304 The Antelope. 



already explained, the horns of North American ruminants are of 

 two kinds : solid, like those of the deer, and hollow, like those of 

 the ox. To this latter class belong those of the antelope, but with 

 this modification, that the horny epidermic sheath which incloses 

 them is not, as is the case with all other hollow-horned ruminants, 

 a permanent covering. The zoologist knows that scales, feathers, 

 hair, claws, hoofs, and horns are but modifications of the epidermis, 

 and grade into one another in such a way that it is often impos- 

 sible to decide at what point one form of covering ends and another 

 begins. The sheath of the antelope's horn is one form of dermal 

 outgrowth. Chemically, there is scarcely any difference between it 

 and the hair, and to all intents and purposes it is composed of hairs 

 agglutinated together. Herein lies the fundamental difference be- 

 tween the shedding of the deer's antlers and that of the antelope's 

 horns. The deer loses a bony outgrowth — a portion of the skeleton ; 

 while the antelope parts with a dermal outgrowth — a portion of the 

 integument. 



When the antelope sheds its horns, therefore, they do not drop 

 off close to the skull, leaving the head bare like a deer's under 

 the same circumstances, but the sheath falls off from the core, which 

 is now tipped with a new horn, and clothed elsewhere with a thick 

 hairy skin, which before long becomes hard black horn. The adult 

 male antelope is therefore never entirely without horns. The 

 sheath is lost in November or December after the rutting season 

 is over. 



Another remarkable characteristic of the antelope is the absence 

 of the supplementary hoofs, or " dew-claws," which represent the 

 second and fifth digits of the foot. These are present in all the 

 other Pecora except the giraffes. 



From the combination of anomalous characters found in this 

 species, it has been considered with great interest by naturalists, 

 and a very high authority has separated it from the true antelopes 

 and placed it in a family (Antilocapridce) by itself, thus making 

 the single genus and species (Antilocap7'a Americana Ord) the 

 equivalent in zoological rank of so important a family as the Bovidce. 



The prong-horn antelope stands nearly three feet high at the 

 withers, and is from four and one-half to five feet in length. Its 

 body is short and stout, head long and slim, neck rather short and 



