CHAMA, CARDIUM AND VENUS 



n 



ternal, and the pallial sinus is small. Externally the 

 shell is smooth, yellowish white, sometimes marked 

 with conspicuous purple rays, and is partly covered 

 with a glossy epidermis. The inside is white, with 

 purple muscle-scars. The Tivelas live from Santa 

 Cruz southward, and they burrow but slightly. 

 Sometimes at low tide the farmers come down with 

 a plow and run furrows in the sand, turning out the 

 mollusks like potatoes. They are highly esteemed 

 by lovers of a good clam chowder, and occasionally 

 they get into the city markets, where they are called 

 Pismo clams. 



Amiantis cal- 

 losa^ Conr., the 

 White Amian- 

 tis, is shown 

 in Figure 50. 

 This is a beauti- 

 ful, pure white, 

 southern shell, 

 three or four 

 inches in 

 length. The 

 valves are thin at the 

 edges and thick near the 

 u m b o n e s. Externally 

 there are no ribs what- 

 ever, but many concen- 

 tric, rounded ridges, some 

 of which divide into two. 



Fit aria newcomhiana^ 

 Gabb, Newcomb's Pita- Fig. 51, x g (*) 



Fig. 50 



