark, 151 ^
Blythia, 3662.
Boa, 362, 3652.
Boar, 58 11.
Boar-fish, 2362.
Boatswain-bird, 4612.
Body cavity, Amphibia,
277 ; Elasmobranchii,
140 ; Mammalia, 512 ;
Teleostei, 208 ; Ver-
tebrata, 49.
Bohr on air-bladder,
205.
Bola, 2201.
Boleophthalmus, 241 1.
Boleosoma, 2342.
Bolieria, 3652.
Bolodon, 5412.
Bombay duck, 2261.
Bombinator, 273, 276,
293, 3101.
Bonasa, 4652.
Bone-dog, 1522.
Boneia, 6461.
Bonito, 2382.
Bontebok, 5902.
Booby, 461 2.
Boodon, 3662.
Borborocoetes, 3112.
Borhyaena, 541 *.
Bos, 591 2.
Boselaphus, 591 l.
Botaurus, 4612.
Bothragonus, 2422.
Bothriolepis, 262.
Bothrolycus, 3662.
Bothrophthalmus, 3662.
Botia, 221 1.
Bottosaurus, 3831.
Boulenger on Teleostei,
212.
Boulengerina, 3701.
Bovichthys, 2432.
Bower-bird, 4771.
Box, 236^.
Box-tortoise, 4132.
Brachyaspis, 3701.
Brachycephalus, 3121.
Brachydeirus, 260.
Brachylophus, 3502,
Brachymeles, 3541.
Brachymystax, 2161.
Brachyodont, 505.
Brachyophis, 3682.
Brachyopsis, 2422.
Brachyorrhus, 3662.
BrachyphyUa, 6482.
Brachypleura, 2402.
Brachypteracias, 471 l.
Brachysomophis, 2251.
Brachytarsomys, 6331,
634].
Brachyteles, 6572.
Brachyuromys, 6341,
657i.
Brachyurus, 6571.
Brady pus, 511, 5442,
545.
Bradytherium, 5432.
Brain, Amphibia, 273 ;
birds, 435 ; Croco-
dilia, 378 , Dipnoi,
254, 255, 256; Elas-
mobranchii, 132, 133,
134 ; fishes, 66 ; Gan-
oidei, 163 ; Lepidos-
teus, 178; lizards,
344 ; Mammalia, 494 ;
Marsipobranchii, 106 ;
Reptilia, 320, 321 ;
snakes, 362; Teleos-
,tei, 193, 194.
672
INDEX.
Brama, 92, 199, 2392.
Bramatherium, 5901.
Brambling, 4781.
Branch. = branchial.
Branchial arch, 62.
Branchial arches, Am-
phibia, 269 ; Elasmo-
branchii, 127 ; Teleos-
tei, 191.
Branchial arteries, 85.
Branchial rays, 129.
Branchiosaurus, 314,
3151.
Branchiostegal rays,l 91 .
Branchiostoma, 10.
Brauer on Excretory
organs of Gymno-
phiona, 87.
Bream, 2191,2192,2202;
black sea, 2361 ; sea,
2361.
Breeding, Amphibia,
296 ; Mammalia, 517 ;
Teleostei, 210.
Bregmaceros, 2331.
Breviceps, 3121.
Brevoortia, 2142.
Brill, 2402.
Brine-pools, fishes of,
2262.
Broad-bill, 4742.
Brontes, 2221.
Brontops, 6021.
Brontornis, 4601.
Brontosaurus, 385, 3852.
Brontotherium, 6021.
Brood-pouch, Amphi-
, bia, 496 ; Syngna-
thidae, 229, 230.
Brookesia, 3551.
Brosmius, 233j.
Brotula, 2442.
Brotulophis, 2442.
Brown-adder, 3702.
Brown canals, 26, 23.
Brunner's glands, 510.
Bruta, 542.
Brycon, 2172.
Bryconaethiops, 2172.
Bryconops, 2172.
Bryssetaeres, 2432.
Bubalis, 5902.
Bubo, 4721.
Buccal nerve, 137.
Bucco, 4732.
Bucerus, 4712.
Buck, prong, 5901 ; reed,
water, black, 591 ;
bush, 591 *.
Bucorvus, 4712.
Budgerigar, 4702.
Budgett on air-bladder,
205 ; on Polypterus,
174.
Budorcas, 591 2.
Buffalo, 59 12.
Buffelus, 591 2.
Bufo, 276, 293, 295,
3102.
Bulbul, 4752.
Bulbus arteriosus, 85.
Bui bus cordis, 281.
Bulla ossea, 498.
Bullfinch, 4781.
Bull-frog, 3131.
Bull-head, 2421.
Bungarus, 3701.
Bungia, 2192.
Bunocephalichthys,
222 !.
Bunocephalus, 2221.
Bunocottus, 2421.
Bunodont, 504.
Buno-lophodont, 577.
Bunting, meadow, snow,
yellow, 4781.
Buphaga, 4772.
Burbot, 2331.
Burramys, 537 *.
Bursa entiana, 139.
Bursa Fabricii, 440.
Bustard, great, little,
4662.
Butcher-bird, 4762.
Buteo, 4632.
Butirinus, 206, 2142.
Butter-fish, 238, 2441.
Butterfly blenny, 2441.
Buzzard, 4632 ; honey,
4632 ; rough-legged
4632 ; turkey, 4631.
Byssacanthus, 147.
Bythites, 2442.
Cabassou, 547 J.
Cabrita, 3531.
Cacatua, 4702.
Caccabis, 4652.
Cachalot, 5621.
Cachius, 2202.
Cachryx, 351 *.
Cacomantis, 4691.
Cacopus.S^1.
Cacosternum, 3122.
Caenolestes, 534, 5381.
Caenopithecus, 6531.
Caenotherium, 5851.
Caenotropus, 2171.
Caesio, 201, 2361.
Caesioperca, 2351.
Caiman, 372, 3832.
Calabaria, 3652.
Calamaria, 3672.
Calamelaps, 3682.
Calamodon, 6082.
Calamoichthys, 72, 176.
Calamus, 236\
Calamus of feather, 420.
Calandruccio on eels,
223.
Calcar, 643.
Calcareous gland, see
corrigenda.
Caldwell on eggs of
monotremata, 526.
Callagur, 4131.
Callanthias, 2351.
Callechelys, 2251.
Callichrous, 221 2.
Callichthys, 210, 222'.
Callinycteris, 6462.
Callionymus, 2411.
Callipash, 4141.
Callipee, 4141.
Callisaurus, 351 1.
Callithrix, 6572.
Callomystax, 2221.
Callophis, 3701.
Callophysus, 2212.
Callopistes, 3522.
Callorhynchus, 158.
CaUuella, 3121.
Callula, 3122.
Callyodon, 2381.
Calodactylus, 3491.
Calophrynus, 3121.
Caloprymnus, 5352.
Calotes, 345, 3501.
Calotomus, 2381.
Calyptocephalus, 3112.
Calyptomena, 4742.
Calyptorhynchus, 4702.
Cambing-utan, 59 12.
Cameleopard, 5901.
Camelus, 5871.
C. Amer. = Central
America.
Campanula halleri, 195.
Campephagidae, 4761.
Campodus, 1511.
Campostoma, 2192.
Camptomus, 541 2.
Canary, 4781.
Canis, 613, 614, 6212,
621.
Cannon bone, 493, 5761.
Cantharus, 2361.
INDEX.
673
Cantoria, 3682.
Cantridermichthys,2421.
Cape pigeon, 461 *.
Capercally, 4652.
Capito, 473-).
Capitodus, 2361.
Capoeta, 2191.
Capra, 5912.
Capreolus, 5892.
Capri mulgi, 472 l.
Caprimulgus, 4721.
Caprodon, 2351.
Capromys, 635 1.
Capros, 2362.
Capuchin, 6572.
Capybara, 6352.
Caracal, 6191.
Caranx, 339 l.
Carapace, 402.
Carapus, 2181.
Carassius, 2191.
Carcharias, 127, 123,
139, 144, 148, 151 ],
brain, 134 ; fresh-
water species, 118,
148 ; spiracle, 120.
Carchariidae, cruciform
centra, 123, 124.
Carcharodon, 92, 151 2.
Cardiac gland, 531.
Cardinal-fish, 2342.
Cardinal veins, 86.
Cardioglossa, 3132.
Carelophus, 244 i.
Careproctus, 2422.
Carettochelys, 415.
Cariacus, 5892.
Cariama, 4662.
Carinatae, 4601. .
Carine, 472 1.
Car moot, 221 *.
Carnassial tooth, 6132.
Carnivora, 612.
Carollia, 6482.
Carotid canal, 61-.
Carotid gland, 289.
Carp, 2182, 2191 ; Cru-
cian, 2191 ; Prussian,
2191.
Carpet-'snake, 3652.
Carphophis, 3672.
Carpiodes, 2182.
Carpomys, 6341.
Carpophaga, 4691.
Carpus in adaptive re-
duction, 579 ; mam-
malia, 492 ; serial,
successional, alternat-
ing, interlocking,5752.
Carterodon, 635 l.
Cartilage, marsipobran-
chii, 98.
Cartilaginous fishes, 118.
Caruncula lacrymalis,
497.
Casarea, 3652.
Cassina, 3131.
Cassowary, 4581.
Castor, 6322.
Casuarius, 4581.
Cat, native, 5382 ; wild,
caffre, domestic, tiger,
6191.
Cat-fish, 2211, 2212 .
electric, 2221.
Catarrhina, 6561.
Cateostomi, 228.
Catharista, 4631.
Cathartes, 4631.
Cathorops, 222 *.
Catla, 2191.
Catoprion, 2181.
Catopteridae, 170.
Catostomus, 2182.
Catreus, 4652.
Caturus, 180.
Cauda equina, 495.
Caudal fin, peculiarities
of, 55 ; Teleostei, 188.
Caudata, 304.
Caularchus, 2432.
Caulolatilus, 2352.
Caulolepis, 2341.
Causus, 3712.
Cavia, 6352.
Caviare, 170.
Cavum epipterygium,
41.
Cavy, Patagonian, 6352.
Cebidichthys, 2441.
Cebus, 6572.
Cedar bird, 4762.
Celaenomys, 633 1.
Cement of teeth, 500.
Cemophora, 3672.
Cent. = central.
Centetes, 641 1.
Central canal of the
nervous system, 2.
Centrarchus, 2341.
Centrina, 1521.
Centriscus, 2291.
Centrogenys, 2342, 2351.
Centrolabrus, 2381.
Centrolene, 3112.
Centrolophus, 231 2.
Centromochlus, 2221.
Centronotus, 2441.
Centrophorus, 118, 125,
126, 1522.
Centropogon, 2421.
Centropomus, 2351.
Centropristis, 2351.
Centropus, 4701.
Centropyx, 3522.
Centroscyllium, 118,
1522.
Centurio, 6482.
Cephalacanthus, 2431.
Cephalaspis, 94, 261,
261.
Cephalochorda, 10.
Cephalophus, 5902.
Cephaloptera, 1542.
Cephalorhynchus, 5632.
Cephalotes, 6462.
Cepola, 2352.
Ceramodactylus, 3491.
Cerastes, 3712.
Ceratias, 2461.
Ceratichthys, 2191.
Ceratobatrachus, 3122.
Ceratobranchial, 130.
Ceratodus, 259, 260,
Ceratohyal, 129.
Ceratohyla, 3112.
Ceratophora, 345, 3501.
Ceratophrys, 273, 3112.
Ceratopsia, 3872.
Ceratoptera, 1542.
Ceratorhinus, 601 l.
Ceratosaurus, 385 l.
Ceratotrichia, 54.
Cerberus, 3682.
Cercocebus, 6582.
Cercolabes, 6352.
Cercoleptes, 6232.
Cercomys, 635 l.
Cercopithecus, 6582.
Cercosaura, 3522.
Cere, 419.
Cerebellum, 67.
Cerebrum, 67.
Cereopis, 4631.
Ceriornis, 4652.
Ceroma, 438.
Certhia, 4772.
Cervalces, 5892.
Cervicapra, 591 1.
Cervulus, 5891.
Cervus, 588, 589, 5891.
Ceryle, 471*.
Cestracion, 143, 150.
Cetacea, 483, 553.
Cetengraulis, 2141.
Cetiosaurus, 3852.
Cetomimus, 2262.
Z. — II.
X X
674
INDEX.
Cetopsis, 2221.
Cetorhinus, 152 ^
Cetotherium,; 561.
Ceyx, 471 !.
Chaca, 221 l.
Chad, 2361.
Chaenichthys, 2432.
Chaenobryttus, 2341.
Chaenomugil, 231 2.
Chaetodon, 2362, 237 S
2372.
Chaetomys, 6352.
Chaetostomus, 2221.
Chaetura, 4731.
Chaffinch, 4781.
Chaibassia, 4132.
Chaima, 6582.
Chaja, 4622.
Chalarodon, 3502, 351 1.
Chalceus, 2172.
Chalcides, 354'.
Chalcidoseps, 3541.
Chalcinopsis, 2171.
Chalcinus, 21 72.
Chalicotherium, 6091.
Chalinolobus, 6472.
Chamaeidae, 4761.
Chamaeleolis, SSO^SSl1.
Chamaeleon, 335, 3551.
Chamaesaura, 335, 3512.
Chamaetortus, 3682.
Chamistes, 2182.
Chamois, 59 12.
Champsodon, 2432.
Champsosaurus, 334.
Channa, 2321.
Channomuraena, 2251 .
Chanodichthys, 2202.
Chanos, 200, 2142.
Characodon, 2271.
Charadriiformes, 4662.
Charadrius, 4671.
Charasia, 3501.
Charina, 3652.
Chart, 215a,2161.
Chasmodes, 2441.
Chatoessus, 2141.
Chauliodus, 2162.
Chauna, 462, 4622.
Chaunax, 2461.
Cheeta, 6191.
Cheilio, 2381.
Cheirodus, 170.
Cheirolepis, 170, 171.
Cheiropterygium, 52.
Chela, 2202.
Chelidon, 4761.
Chelidosaurus, 3151.
Chelmo, 2371.
Chelodina, 4142.
Chelone, 4132.
Chelonemydidae, 4141.
Chelonia, 402.
Chelosania, 3501.
Chelydra, 412, 4131.
Chelys, 4142.
Chersodromus, 3662.
Chersydrus, 3662.
Chestnut, 5962.
Chevron bone, 318.
Chevrotains, 587 2 ;
water, 5881.
Chiasmodon, 231 2.
Chiasmodus, 231 2.
Chilara, 2442.
Chilinus, 2381.
Chillingham cattle, 59 12.
Chilobranchus, 2222.
Chilodactylus, 2352.
Chilodipterus, 2342.
Chilomeniscus, 3672.
Chilomys, 6341.
Chilonycteris, 6482.
Chilorhinus, 225 *.
Chiloscyllium, 151 *.
Chimaera, 62, 155, 158 ;
lateral line, 80 ; peri-
cardium, 85.
Chimarrhichthys, 2432.
Chimarrogale, 6401.
Chimpanzee, 60 12.
Chinchilla, 6352.
Chioglossa, 3071.
Chionididae, 4672.
Chipmunk, 6322.
Chirixalus, 3131.
Chirocentridae, 2151.
Chirocentrodon, 2142.
Chiroderma, 6482.
Chirodon, 2172.
Chirogale, 6521.
Chiroleptes, 31 12.
Chiromantis, 3131.
Chiromys, 653 ].
Chironectes, 5391.
Chironemus, 2352.
Chiropodomys, 6341.
Chiroptera, 641.
Chirostoma, 2312.
Chirotes, 335, 3522, 3531.
Chirothricidae, 2262.
Chiru, 591 1.
Chirus, 2421.
Chitonotus, 2422.
Chitra, 415.
Chlamydera, 4771.
Chlamydophorus, 5462.
Chlamydosaurus, 3501.
Chlamydoselachus, 62,
118, 119, 123, 124,
148, 149 ; lateral
line, 80.
Chlamydotherium, 5472.
Chlopsis, 2251.
Chlorichthys, 2381.
Chlorophilus, 31 11.
j Chlorophis, 3672.
I Chlorophthalmus", 2262.
Chloroscombrus, 2392.
Choeronycteris, 6482.
Choeropotamus, 5821.
Choerops, 2381.
Choeropus, 530, 5382.
Choloepus, 5451.
Chologaster, 2271.
Chondrodactylus, 3491
Chondropython, 3652.
Chondrostei, 167.
Chondrosteus, 170.
Chondrostoma, 2201.
Chonerinus, 2472.
Chordata, 1.
Chordo-centrous, 59.
Chorinemus, 2392.
Chorion, 520.
Chorismodactylus, 242 l.
Chorisochismus, 2432.
Choroid gland, 196 ; of
fishes, 77.
Choroid plexus, 67, 70.
Chough, 4772.
Chriacus, 6532.
Chriodorus, 231 *.
Chromis, 2372.
Chrotomys, 6331.
Chrysemis, 4131.
Chrysichthys, 221 2.
Chrysochloris, 497, 6411.
Chrysococcyx, 4692.
Chrysolophus, 4652.
Chrysopelea, 3682.
Chrysophrys, 91, 2361.
Chrysothrix, 6562, 6572.
Chrysotis, 4702.
Chthonerpeton, 304.
Chub, 2191, 2192, 2201.
Cicatricula, 450.
Cichla, 2372.
Cichlops, 2352.
Ciconia, 449, 461 2.
Ciconiiformes, 461 *.
Cilia of feather, 421.
Ciliary ganglion, 135.
Ciliary nerves, 135.
Ciliated pit, 21.
Cimolestes, 5381.
Cincinnurus, 476, 4771.
INDEX.
675
Cinclus, 476 1.
Cingulum, 503.
Gnixys, 4132.
Cinosternum, 4131.
Cinyxis, 409.
Circus, 4632.
Cirrhilabrus, 2381.
Cirrhina, 2192.
Cirrhites, 2352.
Cistudo, 407, 4132.
Citharichthys, 2402.
Citharinus^l?1.
Citharns, 2402.
Citula, 2392.
Civet, African, palm,
Indian, 6201.
Cladistia, 176.
Cladodus, 145, 146.
Cladoselache, 56, 57,
145, 14<>.
Cla mat ores, 4742.
Claosaurus, 3872.
Clarias, 220, 221 *.
Clarotes, 221 2.
Claudius, 4131.
Clavicle, 162 ; Mamma-
lia,491;Teleostei,192.
Clawed-toad, 309.
Qaws, 483.
Cleavage of Amphioxus,
31.
Cleithrum, 162.
Clemmys, 4131.
Clepsydrops, 333.
Clepticus, 2381.
Clidastes, 335.
Climatius, 147, 147.
Climbing perch, 2321.
Clinoid, 60.
Clinus, 2441.
Clitoris, 480, 516 ; Che-
Ionia, 410 ; Reptilia,
328.
Cloaca, 48 ; birds, 440.
Club-shaped gland, 43.
Clupanodon, 2142.
Clupea, 208, 2141.
Clupeichthys, 21 42.
Clupeoides, 2142.
Cnemial crest, 434.
Cnemidophorus, 3522.
Cnidogianis, 221 l.
Coaita, 6572.
Coati-mundi, 6232.
Cobitis, 198, 2202, 221 1.
Cobra, 3702.
Cobus, 591 1.
Coccolepis, 170.
Coccosteus, 94, 260, :>('»().
Coccothraustes, 4781.
Coccystes, 4692.
Coccyzus, 4701.
Cochlea, Amphibia, 276.
Cochliodontidae, 155.
Cochlognathus, 2192.
Cock-and-hen-paddle,
2422.
Cockatoo, 4702.
Cock of the rock, 4751.
Cockup, 2351.
Cod-fish, 2322; cultus,
2421 . Murray, 235 1.
Codophryne, 311 *.
Coecilia, 304.
Coelacanthus, 175.
Coelogenys, 498, 6352.
Coelolepis, 147.
Coelom, of Amphioxus,
26 ; of Chordata, 7.
Coelonotus, 230 l.
Coelopeltis, 3682.
Coelops, 647i.
Coelurus, 3851.
Coendu, 6352.
Coerebidae, 4772.
Coffer-fish, 247 1.
Coffin- joint, 5961.
Cogia, 562i.
Coilia, 2141.
Coleonyx, 3492.
Coleura, 6481.
Colii, 4731.
Colinus, 4652.
i Collar cavity, 7.
CoUechthys, 2352.
Collocalia, 4721, 4731.
Colobodus, 180.
i Colobus, 6591.
1 Colodon, 5941.
Colopus, 3491.
Colostethus, 3131.
Colour, birds, 426.
Colour change, 3551 ;
in Amphibia, 273 ; in
birds,426; in Chamae-
leon, 355 ; in fishes,
91 ; in lizards, 337 ;
in Reptilia, 317.
Colpognathus, 2351.
Coluber, 3672.
Columba, 4682, 469.
Columbae, 4682.
Columbia, 2271.
Columella auris, 269 ;
Amphibia, 276 ; birds,
428, 437 ; Crocodilia,
376 ; Reptilia, 323.
Columella cranii, 319.
Colymbiformes, 4602.
Colymbosaurus, 398 l.
Colymbus, 4602.
Commensal fishes, 227 2.
| Communis system of
nerves, 76.
: Compsognathus, 385 l.
i Compsophis, 3662.
j Conchopoma, 259.
Condor, 463 *.
Condylar foramen, 488.
Condylarthra, 609.
Condylura, 6402.
Conepatus, 6241.
Coney, 5662.
Conger, 2242 ; deep-sea,
2242.
Congrogadus, 2442.
Congromuraena, 2241,
2242.
Conilurus, 6331, 6341.
Connochoetes, 5902.
Conocara, 2142.
Conodon, 2361.
Conodonts, 262.
Conolophus, 351 *.
Conophis, 3691.
Conopophaga, 4751.
Conorhynchus, 2212.
Conoryctes, 609 l.
Contia, 3672.
Conus arteriosus, 85.
Cook, the, 2372.
Coot, 4661.
Cophias, 3522.
Cophotis, 3501.
Cophyla, 3122.
Copidoglanis, 221 *.
Copper-head, 37 12.
Coprodaeum, 440.
Copulation, Amphibia,
296 ; birds, 450 ;
Cetacea, 559 ; Chelo-
nia, 411 ; Elasmo-
branchii, 14.
Copulatory organ in
Teleostei, 2262.
Coraciae, 471 l.
Coracias, 471 l.
Coraciiformes, 471 1.
Coracina, 475 l.
Coracoid, 130.
Coral-fish, 2342.
Corallus, 3652.
Cordylosaurus, 3532.
Coregonus, 197, 212,
2162.
Coridodax, 238 l.
676
INDEX.
Coris, 2381.
Cork-wing, 2372.
Cormorant, 46 12.
Corncrake, 4661.
Cornufer, 3131.
Coronella, 3672.
Corpora bigemina, 67.
Corpora striata, 69.
Corpus callosum, 480,
495.
Corpus cavernosum,5 1 4.
Corpus luteum, 518.
Corpus spongiosum, 514.
Corucia, 3541.
Corvula, 2352.
Corvus, 4772.
Corynopoma, 2171.
Coryphaena, 2392.
Coryphaenoides, 2322.
Coryphodon, 60S1.
Corythaix, 4701.
Corythomantis, 311 1.
Corythophanes, 351 1.
Cosmopol. = cosmopoli-
tan.
Cossyphus, 2381.
Cotile, 4761.
Cotinga, 4751.
Cottoperca, 2432.
Cottus, 91, 212, 210,
2421.
Coturnix, 4652.
Cotyledon, 520.
Cotylis, 2432.
Cotylophora, 5881.
Coua, 4701.
Coverts, 424.
Cowper's glands, 514.
Coypu, 635 1.
Craig fluke, 2402.
Crampton's muscle, 436.
Crane, 4661.
Cranial nerves, 47 ; Am-
phibia, 274 ; Elasmo-
branchii, 134, 136;
Marsipobranchii,107 ;
Pisces, 72; Reptilia,
321 ; Teleostei, 195.
Cranial segments, 72.
Craniata, 45.
Cranium of fishes, 60.
Crateromys, 6341.
Craurothrix, 633 1, 6341.
Crax, 449, 4651.
Creagrutus, 2172.
Creeper, 4772.
Cremnobates, 2441.
Crenidens, 2361.
Crenilabrus, 2372.
Crenuchus, 2172.
Creodonta, 611.
Crepidogaster, 2432.
Crested screamer, 4622,
Crex, 466i.
Cricetomys, 6341.
Cricetus, 6332.
Cricosaura, 352 l.
Crinia, 3112.
Crista acustica, 323.
Cristiceps, 2441.
Crocidura, 6401.
Crocodilia, 372.
Crocodilurus, 3522.
Crocodilus, 3831.
Cromeria, 21 62.
Cromileptes, 2351.
Crop, 438.
Crossbill, 4781.
Crossochilus, 2192.
Crossopholis, 170.
Crossopterygii, 171.
CrossoptUon, 4652.
Crossopus, 6401.
Crossorhinus, 151 *.
Crossostoma, 2202.
Crotalus, 3721.
Crotaphytus, 351 '.
Crotophaga, 4701 .
Crow, carrion, hooded,
4772.
Cruciform centra, 123.
Crumen, 484.
Crunomys, 6331.
Crura cerebri, 67.
Cryptacanthodes, 2441.
Cryptobranchus, 280,
305.
Cryptoclidus, 3981.
Cryptodelma, 3501.
Cryptodira, 4122.
Cryptoprocta, 6192.
Cryptopsophis, 304.
Crypto pterus, 221 2.
Cryptosaras, 2461.
Cryptotis, 3112.
Cryptotomus, 2381.
Crypturi, 4641.
Crypturus, 4641.
Crystallaria, 2342.
Crystallogobius, 241 *.
Ctenacanthus, 262.
Ctenacodon, 5412.
Ctenoblepharis, 351 '.
Ctenodactylus, 6351.
Ctenodipterini, 259.
Ctenodus, 259.
Ctenoid scales, 53.
Ctenolabrus, 195, 2372.
Ctenolates, 2351.
Ctenomys, 635 l.
Cten o pharyngodon ,
220'.
Ctenosaura, 351 1.
Ctenothrissidae, 2151.
Cubiceps, 231 2.
Cuckoo, 4692 ; Euro-
pean, 4692 ; great
spotted, 46921.
Cuckoo-shrike, 4761.
Cuculi, 4692.
Cuculiformes, 4692.
Cuculus, 4692.
Culmen, 438.
Culter, 2202.
Cultuscod, 2421.
Curassow, 465 l.
Curlew, 467 ] ; stone,
4672.
Cursorius, 4672.
Cuscus, 5371.
Cutaneous glands, 483.
Cut-lips, 2192.
Cyamodus, 4021.
Cyanops, 4732.
Cyathaspis, 261.
Cybium, 2382.
Cyclagras, 3672.
Cyclanorbis, 415.
Cyclemys, 4132.
Cycleptus, 2182.
Cyclobatis, 1542.
Cyclocorus, 366-.
Cycloderma, 415.
Cyclodus, 3541, 345.
Cycloid scales, 53.
Cyclopsittacus, 4702.
Cyclopterus, 210, 2422.
Cyclorhamphus, 3112.
Cyclospondylous, 124,
125.
Cyclostomata, 95.
Cycloturus, 5442.
Cyclura, 3511.
Cygnus, 4622.
Cylindrophis, 3661.
Cymatogaster, 237 l.
Cymatosaurus, 3972.
Cymolutes, 2381.
Cynaelurus, 6191.
Cynictis, 6201.
Cynocephalus, 6582.
Cynodictis, 6221.
Cynodon, 2172.
Cynogale, 6201.
Cynoglossus, 2402.
Cynognathus, 4002,
"401.
INDEX.
677
Cynoidea, 617 J, 621.
Cynolebias, 2271.
Cynomys, 6322.
Cynonycteris, 646 ».
Cynopithecus, 6582.
Cynopterus, 6461.
Cynoscion, 235-.
Cyphosus, 2341.
Cyprinion, 2192.
Cy prinisil urif ormes,
"2162.
Cyprinodon, 2262.
Cyprinodonta, 91.
Cyprinus, 208, 21 82.
Cypseli, 4722.
Cypselus, 4722.
Ctystophora, 6272.
Cyttopsis, 240 1.
Cyttus, 2401-
Dab, 2402.
Daboia, 37 12.
Dace, 220 ; long-nosed,
2192.
Dacelo, 471 1.
Dactychilikion, 3491.
Dactylagnus, 2432.
Dactylanthias, 2351.
Dactylethra, 309.
Dactylomys, 6351.
Dactylopsila,.5371.
Dactylopterus, 92, 205,
2431.
Dactylosaurus, 3972.
Dactyloscopus, 2432.
Daector, 2441.
Dalliidae, 226-1.
Damaliscus, 5902.
Damonia, 4131.
Dangila, 2192.
Danio, 2201.
Dapedius, 179, 179.
Daption, 461 l.
Darter, 2342, 4612.
Dassy. 5662.
Dasyatis, 1542.
Dasyinys, 634 l.
Dasypeltis,3681.
Dasypotherium, 5472.
Dasyprocta, 6352.
Dasypus, 547 1.
Dasyurus, 530, 5382.
Dawsonia, 31 51.
Death-adder, 3701.
Deciduata, 520.
Decodon, 2381.
Deep-sea, Elasmobran-
chii, 118.
Deep-sea fishes, 73.
Deer, 5882, 5891 ; red,
fallow, musk, 589 1 ;
rein, roe, water,
5892.
Delage, on eel s,224i.
Delma, 3501.
Delphinapterus, 5632,
5641.
Delphinoidea, 561.
Delphinus, 5<;3, 5641.
Dendraspis, 370 1.
Dendrelaphis, 3672.
Dendrobates, 273,
3132.
Dendrocolaptes, 4751.
Dendrocopus, 4741.
Dendrodus, 175.
Dendrohyrax, 5662.
Dendrolagus, 5352.
Dendromys, 6341.
Dendrophis, 3672.
Dendrophryniscus,
3121.
Denisonia, 3701.
Dental formula, 502.
Dentition, prelacteal,
507 ; horse, 595 ;
Mammalia, 499 ; Mar-
supialia, 530.
Deomys, 6341.
Dercetiformes, 227.
Dercetis, 2272.
Derichthys, 2241.
Dermatemys, 41 31.
Dermochelys, 4122.
Dermophis, 304.
Dermoptera, 641 2.
Dermotrichia, 52, 54.
Desman, 6402.
Desmathippus, 5981.
Desmodus, 6482.
Desmognathous, 430.
Desmognathus, 305.
Deuterosaurus, 401 J.
Development, Amphibia
207, 298, 299 ; Am-
phioxus, 31 ; birds,
450 ; Dipnoi, 257 ;
fishes, 91 ; Gymno-
phiona, 303 ; Mam-
malia, 520 ; Marsipo-
branchii, 113 ; Rep-
tilia, 328; Teleostei,
210.
Diademodon, 401 1.
Diaglena, 311 '.
Diagramma, 236 1.
Diana, 2392.
Diaphorocetus, 5622.
Diaphragm, birds, 447 ;
Crocodilia, 324, 379 ;
Mammalia, 480.
Diastema, 500.
Dibamus, 3542.
Dibranchus, 2461.
Dicaeidae, 4772.
Dicamptodon, 3061.
Diceratherium, 6012.
Dicerobatis, 1542.
I Dichobune, 5851.
\ Dichodon, 585].
1 Dicholophus, 4662.
Diclidurus, 6481.
I Dicotyles Cuv., omitted
in text, 5821.
Dicrocerus, 5892.
Dicrodon, 3522.
I Dicrostonyx, 6341.
Dicruridae, 4762.
I Dictyosoma, 2441.
| Dicynodon, 401 2.
I Dicynodontia, 401.
! Didelphia, 529.
Didelphys, 531, 532,
533, 5391.
Didunculus, 4691.
Didus, 4601,469i.
Didymodus, 148.
Diemenia, 3701.
Digitigrade, 493.
Digits, Mammalia, order
of disappearance of,
480.
• Dimades, 3672.
Dimetrodon, 333.
Dimorphodon, 389, 3902.
Dinematichthys, 2442.
; Dingo, 6221.
! Dinichthys, 260.
l Dinictis, 6191.
i Dinoceras, 604, 605J.
Dinocyon, 6221.
Dinodon, 3672.
Dinomys, 6352.
Dinoperca, 2351.
Dinornis, 4582.
Dinosauria, 383.
Dinotherium, 5721, 573.
; Diodon, 203, 2472.
Diomedea, 4611.
Diphycercal, 55.
Diphylla, 6482.
| Diphyodont, 501.
Diplacanthus, 147.
Diplesium, 2342.
Diplobune, 584, 584.
Diplocrepis, 2432.
\ Diplocynodon, 3831.
678
INDEX.
Diplodactvlus, 3491. Dorcatherium, 5881,
Diplodocus, 3852. 5881.
Diplodus, 2361.
Dorcatragus, 591 l.
Diploglossus, 351 2.
Dorcopsis, 5352.
Diplolaemus, 3511.
Dormouse, 633 1.
Diplomesodon, 6401.
Dorosoma, 2141.
Diplomystax, 221 2.
Dorsalia, 98.
Diplopterus, 175, 4701.
Diplospondyly, 125.
Dorsopharyngeal coe-
lom, 27,23.
Dipnoi, 248.
Doryichthys, 2301.
Dipodomys, 6342.
Dotterel, 467 ].
Diporophora, 350 1.
Douroucouli, 6572.
Dipper, 4761.
Dove, ring, 469 l ; stock,
Diprotodon, 5372.
4691 . turtle, 4691.
Diprotodontia, 534.
Doydixodon, 2331.
Dipsadoboa, 3691.
Dracaena, 3522.
Dipsadomorphus, 369 l.
Draco, 338, 3501.
Dipsas, 371 !.
Dragon, flying, 3501.
Dipsosaurus, 351 l.
Dragonets, 24 R
Dipterodon, 2361.
Drepane, 237*.
Dipterus, 250, 259.
Drepanididae, 4772.
Diptychus, 2191.
Drepanodon, 3672.
Dipus, 6342.
Dromaeognathous, 429.
Diretmus, 2392.
Dromaeus, 4581.
Dirosema, 3672.
Dromas, 4672.
Discoboli, 2422.
Dromatherium, 5392.
Discocephali, 2412.
Dromedary, 5871.
Discoglossus, 265, 270,
Dromicia, 5362.
293, 3101.
Dromicordryas, 367 '.
Discognathus, 219 1.
Dromicus, 3672.
Discopyge, 1541.
Dromophis, 3691.
Dispholidus, 369 l.
Drongo, 47 62.
Dist. = Distribution.
Drum-fish, 2352.
Distichodus, 2172.
Drymobius, 3672.
Distira, 3692, 37Qi.
Dryocalamus, 3672.
Distoechurus, 5362.
Dryolestes, 5402.
Distribution, Amphibia,
Dryophiops, 369 l.
300; Mammalia, 524.
Dryophis, 369 ^
Ditrema, 91,237'.
Dryopithecus, 6602.
Ditypophis, 3691.
Dryornis, 460 l.
Diver, 4602 ; great -
Duck, 4622 ; wild, eider,
northern, 4602.
463i.
Docidophryne, 271.
Ductor, 2391.
Dodo, 4691.
Ductus Botalli, 289 ;
Doedicurus, 5481.
Reptilia, 327.
Dog, 621 ; prairie, 6322.
Ductus Cuvieri, 86.
Dog-fish, 1511.
Ductus endolymphati-
Dolichopithecus, 6591.
cus, 77, 323 ; see also
Dolichosauria, 334.
Corrigenda.
Dolichosaurus, 334.
Ductus thoracicus, 512.
Dolichosoma, 3151.
Ductus venosus Arantii,
Dolichotis, 6352.
521.
Doliichthys, 241 l.
Dugong, 552'.
Doliophis, 3701.
Dunlin, 4673.
Dolphin, 2392, 5641.
Duplicidentata, 636 1.
Doras, 205, 2221, 2212 ;
Dussumieria, 2141.
migration over land,
Duvernoy, glands of,516.
92.
Duymaeria, 2381.
Doratonotus, 2381.
Dyscophus, 3122.
Eagle, 4632 ; golden,
4632 ; ' sea, 4632 ;
spotted, 4632.
Eagle-rays, 1542.
Ear, Amphibia, 276 and
Corrigenda ; birds,
419, 437 ; Chelonia,
410 ; Elasmobranchii,
121 ; Mammalia, 498 ;
Marsipobranchii, 110 ;
Reptilia, 322; Tele-
ostei, 196.
Ebenavia, 349 1.
Echeneiformes, 241 2.
Echeneis, 241 2.
Echidna, 528, 526, 2251.
Echinomys, 635 l.
Echinorhinus, 123, 1522.
Echiostoma, 216-'.
Echis, 3712.
Ecpleopus, 3522.
Ectophylla, 6482.
Ectopistes, 469 '.
Ectoptergoid, 320.
Edalorhina, 31 12.
Edaphodon, 158.
Edentata, 542.
Edible nest, 4722.
Eels, 2231, 2241, 2242,
2251 , breeding of,
91, 223 : deep-sea,
224? ; electric, 2181 .
marine, 2242.
Eel-fares, 224-.
Eel pout, 233 1.
Effodientia, 548.
Egernia, 3541.
Eggs, Amphibia, 295,
296 ; Aspredo, 2221 ;
birds, 450 ; Chelonia,
411 ; Crocodilia, 380;
Dipnoi, 256, 258 ;
eels, 2241; Elasmo-
branchii, 143 ; fishes,
91 : lizards, 347 ;
snakes, 363 ; Mam-
malia, 518 ; Marsipo-
branchii, 115; Mar-
supialia, 533 ;Mono-
tremata, 526, 528 ;
Reptilia, 328 ; Rho-
deina, 220 ; Teleostei,
210.
Eigenmannia, 218 '.
Elacate, 2382.
Elachistodon, 3692.
Eland, 59 11.
Elanura, 2422.
Elapechis, 3702.
INDEX.
679
Elaphodus, 589 l.
Elapognathus, 3702.
Elapoides, 367 l.
Elapomoius, 3691.
Elapomorphus, 369 '.
Elapops, 3691.
Elapotinus, 369 ].
Elaps, 3702, 371.
Elasmobranchii, 118;
deep sea, 118 ; osse-
ous tissue, 122.
Elasmosaurus, 3981.
Elasmotherium, 6012.
Elassoma, 2341.
Electrical organs of
fishes, S3.
Electric cat-fish, 2221.
Electric eel, 2181.
Electrophorus, 2181.
Eleginus, 2331, 2432.
Eleotris, 241 1.
Elephant, sea, 6272.
Elephas, 569, 571, 572.
Elginia, 4001.
Eligmodontia, 634 l.
Eliomys, 6331.
Eliurus, 6341.
Elk, Irish, 5892.
Ellipesurus, 1542.
Ellobius, 6341.
Elopichthys, 2202.
Elops, 2142.
Elosia, 31 12.
Elotherium, 582 >.
Elseya, 4142.
Elvers, 2232, 2242.
Emballonura, 6481.
Emberiza, 4781.
Emeu, 433, 4581.
Emmelichthys, 2361. •
Emyda, 415.
Emydura, 4142.
Emys, ^6', 41 1,4132.
Enaliornis, 4592.
Enamel, Cetacea, 560.
Enamel organ, 506.
Encheliophis, 2272.
Enchelycore, 2251.
Enchodus, 2252.
Endostyle, 22, 23, 39,
43.
Engraulis, 2141.
Engystoma, 3121 .
Engystomops, 3102.
Enhydra, 624'.
Enhydrina, 3701.
Enhydris, 3701.
Enneacanthus, 2341.
Enophrys, 2422.
Entelops, 545 l.
Entepicondylar fora-
men, 331, 491.
Enterocoelic, 7.
Enteropneusta, 1, 3.
Enyalioides, 3511.
Enyalius, 351 ].
Enygrus, 3652.
Eohippus, 599 !.
Eonycteris, 6462.
Eos, 4702.
Eosphargis, 4122.
Epalzeorhynchus, 2192.
Epanorthus, 5381.
Ephippion, 2472.
Ephippus, 2371.
Epibranchial, 130.
Epibulus, 2381.
Epiceratodus, 259.
Epicoracoid, 271.
Epicrates, 3652.
Epicrium, 291.
Epididymis, Reptilia,
328.
Epigonus, 2342.
Epihippus, 599 1.
Epinephelus, 2351.
Epinnula, 2382.
Epiphysis cerebri, 69,
70.
Epipterygoid, 319.
Epipubis, 377.
Episternum, Mammalia,
490.
Epistropheus, 373.
Epomophorus, 6461.
Eq. = equator.
Eques, 2352.
Equula, 2392.
Equus, 5942, 591, 595,
598 ; ancestry of, 599.
Eremias, 3531.
Eremophilua, 222 l.
Erethistes, 222 1.
Erethizon, 6352.
Eretmosaurus, 398 l.
Ericulus, 641 !.
Ericymba, 2192.
Erilepis, 242 l.
Erimyzon, 2182.
Erinaceus, 498, 6392.
Eriodes, 6572.
Erismatura, 463].
Erithacus, 4752.
Ermine, 6242.
Erne, 4632.
Erpetosaurus, 382 l.
Erythrichthys, 2361.
Erythrinus, 200, 2171.
Erythrolamprus, 3691.
Erythromachus, 4661.
Eryx, 3652.
Esociformes, 225.
Esox, 197, 208, 2252 ;
lateral line, 82.
Esthonyx, 60S1.
Eteirodipsas, 369 l.
Etelis, 2352.
Etheostoma, 2342.
Ethiop. = Ethiopian.
Ethmo-palatine liga-
ment, 129.
Ethmoidal, 60.
Etmopterus, 1522.
Etroplus, 2372.
Etrumeus, 2141.
Euanemus, 221 2.
Eublepharis, 3492.
Eucalia, 2291.
Euchoreutes, 6342.
Eucinostomus, 2361.
Euctenogobius, 241 1.
Euderma, 6472.
Eudiastatus, 6572.
Eudocimus, 461 -.
Eudromia, 4641 .
Eudromias, 467 J.
Eudynamis, 4701.
Eudyptes, 4602.
Euelephas, 5712.
Euglyptosternum, 221 2.
Eugnathichthys, 2172.
Eugnathus, 180.
Eulabeornis, 4661.
Eumeces, 3541.
Eumicrotremus, 2422.
Eunectes, 3652.
Euoxymetopon, 239 J
Eupetaurus, 6322.
Eupleres, 6202.
Eupomotis, 2341.
Euposaurus, 334.
Euprotogonia, 611 1.
Euprotomicrus, 1522.
Eur. = European.
Eurostus, 3682.
Eurydactylus, 3491.
Eurylaemus, 4742.
Eurynotus, 170.
Eurypharynx, 2251.
Eurypyga, 4662.
Eurystole, 231 2.
Eurystomus, 471 l.
Euspondylus, 3522.
Eustachian tube, birds,
427, 4292 ; Chelonia,
410 ; Crocodilia, 376,
377.
680
INDEX,
Eustira, 2202.
Eusuchia, 375, 381, 382.
Eutatus, 5472.
Eutheria, 542.
Euthynotus, 181.
Eutropiichthys, 221 2.
Eutropius, 221 2.
Evolution of birds, 418 ;
Chelonia, 411 ; Rhyn-
chocephalia, 333.
Evoplites, 2352.
Evorthodus, 241 *.
Evotomys, 6341.
Excretory organs of
Amphioxus, 27, 28, 29.
Exocoetus, 92. 185,
230, 231 *.
Exoglossum, 2192.
Exostoma, 222 1.
External gills, Am-
phibia, 278 ; Dipnoi,
252; Elasmobranchii,
120 ; Polypterus, 175.
Eyelids, birds, 41 9, 436;
Chelonia, 410 ; Croco-
dilia, 372 ; lizards,
336; Reptilia, 317,
322.
Eyes, Amphibia, 276;
birds, 436; Chelonia,
410; Crocodilia, 378 ;
Elasmobranchii, 121 ;
fishes, 77 ; Mammalia,
497 ; Marsipobranchii,
109, 115; Reptilia,
322; Teleostei, 195.
Facial angle, 489.
Falciform ligament,
birds, 440.
Falco, 4632.
Falcon, 4632 ; pere-
grine, 4641.
Falconiformes, 463 l.
Fall fish, 2201.
Fallopian tube, 515.
Farancia, 3672.
Fat- body, Amphibia,
292, 295.
Feathers, 420.
Felis, 613, 614, 6191.
Fenestra ovalis, 267.
Fenestra rotunda, Am-
phibia, 276.
Feresa,5641.
Ferreiro, 31 11.
Ferret, 6242.
Fertilisation, Mamma-
lia, 518.
i Feylinia, 3542.
Francolinus, 4652.
Fiber, 6332.
Fratercula, 4681.
Ficimia, 3672.
Fregata, 4612.
Fieldfare, 4752.
Freshwater Selachii,
i Fierasfer, 210, 2272.
148.
! Fighting-fish, 2371.
Frigate-bird, 4612.
File-fish, 2471.
Fringilla, 4781.
Filoplumes, 421.
Frog-fish, 2461.
Finch, chaf-, gold-,
Frogs, 3122.
haw-, 4781.
Fulcra, 56.
Finfoot, 4662.
Fulica, 466i.
Fin-rays of Vertebrata,
Fuligula, 463'.
52.
Fulmarus, 4611.
Fins, paired, origin of,
Fundulus, 2271.
57.
Furia, 6481.
Fins, Teleostei, 185.
Furina, 3702.
Fin- whale, 561.
Furnarius, 4751.
Fire-bellied toad, 3101.
f.w. Afresh- water.
Firmisternal, 271.
Firmisternia, 3121.
Gadiculus, 2322.
First ventricle, 68.
Gadiformes, 232.
Fish, the smallest, 241 i;
Gadomus, 2322.
subterranean, 2442.
Gadus, 186, 203, 207,
Fishes, 51.
2322.
Fishes, deep sea, 93.
Gaertner's canal, 328.
Fishes, geological his-
Galago, 652 1.
tory of, 94 ; habits of,
Galarix, 639 '.
91-93 ; poison spines
Galaxias, 2252.
of, 2421, 2432, 2441.
Galbula, 4732.
Fissipedia, 612.
Galeichthys, 221 2.
Fistularia, 2291.
Galeocerdo, 151 2.
Fitzroyia, 2262.
Galeoidcs, 231 -.
Flamingo, 46 12.
Galeopithecus, 641 l.
Flat-fish, 2401 ; double,
Galesaurus, 4002.
2401.
Galeus, 134, 151 2.
Flocculus, 495.
Galictis, 6241.
Flounder, 2402.
Galidea, 6202.
Flower- pecker, 4772.
Galidictis, 6202.
Flukes of Cetacea, 553.
Galli, 4642.
Flute-mouths, 2291.
Galliformes, 4642.
Fly-catcher, 4752.
Gallinago, 4671.
Flving-fish, 92, 231 '-.
Gallinula, 466'.
Fodiator, 231 l.
Galloperdix, 4652,
Foramen lacerum, 485.
Gallus, 4652.
Foramen Panizzae,
Gambusia, 227 1.
325.
Gamposteonyx, 313*.
Fordonia, 3682.
Ganglion habenulae,
Fore-brain, 67
107.
Foreskin, 515.
Gannet, 461 2.
Fork-tail, 4752.
Ganodonta, 543, 60S1.
Formicarius, 4751.
Ganodus, 158.
Fornix of Gottsche,
Ganoidei, 159.
194.
Ganoid scales, 53.
Fossa, 6201.
Ganoin, 53, 160, 162.
Four-eyed fish, 227 *.
Gar-fish, 231 *.
Fourth ventricle, 67.
Gar- pike, 179.
Fowl, 4652.
Gar-pipe, 23 11.
Fox, 6221 ; flying, 6461.
Garrulus, 4772.
Fox-shark, 1521.
Garzonidae, 5381.
INDEX.
681
Gasserian ganglion, 135.
Gasterosteus, 91, 210,
228*, 229 !.
Gastromyzon, 2202.
Gastropelecus, 2172.
Gastropholis, 3531.
Gastropyxis, 3672.
Gastrosteiformes, 228.
Gastrostomus, 2251.
Gastrotokeus, 2301.
Gastrula of Amphioxus,
33.
Gaur, 59 12.
Gavialis. 375, 3831.
Gayal, 59 12.
Gazella, 591 l.
Gazza, 2392.
Geagras, 3672.
Gecinus, 4741.
Gecko, 345, 349 '.
Geckolepis,349i.
Geese, 4622.
Gegenophis. 304.
Gehyra, 3491.
Geikia, 4012.
Gelocus, 5881.
Gempylus, 2382.
Gemsbok, 59 11.
Generative ducts, Tele-
ostei, 209.
Genet, 6201.
Genetta, 6201.
G emeu late ganglion,
136.
Genidens, 2212.
Genital pores, Marsipo-
branchii, 111.
Gennaeus, 4652.
Genyophryne, 3122.
Genypterus, 2442.
Geocalamus, 3531. •
Geococcyx, 4701.
Geodipsas, 3691.
Geoemyda, 407, 4132.
Geogale, 6402.
Geomys, 6342.
Geophis, 367-'.
Georychus, 6342.
Geosaurus, 3822.
Geotria, 116.
Geotrypetes, 304.
Gephyroberyx, 2341.
Gerardia, 3682.
Gerbillus, 6331.
Germinal disc, 450.
Germo, 2382.
Gerres, 2361.
Gerrhonotus, 351 2.
Gerrhosaurus, 353.
Gestation, Cetacea, 559 ;
Elephant,570 ; Marsu-
pialia, 529 ; Mamma-
lia, 522.
Gibbon, 661 i.
Gila, monster, 3521.
Gilbertia, 2351.
Gillellus, 2432.
Gills, Amphibia, 278 ;
Dipnoi, 251 ; 249,
Elasmobranchii, 119;
external of fishes, 66 ;
fishes, 66 ; Ganoidei,
163 ; Teleostei, 199.
Gill rakers, 192, 198;
Amphibia, 280.
Gill slits, 6 ; primary
secondary, 36.
Gilt-head, 2361.
Ginglymostoma, 151 x.
Giraffa, 5901.
Girardinus, 2271.
Girdle-bone, 269.
Girella, 2361.
Giton, 2181.
Gizzard, 439.
Glands, sweat and seba-
ceous, 483.
Glanidium, 2221.
Glanspenis, 515.
Glareola, 4672.
Glass-snake, 35 12.
Glauconia, 3651.
Glenoid, 130.
Glires, 6272.
Glis, 6331.
Globe-fish, 2472.
Globicephalus, 5641.
Glomerulus, 87.
Glossamia, 2342.
Glossophaga, 6482.
Glossotherium, 5452.
Glutton, 6242.
Glyphodon, 3702.
Glyphoglossus, 3121.
Glypholycus, 3671.
Glyphonycteris, 6482.
Glyptauchen, 2421.
Glyptodon, 5481.
Glyptolepis, 175.
Glyptosternum, 221 2.
Gnathonemus, 2141.
Gnu, 5902.
Goat, Rocky mountain,
59 12.
Goatsucker, 472 l.
Gobies, 24 11.
Gobiesox, 2432.
Gobiiformes, 241'.
Gobiodon, 241 l.
Gobius, 241 1, 212 ;
lateral line, 82.
God wit, 467 1.
Gotte on osseous tissue,
122.
Goldfinch, 478 l.
Goldfish, 2191, 2201.
I Gold-sinny, 2372.
! Golunda, 6341.
I Gomphodontia, 4011.
j Gomphosus, 2381.
| Gonads, Amphibia, 292;
Amphioxus, 30, 2 ;
43 ; birds, 449 ; fishes,
88, 90 ; Mammalia,
513 ; Marsipobranchii,
112; Reptilia, 328;
Vertebrata, 49.
Gonatodes, 3491.
Gonionotophis, 3671.
Goniopholis, 3822.
Gonioplectrus, 2351.
Gonorhynchidae. 21 62.
Gonyocephalus, 3501.
Gonyophis, 3672.
j Gonys, 438.
Goosander, 4631.
Goose bean, grey, snow,
4631.
Gopher tortoise, 4132.
Goral, 5912.
Gordonia, 4012.
Gorilla, 660, 6612, 662.
Goshawk, 4632.
Goura, 4691.
Gourami, 2371.
Grallaria, 4751.
Grammatostomias.
2162
j Grammicolepis, 2401.
; Grammistes, 2351.
Grampus, 5641.
Graphiurus, 6331.
Grass -parakeet, 4702.
Grass-snake, 3671.
Grassi on eels, 223
Gravigrada, 545 1.
I Grayia, 3672.
i Grayling, 21 62.
Grebe, great crested,
4602.
[ Greek tortoise, 4132.
| Greenland shark, 1522.
Greenlet, 477 l.
Grey mullet, 23 12.
Griffon, 4632.
Grilse, 2152.
682
INDEX.
Grinder-teeth, 499.
Grison, 6241.
Groundling, 22 11.
Grousehazel, black, red,
willow, 4652 ; sand,
4681.
Gruiformes, 466 '.
Grus, 4661.
Gryptotherium, 5452.
Grysbok, 5902.
Guanaco, 5871.
Guarcharo, 4722.
Gudgeon, 2191.
Guereza, 6591.
Guib, 591 1.
Guillemot, black, 4681.
Guinea-fowl, 465 1.
Guinea-pig, 6352.
Guira, 4701.
Guitar-fish, 1541.
Gull, 4672.
Gulo, 6242.
Gunelichthys, 2441.
Gurnard, 2422 ; deep
sea, flying, long- finn-
ed, red, streaked,
sapphirine, Bloch's,
2431.
Guttera, 4651.
Gygis, 4681.
Gymnachirus, 2402.
Gymnarchus, 194. 202,
203, 205, 208, 210,
2141.
Gymnobelideus, 5362.
Gymnobucco, 4732.
Gymnocanthus, 2422.
Gymnocrotaphus, 236 1.
Gymnocypris, 2191.
Gymnodactylus, 3492.
Gymnoderus, 4751.
Gymnodontes, 247 l.
Gymriomuraena, 2251.
Gymnophiona, 300.
Gymnophthalmus, 3522.
Gymnopis, 304.
Gymnotus, 2181, 201,
electrical organ, 84.
Gymnura, 502, 6392.
Gymnuromys, 6331,
634i.
Gypaetus, 4632.
Gyparchus, 4631.
Gyps, 4632.
Gyrfalcon, 4632.
Gyri, 494.
Gyrinichthys, 2422.
Gyrodus, 180.
Gyrosteus, 170.
Habits, Amphibia, 264,
300 ; Dipnoi, 257 ;
fishes, 91-93 ; Gym-
nophiona, 302 ; Marsi-
pobranchii, 115 ; Tele-
ostei, 211.
Haddock, 2322.
Haemal arches, 60.
Haematopus, 467 l.
Haemulon, 2361.
Hag-fish, 117.
Hainosaurus, 335.
Hairs, 482.
Hairtail, 2391.
Hake, 2261, 2331.
Halargyreus, 2322.
Halcyon, 471 1.
Haldea, 367i.
Half- vertebra, 161.
Haliaetus, 4632.
Halibut, 2401.
Halichoeres, 238'.
Halichoerus, 627 l.
Halicore, 511, 5521.
Halidesmus, 2442.
Halieutaea, 2461.
Halimochirurgus, 2462.
Haliophis, 2442.
Halitherium, 5522.
Hallomys, 6331, 6341.
Hallopus, 3851.
Halmaturus, 5351.
Halocypselus, 231 l.
Haloporphyrus, 233 l.
Halosaurus, 2272.
Hamadryad, 3702.
Hammerhead, 46 12.
Hammerhead sharks,
1512.
Hamster, 633-.
Hamuti, 421.
Hapaku, 235 1.
Hapale, 6562.
Hapalemur, 6521.
Hapalomys, 6341.
Hapalops, 546 1.
Haphlochilus, 2271.
Haplocercus, 3671.
Haplocerus, 591 2.
Haplochiton, 2252.
Haplodactylus, 2361.
Haploderma, 4732.
Haplodon, 6322.
Haplogale, 6232.
Haplomi. 225.
Haplopeltura, 371 !.
Hapsidophrys, 3672.
Kara, 221 2.
Hardella, 4131.
Harderian gland, Mam-
malia, 497 ; Reptilia,
322.
Hare, Cape jumping,
635 !; common, moun-
tain, tailless, 6361.
Hariotta, 158.
Harpactes, 4732.
Harpagifer, 2432.
Harpe, 238 1.
Harpesaurus, 350 l.
Harpiocephalus, 6472.
Harpodon, 2261.
Harpyia, 646 1.
Harpyonicteris, 6461.
Harrier, hen, 4632 ;
marsh, 4632 ; Mon-
tagu's, 4632.
Hartebeest, 5902.
Harttia, 2221.
Hatching of Amphi-
oxus, 35.
Hatschek's, nephridium,
41, 21 ; pet, 20.
Hatteria, 334, 345.
Hawfinch, 4781.
Hawk, carrion, 4632.
Hawks, 4632 ; fish, 4641;
sparrow, 4632.
Hawksbill turtle, 4141.
Head-kidney, Teleostei,
209.
Heart, Amia, 182 ;
fishes, 85 ; Lepidos-
teus, 178 ; Monotre-
mata, 527 ; Polyp -
terus, 174 ; Reptilia,
325, 326 ; snakes, 362.
Hedgehog, 6392.
Helatetes, 594i.
Heleioporus, 31 12.
Helicoleims, 242 l.
Helicophagus, 221 2.
Helicops, 367i.
Helictis, 624i.
Heliornis, 4662.
Helladotherium, 5901.
Hellbender, 305.
Helmictis, 2242.
Helminthophis, 365i.
Helocephalus, 351 1.
Heloderma, 352 J.
Helogale, 62Qi.
Helogenes, 221 2.
Helostoma, 237 l.
Hemerocoetes, 2432.
Hemibranch, 66.
Hemibranchii, 228.
Hemibungarus, 3702.
INDEX.
683
Hemicentetes, 641 1.
Hemicuiter, 2202.
Hemidactylns, 3492.
Hemigale,"620l.
Hemigaleus, 1512.
Hemigalidea, 6202.
Hemiganns, 60S2.
Hemigymnus, 238 l.
Heinilieterocercal, 56,
161.
Hemilepidotus, 2421.
Hemiodus, 2171.
Hemiphractus, 3112.
Hemipimelodus, 2212.
Hemipodius, 4642.
Heinipterygoid, 429.
Hemirhagerrhis, 3691.
Hemirhamphus, 231 1.
Hemirhombus, 2402.
Hemisaurida, 226 l.
Hemisilurus, 2212.
Hemisorubim, 2212.
Hemisphaeriodon, 3541'
Hemisus, 3121.
Hemitragus, 5912.
Hemitripterus, 2421.
Henicuridae, 4752.
Heniochus, 2362, 2371.
Heptanchus, 62, 119,
125, 126, 150 ; verte-
bral column, 124 ;
lateral line, 80.
Heptapterus, 2221.
Heptodon, 5941.
Hermaphrodite fishes,
90, 235.
Hermosilla, 2341.
Heron, night, 461 2
Heros, 2372.
Herpele, 304.
Herpestes, 614, 6201.
Herpetocetus. 561.
Herpetodryas, 3672.
Herpeton/3682.
Herpetoseps, 3541.
Herring, 2142.
Herrings, king of the,
245 ! ; spawning of, 91.
Hesperornis, 433, 434,
438, 4582, 4W.
Heteracanth, 186.
Heterobranchus, 200,
221 1.
Heterocephalus, 6342.
Heterocercal, 55.
Heterocoiiger, 2242.
Heterodactylus, 3522.
Heterodiphycercal, 56,
170.
Heterodon, 3672.
Heterodont, 500.
Heterodontus, 150.
Heteromi, 227.
Heteromys, 6342.
Heteronota, 349-\
Heteropygii, 227 ].
Heterostichus, 2441.
Heteiostraci, 261.
Heterotis, 200, 202, 210,
2151.
Hexagrammos. 2421.
Hexanchus, 62, 119,
123, 125, 150; cran-
ium, 61.
Hibernation, Amphibia,
300 ; Reptilia, 329 ;
carp, 2 IS2 ; Mam-
malia, 523 ; Teleostei,
211.
Himantodes, 3691.
Himantolophus, 2461.
Himantopus, 467 l.
Himantornis, 4661.
Hind-brain, 60.
Hiodon, 2142.
Hipistes, 3682.
Hipparion, 597, 598.
Hippidion, 5962.
Hippocampus, 91, 92,
183, 229, 23Qi.
Hippocephalus, 2422.
Hippoglossoides, 2402.
Hippoglossus, 2401.
Hippopotamus, 582,
5822.
Hipposiderus, 6471.
Hippotigris, 5962.
Hippotragus, 591 1.
Hirundo, 4761.
Histiophorus, 239V
Hoazin, 4661.
Hobby, 4641.
Hock, 5961.
Hodomys, 6341.
Hoe, 1522.
Hog, wart, river, 581.
Holanthias, 2351.
Holaspis, 353i.
Holbrookia, 351 1.
Holobranch, 199.
Holocanthus,2362,237i-
Holocentrum, 201, 202,
2332, 2341.
Holocephali, 155.
Holochilus, 634i.
Hologerrhum, 369 1.
Holoptychius, 175.
Holorhinal, 428.
Holosteus.. 231i.
Homacanth, 186.
Homacanthus, 147, 262.
Homacodon, 577, 5821.
Homaeosaurus, 344.
Homalocranium, 3691.
Honialodontotherium,
608, 609i.
Homalopsis, 3682.
Homaloptera, 2202.
Homalosoma. 3672.
Homea, 117.
Homelyn-ray, 1542.
Homo, 516, 6622.
Homocentrus, 6572.
Homocercal, 56.
Homonota, 349-.
Homopholis, 3492.
Homopus, 4132.
Homorelaps, 3702.
Homosteus, 260.
Homunculus, 6572.
Honey-eater, 47 7 -.
Honey-guide, 4741.
Hoofs, 483.
Hoopoe, 47 12.
Hoplichthys, 242 1.
Hoplocephalus, 3702.
Hoplocercus, 351 *.
Hoplocetus, 5622.
Hoplodactylus, 3492.
Hoplognathus, 2352.
Hoplophagrus, 2352.
Hoplophoneus, 619i.
Hoplophorus, 548 1.
Hoplunnis, 2251.
Hoplurus, 3502, 351 1.
Hormonotus, 367i.
Hornbill, 47 12.
Horned pout, 22 12.
Horned-screamer, 4622.
Horned toads, 31 12,
3511.
Horned viper, 37 12.
Horns, deer, 588 ; ante-
lope, 590.
Horse, 594.
Routing, 2162.
Humming-birds, 4731.
Hundfisch, 2261.
Huro, 2341.
Huxley, birds' skull,
429 ; on Crossoptery-
gii, 171 ; on Croco-
diles, 381.
Hyaena, 6202.
Hyaenarctos, 6231.
Hyaenictis, 6202.
Hyaenodon, 61 22.
684
INDEX.
Hybognathus, 2192.
Hyborhynchus, 2192.
Hybridism, Teleostei,
211.
Hybrids, 2191, 2192,
2202.
Hydaspitherium, 5901.
Hydrablabes, 3671.
Hydraethiops, 3671.
Hydraspis, 4142,
Hydrelaps, 3701.
Hydrocalamus, 3692.
Hydrochoerus, 6352.
Hydrocyon, 2172.
Hydrolagus, 158.
Hydromedusa, 4142.
Hydromorphus, 3672.
Hydromys, 6331.
Hydrophasianus, 4672.
Hydrophis, 3701, SjO.
Hydropotes, 5892.
Hydrops, 3672.
Hydropsalis, 472 l.
Hydrosaurus, 352 l.
Hydrus, 3692.
Hyla, 295, 3111.
Hylactes, 4751.
Hylambates, 3131.
Hylella, 3111.
Hylixalus, 3131.
Hylobates, 661 1.
Hylodes, 296, 31 12.
Hyloplesion, 3152.
Hylopsis, 3112.
Hylorhina, 3112.
Hymen, 516.
Hymenocephalus, 2322.
Hymenochirus, 265,
3101.
Hynnis, 2392.
Hynobius, 3061.
Hyoid arch, 62.
Hyoid segment, 73.
Hyo-mandibular, 62,
129.
Hyomoschus, 5881.
Hyopotamus, 582, 583,
5832.
Hyoprorus, 2242.
Hyopsodus, 6531.
Hyostylic, 62.
Hyperoartia, 116.
Hyperodapedon, 334.
Hyperolia, 31 12.
Hyperoodon, 5622.
Hyperopisus, 2141.
Hyperotreta, 116.
Hyperpharyngeal
groove, 22, 23.
Hybodus, 1511.
Hypnos, 154.
Hypobranchial, 130.
Hypocentrum, 161.
Hypoclydonia, 2342.
Hypogeomys.eSS1, 6341.
Hypogeophis, 278, 304.
Hypoglossal nerve, 321.
Hypoischium, 342.
Hypomesus, 2162.
Hypopachus, 3121.
Hypopharyngeal
groove, 22, 23.
Hypophthalmichthys,
2201.
Hypophthalmus, 221 2.
Hypophysis, 72.
Hypoprion, 151 l.
Hypoptopoma, 2221.
Hyporhachis, 421.
Hyporhamphus, 231 1.
Hypostomides, 230.
Hypsagonus, 2422.
Hypsiglena, 3672.
Hypsignathus, 6462.
Hypsilophodon, 3871.
Hypsiprymnodon, 5361.
Hypsiprymnopsis, 541 2.
Hypsiprymnus, 5352.
Hypsirhina, 3682.
Hypsirhynchus, 3672.
Hypsocormus, 181.
Hypsodont, 505.
Hypural bones, 55, 56.
Hyrachinus, 6012.
Hyracodon, 5381, 6012.
Hyracoidea, 565.
Hyracops, 610, 6111.
Hyracotherium, 5991,
599.
Hyrax, 502, 5662.
Hysterocarpus, 237 1.
Hystricodon, 2172.
Hystricomorpha, 635 1.
Hystrix, 6352.
laltris, 3691.
Ibex, 5912.
Ibis, 4612 ; sacred, 4612 ;
scarlet, 461 2.
Ibycter, 4632.
Icelinus, 2422.
Icelus, 2421.
Ichneumon, 6201.
Ichnotropis, 3531.
Ichthyborus, 2172.
Ichthyocampus, 230 l.
Ichthyodectes, 2151.
Ichthyodorulites, 262.
Ichthyomys, 6341.
Ichthyomyzon, 116.
Ichthyophis, 304.
Ichthyopsida, 50, 264.
Ichthyopterygimn, 52.
Ichthyornis, 438, 460 l.
Ichthyornithes, 460 l.
Ichthyosauria, 391.
Ichthyosaurus, 392, 395.
Ichthyotomi, 147.
Icichthys, 2312.
Icochilus, 6072.
Icosteus, 231 2.
Ictalurus, 2221.
Icteridae, 4781.
Icticyon, 6221.
Ictiobius, 2182.
Ictitherium, 6202.
Ictonyx, 6241.
Id, 2201.
Idiopholis, 3672.
Idiurus, 632 l.
Iguana, 351 l.
Iguanodon, 386, 386.
Ilisha, 2142.
Ilyophis, 2242.
Ilysia, 3661.
Incubation, birds, 453.
Incus, 498.
Ind.= India.
Indicator, 4741.
Indris, 6512.
Indrodon, 6531.
Inferior pharyngeal
bones, 192.
Inferior vena cava, Am-
phibia, 290 ; Dipnoi,
254.
Infraclavicle, 162.
Infratemporal arcade,
319.
Infundibular gland, 72.
Infundibulum, 67.
Inia, 563 '.
Insectivora, 636 ; vera,
641 2.
Insectolophus, 5941.
Intercentral bone, Rep-
tilia, 318.
Interclavicle, Mam-
malia, 490.
Interodon, 5452.
Interspinous bones, 185.
Iphisa, 3522.
Ipnops, 187, 2261.
Iridio, 2381.
Irrisor, 471 2.
Ischnacanthus, 147.
Ischnoglossa, 6482.
INDEX.
685
Ischognathus, 367'.
Ischyodus, 158.
Isistius, 121, 1522.
Isthmus, 184.
Istiophorus, 2391.
Iter a tertio ad quartum
ventriculum, 07.
Ithagenis, 4652.
Ithycyphus, 3691.
Ixalus, 3131.
lynx, 4742.
Jacaniar, 4732.
Jacamarhalcyon, 4732.
Jacana, 4672.
Jacare, 3832.
Jack, 2261.
Jackass, laughing, 47 11.
Jackdaw, 4772.
Jacobson's anastomo-
sis, 321.
Jacobson's organ, 323,
497.
Jaguar, 6191.
Japalura, 350 l.
Jay, 47 7 2.
Jenynsia, 227 l.
Jerboa, 6342.
John Dory, 2401.
Jordania/2421.
Joturus, 2312.
Jugular fin, 185.
Jugulare ganglion, 274.
Jugulares, 2431.
Julis, 2381.
Jungle-fowl, grey, 4652 ;
red, 4652.
Kachuga, 4131.
Kagu, 4662.
Kaka parrot, 4702.
Kakapo, 4702.
Kamptotrichia, 54.
Kangaroo, 5351 ; tree,
rat, 5352 ; musk,
5361.
Kannabateomys, 6351.
Kaola.SS?1.
Katadromus, 91.
Kathetostoma, 2432.
Kea, 4702.
Kelp-fish, 2381.
Kelt, 2152.
Keraterpeton, 3152.
Kerivoula, 6472.
Kestrel, 4641.
Ketengus, 221 2.
Killer, 5632.
Killifish, 227 1.
King-bird, 4751.
King-cobra, 3702.
King-fish, 228 !.
Kingfisher, 47 11.
King of the Herrings,
158.
Kinkajou, 6232.
Kionocrania, 339.
Kipper, 2152.
Kirombo, 47 11.
Kirtlandia, 231 2.
Kite, red, black, 4632.
Kittiwake, 4672.
Kiwi, 4581.
Klipspringer, 5902.
Kneria, 2262.
Kolliker, on osseous tis-
sue, 122.
Kogia, 5621.
Krait, 3701.
Kudee, 591 1.
j Kuhlia, 2341.
Kurtiformes, 2402.
Kurtus, 2411.
Labes, 219i.
Labia majora and
minora, 516.
Labichthys, 2242.
Labidesthes, 231 2.
Labrax, 2351.
Labrichthys, 2381.
Labroides, 2381.
Labrus, 198, 2372.
Labyrinthodon, 3151.
Lacerta, 3532.
Lacertilia, 335.
Lac ert ilia vera, 348.
Lachesis, 3712.
Lachnolaemus, 2381.
Lacrymal glands, Am-
phibia, 276 ; Rep-
tilia, 322 : Mammalia,
497.
Lactarius, 2392.
Lactophrys, 2471.
Ladislavia, 2191.
| Laemanctus, 351 1.
| Laemargus, 121, 124,
135, 139, 144, 152a.
Lammergeier, the, 4632. |
Laemonema, 2331.
Lagena, 77.
Lagenorhynchus, 5641.
Lagidium, 6352.
Lagochila, 2182.
Lagomys, 636 l.
Lagopus, 417, 420, 4652.
Lagorchestes, 5352.
Lagostomus, 6352.
Lagostrophus, 5352.
Lagothrix, 6572.
Lais, 22 12.
Lama, 5871.
Lambdotherium, 6021.
Lamina cribrosa, papy-
racea, perpendicular is,
486.
Lamimplantar, 420.
Lamna, 1512.
Lamnidae, vertebral
column, 124, 125.
Lamnodus, 175.
Lamprey, 116.
Lampris, 2281.
Lamprophis, 3671.
Langaha, 369 l.
Langur, 659 l.
Lanius, 4762.
Lantanotherium, 6391.
Lantern-fish, 2261.
Lanthanotus, 3521.
Laosaurus, 3872.
Lapwing, 467 l.
Lari, 4672.
Larimus, 2352.
Lariosaurus, 3972.
Lark, crested, sky-,
shore, wood-, 4752.
Larus, 4672.
Larva of Amphioxus,
36 ; of eels, 223.
Latastia, 3532.
Latax, 6241.
Lateolabrax, 2342.
Lateral line, Amphibia,
273 ; fishes, 79-82 ;
Marsipobranchii, 97,
108 ; Teleostei, 187.
Lateral temporal fossa,
319.
Lateral ventricle, 67.
Lates, 2351.
Latilus, 2352.
Latris, 2352.
Latrunculus, 241 *.
Lebiasina, 2171.
Legs, birds, 424.
Leiodoii, 335.
Leiponyx, 6462.
Lemming,Scandinavian,
6332.
Lemmus, 6332.
Lemon sole, 2402.
Lemur, ringtailed, 6521.
Lemuravus, 6531.
Lemuroidea, 649.
Lenomys, 6341.
686
INDEX.
Lenticular ganglion, 135.
Lentipes, 241 *.
Leopard, clouded, hunt-
ing, 619 ; sea, 6272.
Lepadogaster, 2432.
Ledidion, 2331.
Lepidobatrachus, 31 12
Lepidoblennius, 2441.
Lepidocephalichthys,
2211.
Lepidocephalus, 221 ' .
Lepidodactylus, 3492.
Lepidolemur, 6521.
Lepidophyma, 3521.
Lepidopsetta, 2402.
Lepidopus, 239 l.
Lepidosauria, 334.
Lepidosiren, 259.
Lepidostei, 176.
Lepidosternon, 3531.
Lepidosteus, 100, 161,
162, 163, 164, 179,
pronephros of, 87.
Lepidotrichia, 54.
Lepidotus, 180, 180.
Lepomis, 2341.
Lepophidium, 2442.
Leporinus, 2171.
Leposoma, 3522.
Lepterpeton, 3152.
Leptobarbus, 2192.
Leptobrachium, 3102.
Leptocalamus, 3672.
Leptocarcharias, 151 2.
Leptocardii, 11.
Leptocephalidae, blood,
85.
Leptocephalus, 2231,
2241.
Leptodactylus, 31 12.
Leptodira, 3691.
Leptognathus, 371 ^
Leptogonus, 2422.
Leptoichthys, 2301.
Leptolepis,'213.
Leptomanis, 5491.
Leptonychotes, 6272.
Leptophis, 3672.
Leptopterygius, 2432.
Leptoptilus, 4612.
Leptoscopus, 2432.
Leptosoma, 471 1.
Leptotragulus, 5872.
Lepus, 6361.
Letharchus, 2251.
Lethostole, 231 2.
Lethotremus, 2422.
Lethrinus, 2361.
Leucaspius, 2202.
Leuciscus, 2192.
Leucocytes (colourless
blood corpuscles,
lymph corpuscles),
49.
Leucoryx, 591 l.
Leucosomus, 2201.
Leuresthes, 231 2.
Leydig's duct, 292.
Liachirus, 2402.
Lialis, 3501.
Liasis, 3652.
Lichanura, 3652.
Lichia, 2392.
Lichonycteris, 6482.
Lieberkuhn's glands,
510.
Ligamentum denticula-
tum, 26.
Limacomys, 6341.
Limbs of snakes, 355.
Limicolae, 4671.
Limnodynastes, 31 12.
Limnomedusa, 3112.
Limnurgus, 2271.
Limosa, 4671.
Ling, 2331.
Linnet, 4781.
Linophryne, 2461.
Linota, 417, 4781.
Linsang, 6201.
Liocassis, 2212.
Liocephalus, 351 l.
Lioheterodon, 3671.
Liolaemus, 351 J.
Liolepis, 3501.
Lion, 6191.
Lionurus, 2322.
Liopelma, 300, 3101.
Liophidium, 3671.
Liophis, 3672.
Liophryne, 3121.
Liopropoma, 2351.
Liopsetta, 2402.
Liosaurus, 351 l.
Lioscorpius, 242 l.
Liparis, 2422 ; lateral
line, 82.
Liparops, 2422.
Lipoa, 465 l.
Lipogenyidae, 2272.
Liposarcus, 222 1.
Lipoterna, 602 ; affini-
ties of, 574.
Lirus, 2312.
Listriodon, 5821.
Lithocranius, 591 *.
Liver, of Amphioxus,
26, 23.
Lizard, common Eng-
lish, 3532 ; spiny-
tailed, 3502 ; poison-
ous, 3521; eyed, 3532 ;
sand, 3532.
Loach, 2202, 222* ;
spined, 22 \\
Lobi inferiores, 72.
Lobiophasis, 4652.
Lobodon, 6272.
Lobotes, 2341.
Loddigesia, 4731.
Loggerhead turtle, 4141.
Loncheres, 6351.
Lonchoglossa, 6482.
Lonchorhina, 6482.
Lonchurus, 2352.
Lophiiformes, 2452.
Lophiodon, 5932.
Lophiogobius, 241 l.
Lophiomeryx, 5881.
Lophiomus, 246 l.
Lophiomys, 6331 2.
Lophiosilurus, 221 2.
Lophius, 185, 187, 197,
X45, 2461.
Lophobranchii, 229.
Lophocalotes, 3501.
Lophoceros, 4712.
Lophodont, 504.
Lophogyps, 4632.
Lopholatilus, 2352.
Lophonectes, 2402.
Lophophorus, 4652.
Lophopsittacus, 4702.
Lophornis, 4731.
Lophostoma, 6482.
Lophotidae, 2451.
Lophotiformes, 2442.
Lophura, 3502, 4652.
Lophuromys, 6341 .
Lore, 419, 438.
Lorenzini's ampullae,
79, 82.
Loricaria, 222 1.
Loricata, 5431.
Loriculus, 4702.
Loris, 6522.
Lorius, 4702.
Lota, 2322, 2331.
Lotella, 2331.
Loxia, 4781.
Loxocemus, 3652.
Loxodon, 1512.
Loxolophodon, 6051.
Loxopholis, 3522.
Love-bird, 4702.
Lucania, 2271.
Luce, 2261.
INDEX.
f>87
Lucifuga, 2442.
Luciocephalns, 2371.
Luciogobius, 2411.
Lucioperca, 2342.
Luciosoma, 2192.
Luciotrutta, 2161.
Lucius, 2252.
Luminous organs, Elas-
mobranchii, 121.
Lump-sucker, 2422.
Lung, 48.
Lungless Amphibia,278,
>*» 305, 3061.
Lungs, Amphibia, 280 ;
birds, 442-448 ; Che-
Ionia, 409 ; Crocodilia,
379 ; Dipnoi, 252 ;
Mammalia, 512 ; liz-
ards, 344 ; snakes,
362 ; Reptilia, 324.
Luperosaurus, 3492.
Luscinia, 4752.
Lutra, 611, 6241.
Luvarus, 2392.
Lycaon, 6221. '
Lycodapus, 2272.
Lycodon, 3681.
Lycodontis, 2251.
Lycodryas, 3691.
Lycognathophis, 3671.
Lycognathus, 3691.
Lyconus, 2322.
Lycophidium, 3671.
Lycosaiirus, 4002.
Lygodactylus, 3492.
Lygosoma, 3541.
Lymph hearts, Croco-
dilia, 327.
Lymphatics, 49 ; Am-
phibia, 290 ; birds,
442 ; Mammalia, 512 ;
Reptilia, 327.
Lyncodon, 6242.
Lynx, 6191.
Lyosphaera, 2472.
Lyre-bird, 4751.
Lyriocephalus, 3502.
Lyrurus, 4652.
Lysiurus, 5471.
Lystrophis, 3681.
Lytorhynchus, 3681.
Mabuia, 3541.
Macacus, 6582.
Macaw, 4702.
Macdonaldia, 2272.
Machaerodus, 6191.
Machetes, 467 l.
Mackerel, 2382 ; horse,
2391.
Macquaria. 2351.
Macrauchenia, 6031.
Macrelaps, 369 l.
Macrocalamus, 3681.
Macroclemmys, 413*.
Macrodipteryx, 4721.
Macrodon, 2171.
Macroglossus, 6462.
Macrones, 203, 2212.
Macrophyllum, 6482.
Macropisthodon, 3671.
Macropoma, 175.
Macroprotodon, 3691.
Macropteryx, 4731.
Macropus, 529, 531,
532, 535.
Macrorhamphosus,
2291.
Macrorhinus, 6272.
Macrorhynchus, 3822.
Macroscelides, 639 l.
Macroscincus, 3541.
Macrose mius, 180.
Macrotherium, 6091.
Macrotus, 6482.
Macruronus, 2322.
Macrurus, 2322.
Macula acustica, 323.
Madgr. = Madagascar.
Madoqua, 591 *.
Maena, 2361.
Magpie, 4772.
Mail-cheeked fish, 241 2.
Malacanthus, 2352.
Malacocephalus, 2322.
Malacoclemmys, 4131.
Malacomys, 6341.
Malacopterus, 2381.
Malacopterygian, 185.
Malacopterygii, 213.
Malacosteus, 2162.
Malacothrix, 6341.
Malapterurus, 205,222*;
electrical organ, 84.
Malleolar bone, 5882.
Malleus, 498.
Mallomys, 6341.
Mallotus, 2162.
Malpishian, body, 87.
Malthe, 200, 2461.
Mammalia, 479 ; origin
and relations of, 481.
Mammary glands, 484.
Mammoth, 571 2.
Mammoth-Cave, fish of,
2271.
Man, 6622 ; races of 664.
Manatherium, 5521.
Manatus, 5521.
Mancalias, 2461.
Manculus, 3061.
Mandibular arch, 62.
Mandibular somite, 73.
Mandrill, 6582.
Manis, 483, 498, 549 1.
Mannakin, 4751'
Manolepis, 3691.
Manta, 1542.
Mantipus, 3122.
Mantophryne, 3122.
Manus, Amphibia, 271 ;
birds, 423, 433 ; Chel-
onia, 409 ; Crocodilia,
377 ; lizards, 342.
J Mar. = marine.
Marmoset, 6561.
I Marmot, pouched, al-
pine, 6322.
Marrow, birds, 419.
Marsipobranchii, 95 ;
genital ducts of, 88 ;
muscles, 97 ; cartil-
age, 97 ; skull, 98-
103 ; branchial arches
98, 103; brain, 106 -,
nasopalatine canal,
99, 104, 109 ; respira-
tion 105; resemblance
of mouth to that of
Amphibian larvae, 96.
Marsupialia, 529.
Marsupium, 529.
Marten, 6241.
Martin, house, sand,
4761.
Massoutiera, 6351.
Mastacembelus, 2451.
Mastacomys, 633 *-, 6341.
Mastodon, 5721, 572.
Mastodonsaurus, 3151.
Mastoid, 485.
Matamata, 4142.
Mauroticus, 2162.
Meckel's cartilage, 62.
Med. = Mediterranean
Sea.
Meda, 2201.
Medialuna, 2341.
Medullary plate and
canal, 33, 34.
Meerkat, 6201.
Megacephalon, 4651.
Megachiroptera, 6461.
Megaderma, 6471.
Megaladapis, 6522.
Megalaema, 4732.
688
INDEX.
Megalestris, 4672.
Megalichthys. 175.
Megalixalus, 3131.
Megalneusaurus, 398 1.
Megalobatrachus, 271.
Megalobrycon, 2172.
Megalocottus, 2422.
Megaloglossus, 6462.
Megalohyrax, 567 *.
Megalomys, 634 l.
Megalonyx, 5461.
Megalophrys, 31C2.
Megalops, 2142.
Megalosaurus, 3851.
Megalurus, 182.
Megapodes, 465 1.
Megapodius, 4651.
Megaptera, 561.
Megatherium, 5451.
Meibomian glands, 497.
Meiglyptes, 4741.
Melanerpes, 474*.
Melanerpeton, 3151.
Melanobatrachus, 3121.
Melanobranchus, 2322.
Melanocetus, 2461.
Melanonus, 2322.
Melanophidium, 3661.
Melanoseps, 3541.
Meleagris, 4652.
Meles, 614, 6241.
Meliphaga, 4772.
Melittophagus, 4712.
Melletes, 242-.
Mellisuga, 473 '.
Mellivora, 624>.
Melonycteris, 6462.
Melopsittacus, 4702.
Melursus, 6231.
Membrana basilaris,323.
Membrana elastica, 58.
Membrana semilunaris,
443
Membrana tympani-
formis interna, 443.
Membrane bones, 61.
Membrane of Reissner,
323.
Mendosoma, 2352.
Mene, 2392.
Menidia, 2312.
Meniscotherium, 6111.
Meniscus, 432.
Menobranchus, 282,293,
307-'.
Meriopoma, 264, 305.
Menstruation, 517.
Menticirrus, 2352.
Menura, 4751 .
Mephitis, 6241.
Mergalus, 4681.
Merganser, redbreasted,
4631.
Mergus. 463 l.
Meriones, 6332.
Merlin, 464'.
Merluccius, 2331.
Meroblastic Amphibia,
302, 305.
Merops, 4712.
Merry sole, 2402.
Merychippus, 5962.
Merycoptamus, 5832.
Mesenchymatous, 15.
Mesentery, ventral, 39.
Mesiteia, 151 1.
Mesites, 4642.
Mesodon, 180, 181.
Mesogaster, 231 l.
Mesogonistius, 2341.
Mesohippus, 5972.
Mesomys, 635 l.
Mesonephros, 87 ; duct
of, 89.
Mesonephros, Amphibia,
292.
Mesonyx, 6121.
Mesopithecus, 6591.
Mesoplodon, 5622.
Mesopterygium, 56.
Mesorachic, 57.
Mesorchium, 141.
Mesosaurus, 334, 3981.
Mesosuchia, 375, 331.
Mesovarium, 141.
Mesturus, 180.
Metachirus, 539 l.
Metadiscoidal, 653.
Metamorphosis, Am-
phibia, 299 ; eels, 2241
Metanephros, 87, 90 ;
Amphibia, 292.
Metapleural folds, 12.
Metapodia, 5761.
Metapodium, 493.
Metapterygium, 56.
Metatarsus, birds, 434.
Metatheria, 529.
Metencephalon, 67.
Metopoceros, 3511.
Metriorhynchus, 3822.
Miacis, 61 22.
Microureus, 539 *.
Micrablepharus, 3522.
Micracanthus, 2371.
Micrelaps, 369 '.
Micrixalus, 313 l.
Microcebus, 6521.
Microchiroptera, 6462.
Microchoerus, 6531.
Microdipodops, 6342.
Microgale, 641 J.
Microhyla, 3121.
Microlestes, 541 2.
Micronodon, 539-.
Micropechis, 3702.
Micropisthodon, 3671.
Micropogon, 2352.
Micropterus, 2341.
Micropteryx, 239L>.
Micropus, 2421.
Microsauria, 3152.
Microscalabotes, 349 -.
Microstoma, 2162.
Microtus, 633-.
Midas, 6562.
Mid- brain, 67.
Midriff, 480.
Migration, birds, 417,
453; , eels, 2242 ;
fishes, 91 ; of fishes
over land, 2212 ;
Mammalia, 523 ;
Teleostei, 212.
Miistius, 238 '.
Miller's dog, 1512.
Miller's thumb, 242 1.
Milvus, 4632.
Mimon, 6482.
Mimophis, 369 *.
Miniopterus, 6471'.
Mink, 624-'.
Minnow, 2191, 2201.
Minous, 2421.
Minytrema, 2182.
Mioclaenus, 6111.
Miodon, 3691.
Miohippus, 5981.
Misgurnus, 2202.
Mistichthys, 2411.
Mitchillina, 2142.
Mitsukurina, 150, 1521.
Mixa, 438.
Mixipterygium, 119.
Mixocebus, 6521.
Mixodectes, 6531, 6532.
Mixophyes, 31 12.
Mixosaurus, 3951.
Mniotiltidae, 4772.
Moa, 433, 4582.
Mochocus, 222 l.
Moeritherium, 5731.
Mola, 2472.
Molacanthus, 2472.
Molar, 501.
Mole, 6402 ; Cape gold-
en, 6411.
INDEX.
689
Mole-marsupial, 5391.
Molge.3071.
Mollienesia, 227 1.
Moloch, 3502.
Molossus, 6481 .
Molva, 233 !.
Momotus, 471 !.
Monacanthus, 2471.
Monachus, 6272.
Mongoose, 6201.
Monimostylica, 319.
Monitor, 3521.
Monkey, Bengal, 6582 ;
Diana, green, probos-
cis, 659 ; howling,
657 l ; squirrel, spider,
6572-
Monk-fish, 153, 2461.
Monocentris, 2341.
Monocondylea, 318.
Monodelphia, 542.
Monodon, 5632.
Monopeltis, 3531.
Monophyllus, 6482.
Monophyodont, 501.
Monoploctis, 3522.
Monopterus, 2222.
Monotremata, 525.
Moon-eyes, 2142.
Moorhen, 4661.
Moose, 5892.
Mora, 2322.
Mordacia, 116.
Moreau on air-bladder,
204.
Morenia, 4131.
Moreno on Glossothe-
rium, 545 2.
Moringua, 2251.
Mormon, 4681.
Mormops, 6482.
Mormyrops, 2141.
Mormyrus, 2411 ; elec-
tric organ, 84.
Morone, 2351.
Morosaurus 3852.
Morse, 6261.
Mosasauria, 334.
Mosasaurus, 335.
Moschus, 5891.
Moseleya, 23 22.
Motacilla, 4752.
Motella, 2331.
Mother Carey's chicken,
46U.
Motmot, 47 11.
Moult, birds, 422.
Mouse, harvest, house,
wood, 6332.
Mouse- bird, 4731.
Mouth, derivation of, 3,
5 ; of Vertebrata, 71,
72.
Moxostoma, 2182.
Mucous canals, 79.
Mud-fish, 257.
Mud-fish (Teleostean),
232^.
Mud- minnow, 2261.
Mud-tortoises, 415.
Mugil, 2312.
Mugiliformes, 230.
Miiller, J., on Ganoids,
160.
Miillerian duct of fishes,
87 ; development of
in Elasmobranchs, 88
Mullet, grey, 23 12 ; red,
2362.
Mulloides, 2362.
Mullus, 2362.
Multituberculata, 541.
Munro foramen of, 67.
Muntjac, 5891.
Muraena, 225 ^
Muraenesox, 2242.
Muraenichthys, 2251.
Muraenidae, 2232.
Muraenolepis, 233 l.
Muraeno saurus, 3981.
Murray-cod, 2351.
Mus, 483, 6331.
Muscardinus, 6331.
Muscicapa, 4752.
Muscles, Amphibia, 273 ;
Amphioxus, 16 ; eye,
73 ; Marsipobranchii,
97 ; mesenchymatous
(visceral), 46 ; som-
atic, 46.
Musk-ox, 59 12.
Musk-rat, 6332.
Musophaga, 4701.
Musquash, 6332.
Mustela, 6241.
Mustelus, 127, 144,
1512 ; spiracle, 120.
Mycetes, 513, 6562,
657'.
Mycteria, 4612.
Myctophum, 2262.
Mydaus, 6241.
Myelencephalon, 67.
Mylesinus, 2181.
Myletes, 2181.
Myliobatidae, 92.
Myliobatis, 125, 144,
148, 1542.
Mylodon, 5452.
Myoleucus, 2201.
Mylopharodon, 220 ^
Myobatrachus, 3102.
Myocastor. 6351.
Myocoele, 8.
Myodes, 6332.
Myogale, 502, 6402.
Myomere, 16.
Myomorpha, 6331.
Myopotamus, 6351.
Myoscalops, 6342.
Myosepta, 40.
Myosorex, 640 '.
Myotome. 8 : of Am-
phioxus, 12.
Myoxocephalus, 2422.
Myoxus, 6331.
Myriacanthidae, 158.
Myrichthys, 2251.
Myripristis, 202, 2341.
Myrmecobius, 530,
5391.
Myrmecophaga, 511,
5441.
Myroconger, 2251.
Myron, 3682.
Myrophis, 2251.
Myrus, 2251.
Mystacina, 6481.
Mystacoceti, 560.
Mystacoleucus, 2192.
Mystriophis, 2251.
Mystriosaurus, 3821.
Mystromys, 6341.
Myxine, 117 : thread
cells, 97.
Myxodagnus, 2432.
Myxodes, 2441.
Myxopoda, 6472.
Naia, 3702.
Nails, 483.
Nakong, 5911.
Nandinia, 6201.
Nandus, 2341.
Nannaethiops, 2172.
Nannobatrachus, 3131.
Nannobrachium, 226-.
Nannocampus, 2301.
Nannocharax, 2172.
Nannophrys, 3131.
Nannosciurus, 6322.
Nannostomus, 2171.
Nannosuchus, 3822.
Naosaurus, 333.
Narcine, 1541.
Narcobatis, 1541.
Nardoa, 3652.
Z — II
Y Y
690
INDEX
Nares, perviae, and im-
perviae, 428.
Narwhal, 5633.
Nasal sacs, Dipnoi, 249.
Naealis, 6591.
Naseus, 2371.
Nasiterna, 4702.
Naso-palatine canal or
pouch of Marsipo-
branchii, 99, 104,
109.
Nasua, 6232.
Natalus, 6482.
Natterjack, 3102.
Naucrates, 2392.
Naultinus, 3491, 3492.
Nautichfhys, 2421.
Nautiscus, 2422.
Nealotus, 2382.
Nearct.=Nearctic.
Nebris, 2352.
Necrodasypus, 5432.
Necrolemur, 6531.
Necromanis, 5491.
Necrornis, 4701.
Nectarina, 4772.
Nectes, 3102.
Nectogale, 640*.
Nectomys, 6341.
Nectophryne, 31 02.
Necturus, 268, 269,
3071, 307.
Nelsonia, 6341.
Nemacheilus, 2202.
Nemadactylus, 2352.
Nematogenys, 2221.
Nemichthys, 2242.
Nemipterus, 2352.
Nemophis, 2441.
Nemorrhaedus, 591 2.
Neobalaena, 561.
Neoclinus, 2441.
Neoconger, 2251.
Neoliparis, 2422.
Neomaenis, 2352.
Neomeris, 5632.
Neomylodon, 5452.
Neophron, 431, 4632.
Neoplagiaulax, 5412.
Neornithes, 456.
Neossoptiles, 422.
Neoteny, 280, 305.
Neotoma, 6341.
Neotomys, 6341.
Neotragus, 591 *.
Nephridia, 49.
Nephridium, Amphibia,
292, 293.
Nephrotome, 87, 142 ;
Amphibia, 278, 292,
•295 ; of fishes, 87.
Nephrurus, 3492.
Nerfling, 2201.
Nerophis, 230 l.
Nervous system of Am-
phioxus, 17, 19 ; Mar-
sipobranchii, 106.
Nesodon, 6061 ; denti-
tion of, 507.
; Nesokia, 6341.
Nesomys, 6331, 634*.
Nesonetta, 4622.
Nesonycteris, 6462.
Nesopithecidae, 6572.
; Nesotragus, 5.
! Nestor, 4702.
Nests, birds, 452;
stickleback, 2291.
Nettastoma, 2242.
i Neurenteric canal, 2 ; of
Amphioxus, 33.
Neuropore, 33.
Neusticosaurus, 3972.
Neusticurus, 3522.
Newt, 3071.
Nicoria, 4132.
Nictitating membrane,
Reptilia, 317.
Nightingale, large,
thrush, 4752.
Night- jar, 4722.
Nilghai, 591 1.
Nine-eyes, 116.
Niphon, 2342.
Noctilip, 6481.
Noddy, 4681.
Nomarthra, 548.
Nomeus, 2312.
Nonnat, 2312.
Norops, 351 *.
Notacanthus, 2272.
Notaden, 3102.
Notagogus, 180.
Notechis, 3702.
Nothopsis, 3662.
Nothosaurus, 3972.
Nothropus, 5461.
Nothrotherium, 5461.
Nothura, 4641.
Notidani, 149.
Notiomys, 6341.
Notiosorex, 6401.
Notochord, 2; of Am-
phioxus, 12 ; Dipnoi,
249; Pisces, 58; in
skull, 126, 127.
I Notodelphys, 31 11.
Notoglanis, 2212.
Notograptus, 2441.
Notopteris, 6462.
Notopterus, 2151.
Notornis, 4661.
Notoryctes, 497, 5391.
Notothenia, 2432.
Nototherium, 5381.
Nototrema, 296, 311 l.
Noturus, 221 2.
Novacula, 238 '.
Nucifraga, 4772.
Nucras, 3532.
Numenius, 467 l.
Numida, 4651.
Nuria, 2192.
Nurse-hound, 151 *.
Nutcracker, 4772.
Nuthatch, 4771.
Nyctea, 4721.
Nycteris, 6471.
Nyctibatrachus, 3131.
Nyctibius, 472 1.
Nycticebus, 652 l.
Nycticejus, 6472.
Nycticorax, 461 2.
Nyctimantis, 311 1.
Nyctinomus, 6481.
Nyctiornis, 471 2.
Nyctipithecus, 6572.
Nyctophilus, 6472.
Oblata, 236i.
Ocadia, 4131.
Occa, 2422.
Occipital, 60.
Occipito- spinal nerves,
73.
Oceanites, 461 *.
Ocelot, 6191.
Ochetobius, 2201.
Ochotona, 6361.
Octodon, 6351.
Oculo-motor ganglion,
135.
Ocydromus, 466 l.
Odax, 2381.
Odontanthias, 2351.
Odontaspis, 1521.
Odontoceti, 561. .
Odontognathus, 2142.
Odontolcae, 4582.
Odontophorus, 4652.
Odontopyxis, 2422.
Odontostomus, 2262.
Oedicnemus, 4672.
Oedura, 3492.
Oenoscopus, 182.
Oestrus, 517.
Ogcocephalus, 2461.
INDEX.
691
Ogmius, 369 l.
Ogmodon, 3702.
Ogmgrhinus, 6272.
Oil- bird, 47-2-\
Oil gland, birds, 419.
Okapia, 5901.
Old-wife, 2361.
Olecranon, 49-J.
Olfactory lobes, 68.
Olfactory organ of Am-
phioxus, 18 ; of fishes,
' 78.
Oligodon, 368 l.
Oligopleuridae, 213.
Oligorus, 235'.
Oligosarcus, 2172.
Olistherops, 2381.
Olm, 3072.
Oinmatophoca, 6272.
Omomys, 653 1.
Omosternum, 270.
Onchorhynchus, 2161.
Oneirodes, 2461.
Onychodactylus, 273,
306 i.
Onychodectes, 6091.
Onychodontidae, 175.
Onychogale, 5352.
Onychomys, 634].
Onchus, 147, 262.
Opah, 228',
Operculum, Amphibia,
279, 280 ; Dipnoi,
249.
Ophichthus, 2251.
Ophichthys, 2231, 2251.
Ophiderpeton, 3151.
Ophidia, 355.
Ophidium, 2442.
Ophiocephalus, 201, 210,
232i.
Ophiodes, 3512.
Ophiodon, 2421.
Ophiognomon, 3522.
Ophiomorus, 3541.
Ophiops, 3532.
Ophiopsis, 180.
Ophiopsiseps, 3542.
Ophioscion, 2352.
Ophisaurus, 351 2.
Ophryoessa, 351 1.
Ophrysia, 4652.
Ophthalmic ganglion,
135.
Ophthalmicus profun-
dus, 73, 135.
Ophthalmo sanrus, 3951.
Opisthocoolous, 161,
317.
Opisthocomus, 466 l.
Opisthoglypha, 3682.
Opisthognathus, 235-'.
Opisthomi, 245J.
Opisthoneina, 2142.
Opisthopterus, 2142.
Opisthotropis, 367'.
Opossum, 5391.
Opsanus, 244 ' .
Opsariichthys, 2201.
Optic chiasma, 69.
Optic lobes, 67.
Optic thalami, 69.
Optic vesicles, 68.
Or. = Oriental.
Oral cirri, 11, 19.
Oral hood, 19.
Orang-utan, 6611.
Orcella, 5632.
Orcynus, 2382.
Oreas, 591 1.
Oreinomys, 6332.
Oreinus, 2191.
Oreobatrachus, 3131.
Oreodon, 579, 5851.
Oreonectes, 221 '.
Oreophasis, 465 1.
Oreophrynella, 3121.
Oreopithecus, 6591.
Oreopsittacus, 4702.
Oreosaurus, 3522.
Oreosoma, 2401.
Oreotragus, 5902.
Orestias, 2271.
Oriole, American, 4781,
golden, 4771.
Oriolus, 477i.
Ornithochirus, 3902.
Ornithodelphia, 525.
Ornithopoda, 386.
Ornithorhynchus, 490,
494, 529, 526.
Ornithoscelida, 383.
Ornithosuchus, 3821.
Orodus, 151i.
Orohippus, 5991.
Oronasal groove, 120.
Ortalis, 4651.
Orthacodus, 1521.
Orthagoriscus, 92, 183,
198, 195, 223, 2472.
Orthodon, 2201.
Orthognathism, 489.
Orthopoda, 386.
Orthopristis, 2361.
Orthostichous, 56.
Orthostomus, 241 1.
Orycteropus, 542, 5491.
Oryx, 591 1.
Oryzomys, 634'.
Oryzoryctes, 641].
Os" cloacae, 342.
Os coccygis, 265.
Os cines, 475.
Os innominatum, 491.
Osmerus, 208, 2161.
Os penis, 515.
Osphromenus, 237 l.
Os planum, 486.
Osprey, 4641.
Osseous tissue of Elas-
mobranchii, 122.
Ostariophysi, 2162.
Osteobrama, 2202.
Osteochilus, 2192.
Osteoderms, 317, liz-
ards, 337.
Osteogeniosus, 221 2.
Osteoslossum, 2151.
OsteoTaemus, 3832.
Osteolepis, 175.
Osteostraci, 261.
Ostracion, 246, 2471.
Ostracodermi, 260.
Ostrich, 4572.
Otaria, 6261.
Otidiphaps, 4691.
Otis, 4662.
Otocoelus, 4001.
Otocryptis, 3502.
Otocyon, 6221.
Otogyps, 4632.
Otolemur, 6521.
Otolithus, 2352.
Otomys, 6332.
Otonycteris, 6472.
Otophidium, 2442.
Otrynter, 2361.
Otter, 6241.
Ouacaria, 657 1.
Oudenodon., 4012.
Oulachan, 2162.
Ounce, 619i.
Ourebia, 5902.
Ova, Mammalia, 518.
Ovary, Mammalia, 515.
Ovibos, 5912.
Oviduct, 87 ; Dipnoi,
256.
Oviposition, Amphibia,
296 ; Amphioxus, 30.
Ovis, 5912.
Ovulation, Mammalia,
517.
Ovum, Mammalia, 480 ;
Vertcbrata, 50.
Owl, barn, 47 12 ; fern,
692
INDEX.
4721 ; eagle, 4721 ;
long - eared, 4721 ;
screech, 47 12 ; short-
eared, tawny, wood,
4721.
Oxen, 59R
Oxpecker, 47 7 2.
Oxybelis, 369 L.
Oxyconger, 225 l.
Oxydoras, 2212.
Oxyglossus, 3122.
Oxylebius, 2421.
Oxymetopon, 241 l.
Oxymycterus, 6341.
Oxyiiotus, 152i, 4751.
Oxyrhabdium, 36?i.
Oxyrhamphus, 4751.
Oxyrhopus,369!.
Oxyrrhina, 134.
Oxyurus, 2242.
Oyster-catcher, 467 x.
Pac.— Pacific.
Paca, 6352.
Pachy calamus, 3531.
Pachycorrnus, 181.
Pachydactylus, 3492.
Pachymetopon, 2361.
Pachymilus, 158.
Pachyiiolophus, 5991.
Pachypleura, 3972.
Pachytriton, 3071.
Pachyuromys, 6332.
Pachyurus, 2352.
Paedogenesis, 280.
Pagellus, 2361-
Pagrus, 2361.
Palaeaspis, 261.
Palaeeudyptes, 4602.
Palaehoplophorus, 5481.
Palaelodus, 462 l.
Palaeochoerus, 582 1.
Palaeohatteria, 333.
Palaeomastodon, 5722.
Palaeomeryx, 5892.
Palaeoniscus, 170.
Palaeopeltis, 5481.
Palaeopetaurus, 5371.
Palaeophis, 365.
Palaeoprionodon, 6232.
Palaeornis, 4702.
Palaeorycteropus, 5491
Palaeoscylliuni, 1511.
Palaeospinax, 151 l.
Palaeospondylus, 117.
Palaeosyops, 6021.
Palaeotapirus, 5941.
Palaeotherium, 597^
597, 598.
Palaeotragus, 5901.
Palamedea, 4622.
Palapteryx, 458-'.
Palate, birds, 429 ; Rep-
tilia, 320.
Palatine nerve, 137.
Palatoquadrate, 62, 128.
Palinurichthys, 2392.
Palla, 59li.
Pallasina, 2422.
Pallium, 69.
Paloplotherium, 5972,
598.
Palorchestes, 5352. •
Paludicola, 31 12.
Pammelas, 2392.
Pancreas, Dipnoi, 252 ;
of fishes, 64 ; Teleos-
tei, 197, 199.
Panda, 6231.
Pandion, 4641.
Pangasius, 221 2.
Pangolin, 5482.
Panochtus, 5482.
Panolopus, 3512.
Pantholops, 591 *.
Pantodactylus, 3522.
Pantodontidae, 2151.
Pantolambda, 6032.
Pantolestes, 582 l.
Pantosteus, 2182.
Panyptila, 4722, 4731.
Papilla acustica basi-
laris, 323 ; lagenae,
323.
Papillae circumvallatae,
495.
Papio, 6582.
Paracanthobrama, 2192.
Parachordal cartilages,
58, 60.
Paradiplomystax, 221 2.
Paradise, bird of, 4771.
Paradise- fish, 2371.
Paradisea, 477'.
Paradoxurus, 6201.
Paragoiiiates, 2172.
Parakeet, grass, 4702.
Paralepis, 2261.
Paralichthys, 2402.
Paraliparis, 2422.
Paraluteres, 2471.
Parameryx, 5872.
Paramisgurnus, 221 *.
Paramyrus, 2251.
Paranthias, 235 1.
Paraphoxinus, 2201.
Paraphysis, 72.
Paraptenodytes, 4602.
Parapterum, 224.
Parascopelus, 2261
Parascorpis, 235 !.
Parascyllium, 151 1.
Parasuchia, 381.
• Parasuchus, 381.
Pard, 6191.
Pardachirus, 2402.
Pareiasauria, 399.
Pareiasaurus, 4001, 400.
Parexocoetus, 2311.
Pariasaurus, 400.
Paricelinus, 242 1.
Parietal foramen, 330.
Parietal organ, 70 ; liz-
ards, 344 ; Marsipo-
branchii, 106.
Pariodon, 222 l.
Parma, 2372.
Parodon, 2171.
Paropsis, 2392.
Parotic process, 319.
Parotoids, 273, 308.
Parr. 2152.
Parra, 4672.
Parrot, grey, kaka, 4702.
Pars basilaris of cochlea,
323.
Partridge, red-legged,
American, 4652.
Parus, 477 !.
Passer, 478'.
Passeres, 4742, 4751.
Passeriformes, 4742.
Pastern, 5961.
Pastor, 4772.
Pataecus, 2441.
Patagium, 642, 645, 491.
Patagona, 4731.
Patagornis, 460 l.
Patella, 492.
Patriofelis, 6122.
Pavo, 4652.
Peacock, 4652.
Peba, 547 2.
Peccary, 5821.
Pecora, 5862, 588.
Pecten, 436 ; Croco-
dilia, 378.
Pectinate, 66.
Pectinator, 6351.
Pectineal process, 434.
Pectoral fin and girdle,
Teleostei, 192.
Pectoral girdle, Am-
phibia, 271 ; birds,
432; Chelonia, 409;
Crocodilia, 377 ; Dip-
noi, 251 ; Elasmo-
INDEX.
693
branchii, 130 ; Mam-
malia, 491 ; Reptilia,
320.
Pedetes, 493, 635'.
Pediculati, 2452.
Pedionomus, 4642.
Peewit, 4(57 1.
Pegasus, 230-.
Pelagorliynchus, 227-.
Pelagosaurus, 3821.
Pelamys, 2382.
Pelea, 5911.
Pelecanus, 461-'.
Pelecus, 2202.
Pelican, 4612.
Pelion, 3151.
Pellona, 21 42.
Pellonula, 2142.
Pelobates, 265, 299,
3102.
Pelochelys, 415.
Pelodytes, 31 02.
Pelomedusa, 4142.
Pelor, 2421.
Pelosaurus, 3151.
Pelotrophus, 2202.
Peltephilus, 5481.
Pelvic fin,Teleostei, 192 ;
Teleostei,' thoracic,
jugular, abdominal,
185.
Pelvic girdle, Amphibia,
:><:> ; birds, 433 ;
Chelonia, 409 ; Croco-
dilia, 377 ; Dipnoi,
251 ; Elasmobranehii
131 ; Mammalia, 491 ;
Reptilia, 320.
Pelycodus, 653 '.
Pelycosauria, 333.
Pempheris, 2341.
Penelope, 449, 465 l.
Penguin, king, Cape,
4602.
Penis, birds, 441, 449 ;
Chelonia, 410 ; Croco-
dilia, 379 ; lizards,
347 ; snakes, 363 ;
Mammalia, 514 ; Rep-
tilia, 328.
Pennae, 421.
Pennula, 466'.
Penny-dog, 1512.
Pentanemus, 2312.
Pentaroge, 2421.
Peprillus, 231 2.
Peragale, 5382.
Peramples, 530, 533,
498, 5382.
i Peramus, 5402.
i Peramys, 539 l.
Peratherium, 5391.
Perca, 199, 208, 2342 ;
skull, 189.
Percalates, 235 l.
Percarina, 2342.
Percesoces, 230.
Perch, 2342; of the
Ganges, 2351 ; sea,
2351 ; marine, 2352 ;
climbing, 2321 ; of the
Nile 2351.
Percichthys, 2342.
Perciformes, 233.
Percilia, 2342.
Percina 2342.
Percis, 2422.
Percophis, 2432.
Percopsis, 2271.
Perdix, 4652.
Perennibranchiate Am-
phibia, 280.
Pericardium, 49 ; of
fishes, 85.
Perichondrial ossifica-
tion, 122, 124.
Periophthalmus, 183,
185, 241.
Periptychus, 611 1.
Perissodactyla, 592.
Peristedion, 206, 243 l.
Peristethus, 243 '.
Peritoneal, 49.
Peritoneal canals, Croco-
dilia, 379 ; Chelonia,
410.
Pernis, 4632.
Perochirus, 3492.
Perodactylus, 3522.
Perodicticus, 6522.
Perogiiathus, 6342.
Peromyscus, 6341.
Pes, lizards, 342 ; birds,
424, 434 ; Crocodilia,
377 ; Chelonia, 409.
Pesce Ray, 23 12.
Pessulus, 443.
Petalodontidae, 155.
Petalognathus, 368 l.
Petaurista, 6322.
Petauroides 537 l.
Petaurus, 533, 5362, 536.
Petrel, storm, fulmar,
46R
Petrobates, 3152.
Petrodromus, 639 l.
Petrogale, 5351.
Petromys, 635 '.
Petromvzon, 95, 96,
116. "
Petrosaurus, 351 *.
Petroscirtes, 2441.
Petrosuchus, 3822.
Pej'er's patches, 510.
Pezophaps, 469 l.
Phacochoerus, 581 2.
Phaethon, 435, 461 2.
Phaethornis, 4731.
Phago, 2172.
Phalacrocorax 437,
4612.
Phalangeal formula,
lizards, 343.
Phalanger, 534, 535,
5371.
Phalangista, 532, 533.
Phalarope, grey, 4671.
Phalaropus, 4671.
Phalcobaenus, 4632.
Phaneroglossa, 3101.
Phaneropleuron, 259.
Pharomacrus, 4732.
Pharyngeal apertures,
6,48.
Pharyngobranchial, 130.
Pharyngobranchii, 11.
Phascolarctus, 531, 533,
537 1.
Phascologale, 533, 5382.
Phascolomys, 531, 5372.
Phascolonus, 5372.
Phascolotherium, 5401.
Phasianus, 4652.
Phasidus, 465 l.
Pheasant, argus, golden,
peacock, silver, 4652.
Phelsuma, 3492.
Phenacodus, 611 l.
Phenacomys, 6341.
Philander, 539 ^
Philepitta, 4742.
Philodryas, 369 '.
Philothamnus, 3681.
Phinok, 2161.
Phlaeomys, 633 l.
Phoca, 627 !.
Phocaena, 5632.
Phococetus, 5622.
Phoenicophaes, 4701.
Phoenicopterus, 4621.
Pholidichthys, 2441.
Pholidobolus, 3522.
Pholidophoridae, 213.
Pholidopleurus, 180.
Pholidurus, 170.
Pholis, 2441.
Phororhacos, 460 1.
694
INDEX.
Phosphorescent organs,
Teleostei, 187.
Photonectes, 2162.
Phoxophrys, 3502.
Phractamphibia, 3132.
Phractocephalus, 2212.
Phractolaemidae, 2151.
Phrynella, 3122.
Phryniscus, 276, 3121.
Phrynobatrachus, 3131.
Phrynocara, 3122.
Phrynocephalus, 3502.
Phrynoderma, 3131.
Phrynomatitis, 3121.
Phrynonax, 3681.
Phrynopsis, 3131.
Phrynorhombus, 2402.
Phrynosoma, 3502,351!.
Phtheirichthys, 241 2.
Phycis, 2331.'
Phyllobates, 3122.
Phyllodactylus, 3492.
Phylloderma, 6482.
Phyllodromus, 3131.
Phylloraedusa, 311 *.
Phyllonycteris, 6482.
Phyllopezus, 3492.
Phyllopteryx, 2301.
Phyllorhina, 6471.
Phyllostoma, 6482.
Phyllotis, 6341.
Phymaturus, 3511.
Physeter, 562 l.
Physiculus, 2331.
Physignathus, 3502.
Physodon, 151 1, 5622.
Physostomi, 65, 213.
Pia mater, 67.
Piabuca, 2172.
Piabucina, 2172.
Piaya, 4701.
Pica, 6361, 4772.
Pichyciego, 54G2.
Pici, 4732.
Picked dog-fish, 1522.
Pickerel, 2261.
Picoides, 4741.
Picumnus, 4741
Picus, 4741.
Pig, 5811.
Pigeon, fruit, passenger,
4691 . roct}
wood, 4691.
Pike, 2252, 2261.
Pike-perch, 2342.
Pilchard, 2142.
Pileoma, 2342.
Pilot-fish, 2392.
Pimelepterus, 2341.
Pimelodus, 221 2.
Pimephales, 2191.
Pineal body, 70, 274.
Pineal eye, 71 ; lizards,
345 ; Marsipobranchii,
106.
Pineal foramen, 330 ;
lizards, 340.
Pink, 2152.
Pinna, 479.
Pinnipedia, 624.
Pipa, 265, 276, 296,
3101.
Pipe-fish, 2291, 2301.
Piper, the, 2431.
Pipers, 4682.
Pipistrelle, 6472.
Pipit, meadow, 4752.
Pipra, 475*.
Piramutana, 221 2.
Piratinga, 22 12.
Pirinampus, 2212.
Pisces, 51.
Pisiform, 492.
Pisoodonophis, 2251.
Pistosaurus, 3972.
Pit organs, 79, 81.
Pit- viper, 37 12.
Pithecanthropus, 6602.
Pithecia, 656', 6571.
Pithecocheirus, 634'.
Pitheculus, 6572.
Pitta, 4742.
Pituitary body. 72 ;
Elasmobranchii, 73 ;
Marsipobranchii, 107.
Placenta, 481 ; Elas-
mobranchii, 144 :
Marsupialia, 533 ;
zonary, discoidal,
cotyledonary,metadis-
coidal, diffuse, 520.
Placentalia, 520.
Placodontia, 402 l.
Placodus, 402 1.
Placoid scales, 53, 121.
Placopharyiix, 2182.
Placosoma, 3522.
Plagiarthrus, 567'.
Plagiaulax, 541 2.
Plagiodontia, 6351.
Plagiopholis, 3671.
Plagiostoini, 148.
Plagiotremus, 2441.
Plagusia, 2402.
Plagyodus, 226 l.
Plaice, 2402.
Pla-kat, 2371.
Planirostra, 163.
Plantain-eater, 4701.
Plantigrade, 493.
Plastron, 402.
Platacanthomys, 6331.
Platalea, 449, 4612.
Platanista, 497, 5631.
Platax, 2392.
Platecarpus, 335.
Platemys, 414-.
Platessa, 199.
Plathander, 309.
Platiirus, 3692, 37Qi.
Platycephalus, 2421.
Platycercomys, 6342.
Platycercus, 4702.
Platychaerops, 6072.
Platychelis, 4131.
Platydactylus, 3492.
Platyglossus, 238 l.
Platygnathus, 175.
Platyhyla, 3122.
Platynematichthys,
221 2.
Platypelis, 3122.
Platyplectrurus, 366 '.
Platypoecilus, 227J.
Platyptera, 241 l.
Platypus, 529.
Platyrhina, 1542.
Platyrhinoiclis, 1541.
Platyrrhina, 6552.
Platysaurus, 351 2.
Platysomus, 170.
Platysternuin, 4131.
Platystethus, 2392.
Platystoma, 205, 221 2.
Platystomatichthys,
2212.
Platytroctes, 21 42.
Plecoglossus, 2161.
Plecostomus, 2221.
Plecotus, 6472.
Plectognathi, 2461.
Plectranthias, 2351.
Plectromantis, 31 12.
Plectromus, 234 l.
Plectropoma, 235 l.
Plectropterus, 4631.
Plectrurus, 366 l.
Plesiadapis, 6531, 6532.
Plesictis, 6232.
Plesiocetus, 561.
Plesiomeryx, 585 1.
Plesiops, 235 l.
Plesiosauria, 395.
Plesiosaurus, 3'M, 3981.
Plesiosorex, 639 l.
Plethodon, 306'.
Plethodontohyla, 3122.
IXDEX.
695
Pletholax, 3501.
Pleuracanthidae, 57.
Pleuracanthus, 147, 148;
pectoral fin, 132.
Pleuras pidotheriu in ,
6111.
Pleurocentrum, 161.
Pleurodira, 414.
Pleurodont, 343.
Pleurogrammus, 242 1.
Pleuronectes, 195, 212,
240^.
Pleuronura, 3151.
Pleuropterygii, 145.
Pleurorachic, 57.
Pleurosaurus, 334.
Plica semihunaris, 497.
Pliohippus, 5962.
Pliohyrax, 567 ',
Plionemus, 2391.
Pliopithecus, 6602.
Pliosaurns, 3981.
Ploceidae, 4772.
Plohophorus, 5481.
Plotosus, 221 *.
Plotus, 4612.
Plover, golden, green, j
ringed, 467 l.
Plumulae, 421.
Pluvianus, 4672.
Pneumatic duct, 65.
Pneumaticity of birds, !
419.
Pneustes, 351 ].
Pocket-gopher, 6342.
Podabrus, 242 ^
Podargus, 4722.
Podica^ 4662.
Podicipes, 4602.
Podocnemis, 4142.
Podothecus, 2422.
Poebothrium, 5871.
Poecilia, 2271.
Poeciloconger, 2242.
Poecilogale, 6242.
Poephagus, 591 2.
Pogonias, 203, 2352.
Pogonodon, 6191.
Pogonomys, 6331, 6341,
Pogonoporca, 2351.
Pogonorhynchus, 4732.
Poiana, 620 l.
Poison, snakes, 364.
Poison- fangs, snakes,
359.
Poison- sflands, snakes,
360.
Poisonous lizard, 3521.
Poisonous Teleostei,2 1 1 .
Polecat, 6242.
Polemon, 3691.
Pollack, 2322.
Pollan, 21 62.
Polyacauthus, 2371.
Polyborus, 4632.
Polycaulus, 2421.
Polychrus, 351 l.
Polydactylus, 231 2.
Poly mastodon, 541 2.
Polar bodies of Amphi-
oxus, 32.
Polymixia, 2341.
Polynemus, 2312.
Polyodon, 160,163,164,
168, 169, 170.
Polyodontophis, 3671 .
Polyplectron, 4652.
Polyprion, 235 '.
Polyprotodontia, 538.
Polypterus, 72, 160, 161,
162, 163, 166, 176;
male genital duct, 89 ;
skull, 1 72 ; heart, 174.
Polyptychodon, 398 l.
Pomacanthus, 2371.
Pomacentrus, 2372.
Pomadasis, 2361.
Pomatomus, 2342, 2392.
Pomodon, 2351.
Pomolobus, 2142.
Pomoxis, 2341.
Pond-tortoise, 41 32.
Pons varolii, 495.
Pontinus, 2421.
Pontistes, 5631.
Pontivaga, 563 l.
Pontoporia, 5631.
Pope, 2342.
Porbeagle, 151 2.
Porcupine, 635 1.
Porcupine-fish, 2472.
Porgy, 236 l.
Porichthys, 2441.
Poromera, 353-.
Porpoise, 5632.
Portal circulation, 86.
Portheus, 2151.
Port- Jackson shark, 150
Posterior commissure,
71.
Posterior temporal ar-
cade, 320.
Potamochaerus, 581 *.
Potamogale, 6402.
Potorous, 530, 5352.
Powder-downs, 421.
Power, 2322.
Praecoces, 451.
Prairie-hen, 4652.
Praopus, 5472.
Pratincola, 4752.
Pratincole, 467.
Predentata, 386.
Premandibular somite,
73.
Premolar, 501.
Preoral cavity, 8.
Preoral pit, XO, 21.
Preoral somite, 73.
Prepuce, 515.
Prespiracular cartilage,
129.
Priacanthus, 201, 2351.
Priacodon, 5401.
Price on excretory or-
gans of Bdellostoma,
87.
Primaries, 423.
Primary gill-slit, 22.
Primary tubules, 292.
Primates, 653.
Priodon, 5471.
Priodontes, 5471, 547.
Prion, 461 1.
Prionistius, 2422.
Prionodactylus, 3522.
Prionodon, 126, 151 1,
6201.
Prionodura, 4771.
Prionotus, 2431.
Prionurus, 237 l.
Pristidactylus, 351 *-.
Pristigaster, 2142.
Pristiophorus, 153 ;
snout, 119.
Pristipoma, 236 l.
Pristis, 153; snout, 119.
Pristiurus, 118, 150;
spiracle, 120.
Pristurus, 3492.
Proaelurus, 6191.
Proatlas, 373.
Proboscis cavity, 7.
Proboscidea,567 ; affini-
ties of, 571.
Procamelus, 5871.
Procavia, 566, 5662.
Procellaria, 4611.
Procellariiformes, 461 l.
Processus falciformis,
195.
Prochilodus, 2171.
Procoelous, 317.
Procolophon, 4001.
Proctodaeum, 48.
Proctoporus. 3522.
Procyon, 6232.
696
INDEX.
Prodelphinus, 5641.
Proechidna, 529.
Profundus ganglion,
135.
Proganochelys, 4141 .
Prognathisni, 489.
Promegatherium, 5452.
Promyliobatis, 155.
Promylodon, 5461.
Pronephros, 86 ; duct
of, 87 ;Ganoidei, 165;
Teleostei, 210 ; Dip-
noi, 256 ; Amphibia,
292 ; Marsipobran-
chii, 112.
Prooestrum, 517.
Prooticum ganglion,
274.
Propalaeoplophorus,
5481.
Propalaeotherium, 599 1,
Propithecus, 6512.
Propraopus, 5472.
Propterus, 180.
Propterygium, 56.
Prorastomus, 5522.
Prosencephalon, 67.
Prosimiae, 649.
Prosopodasys, 2421.
Prosqnalodon, 5622.
Prostate, 514.
Prostherapis, 3131.
Prosy mna, 3681.
Protapirus, 5941 .
Proteles, 6202.
Proteroglypha, 3692.
Proteus, 265, 268, 269,
276, 282, -290, 293,
3072.
Pr other otherium, 60S1.
Prothylacinus, 541 l.
Protoadapis, 653 l.
Protocampus, 230 *.
Protocercal, 55.
Protodiscus, 4741.
Protohippus, 5962.
Protolabis, 5871 .
Protopterus, 259, 259.
Protoreodon, 585 l.
Protorohippus, 5991.
Protorosaurus, 333.
Protoselene, 6111.
Protosphargis, 4122.
Protostega, 4122.
Protosyngnathidae,
Prototheria, 525.
Prototroctes, 2252.
Protriton, 315].
Protylopus, 5871.
Protypotherium, 6071.
Proviverra, 61 21.
Prymnomiodon, 367 1.
Psammobatis, 1542.
Psammochelys, 4141 .
Psammodontidae, 155.
Psammodromus, 3532.
Psammodynastes, 369 i.
Psammomys, 6332.
Psammoperca, 2351.
Psammophis, 3691.
Psaramosteus, 262.
Psarisomus, 4742.
Psenes, 231 2.
Psenopsis, 231 2.
Psephophorus, 41 22.
Psephurus, 56, 170.
Psettichthys, 2402.
Psettodes/2401-.
Psettus, 2392.
Pseudablabes, 369 x.
Pseudaelurus, 6201.
Pseudaluteres, 2471.
Pseudaspis, 3681.
Pseudecheneis, 2221.
Pseudechis, 3702.
Pseudelaps, 3702.
Pseudeutropius, 221 2.
Pseudis, 31 12.
Pseudobagrus, 221 2.
Pseudoblennius, 2441.
Pseudobranch, 66 ;
Lepidosteus, 178 ;
Teleostei, 200 ; Dip-
noi, 251 ; Elasmo-
branchii, 120.
Pseudobranchus, 3072.
Pseudocerastes, 371 2.
Pseudochalceus, 2172.
Pseudochilinus, 2381.
Pseudochirus, 5371.
Pseudochromis, 2352.
Pseudocordylus, 3512.
Pseudodax^SS1.
Pseudogobio, 2191.
Pseudogryphus, 4631 .
Psoudolabuca, 2202.
Pseudomonacanthus,
2471.
Pseudopareas, 371 1.
Pseudoperilampus,
2201/
Pseudophryne, 3102.
Pseudophycis, 2331.
Pseudoplectrurus, 3661.
Pseudopus, 335, 351 2.
Pseudorasbora, 2192.
Pseudorca, 5641.
Pseudorhabdium, 3681.
Pseudorhombus, 2402.
Pseudoscarus, 238 1.
Pseudoscopelus, 2312.
Pseudosuchia, 3821.
Pseudotriacis, 1521.
Pseudovomer, 2391 .
Pseudoxenodon, 367 l.
Pseudoxiphophorus,
2271.
Pseudoxyrhopus, 3671.
Psilocephalus, 2471.
Psilodactylus, 3492.
Psilorhynchus, 2202.
Psittaci, 4701.
Psittacotheriurn, 6082.
Psittacula, 4702.
Psittacus, 4702.
Psophiidae, 4662.
Psychrolutes, 2422.
Ptenopus, 3492.
Pteraclis, 2392.
Pteragogus, 2381.
Pteralopex, 6461.
Pteranodon, 3902.
Pteraspis, 261, 261.
Pterichthys, 94, 262,
262.
Pteridium, 2442.
Pteridophora, 477 l.
Pternohyla, 311 J.
Pterocles, 4681.
Pteroclidae, 4682.
Pterodactyl, 3882.
Pterodactylus, 3902.
Pteroglossus, 4741.
Pterois, 2421.
Pteromys, 6322.
Pterophryne, 2461.
Pteroplataea, 144, 1542.
Pteropsarion, 2201.
Pteroptochus, 4751.
Pteropus, 6461.
Pterosauria, 3882.
Pterothrissus, 2142.
Pterygoplichthys, 222] .
Pterygopodium, 119.
Pterylae, 422.
Ptilocercus, 639 l.
Ptilodus, 541 2.
Ptilorhynchus, 4771.
Ptychobarbus, 2191.
Ptychodus, 155.
Ptychognathus, 401 2,
402.
Ptycholepis, 180.
Ptychozoon, 3491, 3492.
Ptyctodontidae, 158.
Ptyctolaemus, 3502.
INDEX.
G97
Ptyodactylus, 3492.
Ptyonotus, 242 *.
Pucrasia, 4652.
Pudua, 5892.
Puff-adder, 37 12.
Puff-bird, 4732.
Puffin, 4681.
Puffinus, 461 !.
Pulmonary artery, Rep-
tilia, 327.
Puma, 6191.
Puncta lacrymalia, 497.
Putorius, 6241.
Pycnodus, 180.
Pycnonotidae, 4752.
Pygoderma, 648-.
Pygomeles, 3541.
Pygopus, 335, 336, 3501.
Pygosteus, 229 l.
Pygostyle, birds, 432.
Pyloric caeca, 64, 197,
199.
Pyrotherium, 5732.
Pyrrhocentor, 470 1.
Pyrrhocorax, 4772.
Pyrrhula, 4781.
Pyrrhulina, 2171.
Python, 362, 3652.
Pythonadipsas, 691'
Pythonichthys, 2251.
Pyxis, 4132.
P. Z. 8. = Proceedings of
the Zoological Society .
Q.J. M.S. -Quarterly
Journal of Micro-
scopical Science.
Quadrate, 02.
Quagga, 5962.
Quail, 4652.
Quassiremus, 2251.
Querimana, 2312.
Quesal, 4732.
Quill, 420.
Quitquit, 4772.
Rabbit, 6361 ; rock,
5662.
Rabula, 2251.
Rachiostichous, 57.
Racoon, 6232.
Radialia, 54.
Radii, 420.
Radulinus, 2422.
Rail, 4661.
Raja, 1541 ; electric or-
gan, 84.
Rallus, 4661.
Rami, 420.
Rana, 269, 270, 272, \
283, 3122.
Ranaster, 3102.
Rangifer, 5892.
Raniceps, 233 l.
Ranidens, 266, 3061.
Ranzania, 2472.
Raphicerus, 5902.
Rappia, 3131.
Rasbora, 2192.
Rasborichthys, 2202.
Rastiinus, 2422.
Rat, black, brown,
Hanoverian, musk,
Norway, water, 6332 :
bamboo, kangaroo,
pouched, 6342 ; Cape
mole, 6342 ; ground,
porcupine, 6351.
Rat-snake, 3681.
Ratel, 6241.
Rathbunella, 2352.
Ratitae, 456.
Rattle-snakes, 37 12 ;
common, 3721.
Raven, 4772.
Razorbill, 4681.
Rectrices, 419, 421.
Recur virostra, 467 l.
Red-eye, 2201.
Red Mullet, 2362.
Redshank, 467 J.
Redstart, 4752.
Redwing, 4752.
Regalecus, 245 *.
Regeneration, Amphibia,
300 ; Reptilia, 329 ;
tail of lizards, 337.
Reindeer, 5892.
Reissner's fibre, 195.
Reithrodon, 6341.
Reithrodontomys, 6341.
Remiges, 421.
Remilega, 241 2.
Remora, 2412.
Renal-portal, 86.
Reptilia, 316.
Respiration, Amphibia,
280; birds, 448; !
fishes, 65 ; Marsipo-
branchii, 105.
Respiratory organs,
Amphibia, 278 ; birds,
442 ; Chelonia, 409 ;
Reptilia, 324 ; Tele-
ostei, 199.
Retia mirabilia, Ce-
tacea, 557 ; Mamma-
lia, 511.
Retina, 68.
Rhabdophidium, 3681.
Rhabdops, 367 ',
Rhachianectes, 561.
Rhachicentron, 2382.
Rhachis, 420.
Rhacodactylus, 3492.
Rhacophorus, 31 31.
Rhadinaea, 3681.
Rhamnophis, 3681.
Rhamphastus, 4741.
Rhamphichthys, 2181.
Rhaiiiphiophis, 3691.
Rhamphocottus, 2421.
Rhamphodon, 473 ^
Rhampholeon, 355 1.
Rhamphorhynchus, 390,
3902.
Rhamphosuchus, 3831.
Rhamphotheca, 419,
438.
Rhea, 434, 441, 4572.
Rheithrosciurus, 6321.
Rhina, 148, 153.
Rhinatrema, 304.
Rhinelepis, 222 l.
Rhinemys, 4142.
Rhinencephalon, 68.
Rhineura, 353 l.
Rhinhoplocephalus,
3702.
Rhinichthys, 2192.
Rhinobatus, 125, 143,
154i.
Rhinobothryum, 3691.
Rhinocalamus, 3691.
Rhinoceros,. 601 l.
Rhinochetus, 4662.
Rhinochilus, 3681.
Rhinoderma, 277, 296,
312i.
Rhinodon, 92, 148, 1521.
Rhinodoras, 221 2.
Rhinoglanis, 2221.
Rhinoliparis, 2422.
Rhinolophus, 6471.
Rhinonus, 2442.
Rhinonycteris, 647 l.
Rhinophis, 3661.
Rhinophrynus, 3111.
Rhinophylla, 6482.
Rhinopithecus, 6591.
Rhinoplax, 471 2.
Rhinopoma, 6481.
Rhinopomastus, 4712.
Rhinoptera, 1542.
Rhinostoma, 369 l.
Rhipidomys, 6341.
Rhipidostichous, 57.
698
INDEX.
Rhiptoglossa, 3542.
Rough dab, 2402.
Rhizodopsis, 175.
Rudd, 2192, 2201.
Rhizodus, 175.
Ruff, 4671.
Rhizomys, 6342.
Ruminantia, 585.
Rhodeus, 209, 220 1, 220^
Rumination, 586.
Rhomaleosaurus, 3981.
Rupicapra, 591 2.
Rhombochirus, 2412.
Rhomboidichthys, 2402.
Rhombomys, 6332.
Rupicola,4751.
Ruscarius,2422.
Rut, 517
Rhombophryne, 3121.
Ruticilla, 4752.
Rhombosolea, 2402.
Ruvettus, 2382.
Rhombus, 2402.
Rhopalodon, 401 *.
Sable, 6241.
Rhoptropus, 3492.
Saccobranchus, 200,
Rhychotus, 464 1.
221'.
Rhynchelaps, 3702.
Saccoderia, 351 J.
Rhynchobatus, 1541.
Saccodon, 2171.
Rhynchocephalia, 329.
Saccopharynx, 2251.
Rhynchocyon, 6391.
Saccopteryx, 848 l.
Rhynchoedura, 3492.
Saccostpmus, 6341.
Rhynchomys, 6331.
Saccule, 77.
Rhynchonycteris, 6481.
Rhynchops, 4681.
Saccus endolymphati-
cus, 202 ; Amphibia
Rhynchosaurus, 334.
Rhypticus, 2351.
(see Corrigenda) ;
Dipnoi, 255.
Rhytina, 5522.
Saccus vasculosus, 72.
Rhytiodus, 2171.
Sacrum, birds, 430 ;
Ribbon-fish, 2442.
Mammalia, 490 ;
Ribodon, 5521.
Reptilia, 318.
Ribs, abdominal, 318,
Sagenodus, 259.
374 ; Amphibia, 269 ;
Saghatherium, 567 l.
Crocodilia, 374 ;
Saiga, 591 1.
fishes, 60 ; lizards,
Saki, 657 !.
338 ; Mammalia, 489.
Salamandra, 272, 273,
Right- whale, 561.
278, 283, 296, 3062.
Rimioola, 2432.
Salamandrella, 3061.
Ringhals, the, 3702.
Salamandrina, 266, 307 *
Ring-ousel, 4752.
Salanx, 2162.
Ring- vertebra, 161.
Salarias, 2441.
Rissa, 467-\
Salea, 3502.
Rissola, 2442.
Salivary glands, birds,
Ristella, 3541.
438 ; Reptilia, 324.
Rita, 221 2.
Salminus, 2172.
River- hog, 58 11.
Salmo, 199, 208, 212,
Rivulus, 2271.
2152.
Roach, 2192, 2201.
Salmoni-clupeiformes,
Robin, American, 4752 ;
213.
redbreast, 4752.
Samaris, 2402.
Rock-cook, 2381.
Samotberium, 590 1.
Rock-ling, 233 '.
Sand-eel, 23U.
Rodentia, 6272.
Sand-grouse, 4681.
Rohteichthvs, 2192.
Sandpiper, 467 l.
Roller, 47 11.
Sapajou, 6572.
Romerolagus, 6361.
Sar, 2361.
Rondeletia, 2262.
Saragu, 2.W.
Rook, 4772.
Sarcodaces, 2172.
Rorqual, 561.
Sarcophilus, 5382.
Rosenmiiller's organ,
Sarcorhamphus, 4631.
328.
Sarda, 2382.
Sardine, 2142.
Sardinella, 2142.
Sargo, 2361.
Sargodon, 2361.
1 Sargus, 198, 202, 2361.
Sarritor, 2422.
Sasia,474i.
Sauranodontidae, 334.
Saurenchelys, 224-.
Sauresia, 351 2.
Saurodontidae, 21 51.
Sauromalus, 351 ' .
Sauropoda, 3851.
Sauropsida, 50.
Saurpthera, 4701.
Saururae, 454.
Saurus, 2261.
Saury, 23 11.
Savi's vesicles, 79, 81.
Saw-fish, 153.
Saxicola, 4752.
Scald-fish, 2402.
Scales, Amia, 182 ; Am-
phibia, 272 ; Chelonia,
402-404; Crocodilia,
378 ; Dipnoi, 249 ;
fishes, 53 ; Ganoidei,
160 ; Lepidosteus,
177; lizards, 336;
snakes, 356 ; Teleos-
tei, 186.
Scalops, 6402.
Scapanorhynchus, 150,
1521.
Scapanus, 6402.
Scaphiophis, 368 '.
Scaphiophryne, 3121.
Scaphiopus, 3102.
Scaphirhynchus, 163,
164, 170.
Scapteira, 3532.
Scapteromys, 6341.
Scaptonyx, 6402.
Scapula, 130.
Scapus, 420.
Scarichthys, 238 l.
Scartiscus, 351 l.
Scarus, 238 l.
Scatharus, 2361.
Scatophagus, 237 l.
Scaumenacia, 259.
Scelidosaurus, 3872.
Scelidotherium, 5461.
Sceloglaux, 4721.
Scelopleura, 5472.
Sceloporus, 3502, 351 l.
Scelotes, 3541.
Scent glands, 483.
Sceparnodon, 5372.
INDEX.
699
Scharca, 2201.
Schelly, 2lfV2.
Schilbe, 2212.
Schilbichthys, 221 -'.
Schizocoel/49.
Schizodon, 6351.
Schizognathous, 430.
Schizopygopsis, 219 1.
Schizorhinal, 428.
Scbizorrhis, 4701.
Schizostoma, 0482.
Sciades, 221 2.
Sciaena, 200, 2352.
Scincus, 3541, 354.
Scissor, 2172.
Sciuromorpha, 6321.
Sciuropterus, 6322.
Sciurus, 6322.
Scleroblast, 160.
Sclerocoele, 40.
Sclerodermi, 2462.
Scleropages, 2151.
Scleroparei, 241 2.
Sclerotome, 40.
Scolecomorplms, 304.
Scolecophis, 3691.
Scolecosaurus, 3522.
Scoliodon, 1511.
Scolopax, 4671.
Scomber, 2382.
Scomberomorus, 2382.
Scombresox, 231 1.
Scombriformes, 2382.
Scojnbrops, 2342.
Scopelogadus, 2341.
Scopelosaurus, 2262.
Scopelus, 92, 2261.
Scops, 472 l.
Scopus, 461 2.
Scorpaena, 2421.
Scorpaenichthys, 2421.
Scorpion-fish, 2421.
Scorpis, 2371.
Scotonycteris, 6461.
Scotophilus, 6472.
Scott, W. B., on equine
descent, 600.
Screamer, horned ,
crested, 4622, 4662.
Scrotum, 513.
Scrub-bird. 4751.
Scup, 2361.
Scylliogaleus, 151 2.
Scylliorhinus, tSl1.
Scyllium, 118, 135, 150,
151 l : spiracle, 120.
Scymnodon, 1522.
Scymnus, 1522.
Scytalichthys, 225 '.
Sea- bass, 2342.
Sea- bat, 2392.
Sen -bream, 236 1.
Sea-cow, 549.
Sea-devil, 155, 2461.
Sea-horse, 2301.
Seal, 6262 ; common,
elephant, grey, blad-
der-nosed, hooded,
monk, 627 ; eared,
fur, 6261.
Sea-lion,northern, Pata-
gonian, 6261.
Sea-pejcb, 2351.
Sea-poacher, 2422.
Sea-snail, 2422.
Sea-snakes, 3692.
Sea- wolf, 244'.
Sebastes, 241 2.
Sebastodes, 241 2.
Secondaries, 423.
Second ventricle, 67.
Secretary bird, 4632.
Sectator, 2341.
Sectorial tooth, 6132.
Sedgwick on Elasmo-
branch nephridia, 86.
Seeleya, 3152.
Segmental duct, 89.
Segments of head, 72-
74.
Selache, 92, 150, 152'.
Selachii, 148.
Selene, 2391.
Selenichthyes, 228.
Selenidera, 4741.
Selenodont, 504.
Sella turcica, 486.
Semicossyphus, 2381.
Semiplotus, 21 92.
Semionotus, 179.
Semiophorus, 2391.
Semnopithecus, 6591.
Senex, 4632.
Sense organs, Amphi-
oxus, 19 ; fishes, 77 ;
Mammalia, 496.
Sepedon, 3702.
Sepophis, 3541.
Seps, 345, 3541 .
Sepsina, 3541.
Septo- maxillary, 340.
Sericulus, 4771.
Seriema, 4662.
Seriola, 2392.
Seriolella, 239^.
Seriolichthys, 2392.
Serow, 59 12.
Serpentarius, 4632.
Serranus, 211, 235 ! ;
hermaphrodite, 90.
Serrasalmo, 2181.
Serrivomer, 2242.
Serval, 6191.
Sesamoid, 492.
Setarches, 242 J.
Sewin, 2161.
Sexual season, 517.
Shad, 2142.
Shag, 46 12.
Shanny, 2441.
Sharks, 151 1.
Shastasaurus, 3951.
Shearwater, 461 l.
Sheathbill, 4672.
Sheep, 5912.
Sheep's head fish, 2361.
Sheld-drake, 463 '.
Shiner, 2202.
Shoebill, 46 12.
Shrew, 6392 ; common,
6401 ; short-tailed,
water, mole, 640 ;
tree, pen- tailed tree,
elephant, jumping,
6391.
Shrike, grey, lesser grey,
red- backed, wood-
chat, 476-'.
Sicydium, 241 ].
Sigmodon, 6341.
Sillago, 2352.
Silondia, 221 2.
Siluranodon, 221 2.
Silurichthys, 221 2.
Silurus, 208, 2211.
Silverside, 23 12.
Silybura, 3661.
Simenchelys, 2242.
Simla, 661 3.
Simocephalus, 3671.
Simocyon, 622 l.
Simophis, 3681.
Simosaurus, 3972.
Simotes, 3681.
Simplicidentata, 632 l.
Siniperca, 2351 .
Sinopa, 61 21.
Sinus froiitales, etc., 497
Sinus venosus, 85.
Siphagonus, 2422.
Siphneus, 6332.
Siphonium, 375.
Siphonognathus, 2381.
Siphonops, 301, 304.
Siphonostoma, 2301.
Siredon, 269, 280, 293,
306.i
700
INDEX.
Sirembo, 2442.
Siren, 265, 269, 280, 290,
293, 3072.
Sirenia, 549.
Sirenoidei, 259.
Siskin, 4781.
Sisor, 2221.
Sistrurus, 3721.
Sitana, 3502.
Sitta, 4771.
Sivatherium, 5901.
Skates, 1541.
Skate-toothed dog, 1512
Skimmer, 4681.
Skip-jack, 239.
Skipper, 23 11.
Skittle-dog, 1522.
Skua, great, pomato-
rhine, 4672.
Skull, Amphibia, 267 ;
birds, 426; Amia,
182; Chelonia, 406,
407; Crocodilia, 374,
375. 376 ; Dipnoi,
250 ; Elasmobranchii
126, 127, 128; Gym-
no phiona, 301, 302;
lizards, 338, 341 ;
Mammalia, 484 ;
Marsipobranchii, 98-
103 ; Poly pterus, 172,
173; Reptilia, 318;
snakes, 357, 358 ;
Teleostei, 189.
Skulpin, 241 !.
Skunk, 6241.
Slip, 2402.
Sloths, 5442 ; ground,
5451.
Slow- worm, 352 *.
Smaria, 2361.
Smear-dab, 2402.
Smelt, 2161.
Smew, 4631.
Smiliogaster, 2202.
Smilodon, 6191.
Sminthopsis, 5391.
Sminthus, 6342.
Smith-frog, 31 11.
Smolt, 2152.
Smooth-hound, 151 2.
Smooth-snake, 3672.
Snake- bird, 461 2.
Snakes, burrowing, 3651
3661 ; rattle, 37 12,
3721.
Snake-eating cobra,
3702.
Snapper, 2352.
Snapping turtle, 41 31.
Snipe-fish, 2291.
Snipe, jack, 467 l.
Soft-shelled turtle, 415.
Solan goose, 46 12.
Sole, little, 2402 ; band-
ed, lemon, 240 2.
Solea, 2402.
Solenocytes, 23, 29.
Solenodon, 6402.
Solenognathus, 2301.
Solenorhynchus, 2292.
Solenostoma, 210, 2292.
Soleotalpa, 2402.
Solitaire, 4691.
Somactids, 54.
Somateria, 4631.
Somatic nerves, 76.
Somites of Amphioxus
34 ; of head, 73.
Somniosus, 1522.
Sorex, 6392.
Soricidens, 2361.
Soriculus, 6401.
Sorubim, 221 2.
Sotalia, 5641.
Souslik, 6322.
Spade- foot, 3102.
Spalacopus, 6351.
Spalacotherium, 5401.
Spalax, 6342.
Sparagmites, 3151.
Sparassodontidae, 5402.
Sparisoma, 238 l.
Sparnodus, 236 '.
Sparrow, house-, tree-,
4781 ; hedge-, 4752.
Sparus, 202. ~
Spathiurus, 182.
Spathoscalabotes, 3492.
Spatularia, 163, 164,
168, 169.
Spatulariidae, 170.
Spawning, Amphioxus,
30 ; fishes, 91.
Spear-dog, 1522.
Spelerpes, 226, 293,
296, 305.
Spermaceti, 5621.
Spermatophores, Am-
phibia, 296.
Sperm ophilus, 6322.
Sperm-whale, 5621.
Sphaerodactylus. 3492.
Sphaerodon, 2361.
Sphagebranclms, 2231,
2251.
Sphargis, 4122.
Sphenacanthus, 151 l.
1 Sphenisciformes, 4602.
Spheniscus, 4602.
Sphenodon, 317, 318,
320, 321, 334.
Sphenoidal, 60.
Sphenophryne, 3121.
Sphingurus, 6352.
Sphyraena, 197, 2312.
Sphyrna, 133, 134, 151 2.
Spicara, 2361.
Spilotes, 3681.
: Spina sternalis, 432.
I Spinal cord, birds, 435.
Spinal nerves, 47.
Spinal accessory nerve,
321 ; snakes, '362.
Spinax, 121, 1522.
Spines, Elasmobranchii,
122.
Spinivomer, 2242.
Spino-occipital nerves,
73.
Spiny-rayed fish, 2331.
Spiracle, 48, 66 ; Am-
phibia, 278 ; Cetacea,
554 ; Elasmobranchii,
120 ; tadpole, 299.
Spiral valve, 34; Dirnioi,
252.
Splanchnocoele, 40.
Spleen, Amphibia, 290 ;
birds, 442 ; Dipnoi,
•252 ; Mammalia, 512 ;
Reptilia, 327.
Spoonbill, 461 2.
Sprat, 2142.
Spring-bok/5911.
Spur-dog, 152 2.
Spy-slange, 3702.
Squall, 150.
Squaliobarbus, 220' .
Squalodon, 5622.
j Squalorajidae, 158.
j Squalus, 152l.
Squamata, 334.
Squatina, 125, 126, 153.
Squirrel, common, flying
ground, spiny, 6322.
Stagonolepis, 372, 381.
Stapes, 267, 498.
Star-gazer, 2432.
Starling, American, 4781 ;
rose-coloured, 47 72.
Staurotypus, 41 31.
Steatomys, 6341.
Steatornis, 4722.
Stegocephali, 3132.
Stegodon, 5721.
Stegonotus, 3681.
INDEX.
701
Stegophilus, 2221.
Stegosauria, 3872.
Stegosaurus, 3872.
Stegostoma, 151 1.
Steinbok, 5902.
Steindachneria, 2322.
Stelgis, 2422.
Stellerina, 2422.
Steller's sea-cow, 5522.
Stellifer, 2352.
Stenoesaurus, 382 1.
Steno, 5641.
Stenocercus, 351 l.
Stenodactylus, 3492.
Stenoderma, 6482.
Stenoclus, 2181.
Stenogale, 6232.
Stenophis, 3691.
Stenoplesictis, 6232.
Stenops (a synonym of
Loris), 490, 511.
Stenorhina, 36S2.
Stenotomus, 2361.
Stephanoberycidae,
227i.
Stercorarius, 4672.
Stereocyclops, 3121.
Stereolepis, 2351.
Stereornis, 4601.
Stereornithes, 4592.
Stereostermim, 334.
Sterna, 468'.
Sternarchus, 2181.
Sternoptychidae, 92.
Sternoptyx, 2162.
Sternopygns, 2181.
Sternothaerus, 4142.
Sternum, Amphibia, 270,
271 ; birds, 432 ; Cro-
codilia, 374 ; lizards,
338, 339 ; .Mammalia,
489 : Reptilia, 318.
Sterrholophus, 3881.
Sthenurus, 5352.
Stichaeopsis, 2441.
Stichaeus, 2441 .
Sticharium, 2441.
Sticklebacks, 2282; nests
of, 229 ; gigantic
marine, marine, 3-
spined, 229 1.
Stiormatophora, 2301.
Stilosoma, 368 '.
Stilts, the, 4671.
Sting-rays. 1542.
Stink- bird. 4661.
Stoat, 0242.
Stolephorus, 2141.
Stoliczkaia, 3662.
Stomias, 2162.
Stomocoel, 41.
Stomodaeum, 48.
Stone-bass, 2351.
Stonechat, 4752.
Stone-curlew, 4672.
Stone-loach, 221 1.
Stone-lugger, 2192.
Stone-toter, 2192.
Stork, 4612 ; marabou,
46 12.
Stratum malpighi, 46.
Strepsiceros, 591 *.
Strepsilas, 4671.
Strepsodus, 175.
Streptophorus, 3671.
Streptostylica, 319.
Striges 4712. '
Stringops, 432, 4601,
471^.
Strinsia, 2322.
Strix, 4712, 472.
Strobilodus, 180.
Strobilurus, 351 ].
Stromateoides, 2312.
Stromateus, 231 2.
Struthio, 434, 4572.
Sturgeon, 170.
Sturnira, 6482.
Stumus, 4772.
Stygogenes, 2221.
Stylinodon, 60S2.
Stylinodonta, 60S1.
Stylo mastoid foramen,
488.
Stylophorus, 2451.
Stypolophus, 6121.
Sviblingua, 509.
Suboscines, 4751.
Subterranean fish, 2221 ,
2271, 2442.
Subzonal membrane,
518
Sucker, 2432.
Sudis, 2261.
Sula, 4612.
Sulci, 494.
Sun-bird, 4772.
Sun bittern, 4662.
Sun fish, 152S 2341,
2472.
Superior commissure,
71.
Superior pharyngeal
bones, 191.
Supraclavicle, 162.
Supracleithrum, 162.
Suprarenal body, birds,
44-2; Chelonia, 410;
snakes, 361 ; Amphi-
bia, 295 ; Mammalia,
513.
Supratemporal arcade,
319.
Supratemporal fossa,
319.
! Suricata, 620 r.
' Surinam toad, 3101.
; Surmullet, 2362.
Surnia, 4721.
| Sus, 502, 579, 580, 581,
581i.
SwaUow, 476i.
Swan, 4622 ; mute, 4631;
whooper, 463 l.
Swift, common, 4722 ;
alpine, 4722.
Swimming bladder, 65.
Sword-fish, 231i, 2391.
Syndactylism, 531, 535.
Symbranchii, 222.
Symbranchus, 184, 206,
2222.
Sympathetic, Amphibia,
276 ; Marsipobranchii,
108; Reptilia, 322;
snakes, 362; fishes,
75.
Symphimus, 368-.
Sympholis, 3681.
Symphurus, 2402.
Sympterygia, 1542.
Synagris, 2352.
Synanceia, 211, 2421.
Synaphobranchus, 2242.
Synapticula, 24.
Synaptodus, 5352.
Synaptomys, 6341.
Synaptura, 2402.
Synchalinus 3681.
Synetheres, 6359.
Syngnathus, 2301.
Synodontis. 2221.
Synodus, 2262.
Synoecus, 4652.
Synotus, 6472.
I Syrinx, 443.
| Syrnium, 472 1.
Syrrhaptes, 4681.
Systemodon, 5941.
Tachydrornus, 3532.
Tachyeres, 4622.
Tachymenis, 3692.
Tachyoryctes, 6342.
Tactile corpuscles, 495.
Tacypetes, 4612.
Tadorna, 4631.
702
INDEX.
Tadpole, 297.
Taenianotus, 2421.
Taeniodon 18,608'.
Taeniosomi, 2442.
TaeniurA, 1542.
Tail, lizards, 336, 337.
Takin, 5912.
Talegallus, 4651.
Talepoin, 659.
Taliemania, 2142.
Talon of tooth, 503.
Talpa,483, -197, 502,
6402.
Tamandua, 5441.
Tamias, 6322.
Tanagridae, 4772.
Tanganyika, fish of,
237*.
Taniwhasaurus, 335.
Tantalus, 461 2.
Tanysiptera, 471 *.
Taphozous, 6481.
Taphrometopon, 3692.
Tapirus, 593.
Taractes, 2392.
Tarandichthys, 2422.
Tarandus, 5892.
Tarassius, 175.
Tarbophis, 3692.
Tardigrada, 5442.
Tarentola, 3492, 350?.
Tarpon, 2142.
Tarsipes 530, 5362.
Tarsius, 6522.
Tarsus, serial, altern-
ating, 5752.
Tasmanian devil, 5382.
Tatouay, 547 *.
Tatusia, 542, 5472.
Tautoga, 2381.
Taxidea, 624*.
Tectospondylous, 124,
125.
Tectrices, 424.
Teetee, 6572.
Teeth, Amphibia, 277 ;
Crocodilia,378; fishes,
63 ; lizards, 343 ;
Mammalia, 499 ; de-
velopment of, 505 ;
Reptilia, 324; Tele-
ostei, 197 ; succession
of in Mammalia, 507,
508.
Teius, 3522.
Teju, 3522.
Telacodon, 5381.
Teleosaurus, 372, 3821.
Teleostei, 183 ; genital
ducts of, 88.
Telerpeton, 333.
Telescope-fish, 2 191.
Tellia, 2262.
Telmatobius, 3112.
Temera, 1541.
Temnocyon, 6221.
Tcmnodon, 2392.
Temp. = temperate.
Temperature, birds,
416; Monotremata,
528 ; Teleostei, 200.
Tench, 2191.
Tench, 2201 ; golden,
220.
Tenrec, 6411.
Tepraeops, 2361.
Teratolepis, 3492.
Teratoscincus, 3492.
Tern, 468 1.
Terrapins, 4131
Testicular network, 142,
Amphiljia, 291.
Testis, connection of to
kidney, 89 ; Mam-
malia, 515.
Testudo, 4132.
Tetrabelodon, 5722.
Tetraceros, 5902.
Tetradactylus, 3532.
Tetragonopterus, 2172.
Tetragonurus, 2312.
Tetralepis, 367 '.
Tetranematichthys,
2212.
Tetrao, 4652.
Tetraogallus, 4652.
Tetrapturus, 2391.
Tetraroge, 2421.
Tetrodon, 203, 2472.
Teuthis, 2371.
Thalamencephalon, 67.
Thalassemydidae, 4141.
Thalassochelys, 4141,
414.
Thalassophis, 3701.
Thalassophryne, 211,
244i.
Thalassorhinus, 1512.
Thaleichthys, 21 62.
Thamnodynast.es, 3692.
Thamnophilus, 4751.
Thecadactylus, 3492.
Thecodonf, 343.
Thecophora, 4122.
Thelolepis, 147.
Thelotornis, 3692.
Theosodon, 603].
Theragra. 2331.
Theriodesmus, 4011.
Theriodontia, 400.
Theriosachus, 3822.
Theromorpha, 3982.
Theropithecus, 6582.
Theropoda, 384.
Thick-back, 240-.
Thinocorys, 4672.
Third ventricle, 67.
Thoatherium, 60S1.
Thomomys, 6342.
Thoracic 'fin, 185.
Thoracosaurus, 3831.
Thorius, 305.
Thoropa, 311 1.
Thrasher, 1521.
Thrasops, 368 '.
Thrichomys, 635 l.
Thrinacodus, 6351.
Thrissops, 213.
Thrush, blue, mistletoe,
rock, 4752.
Thrynomys, 6351.
Thryopterfi, 6472.
Thunnus, 2382.
Thuringian lizard, 333.
Thursius, 175.
Thylacinus, 530, 533,
5382.
Thylacoleo, 5372.
Thymallus, 2162.
Thymus, Amphibia,
277 ; birds, 442 ;
Mammalia, 512 ;
Reptilia, 327.
Thynnichthys, 2191.
Thynnus, 92, 2382.
Thvrina, 231 2.
Thyrohyal, 269.
Thyroid, Amphibia,
277 ; birds, 442 ;
Mammalia, 512 :
Reptilia, 327.
Thysanopsetta, 2401'.
Tichodroma, 4772.
Tigaii, 474*.
Tiger, sabre-toothed,
6191.
Tiger-shark, 151 1.
Tiger-snake, 3702.
Tiliqua, 3541.
Tilled oiitia, 543. 607.
Tillotherium, 60S1.
Timeliidae, 4752.
Tinamiformes, 4641.
Tinamou, the, 4641.
Tinamus,429,434,4641.
Tinea, 198, 2201.
Tinoceras, 604, 60S1
INDEX.
703
Tit, 4771.
Titanotherium, 6021.
Titmouse, 4771.
Tityra, 4751.
Toad, 3 10; horned, 3511.
Toad-fish. 2441, 2461.
Todus, 471 i.
Tody, 47 11.
Tolypeutes, 5472.
Tomistoma, 383 '.
Toraodon, 3692.
Tompot, 2441.
Tongue, Amphibia, 277.
Tongue bar, 22, 25.
Tongue, birds, 438 ;
fishes, 63 ; lizards,
343.
Tope, 151A
Top-knot, 2402.
Torpedo, 1541 ; elec-
trical organ, 83.
Torsk, 2331.
Tortoise, 4132.
Tortoiseshell, 403.
Tortrix, 3661.
Tetanus, 4671.
Toucan, 4741.
Touraco, 4701.
Toxabramis, 2202.
Toxodon, 606i.
Toxodontia, 60S1.
Toxotes, 2341.
Trabeculae, 60.
Trachelochismus, 2432.
Tracheloptychus, 3532.
Trachelyopterus, 2221.
Trachichthys, 2341.
Trachinocephalus, 2262.
Trachinops, 235 l.
Trachinus, 3432.
Trachischium, 3671.
Trachodon, 3872.
Trachyboa, 3661.
Trachynotus, 2392.
Trachyops, 6482.
Trachypoma, 2351.
Trachypterus, 2451.
Trachyrhynchus, 2322.
Trachysaurus, 3541.
Tragel'aphus. 5911.
Tragulus, 579, 586, 5881
Transpalatinc, 320.
Tree-frogs, 31 11.
Tree-snake, 3672.
Tremataspis, 261.
Trematherium, 5451.
Trematosaurus, 3151.
Treron, 4691.
Tretanorliinus, 367 ^
i Tretioscincus, 3522.
j Triacanthodes, 2462.
Triacanthns, 2462.
1 Triacis, 1512.
Triaenodon, 151 2.
; Triaenophorichthys,
2411.
Triaenops, 647 {.
Tribolonotus, 3541.
Triqeratops, 388, 3881.
Trichechus, 552% 6261.
Trichiurus, 183, 2391.
Trichobatrachus, 31 31.
Trichodon, 2382.
Trichogaster, 2371.
Trichoglossus, 4702.
I Trichomycterus, 2221.
i Trichonotus, 2432.
Trichopleura, 242 i.
Trichosurus, 5371, 537.
Trichys, 6352.
I Triconodon, 5401.
Triconodont, 503.
Trigger-fish, 247 l.
Trigla, 185, 203, 205,
206, 2431.
Trigliiformes, 241 l.
Trislops, 2421.
i Triglyphus, 4011, 5412.
i Trigonodont, 503.
! Trimerorhinus, 3692.
Trimetopon, 3681.
| Trimorphodon, 3692.
Tringa, 4671.
Triodon, 2471.
Trionychoidea, 415.
Trionyx, 415.
i Triprion, 811*.
| Tnptergium, 2441.
| Tripterodon, 2361.
! Trirachodon, 401 l.
Trirhinopholis, 367 l.
Triton, 268, 269, 270,
274, 280, 282, 3071.
Tritubercular, 503.
Tritubercular theory,
504.
Tritylodon, 401 *, 541 2.
Trochilus, 4731.
Trochocopus, 2381.
Troglodytes, 476], 661?.
Trogon,"4732.
Trogones, 4732.
Trogonophis, 3531.
Trop. = tropical.
i Tropho blast, 518, 520.
I Tropic-bird, 4612.
Tropideohis, 3702.
Tropidichthys, 2472.
Tropidodactylus, 351 5.
Tropidodipsas, 3681.
Tropidonotus, 362, 3671 .
Tropidophorus, 3541.
Tropidosaura, 3532.
Tropidurus, 351 *.
Trout, 21 52, 2361.
Trumpeter, 2352, 4662
Trumpet-fish, 2291.
Truncus arteriosus, 282.
Trunk cavity, 7.
Trunk-fish, 247 J.
Trygon, 122, 125, 134,
144, 148, 1542.
Trygonorhina,143, 1541.
Trypanurgos, 3692.
Trypauchen, 241 *.
Tubercular - sectorial,
503.
Tuberculum acusticuin,
75.
Tubinares, 461 J.
Tubulidentata, 5491.
| Tunny, 2382.
Tunny-fish, migration
of, 91.
Tupaia, 6391.
| Tupinambis, 3522.
; Turacin, 426, 4701.
j Turaco-verdin, 4701.
Turacus, 4701.
Turbinal, 487.
Turbot, 2402.
Turdus, 4752.
Turkey. 4652.
Turnix, 4642.
Turnstpne, 467 1.
Tursio, 5641.
Tursiops, 5641.
Turtles, 41 32.
Turtur, 4691.
Twaite-shad, 2142.
Tyloanathus, 2192.
Tylomys, 6341.
Tylopoda, 5862.
Tvlosaurus, 335.
Tylostoma, 6482.
Tylosurus, 231 1.
Tylotriton, 3073.
Tympanic bulla, 485.
Tympanic cavity, liz-
ards, 336, 346.
Tympanic membrane,
* lizards, 336.
Tympanocryptis, 3502.
Tympanuchus, 4652.
Typhlacontias, 3541.
Typhlichthys, 2271.
Typhlogeophis, 3681.
704
INDEX.
Typhlomolge, 3072.
Typhlomys, 633 '.
Typhlonectes, 304.
Typhlonus, 2442.
Typhlophis, 3651 .
Typhlops, 3651, 365.
Typhlosaurus, 3542.
Typhlotriton, 305.
Typotheria, 606.
Typotherium, 6072.
Typothorax, 3821.
Tyrannus, 475 >.
Tyrant bird, 4751.
Tysty, 4681.
Uintatherium, 60S1.
Ulaema, 236 L.
Ulca, 2422.
Ulocentra, 2342.
Uma, 351 *.
Umbilical artery, 521.
Umbilicus of feather,
420.
Umbra, 2261.
Umbrina, 2352.
Unau, 545*.
Unciiiate process, 318.
Undina, 175.
Ungalia, 366 L.
Ungaliophis, 3681.
Ungulata, 573; digits
of, 576.
Unguligrade, 493.
Unke, 3101.
Upeneus, 2362.
Upupa, 4712.
Uraeotyphus, 304.
Uraleptus, 233 '.
Uranidea, 2422.
Uraniscodon, 351 *. '
Uranoscopus, 2432.
Urax, 449.
Urenchelys, 2231 .
Ureter, Amphibia, 290,
292 ; Elasmobranchii,
] 41 ; fishes, 90 ; Rep-
tilia, 328.
Uria, 468i.
Urinary organs, 49.
Urinogenital organs,
Amphibia, 290 ; birds,
449; Chelonia, 410,
411 , Dipnoi, 256 ,
Elasmobranchii, 140,
143; fishes, 86; Lepi-
dosteus, 166; Stur-
geon, 166 ; Polyp-
terus, 166 ; Mam-
malia, 513 ; Marsipo-
branchii, 111 ; Rep-
tilia, 327 ; Scaphi-
rhynchus, 166 ; Poly-
odon, 166; Teleostei,
209.
Urocampus, 230 '.
Urocentron, 351 1.
Urocentrus, 2441.
Uroconger, 2242.
Urocordylus, 3151.
Urodaeum, 440. •
Urodela, 304.
Urogalba, 4732.
Urogymnus, 1542.
Urolophus, 1542.
Uromacer, 368 '.
Uromastix, 3502.
Uromys, 6331, 6341.
Uronemns, 259.
Uropeitis, 366'.
Uroplates, 3492.
Uropterygius, 225 {.
Uropygiuin, 419.
Urostrophus, 351 1.
Urostyle,265-
Urotheca, 3681.
Urotrichus, 6402
Ursus, 613, 614, 6231.
Uta, 351 ].
Uterus, 481,515.
Utricle, 77.
Vagina, 515.
Valvula cerebelli, 194.
Valvula paradoxa, 287.
Vampire, 6482.
Vampvrops, 6482.
Vampyrus, 648, 6482.
Vandeleuria, 6341.
Vandellia,222'.
Vane, 420.
Vanellus,467i.
Varanus, 352 ^
Vas deferens of fishes,
89.
Vasa efferentia, 292.
Vascular system, Am-
phibia, 281 ; Amphi-
oxus, 29 ; birds, 441 ;
Chelonia, 410; Cro-
codilia, 379, 380 ;
Dipnoi, 252, 253 ;
fishes, 85 ; Mammalia,
510; Marsipobranchii,
110; Reptilia, 324;
Teleostei, 206, 207.
Velasia, 116.
Velum of Amphioxus,
20.
Velum transversum, 70.
Vendace, 2162.
Vent, birds, 419.
Ventral fin of Teleostei,
185.
Ventral roots of vagus,
73.
Ventralia, 98.
Ventricles of the brain,
67.
Verilus, 2352.
Vernia, 2251.
Vermilinguia, 5431.
Vertebral column, Am-
phibia, 265 ; birds,
430 ; Chelonia, 405 ;
Crocodilia, 372 ; Dip-
noi, 249 ; Elasmo-
branchii, 122, 123,
124, 125, 126; fishes,
59 ; lizards, 337 ;
Mammalia, 489 ; Rep-
tilia, 317 ; snakes,
357 ; Teleostei, 188.
Vertebrata, 45.
Vervet, 65'.* '.
Vespertilio, 6472.
Vesperugo, 6472.
Vestibule, 515 ; of bird's
cloaca, 440 ; of ear, 77.
Vetelia, 5472.
Vexillum, 420.
Vibrissae, 495.
Vicugna, 5871.
Viuago, 469 '.
Viper, 3711-.
Vipera, 371 2.
Vireonidae, 4771.
Virginia, 368 l.
Viscacha, 6352.
Visceral arches, Elas-
mobranchii, 127.
Visceral clefts, 48.
Visceral nerves, 76.
Visceral skeleton, 61 ;
arches, 62.
Viverra, 620 J.
Viverricula, 6201.
Viviparous Amphibia,
296; fishes, 237 ].
Vocal sacs, Amphibia,
277.
Voice, Amphibia, 281 ;
crocodiles, 380 ; Che-
lonia, 409.
Vole, bank, field, 6332.
V.omer, 2392.
Vulsiculus, 2431.
Vulsus, 241 1.
INDEX.
705
Vultur, 4632.
Vulture, 4632,; Egyp-
tian, 4632 ; king, 4631.
Wagtail, 4752 ; white,
4752.
Wallaby, rock, nail-
tailed, hare, 535.
Wallaso, 2212.
Walrus, 6261.
Walterinnesia, 3702.
Wapiti. 589'.
Warbler, 4752 ; Ameri-
can, 47 7 2.
Wart-hog, 58 12.
Water-hen, 4661.
Watermole, 529.
Water-ousel, 4761.
Water-rail, 4661.
Water-tortoises, 4131.
Water- viper, 37 12.
Waxwing, 4762.
Weasel, 624'.
Weaver- birds, 47 7 2.
Weberian ossicles, 202,
203.
Weever, 2432.
Weka, 4G61.
Wels, 221 1.
W'hale, right, grey,
hump-back, blue, 561;
sperm, bottle-nose,
562 : white, 5632 ;
killer, 5632 ; pilot,
ca'ing, 5641.
Whale-bone, 560.
Whale-sharks, 152*.
Wheel-organ, 20.
Whiff, 2402.
Whitichat, 4752.
White-eye, 4772.
Whitefish, 2162, 2192.
Whithound, 1512.
Whiting, 2322 ; pout,
2322.
Whooper, 4631.
Wings, birds, 4*3.
Wolf, 6221 . Aard, 6202 ;
prairie, 622 ; Tasma-
iiian, 5382.
Wolffian body, 292.
Wolffian duct, 89.
Wolf-fish, 2441.
Wolverine, 6242.
Wombat, 5372.
Woodcock, 4671.
Woodpecker, black,
green,greater spotted,
lesser spotted, 4741.
Wood-swallow, 4762.
Wrasse, Italian, stripped,
2372 ; parrot, rain-
bow, 2381.
Wren, 4761 ; St. Kilda,
4652.
! Wry-bill, 467 l.
j Wryneck, 4742.
\ Xantusia, 352 >.
\ Xenacanthus, 147.
Xenarthra, 543.
Xenelaphis, 368 '.
Xenicus, 4751.
Xenobatrachus, 3121.
Xenocalanms, 3692.
Xenocharax, 2172.
Xenochirus, 2422.
Xenochrophis, 3671,
Xenocypris, 2192.
Xenocys, 2352.
Xenodermus, 3662.
Xenodon, 3681.
Xenomys, 6341.
Xenomystus, 2221.
Xenopeltis, 362, 366 1.
Xenopholis, 3692.
Xenophrys, 3102.
: Xenopterus, 2472.
! Xenopus, 270, 272, 273,
309, 309.
Xenorhina, 3122.
I Xenosaurus, 351 2.
: Xenurophis, 368 l.
< Xenurus, 5471.
I Xeromys, 633 l.
Xerus, 6322.
Xesurus, 237 '.
Xiphias, 239'.
Xiphidion, 244'.
Xiphiidae, 92.
Xiphistemum, 270.
Xiphocercus, 3511.
Xiphochius, 238'.
Xiphodon, 579, 5851.
Xiphorhamphus, 2172.
Xiphostoma, 2172.
Xylophis, 367'.
Xyrauchen, 2182.
Xyrichthys, 2381.
Xystaema, 236 l.
Xystes, 2422.
Yellow-tail, 2392.
Zachaenus, 31 12.
Zamenis, 3681.
Zanclodoii, 385 l.
Zanclus, 2392.
Zaniolepis, 242 l.
Zaocys, 3681.
Zapteryx, 1541.
Zapus,'6342.
Zarthe, 2202.
Zebra, 5962.
Zenion, 2401.
Zenkerella, 632'.
Zeorhombi, 2392.
Zesticelus, 2422.
Zeuglodon, 5642.
Zeugopterus, 2402.
Zeus, 203, 2401.
Zingel, 2342.
Ziphius, 5622.
Zoarces, 91, 243?, 241 1.
Zonosaurus, 3532.
Zonurus, 3512.
Zope, 2202.
Zosteropidae, 4772.
Zygaena, 139, 148, 151 2.
Zygantrum, 356.
Zygosphene, 356.
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