234 



A COURSE ON ZOOLOGY. 



only living representative of a suborder, called probos- 



cidea, 



FIG. 166. 



RHINOCEROS. 



HIPPOPOTAMUS. 



RUMINANTS. 



ELEPHANT. 



FIG. 167. 



The. ruminants or cud-chewing mammals are herbiv- 

 orous, and flesh forms no part of their food. Their 

 teeth are not sharp-edged, but flat, and 

 adapted for grinding; their digits do 

 not terminate in claws, but in a horny 

 hoof, a means of defence and not of 

 attack. In all the ruminants this hoof 

 is split in the median line, and so forms 

 a bifurcated sheath for the two toes 

 that compose the foot; ruminants are 

 said to be cloven-footed. Lastly, the 

 upper jaw is usually without incisors, 

 and the stomach has four distinct com- 

 MOLAR OF AN ox. partments. 



The details of the digestive functions 

 of ruminants are very different from those of animals 

 whose stomachs form a simple sac. When an ox eats, 

 he simply swallows the grass, almost without mastica- 



