1346 



CLASS MAMMALIA. 



consequently articulates largely with the nasal (fig. 1220); but in 

 certain Antelopes this vacuity is present, when the relations of these 

 bones are the same as in the Cervidce. Another very characteristic 

 feature of the Bovida, as a whole, is the hypsodont character of 

 their cheek-dentition. In many of the Antelopes (fig. 1221) this 

 feature is only moderately developed, but in the Sheep, Goats, and 

 Oxen it is carried to an excessive degree ; and in the latter group 

 the valleys of the teeth are filled up by a coating of cement. This 

 feature, like that of the relations of the lachrymal, is, however, not 

 absolutely distinctive of the Bovidce, since we find many Antelopes 



Fig. 1220.— Skull of a hornless Sheep (Om's). Reduced. /, Incisors; c, Canines; m, Cheek- 

 teeth; pmx, Premaxilla; mx, Maxilla; na, Nasal; /, Lachrymal ; ju, Jugal;fr, Frontal ; pa, 

 Parietal. (After Owen.) 



(and especially those having a lachrymal vacuity) with a decidedly 

 brachydont dentition. The upper true molars frequently have a 

 large accessory inner column (fig. 1221). Functional canines are 

 wanting in all existing forms. The lateral digits may or may not 

 be present, but in no living form is there a distal remnant of the 

 lateral metapodials. 



This family does not apparently date further back than the 

 Middle Miocene, where it is represented by members of its least 

 specialised group, the Antelopes ; the Sheep and Oxen not ap- 

 pearing till the Pliocene. It has been suggested that the family 

 originated from the same ancestral forms as the Cervidce. 



Commencing with the Antelopes, and confining our attention to 

 those forms in which the genus has been more or less accurately 

 determined, we find in the Alcelaphine section, which is now con- 



