66 



WEST COAST SHELLS 



The side of the shell is deeply infolded, making a 

 sharp excavation. Its length is only 20 mm., less 

 than an inch. It has been dredged from cold water 

 off the coast of Oregon, and also in the Gulf of Cali- 

 fornia. 



A.xinopsis viridis^ Dall, the 

 Green Axinopsis, is shown in Fig- 

 ure 40. The polished, pale green 

 periostracum gives the shell its 

 specific name. It is only a quarter 

 of an inch across, and so the figure 

 really looks sixteen times too large. 

 Fig.4o, x!(*) Yi^is \^xx\^ mollusk lives in muddy 

 or sandy bottoms along the. coasts from Japan and 

 Bering Straits down to Catalina Island. How full 

 of life are the waters of the ocean. 



Axinopsis sericati/s, Cpr., the Silky Axinopsis, is 

 very similar to the last, but the outline is less cir- 

 cular. It comes from Puget Sound, but also from 

 the coasts of Alaska and California. The silky 

 epidermis suggested its name. 



Diplodonta aleutica^ Dall, the 

 Arctic Diplodonta, ranges from the 

 Pribilof Islands to the Aleutian 

 chain, and eastward to the Shu- 

 magin Islands. The picture. Fig- 

 ure 41, represents a young speci- 

 men, having a silky, olivaceus epi- 

 dermis. Other species grow to the length of an inch 

 or more, and are coarse and chalky. 



Diplodonta orbclla^ Gould, the Round Diplo- 

 donta, is a not uncommon California shell. It is a 



Fig. 41, X \ (*) 



