150 AMERICAN JOURNAL 



Fig. 4. Pilidium fulvum, Forbes. 



a, dentition, laterals on one side removed to show form of 



Rhachidian tooth. 

 4 a, shell, natural size. 



Fig. 5. Scurria mitra, Esch. (not Gray, Adams). 



a, dentition, from a specimen dredged in 4,fms. N. Harbor, 

 Ounga Island, Alaska. 



b, outline and profile of small specimen. 



c, soft parts, with mantle raised up. 



Fig. 6. ? Cryptohranchia instabilis, n. s. 

 Shell natural size, outline and profile. 



