312 University of California Puhlications in Zoology [Vol. 13 



Panope generosa is the largest of the "West Coast clams. This 

 northern form occurs only sparingly in the vicinity of San Francisco. 

 It occurs on sandy or gravelly beaches near the low tide mark, where 

 it burrows deeply. 



Cardium corhis, the true cockle, is a hardy clam living under a 

 variety of conditions from those of an estuary to that of the open 

 ocean. It is perhaps predominantly a mud dweller, although it fre- 

 quently occurs on sandy or gravelly bottoms. It is one of the easiest 

 to procure, since it generally lies on the surface. Although this clam 

 has the reputation of being tough, it is suitable for, and at present 

 is being used, as minced clams. This species is large and lacks the 

 thick, dark epidermis on the siphons, making it more desirable for 

 mincing than similar sized or even larger clams, such as Saxidomus 

 nuttalli or Schizothaerus nuitalli. 



The rock-boring mollusk, Pholadidea penita, occurs quite abund- 

 antly in the softer rocks within the Golden Gate and along the ocean 

 beach. It is said to be very palatable by those living near the rocks 

 in which these, incorrectly called "rock oysters," live. As yet this 

 clam has not been considered of economic importance, although it 

 might well be investigated from that standpoint. 



Besides these well known edible clams there are several native 

 forms that might well serve as food if means for their cultivation 

 were devised. One of these, the Macoma nasuta, occurs very abund- 

 antly on the muddy or sandy beaches along the bay. It is a very 

 small clam, about the size of the native oyster, but it has a good flavor 

 and is easily obtained, since it does not burrow deeply. The true 

 ''razor clam," Solen sicarius, is reported to be excellent. It is a 

 deeply burroAving, sand-dwelling form that is difficult to obtain. It 

 probably thrives best on the sandy beaches along the ocean front. 

 Spisula catillifornis is represented in the Survey collections by a few 

 specimens obtained from the Golden Gate. It is a large but rare 

 clam that might possibly be successfully grown along the sandy beaches 

 outside San Francisco Bay. Certain species of Pccten occur very 

 abundantly in Puget Sound at depth of several fathoms. It is pos- 

 sible that the same or similar species may occur off the Golden Gate 

 in quantities sufficient to have an economic significance. The dredg- 

 ings of the "Albatross", however, failed to reveal any such beds at 

 the few outside stations. 



From the above discussion it is evident that the waters of San 

 Francisco Bay and immediate vicinity offer suitable habitats for a 



