THE BEAD AND NECK 



117 



the 'tusks,' or, more often, 'tushes' (fig. 16, c). They 

 correspond exactly with the tusks of the boar and the 

 great corner teeth of the lion and dog ; but in all the 

 Equidce they play a very subordinate part, not being 

 required either as a means of defence or for the purpose 

 of seizing prey. Following a very general rule among 

 the Mammalia, especially marked in the Ungulates and 

 other groups (as monkeys) in which these teeth are not 

 a necessity for procuring food, they are much more de- 

 veloped in the male than in the female. Indeed, they 

 are practically absent in the latter sex, as, when they 

 do occur as an exception, they are in a more or less 

 rudimentary condition. As the canines were present 

 in both sexes in the Eocene and Miocene Ungulates, 

 their loss in the females of the existing Equidce must be 

 reckoned, like the loss of the anterior premolar, among 

 the numerous instances of specialisation which this 

 group has acquired. 



It may be remarked in passing, that the canines are 

 the only teeth which afford indications by which the sex 

 of an animal may be distinguished, except, of course, such 

 as may be inferred from the general disparity of size 

 which characterises the entire dentition, in common with 

 the rest of the organisation, in many cases. 



In the adult male horse they are always present in 

 both upper and lower jaw, but they are smaller than 

 the incisors, and of different form, being, when unworn, 



