VENERID^E. 63 



Artemis (Poli). Shell round, compressed, marked 

 with concentric lines ; ligament sunk, margins 

 smooth ; hinge with three cardinal teeth, and one 

 front tooth beneath the lunule. Animal with a 

 large, hatchet-shaped foot; edges of the mantle 

 slightly plaited ; siphons entirely united, plain. 



A. exoleta. Fig. 92 ; J- n. s. 

 lincta. 



Cytherea (Lamk.). Shell thick, ovate or round; 

 margins single ; hinge as in Artemis. Animal 

 with the mantle-edges plain; siphons united 

 half-way. 



C. Chione. Fig. 93 ;" J n. s. 



93 



Venus (Linn.) Shell thick, ovate or round, 

 often marked with crossed furrows ; margins 

 minutely notched ; hinge-teeth ; ligament promi- 

 nent ; lunule distinct ; pallial sinus small, angular. 

 Animal with mantle-edges fringed ; siphons sepa- 

 rate. 



V. casina. V. ovata. 



fasciata. striatula. 



gallina. verrucosa. Fig. 94 ; n. s. 



