390 A MANUAL OF DENTAL ANATOMY. 



shed about the time of birth (of. page 300). Thus Pro- 

 fessor Flower tells us that in a Phoca greenlandica a week 

 old scarcely a trace of the milk teeth was left. 



The teeth of Otaria and of some other seals become 

 much worn down, and they also seem to become eroded at 

 the level of the gums, as they are often deeply excavated at 

 points which seem unlikely to have been exposed to friction, 

 but the nature of this erosion has not been adequately in- 

 vestigated. 



The common seals (Phoca) have. a, dental formula 



.3 1 4 1 



i _ c -p _ m - . 

 3 1 l 4 1 



The incisors are of simple form, and the outer are the 

 larger. The canine is a strong recurved tooth, with a 

 large root ; behind it follows a series of molars, each of 



FIG. 171 I 1 ). 



which (with the exception of the first) bears a central 

 principal cusp, with a smaller accessory cusp before and 

 behind it. The forms of the crowns vary a good deal in 

 different genera, in some the cusps being much larger, 

 more deeply separated from one another and recurved ; and 

 in others the accessory cusps being multiplied, so that the 



( { ) Teeth of Phoca greenlandica. 



