CHAPTER XVI : THE ICELAND CYPRINA 



Family CvpRiNiDy^ 



Shell regular, equivalve, oval, valves solid; epidermis thick, 

 dark; ligament prominent, outside; hinge with four large inter- 

 locking teeth; umbones oblique; muscle scars two, oval, polished; 

 joined by pallial line; mantle united posteriorly to form two short 

 ciliated siphons, elsewhere free; foot thick, tongue-like; gills un- 

 equal, two on each side. A small family of chiefly fossil species. 



Genus CYPRINA, Lam. 



Characters of the family. 



The Iceland Cyprina (C Islandica, Linn.) is our sole living 

 representative of a family containing fossils of several genera 

 and over one hundred species. It is found as a fossil in Sicily 

 and Piedmont; living it ranges from the coasts of Norway and 

 England to Labrador and south to Massachusetts. When alive 

 the clam wears a shaggy coat of brown or black epidermis. It is 

 like the quahog in general form, or a giant Astarte. It is found 

 after storms on New England beaches. Length, 3 to 4 inches. 



Another genus is represented by one of the handsomest of 

 bivalve shells, Isocardia vulgaris, Rve., remarkable for the spiral 

 development of its beaks. 



Habitat. — China. 



356 



