54 CONCHOLOGY. 



epidermis, beneath which the shell is of a beautiful purple ; 

 radiated longitudinally, faintly wrinkled transversely, ante- 

 rior cardinal tooth entire, and without a striated canal ; apex 

 turned sideways, with a cordiform depression. 



C. mactroides. The Mactra-like Cytherea. PI. 9, fig. 4. 

 Species thin, convex, triangular ; summits very marked ; 

 margins sharp ; anterior cardinal tooth entire. 



C. pectinata. The pectinated Cytherea. 

 Species oval, thick, solid, more or less compressed, cos- 

 tated, pectinated upon the edges. 



6. Venus. Eighty-eight species. 

 This genus of shells is numerous and varied. It sur- 

 passes all bivalve shells in beauty, and is in form very like 

 the Cytherea, but easily distinguished by the hinge, which 

 almost invariably contains three approximate teeth, and a 

 lateral tooth diverging to the summit. The internal margin 

 of the valves is crenated or dentated, with or without la- 

 mellar striae. 



The shells are of the most beautiful and lively tints ; the 

 exterior as well as the interior colouring is of almost every 

 possible shade and hue. They are found buried a little 

 below the surface on the sandy shores of most parts of the 

 world, particularly in warm climates. 



Shell solid, thick, regular, perfectly equivalve and close, 

 more or less inequilateral ; summits well marked, inclined 

 anteriorly ; hinge sub-similar ; the middle cardinal tooth 

 forked, or three cardinal teeth more or less contiguous and 

 convergent towards the summit ; ligament thick, often arched, 

 convex, and exterior; two distant muscular impressions; 

 cordiform depressions beneath the beaks. 



Venus puerpera. Venus verrucosa. 



V. reticulata. V. rugosa. 



V. pygmaea. V. casina. 



V. corbis. V. crebiscula. 



