710 MANUAL OF ZOOLOGY. 



Antelopes) there are no incisor teeth in the upper jaw, their 

 place being taken by a callous pad of hardened gum, against 

 which the lower incisors impinge (fig. 406). There are also 

 no upper canine teeth, and the only teeth in the upper jaw 

 are six grinders on each side. In the front of the lower jaw is 

 a continuous and uninterrupted series of eight teeth, of which 



Fig. 406. Skull of a hornless Sheep : i Incisors ; c Canines ; m Molars 

 and praemolars. (After Owen.) 



the central six are incisors, and the two outer ones are regarded 

 by Owen as being canines. Upon this view, canine teeth are 

 present in the lower jaw of the typical Ruminants, and they 

 are only remarkable for being placed in the same series as the 

 incisors, which they altogether resemble in shape, size, and 

 direction. Behind this continuous series of eight teeth in the 

 lower j^w, there is a vacant space, which is followed behind 

 by six grinders on each side. The prsemolars and molars are 

 of the "selenodont" type (fig. 399), and have their grinding- 

 surfaces marked with two double crescents, the convexities of 

 which are turned inwards in the upper, and outwards in the 

 lower teeth. 



The dental formula, then, for a typical Ruminant animal, 

 is 



jjSiaaj ,=. ^3=3; ,,3113 = 3,. 

 33 i i 33 3-3 



The departures from this typical formula occur in the Camelidcz, 



