MAMMALIA 



"3 



antelope, they are shed annually, which is not the case with the 

 last-named form, and a further difference is seen in the presence 

 of a small front branch. The two peculiarities mentioned 





Fig. 77. — The Prongbuck {Antilocapra Americana) 



suggest antlers, but otherwise there is no reason for classifying 

 Prongbucks with the deer. 



4. The Ox Family is an exceedingly large one, including those 

 forms which are commonly known as hollow -horned ruminants 

 (Cavicornia), because the unbranched horns, which are never shed, 

 consist of hollow horny sheaths borne upon bony outgrowths from 

 the skull. They may be present in both sexes, or else restricted 

 to the male. The upper incisors and also the canines are absent, 

 their place being taken by a horny pad, against which the lower 

 front teeth bite, as in deer, prong-bucks, and giraffes. The feet 

 are much like those of deer, each possessing two large toes shod 



VOL. I. 



