THE SHEEP AND ITS VARIETIES. 609 



States by the common Virginian deer (Cariacus Virginians s 

 Gray, Fig. 526), the elk or wapiti (Cervus Canadensis Erxle- 

 ben, Fig. 527), and the caribou (Rangifer caribou Audubon 

 and Bachman), which is probably a variety of the European 

 reindeer (R. tarandus Sundevall). In these beautiful, grace- 

 ful forms the solid antlers are cast off annually ; with the 

 exception of the reindeer the females or does have no antlers. 

 The prong-horn antelope (Antilocapra Americana Ord, 



Fig. 528. Head of young Prong-horn Antelope. After Hays. 



Fig. 528) so characteristic of the western plains, also drops 

 its horns in the autumn, though they are hollow when shed 

 and with a persistent core as in the ox and goat. It crops 

 grass, not, like the deer, eating leaves of trees and shrubs ; 

 " in fleetness it excels all other quadrupeds of our conti- 

 nent," though it is short winded, and does not run a great 

 distance (Caton). In its horns, holloAv when cast off, and the 

 gall bladder, which is absent in the Cervida;, the prong-horn 



