104 



VERTEBRATA : MAMMALIA. 



Passing now from artiodactyl ungulates which have 

 permanent, hollow horns, we come next to the Prong- 

 horn " Antelope " (Fig. 110), which differs from the true 

 antelopes in the fact that its horns have a prong or 

 branch, and are not permanent, but deciduous, notwith- 

 standing that the horns have an osseous core similar to 

 that found in the Bovidse described above. It is there- 

 fore referred to a distinct family, the Antilocapridse. The 

 Pronghorn of our Western plains, is a beautiful animal, 

 somewhat larger than our domestic sheep ; its coarse hair 

 is brown above, and the nnder parts and rump are white. 



Quite different from all of the artiodactyl ungulates al- 

 ready named, are the Deer or Cervidse. These have their 



FIG. 112. 



Virginia Deer, Cervus virginianus, Boddaert. 



horns solid and deciduous. Their so-called horns are at 

 first covered with skin similar to that upon the rest of the 

 head. At their base is a ring of bony tubercles, which, 

 as they enlarge, compress and obliterate the blood-vessels 



