482 Bulletin American Museum of Natural History. [Vol. XVI, 



development of a minute cusp behind the secondary cusp, especially on 

 pm 3 and pm 4 . The posterior three lower teeth are generally 4-cusped. 

 The same irregularity in the number of cusps, already mentioned as 

 occuring in Phoca vitulina and P. richardii, is found in P. ochotensis. The 

 lower molar, however, appears to be pretty uniformly 4-cusped, with 

 quite frequently an ' adventitious ' cusp at the postero-inner base of the 

 main cusp. 



The only complete skull is that of the type, an adult female, which 

 measures as follows : Basal length, 200 mm. ; greatest zygomatic breadth, 

 114; mastoid breadth, 117; front border of premaxillae to pterygoid 



hamuli, 105; front- 

 border of upper in- 

 cisors to posterior 

 border of upper mo- 

 V I lar, 67; front bor- 



der of premaxillae 

 to meatus auditori- 

 u s, 142; palatal 

 length (along me- 

 dian line), 78; pal- 

 ato-maxillary 

 suture to pterygoid 

 hamuli, 44; palato- 

 maxillary suture to 

 interior border of 

 foramen magnum, 

 130; palatal width 

 between the mo- 

 lars, 42; length of 

 upper toothrow, 45 ; 



length of nasals, 43; breadth of nasals at fronto-maxillary suture, 

 12; least interobital breadth, 14; length of brain-case, 85; greatest 

 width of brain-case, 91; length of lower jaw, 129; lower tooth- 

 row, 46. The male skulls are imperfect; the parts preserved include 

 the frontal portions, with the complete dentition, and indicate that the 

 males are somewhat larger than the females, with rather heavier teeth. 



This species is represented by five specimens (skins and 

 skulls), collected by Mr. N. G. Buxton on the Taiganose Penin- 

 sula, 20 miles south of the mouth of the Gichiga River, August 

 17 and 1 8, and September 4, 1901. 



In cranial and dental characters Phoca ochotensis is inter- 

 mediate between Phoca vitulina and P. gr&nlandica, but is 

 widely distinct from either. Subgenerically it is a Phoca and 



Fig. 6. Phoca ochotensis. Am. Mus. No. 18169. Outside am 

 crown views of upper and lower teeth. Nat. size. 



