MOLARS. 



185 



TUSKS. 



The tusks are much more developed in the male than in 

 the female; they are 

 prismatic in shape and 

 curve outward and back- 

 ward. In the wild hog 

 they may attain an enor- 

 mous length (six inches 

 or more), pressing the 

 upper lip upward and 

 the lower lip downward 

 and crossing each other 

 in an X, the superior 

 tusk passing behind the 

 inferior; the two fre- 

 quently have their re- 

 spective anterior and pos- 

 terior faces much worn 

 by the constant friction 

 from their contact with 

 each other. The tusks 

 continue to grow during 

 the life of the animal. 

 The growth is diminished 

 in the castrated male. 



MOLARS. 



The molars are di- 

 vided into premolars and 

 post-molars. The first 

 premolar resembles very 

 much the conical corner 

 incisor tooth, but has two 

 roots instead of one. It 

 is placed in the interspace between the tusks and the other molars, 

 being about twice as far from the latter as from the former. 



Fig. 170. 

 Lower jaw of pig, showing permanent dentition. 



