THE AMERICAN BISON 187 



(2) At intervals each horn is cast, after which a new one 

 is formed on the bony cores beneath it. This species 

 terminates our list of creatures with horns formed on 

 essentially the same type as those of the animal known 

 in the United States as the buffalo. Thus the American 

 bison is a very exceptional hollow-horned ruminant ; 



FIG. 50. 



THE PRONG-HORNED ANTELOPE. 



in other words, it is a member of a great group a family 

 which contains, together with the oxen, all the sheep, 

 goats, and antelopes. 



Another great group of allied animals consists of the 

 deer, whereof the magnificent North American deer, the 

 wapiti, may be taken as a type. None of the deer have 

 outgrowths of true horny matter deposited on a bony 

 support. Instead of that they have antlers that is, 



