1 9 02.] Allen, North Pacific Phocidcp.. 473 



From the foregoing it is evident that the number of cusps, 

 whether three or four, is in part a sexual character, and in 

 part due to individual variation, and does not serve to dis- 

 tinguish Atlantic coast from Pacific coast specimens. 



Supernumerary Teeth. In addition to the tendency to the 

 development of supernumerary or adventitious internal cusps 

 on the last molar, and to individual variation in the number 

 of what may be termed normal cusps, already noted, the fre- 

 quency of supernumerary teeth in the seals of the Phoca 

 vitulinatype is a matter of interest. The series of 26 North 

 Pacific and Bering Sea skulls contains 5 cases of super- 

 numerary teeth, as follows: 



No. 6970, Mus. Comp. Zool., Plover Bay, Siberia. Alveolus 

 on left side for a supernumerary pm, in front of pm 1 , appar- 

 ently of nearly the normal size of pm 1 . 



No. 21312, Nat. Mus., Bering Island. A supernumerary 

 incisor between i 1 and i 2 on the right side, nearly equalling in 

 size the normal incisors. 



No. 101330, Nat. Mus., St. George Island, Pribilof Islands. 

 Supernumerary premolar on right side, between pm 3 and pm 4 , 

 about the size and shape of pm 1 ; on the left side a super- 

 numerary tooth between pm 4 and the molar, also of about the 

 size and shape of pm 1 . 



No. 82820, Nat. Mus., Coast of Maine. A supernumerary 

 premolar in the lower jaw, inside the tooth line opposite pnij 

 on the left side, larger than a normal pm 1 , and in form a 

 miniature pm 2 . 



No. 22, Mcllhenny Collection (Acad. Nat. Sci. Phila.), Point 

 Barrow, Alaska. A supernumerary tooth inside the tooth 

 line on the right side, opposite pm 1 , and about one third the 

 size of a normal pm 1 . 



NORTH PACIFIC PHOCID^E. 



i. Erignathus barbatus (Fabricius). 



BEARDED SEAL. 



Erignathus barbatus MURDOCH, Rep. Point Barrow Exped. 1885, 95 

 (Point Barrow). NELSON & TRUE, Rep. Nat. Hist. Coll. Alaska, 1887, 



