100 



NORTH AMERICAN FAUNA 74 



Fig. 66. Examples of the four types of abraded facets on the cheek teeth of Pacific 

 walruses: (a) occlusal facet (O) on P. (b) occlusal and lingual (L) facets on P2, (c) labial 

 facet (B) on ?£, and (d) blending of the incisi\e facet (I) with the labial and occlusal 

 facets on Cj. Inset, abrasion of the vestigial upper incisors (arrows) to the level of the 

 gingival surface. (Photos by K. L. Austerman and G. C. Kelley) 



