MAMMALS. 119 



said to be in the velvet. When the horn is fnlly formed 

 the skin dies and is worn off. In some deer horns are borne 

 only by the male, but sometimes both sexes, as with the 

 reindeer, are provided with them. The long-necked giraffes 

 are closely related to the deer. 



In other ruminants the horns are never shed. In these 

 the horns consist of a central core of bone, covered on the 



FIG. 51 Prong-horned antelope (Antilocapra americana). 



outside with a horny structure in reality modified hair 

 (p. 97). Here belong our domestic cattle, which are be- 

 lieved to have arisen from four different kinds, which 

 formerly were wild in Europe. This wild stock is almost 

 extinct. One of these forms at least was closely similar to 

 our American bison, which has so nearly approached ex- 

 tinction from the desire for "buffalo " robes. The true 

 buffalo are all natives of the Old World, and occupy a posi- 

 tion between the ancestors of domestic cattle and the long 

 series of forms grouped together as antelope, most of 



