CARDIUM. l8l 



Li-o-car'-di-um e-la'-tum. As the last species was 

 essentially a northern mollusk, so this one makes 

 its home in the warmer waters of the south. It 

 has a fine heart-shaped shell, yellowish white in 

 color and covered with a delicate, light brown 

 epidermis. It is nearly smooth, but is marked 

 by about fifty small ribs, and the same number of 

 interlocking teeth on the edge of the valves. Some- 

 times it grows to a great size, six inches or more in 

 diameter. While one of these cockles would be 

 enough for a meal, the shells would answer for bowls 

 to contain the chowder. 



Liocardium siibstriatum, Conr. , sub-stri-a'-tum. 

 This is a smooth little cockle, and like the last one 

 it lives in the south. Its shape is 

 shown in Fig. 154, which gives an 

 enlarged view, for the shell is not 

 much more than half an inch in 

 length. Its color is a light drab, 

 spotted with yellow. With a glass, 

 very fine lines of growth may be 

 observed; from this circumstance it 

 Fig. 154. takes its name, which may be freely 



translated, fine-lined. In shape and color it greatly 

 resembles a sparrow' s Qgg, and contrasts strongly with 

 its neighbor, the giant elatum. 



All of the Cardiums are beautiful in outline and 

 regular in growth. They are free movers, having a 

 strong foot, with which they can dig or jump. 



Quite unlike them in all these respects is the next 

 genus, one species of which is illustrated in Fig. 155. 

 The outer surface is gray or greenish, sometimes 

 dashed with rosy red. It is very rough, being cov- 

 ered by many close frills, which are translucent, like 



