1 78 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 6 



face and occasionally others scattered irregularly over the apertural face. 



Diameter 0.80-1.00 mm; thickness 0.40-0.50 mm. 



This is the only species of the genus known from the West Coast of 

 America, but is fairly common as a living species and is recorded from the 

 Pleistocene and Pliocene of California. 



Stations: A-1, A-2, A-3, A-4, A-6, A-15, A-20, A-22, A-23, V-3, 

 Silex, Oregon, C-1, C-9, 225, Penang. 



Distribution. — These localities indicate a continuous range from oflf 

 the coast at Cordova, Alaska, southward to the east side of Cedros Island, 

 Mexico, in shallow waters. The bottom sample from Penang, low tide, 

 also contained a few specimens which have been placed with those from 

 this edge of the Pacific Ocean. 



