ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



79 



Fig. 51. Calcified dentition of a newborn Pacific walrus calf. Primary teeth present on 

 one or both sides include i^-^, c^ p2-3, and in the skull (upper-ventral view) and 13, cj, 

 P2.3.4, and mj in the mandible (lower-dorsal view); secondary teeth are as labelled. 

 (Photo by K. L. Austerman) 



the maximal formula was 



. 1-2-3 1 2-3-4 1 - _ 



The follicle of pi was identified in less than half of these specimens; in no case 

 was there any sign of its being calcified. Calcified tissue was absent in most cases 

 also from the follicles of il, i^, and the lower incisors. Even where there were no 

 secondary successors, most of the primary incisors showed resorption of half or 

 more of the tooth. Resorption seemed to have begun usually at the level of the 

 cemento-enamel junction rather than on the apical part of the root. Partial 

 resorption of the primary canines and premolars also was common, but it usually 

 had begun on the lingual aspect of the root, adjacent to the secondary tooth. 



