276 



POPULAR CONCHOLOGY. 



Cardita. Brug. (Venericardia Lam,) — Shell equi- 

 valve, oblong, inequilateral, 

 having in one valve two un- 

 equal teeth, one short and 

 straight under the bosses, the 

 other oblique, and in the other 

 valve one thick, oblique, elon- 

 gated tooth ; valves more or cardua. 

 less strongly ribbed or smooth, 



waved at the edge. Animal, having the mantle lobes 

 entirely separated as far as a small united portion which 

 divides the mantle cleft from a round hinder opening, 

 which is the common opening for the egress of the water, 

 &c, the mantle edge is without distinct cirrhi ; the foot 

 is compressed, triangular, wrinkled, with a byssus; the 

 gills form on each side a pair, which run out behind, into 

 a point by which they are fastened to the above-men- 

 tioned united part of the mantle, in front they are rounded, 

 and the inner stretches farther than the outer. — 50 spe- 

 cies * ; also fossil. 



Some species are said to attach themselves by a byssus 

 to rocks. They are brought from Amboyna, New Hol- 

 land, Africa, and the Northern Seas. 



Trapezium. Megerle. (Libitina Schum. ; Cypricardia 

 Lam.) — Shell oblong, finely radiated 

 from the summit to the base, equi- 

 valve, very inequilateral, bosses 

 very near^one end ; three cardinal 

 and one lateral tooth in each valve. 

 Animal unknown. — 13 species f ; 

 also fossil. 



Found principally in masses of coral in St. Domingo, 



Trapezium. 



* Reeve's Iconica. 



t Ibid. 



