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
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