636 AFRICAN GAME ANIMALS 



to the modern horses, only the remote ancestral forms of 

 which were three-toed like the rhinoceros. In shape of 

 body the rhinoceros is not very unlike the hippopotamus, 

 the body being almost equally long, but the legs are in 

 most of the forms decidedly longer, so that the animal is 

 capable of travelling at really astonishing speed considering 

 its immense size. The skin is very thick, dense in texture, 

 and usually quite hairless. The skin of the two African 

 genera resembles in general appearance that of the elephant, 

 but it is of a very different quality, being much denser and 

 more armor-like. The hair is confined in the existing 

 species chiefly to the tips of the ears and the tail, but the 

 recently extinct woolly rhinoceros, which lived far north in 

 Europe and Asia, was clothed by a coat of long hair to pro- 

 tect it from the cold. In dental characters the various 

 genera of rhinoceroses exhibit much diversity, but the cheek- 

 teeth show a peculiar pattern of folds which are character- 

 istic of the family. The great bulk of the genera had well- 

 developed incisor teeth in both jaws, and some of the very 

 ancient types had canine teeth as well, but the living African 

 forms lack all indication of either incisor or canine teeth. 

 The cheek-teeth usually consist of the full number found 

 in mammals, that is, four premolars which have milk pred- 

 ecessors and three molars. The premolars and molars are 

 quite alike in shape and size, except the first premolar 

 which is usually small and sometimes wanting. The cheek- 

 teeth, as a rule, are composed only of dentine and enamel 

 and are broad-crowned, the crowns being thrown into two 

 transverse folds projecting inward with deep valleys sepa- 

 rating them. Certain forms, however, such as the white 

 rhinoceros of Africa and the woolly rhinoceros of the boreal 



