352 COMPARATIVE ZOOLOGY. 
Ungulates — Hog, Hippopotamus, and Ruminants have 
two or four toes. The Hog and Hippopotamus have the 
four kinds of teeth, and, in the wild state, are vegetarian. 
The Ruminants have two toes on each foot, enveloped in 
hoofs which face each other by a flat side, so that they ap¬ 
pear to be a single hoof split or “ cloven.” Usually there 
are also two supplementary hoofs behind, but they do not 
ordinarily touch the ground. All chew the cud, and have 
a complicated stomach. They have incisors in the lower 
jaw only, and these are apparently eight; but the two 
outer ones are canines. 180 The molars are flat, typical 
grinders. The dental formula of the Ox is— 
i °~° , c °~° , pm 3 ~~_ 3 , m 3 — 3 = 32 . 
With few exceptions, as the Camel, all Ruminants have 
horns, which are always in pairs. Those of the Deer are 
solid, bony, and deciduous; those of the Giraffe and An- 
Fig. 344.—ludiau Rhinoceros (R. unicornis). 
