84 University of California Publications in Geology [Vol. 13 



Table Showing Variations in Dental Formulae of the Suborder Pinnipedia 



Incisors Canines Premolars Molars 



, A A A A ' 



ODOBENIDAE Upper Lower Upper Lower Upper Lower Upper Lower 



Prorosmarus 



X 



2 



X 



1 



X 



4 



X 







Alachtherium antverpiensis 



















Milk dentition 



3 



X 



1 



X 



4 



X 



1 



X 



Permanent dentition .... 



2 



X 



1 



X 



4 



X 



1 



X 



Alachtheriuiri cretsii 



X 



2 



X 



1 



X 



3 



X 







Tricheeodon 



2 



X 



1 



X 



4 



X 



1 



X 



Odobenotheriuni 



1 

 1 



A 

 U 



1 



~l 



1 



6 



Q 

 O 



A 

 U 



A 



u 



Odobenus 



















Milk dentition 



Q 

 O 



Q 



1 



~l 



1 





A 



<± 



1 



1 



X 



Permanent dentition — 



X 



U 



1 



1 



6 



Q 



o 



u 



A 



u 



Otariidae 



















Eumetopias 



3 



2 



1 



1 



4 



4 



1 or 2 



1 



Allodesmus 



X 



2 



X 



1 



X 



4 



X 



2 



Zalophus — ' 



3 



2 



1 



1 



4 



4 



1 or 2 



1 



Desmatophoea 



3 



2 



1 



1 



4 



4 



1 



1 



Arctoeeplialus 



3 



2 



1 



1 



4 



4 



1 or 2 



1 



Callotaria 



3 



2 



1 



1 



4 



4 



1 or 2 or 3 



1 



Phocidae 



















Phocinae 



















Phoca 



















Milk dentition 



3 



2 



1 



1 



3 



3 











Permanent dentition .... 



3 



2 



1 



1 



4 



4 



1 



1 



Erignathus 



3 



2 



1 



1 



4 



4 



1 



1 



Halichoerus 



3 



2 



1 



1 



4 



4 



1 or 2 



1 



Monachinae 



















Monaehus 



2 



2 



1 



1 



4 



4 



1 



1 



Paleophoca 



X 



2 



X 



1 



X 



4 



X 



1 



Pristiphoca 



2 



X 



1 



1 



4 



4 



X 



1 



Monotherium 



3 



2 



1 



1 



4 



4 



1 



1 



Lobodoninae 



















Leptonychotes 



2 



2 



1 



1 



4 



4 



1 or 2 



1 



Hydrurga 



9 



2 



1 



1 



4 



4 



1 



1 



Lobodon 



2 



2 



1 



1 



4 



4 



1 



1 



Ommatophoea 



2 



2 



1 



1 



4 



4 



1 or 2 



1 



Cystophorinae 



















Cystophora 



2 



1 



1 



1 



4 



4 



1 or 2 



1 



Mirounga 



2 



1 



1 



1 



4 



4 



or 1 







There appears to be considerable variation in the number of cusps 

 exhibited by the molariform teeth of the Phocidae. The number of 

 cusps on the lower molars varies from three to four in Phoca vitulina, 

 P. richardii, P. ochotensis, and P. hispida} 10 This variation is true 



i"o Allen, J. A., op. tit., p. 478. 



