CARNARIA. 105 
to render them good swimmers; and all the details of their anatomy con- 
firm these first indicia. 
We have as yet distinguished two genera only, Phoca and Trichechus. 
Puoca, Lin. 
Seals have six or four incisors above, four or two below, pointed canini 
and grinders to the number of twenty, twenty-two, or twenty-four, all 
trenchant or conical, and without any tuberculous part whatever; five toes 
to all the feet, the anterior ones regularly decreasing in length from the 
thumb to the little toe, while in the hinder feet the thumb and the little 
toe are the longest, and the intermediate ones the shortest. The fore feet 
are enveloped in the skin of the body as far as the tarsus, the hinder ones 
almost to the heel. Between the latter is a short tail. The head ofa 
seal bears a resemblance to that of a dog, whose intelligence and soft ex- 
pressive look it also possesses. It is easily tamed, and soon becomes at- 
tached to its keeper, or those who feed it. The tongue is smooth, and 
sloped at the end, the stomach simple, cecum short, and the intestinal 
canal long, and tolerably regular. These animals live on fish; always eat 
in the water, and close their nostrils when they dive by a kind of valve. 
As they remain a long time under water, it was supposed that the foramen 
ovale remained open, as in the human fcetus—but it is not so: there is, 
however, a large venous sinus in the liver, which must assist them in 
diving, by rendering respiration less necessary to the motion of the blood. 
Their blood is very abundant and very black. 
Puoca, properly so called, or, without external ears. 
The true Phoce have pointed incisors; all the toes enjoy a certain de- 
gree of motion, and are terminated by pointed nails planted on the edge 
of the membrane, which unites them. 
They are subdivided from the number of their incisors. The Catocr- 
PHALA, Fr. Cuv., have six above and four below; such is the 
Phoca vitulina, L.; Buff. XIII. xlv., and Supp. VI. xlvi; Ph. 
littorea, Thienem. pl. vi. (The Common Seal). From three to five 
feet in length; of a yellowish grey, more or less shaded and spotted 
with brown, according to its age; sometimes brownish, with small 
yellow spots. When very old it becomes whitish. Common on the 
coast of Europe in great herds. It is also found far to the north; 
we are even assured that it is this species which inhabits the Caspian 
sea, and the great fresh water lakes of Russia and Siberia, but this 
assertion does not appear to be founded on an exact comparison. In 
fact, the European seas contain several Phoce, which have long been 
confounded, some of which are perhaps mere varieties of the others. 
Thus, some of them have the back covered with small clouded, 
confluent, brownish spots, on a yellowish ground— Ph. hispida, 
Schreb. 86*. These are the most common ones of the northern 
ocean. In others again the ground is dark, traversed with undulat- 
* I suspect we should refer to it the Ph. scopulicola, Thienem, pl. y. 
