788 
Genus.—Didelphys. 
1 3 4—4 
1 3 uM 4—4 
middle incisors of upper jaw rather longer than others, and 
separated from them by a slight interval—Upper canines 
stronger than the lower—Pramolars conical—Molars fur- 
nished with sharp cusps. 
Head.—Long, gape of jaw very far back. 
Pouch.—Tolerably developed. 
Tail—Long, covered with fur at the base, and with scales 
towards the extremity ; prehensile. 
50. Two 
aE ye 
5—5 i 
I. 2 4Gh, 
Teeth.—I 1 I 
Genus.—Cheironectes. 
Feet.—Toes of the hinder feet connected by a web. 
There is also a development of the pisiform bone, which 
supports a fold of the skin, and looks like a sixth toe. 
Pouch.—Well developed. 
Tail—Longer than body. 
Fan ily.—PH6c IDA. 
Teeth.—Incisors variously deciduous; molars with flat- 
tened crowns, or sometimes furnished with cusps. 
Feet.—Furnished with five toes, short and palmate ; the 
hinder feet being turned backwards so as to approach each 
other. 
Body.—Gradually tapering from the shoulders to the tail, 
which is very short and conical, Clothed with smooth hair, 
pressed firmly against the body. 
Sub-family.—Phocina, 
5—5 . 6—6 
Teeth.—Incisors permanent ; molars 55’ or 
—5 
Ears.—Very small, or wanting. 
Genus.—Leptonyx. 
Teeth —L. 2-2, ©. 1, PS 8 MS = 98. 
much pointed ; molars divided into three long, conical, and 
slightly curved points. 
Head.—Muzzle narrow and elongated. 
Neck.—Long and tapering. 
Limbs.—Nails very small, especially those of the hinder 
feet. 
Incisors 
Genus. Stemmatopus. 
1 3—3 2 
=p 1g 3-3’ M5 9 
conical; canines stout and large. 
Head.—Adult male furnished with a large membranous 
and muscular sac, which is divided into two channels by a 
development of the septum of the nose, 
= 30. Incisors 
oon 2 
MestheL)-=1Cs 2 
oo T= eee 2 
Genus.—Phoca. 
‘ pes a Tel = E9) | Oe 
Teeth. 5—5, C. >, P. 55, M. 5 = 84. All the 
molars except the first furnished with double roots. 
Genus.—Trichecus. 
Teeth.—Upper canines enormously developed, and without 
roots. 
Head.—Muzzle tumid and protuberant, covered with thick 
bristles—External ears wanting. 
Genus.—Morunga. 
Teeth as in Stemmatopus. 
Head.—Proboscis-like expansion of nose. 
COMPENDIUM OF GE 
NERIC DISTINCTIONS. 
Genus.—Arctocéphalus. 
$23. 4 110 408635 =o) ae 
Teeth. $8 ¢ Et PF MS 2 (or rarely 
99 
— ) = 84. Four upper and middle incisors broad crowned, 
with groove, two others conical. 
Limbs.—First toe of fore-feet longest, the middle hinder 
toes nearly equal; membrane of hinder feet projecting like 
leathern straps beyond the toes. 
Order.—CETE. 
Teeth.—When present, conical and similar, the palate 
frequently furnished with baleen. 
Body shaped like a fish. 
Limbs.—Short and fin-shaped, the hinder pair forming a 
horizontal tail. 
Skin.—Smooth and hairless, nostrils developed into blow- 
ing-tubes, 
Fam ily. BALENIDE. 
Nostrils two, palate with baleen, jaws without teeth. 
Head,—Very large, equal to one-third the size of the body. 
Genus.—Balena, 
No dorsal fin, abdomen smooth, baleen very long. 
Teeth.—None in adult, only rudimentary in young. 
Genus.—Megiptera. 
Dorsal fin, abdomen furnished with longitudinal folds, 
pectoral fins long, equalling the head in length, baleen short, 
broad, and triangular. 
_ Genus.—Balenéptera. 
Dorsal fin sharp and faleate, abdomen and throat furnished 
with longitudinal folds, pectoral fins moderate, baleen short. 
Genus.—Ph¥salus. 
Dorsal fins faleate, pectorals moderate, abdomen and 
throat with longitudinal folds. Blow-holes semi-lunar, di- 
vided from each other by a groove, and.coyered with a valve 
or flap. Baleen short. 
Family —CatopontTiwa, 
Head very large, upper jaw apparently toothless, the lower 
jaw furnished with many conical teeth, which are received 
into cavities in the upper jaw. Blow-holes united, with a 
semi-lunar opening. 
Genus.—Catodon. 
Dorsal hump rounded, blow-holes in front of the head, 
Head.—Blunt at muzzle, skull much elongated. 
Genus.—Physéter. 
Upper jaw longest, blow-holes on the top of the head near 
the middle, separate, but covered with a common flap or 
yalye. Dorsal fin high and faleate. 
Family. DELPHINIDE. 
Head moderate—Both jaws furnished with teeth, which 
are frequently shed at an early age. Blow-holes united, 
forming a transverse semi-lunar opening on the top of the 
head. 
