CHAMA, CARDIUM AND VENUS 61 
the umbo to the edge of the shell. Internally there 
is a central hinge-tooth, and also strong lateral 
ones, somewhat removed to the right and left. The 
pallial line is simple, for these creatures do not 
burrow. They have a long and strong foot, how- 
ever, by means of which they can move rather 
freely, or even anchor themselves, if such an oper- 
ation 1s necessary. 
Figure 47 gives a 
good end view of Car- 
dium corbis, Mart., the 
Basket Cockle. This is 
the most common spe- 
cies on the west coast, 
occurring as far south 
as San Diego. But the 
true home of this species 
is in the cold water of 
the “norths «At Hort- 
Wrangel in Alaska, I 
collected very fine speci- 
mens, one morning when 
the tide was low, some of which were four inches 
across. ‘The shell is rather brittle, being of an 
earthen texture, and specimens are easily broken. 
Like most of the creatures of the sea, the cockles 
make an excellent article of food. This species 
lives as far north as Bering Sea, and follows down 
the other coast to Japan. It includes C. nuttalli, 
Conr. 
Cardium californiénse, Desh., the California 
Cockle, has a similar range but is reported only 
