ORDERS OF MAMMALIA. 



339 



Sheep, Goats, aud Antelopes, and are characterised by having horns, 

 which may be present in one or both sexes, and consist of a horny 

 sheath surrounding a central bony axis, or " horn-core " (fig. 245). 

 The horns are persistent, and are not periodically sVied, and there 

 is usually only a single pair, though sometimes there are two pairs. 

 In the Prong-buck Antelope alone, the horny sheath which sur- 

 rounds the horn-core is annually shed and reproduced. In their 

 dentition, and in other respects, the Cavicornia are to be regarded 

 as being the most typical examples of the Ruminantia, and they 

 include a number of animals which are of the highest utility to 



Pig. 245. 



-Skull of the Cape Buffalo {Bubahts caffer), viewed from above, 

 showing the horn-cores, (After Cuvier.) 



The Antelopes form a very extensive group, closely resembling 

 the true Deer, but distinguished by the possession of hollow horns, 

 in place of solid antlers. Most of the Antelopes are African, and 

 there are only two European forms (the Chamois being one), while 

 America possesses only the Prong -buck {Antilocapra furcifer). 

 Among the more familiar African species may be mentioned the 

 Koodoo (fig. 246), the Gnu, the Gemsbok, and the Springbok. 

 The Sheep and the Goats (Ovidce) are closely allied to one another, 

 and are well known by their domestic varieties. All the Sheep are 

 natives of the Old World, with the exception of the " Big-horn " 

 (Ovi.1 montana) of the Eocky Mountains. Among the true Oxen 



