BIVALVE SHELLS. 41 



a Summit, e e cicatrix, g g g teeth of the hinge, n the inside. 



Venus aurea The Golden Venus. Plate VI. fig. 10. 



Suborbicular, inequilateral, transversely striated, and striated 

 concentrically; of a fine golden-yellow. One inch long, one 

 and a half broad. Inhabits the British seas. 



The shells of tliis genus inhabit the ocean. They in general liu-k in 

 the sand ; and many of the larger species are only to be found in very 

 deep water. 



Genm ll.—SPONDYLUS. 



Animal a Tethys ; shell hard, solid, and ridged, with un- 

 equal valves ; one valve in general convex, and the other 

 rather flat: hinge with two recurved teeth, separated by a 

 small hollow. 



Spondylus Gcederopus. — The G^deropus Spondylus. 

 Plate VI. fig. 11. Upper valve red, under one white with 

 longitudinal striae and ribs, rough granulations, and some- 

 what tongue-shaped, truncated spines, which are rather 

 short. Three inches long. Inhabits the Mediterranean, 

 and is considered excellent food by the Italians. It is sold 

 in the markets at Nice, and other towns on the Mediter- 

 ranean. 



Some of the Spondyli have ears, and others are devoid of 

 them; they are in general strong, rugose shells. This genus 

 requires considerable attention, as some of the species are 

 subject to such variety, that they are frequently mistaken for 

 distinct shells. 



The shells of this genus inhabit the ocean. They adhere to rooks 

 in deep water, and require considerable force to tear them from their 

 retreats. 



Genus 12.— CHAM A. 



Animal a Tethys; shell bivalve, rather coarse; hinge with 

 a callous gibbosity, obliquely inserted into a slanting cavity ; 

 anterior slope closed. 



Chama Cor The Heart Chama. Plate II. fig. 5, and 



Plate VI. fig. 12. (Isorcardia Cor, Lamarck.) Shell sub- 

 globose, beaks recurved ; anterior slope with a gaping fent, 

 d3 



