The Cockles. Heart Shells 



C. pinnulatum, Conr., is small, th-in, orbicular, with rounded 

 ribs, creamy white, flamed with brown. This is an abundant 

 species, and a favourite food of fishes. Fine specimens may be 

 obtained from their stomachs, to say nothing of the rarer species 

 often discovered there. The mollusk is very active, scurrying 

 over gravelly bottom at a surprising rate by means of its exten- 

 sible, recurved foot. Diameter, h inch. 



Habitat. — Labrador to New York. 



The Basket Cockle (C. corbis, Mart.) is the most abundant 

 and familiar cockle on the west coast. The end view is the ex- 

 act outline of a St. Valentine heart. The beaks meet, the lips 

 interlock their crenulated margins; the surfaces are tlnely striated 

 across the close, rounded ribs. The shells are brittle, often broken 

 when picked up on the beach. The moUusks are eaten, and are 

 sufficiently abundant to appear in the markets north of California. 

 Diameter, 3 to 4 inches. 



Habitat. — Japan to Alaska, southward to San Diego, Cal. 



C. Californiense, Desh., has very close, flat ribs, often so low 

 that the furrows are but scratches on the surface. It ranges 

 with the last species as far as Monterey. Several varieties occur 

 farther north. 



C. quadrigenarium, Conr., is the western counterpart of 

 C. magnum. Its forty or more toothed ribs cover a capacious pair 

 of valves. Inearly youth the shell is smooth. Colour dingy, with 

 yellow teeth and lips. It is taken from deep water. Diameter, 

 4 to 5 inches. 



Habitat. — Pacific coast. 



The Great Cockle (C. elatum, Sby.) has a very ventricose 

 strong shell with yellow shining surface scored with deep grooves. 

 It is the largest of American cockles, attaining six inches in 

 diameter. 



Habitat. — Panama to Santa Barbara, Cal. 



The Ribbed Cockle (C. cosiatum, Linn.) has scarcely a dis- 

 tinctive name in a genus where all shells are ribbed. This species 

 shows an elegance of sculpture that is unexampled in the forms 

 described above. The deep, grooved and ridged sulci are few, 

 because they are so large; the sharp-edged ridges, similarly chis- 

 elled with secondary ridges, are few and well apart. The nine 

 ribs converge in elevated beaks that meet over a straight hinge 

 line. The shells are thin, almost translucent, the white surface 



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