92 



POPULAR CONCHOLOGY. 



others very singular in form; amongst the 

 latter is the species Cardium cardissa, in which 

 the valves are flattened, but in a contrary 

 manner to the generality of flat Bivalves. This 

 genus is found almost every where lying bu- 

 ried in the sand near the sea-shore ; by means 

 of their long elbow-shaped foot, the animals 

 have the power of leaping to a considerable 

 distance. Cardium edule is the common spe- 

 cies, and is frequently used as an article of 

 food. 



51. Cardita. — Shell equivalve, oblong, in- 

 equilateral, having in one valve two unequal 



teeth, one short and straight under the bosses, 

 the other oblique, and in the other one thick, 

 oblique, elongated tooth. Valves more or less 

 strongly ribbed or smooth, waved at the edge. 

 Animal, foot large and thick. — 25 species 

 recent, 7 fossil. 



Some species are said to attach themselves 



