338 COMPARATIVE ZOOLOGY. 
milk-teeth are succeeded by a permanent set. The grind- 
ers have broad crowns. As a rule, all are herbivorous. 
The brain is always convoluted, but the cerebellum is 
largely uncovered. 
Ungulates are divided into the odd and even toed. a. 
The Odd-toed, as the three-toed Rhinoceros and Tapir,’” 
and the one-toed Horse.“ The first is distinguished by 
its very thick skin, the absence of canines, and one or two 
horns on the nose. The tapir has the four kinds of teeth, 
and a short proboscis. The dental formula of the Horse 
is— 
i, om, pm —, mo = 40. 
The canines are often wanting in the mare. The Horse 
walks on the third finger and toe. The metacarpals and 
metatarsals are greatly elongated, so that the wrist and 
heel are raised to the middle of the leg. 6. The Zven-toed 
Ungulates— Hog, Hippopotamus, and Ruminants— haye 
Fig. 334, —Indian Rhinoceros (R, unicornis). 
