NO. 2295. NEW NORTH PACIFIC AIOLLUSKS—DALL. 371 



spherically inflated, short, truncate behind; beaks inconspicuous, 

 situated about the middle of the valves; anteriorly the valves are 

 rounded, behind they are compressed into a short rostrum about 

 one-fourth the whole length; sculpture of rather rude lines of growth, 

 the external layer obscurely granulose, especially in front; interior 

 of the valves chalky white, the muscular impressions distinct, the 

 pallial sinus rounded, slightly less than hah the length of the valve 

 its impression formed by two almost separate rather broad patches ; 

 hinge as usual in the genus. Length, 12; height, 9; diameter, 9 mm. 

 U. S. Nat. Mus. Cat. No. 218977. 



Type-locality — Baulinas Bay, California, Mi's. T. S. Oldroyd. 



This is by far the most inflated and subspherical member of the 

 genus from the west coast. 



