The Cockles. Heart Shells 



bears a brown marginal band, and the sulci are brown. Length, 

 3 or 4 inches. 



Habitat. — East coast of Africa. 



Genus LIOCARDIUM, Swains. 



Shell oval, elongated, oblique, inequilateral ; surface smooth. 



L. serratum, Linn., has only fine, concentric growth lines 

 to roughen its smooth surface. The valves are deep, round 

 saucers, thin as our grandmother's tea set, the white exterior 

 tinged creamy by the rich yellow that lines it. Children playing 

 at housekeeping on Florida beaches call these indispensable little 

 shells, "buttercups." Diameter, 2 inches. 



Habitat. — Cape Hatteras southward. 



The Egg Shell Cockle (L. substriatum, Conr.) thin, show- 

 ing only faint remnants of ribs, is splotched, especially within, 

 with reddish brown, as certain birds' eggs are. The valves are 

 circular with elevated beaks. Diameter, i to i J inches. 



Habitat. — California. 



Genus SERRIPES, Beck. 



Shell subcordate, compressed, thin, almost equilateral; sur- 

 face with obsolete, radiating ribs; beaks prominent; cardinal 

 hinge teeth wanting. 



S. Groenlandicus, Chemn., has the generic characters. It is 

 invested with a drab or olive epidermis. Length, 2 or 3 inches. 



Habitat. — Maine northward, Alaska, Puget Sound. 



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