326 



A MANUAL OF DENTAL ANATOMY. 



tusks of the adult animal are not represented in the canines 

 of the milk dentition, about which there is not much that 



is noteworthy, save that the young pig has dec. m , of 



which the first remains in place till the permanent dentition 

 is nearly complete, and then falls out without having any 

 successor ; or it may perhaps be regarded as a permanent 

 tooth which has had no predecessor. 



The form and direction of the canines are alike peculiar ; 



FIG. 139 



i Nat. Size 



the upper canine, which in its curvature describes more 

 than a semicircle, leaves its socket in a nearly horizontal 

 direction, with an inclination forwards and outwards. After 

 rounding past the upper lip its terminal point is directed 

 upwards and inwards. The enamel upon the lower surface 

 of the tusk is deeply ribbed : it does not uniformly cover the 

 tooth, but is disposed in three bands. The lower canines 

 are more slender, of much greater length, and by wear 

 become more sharply pointed than the upper ones : they 

 pass in front of the latter, and the worn faces of the two 

 correspond. 



The lower canine is in section triangular, one edge being 



(i) Upper and lower teeth of Wild Boar (Sus scrofa). In this specimen 

 the tusks are not so largely developed as they sometimes may be seen to be; 



