THE SHEEP AND ITS VARIETIES. 609 
States by the common Virginian deer (Cariacus Virginianus 
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 (2. twrandus 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, hollow when cast off, and the 
gall bladder, which is absent in the Cervid@, the prong-horn 
