444 
UNGULATES. 
When taken young, peccaries are easily tamed, although it does not appear that 
any attempts have been made to establish a domesticated breed. Large numbers 
of them are destroyed by jaguars and pumas. 
Fossil remains of peccaries, some belonging to living and others 
Extinct Types. . . . , ., „ , ., , T ,, 
to extinct species, occur m the rieistocene deposits of both JNorth and 
South America. In addition to these, certain extinct Pliocene and Miocene hog¬ 
like animals seem to indicate the parent-stock from which both the peccaries and 
the true pigs have been derived. Of these Cheer ohy us, from North America, comes 
closest to the peccaries, while the Old World Hyotherium, of which two upper 
molar teeth are figured on p. 421, is more like the pigs. Listriodon is another 
European type, in which the molars have a pair of transverse ridges instead of 
four tubercles. Finally Cheeropotamus, from the upper Eocene of England and 
France, connects the type of molar tooth characteristic of the pigs with that of the 
extinct anthracothere referred to on p. 421. 
The Hippopotami. 
Family HlPPOPOTAMIDST. 
Although the Greek term hippopotamus, and its English equivalent river- 
horse, are etymologically decidedly objectionable ones to denote the animals we have 
now to describe, yet the former at least is so firmly established in European 
languages that it would be impossible to attempt to change it. The Dutch term 
see-hull, commonly translated sea-cow, but which we think might equally bear the 
interpretation lake-cow, and a name used by the Arabs which means water-buffalo, 
are far less objectionable; but a title equivalent to river-swine, which is said to 
have been conferred on these animals by the ancient Egyptians, is, from a zoological 
standpoint, far and away the best of all. 
The common hippopotamus, together with a much smaller species from West 
Africa, constitute a family by themselves, which is also the last group of the even¬ 
toed Ungulates. Hippopotami are bulky animals, with round, barrel-like bodies of 
great length, very short and thick legs, and enormous heads, in which the muzzle 
is angular and greatly expanded transversely, and has no trace of the terminal disc 
characteristic of the swine and peccaries. Indeed, the ugly head of a hippopotamus 
appears as if it were too large and heavy for its owner, since the animal may fre¬ 
quently be seen resting its ungainly muzzle on the ground, as though to relieve the 
neck from the strain of its weight. The portion of the skull in front of the eyes 
is very much longer than that behind them; and the sockets of the eyes (as 
seen in our figure of the skeleton) are completely surrounded by a very prominent 
bony ring, which has an almost tubular form. In the pigs, on the other hand, the 
socket of the eye is open behind (compare the figure on p. 422). The prominence 
of these sockets causes the relatively small eyes of the hippopotamus to project far 
above the level of the forehead. The ears are small and rounded, and the slit-like 
nostrils are placed rather close together on the highest point of the broad bristly 
muzzle; while both ears and nostrils alike can be completely closed at the will of 
the animal. The neck is extremely short and powerful; and the body is so deep, 
