98 WEST COAST SHELLS 



considerably in different specimens. Pallial sinus 

 large, color white, length about an inch. It lives 

 from Monterey southward. 



Cooperella subdiaphana^ Cpr., the White Cooper- 

 shell. This species has a thin, white, glistening 

 shell, which appears quite swollen. The hinge-teeth 

 are central, and the short ligament is situated almost 

 between the prominent beaks. The length of this 

 southern shell is about half an inch. 



Cooperella scintillaeformis^ Cpr., the Thin 

 Cooper-shell, is another southern species. The 

 shell is very thin and brittle, about the same length 

 as that of the last species, but less swollen. 



Corbula luteola^ Cpr., the Yellow Basket-shell, is 

 a small species found freely in the vicinity of San 

 Diego. The whole shell, which is shaped somewhat 

 like a small Donax, is hardly a quarter of an inch 

 in length, but it is quite strong and is well marked 

 with lines of growth. The edges of a full-grown 

 specimen turn inward like the rim of a paper box. 

 The color is ashy yellow. The ligament is internal, 

 lodged in a small pit, the pallial sinus is small, and 

 the shells are angled at one corner. 



Ned^ra pectinata^ Cpr., the Dipper-shell, is a very 

 small affair, nearly globular, with about twelve 

 prominent radiating ribs. The posterior end is 

 drawn out into a small tube, so that each valve looks 

 like a small dipper. Southern, 6 mm. long. 



We now come to the Myacidae^ a small family, 

 but distinguished as containing one of the most im- 

 portant species on the whole list, if we think of the 

 mollusks only as food for man. Mya arenaria^ Linn., 



