CHAMA, CARDIUM AND VENUS 67 
Smithsonian Institution, and the one most entitled 
to permanence has been selected to remain. 
The specimen figured above was over five inches 
in length, and weighed over a pound, without the 
animal. The valves are very thick and heavy, 
even to their edges, which are smooth and finely 
rounded. Hinge-teeth strong, heavy ligament ex- 
ternal, pallial sinus 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-sears. The Tivelas live from Santa 
Cruz southward, and burrow but shghtly. Some. 
times 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 even get into the city markets. 
Amiantis 
callosa, Conr., 
the White Ami- 
antis, is shown 
in Figure 52. 
This is a beau- 
tit uel, spain e 
white, south- 
ern shell, three 
or four inches 
in length. The 
valves are thin 
at the edges and thick near the umbones. Exter- 
nally there are no rays whatever, but many concen- 
