MAMMALS 



215 



because of the friendly custom cows have of combing each 

 other's hair with their rough tongues, the hair sometimes 



FIG. 390. AFRICAN CAMEL (Camelus dromedarius) . 



being swallowed. Explain the saying that if a cow stops 

 chewing the cud she will die. 



Does a cow's lower jaw move sidewise or 

 back and forth ? Do the ridges on the molars 

 run sidewise or lengthwise ? Is a 

 cow's horn hollow ? Does it 

 have a bony core ? (Fig. 344.) 



The permanent hol- 

 low horns of the cow 

 and the solid decidu- 

 ous horns of the deer 

 are typical of the two 

 kinds of horns pos- 

 sessed by ruminants. 



The prong-horned an- 



FIG. 391. PRONG-HORNED ANTELOPE 

 telope (Fig. 39 1) of (Antelocarpa Americana) . Western states. 



