CONCHIFERA. 



263 



Conocardium. Bronn. — Shell equivalve, thick, the 

 anterior side flatly compressed, the posterior more or 

 less lengthened ; on the fore side, next to the almost 

 straight hinge edge, appears a cylindrical cone-shaped 

 process which seems to indicate a peculiar organisation of 

 the animal, and which has usually opposite to it, one of a 

 longer diameter. — Fossil. 



This fossil shell is little known, and not well described. 



Goldfussia. Castelnau. — This genus has not been 

 particularly characterised, but mentioned slightly as Car- 

 dium? nauliloides. Each valve somewhat resembles a 

 compressed Nautilus ; both sides keeled. — Fossil. 



(Bucardium Muhlf.) — Shell heart- 

 inequilateral ; 



Isocardia. Lam. 

 shaped, equivalve, 

 bosses very prominent, rather spiral, 

 recurved in the same direction, and 

 not touching each other ; cardinal 

 teeth two, lateral, one in each valve ; 

 ligament exterior. Animal, shaped 

 like the shell, open in front for the 

 broad triangular, compressed, pointed 

 foot ; siphonal orifices sessile, their 

 margins fringed, mantle double-edged/ 

 fossil. 



The bosses of this shell are so peculiar that they easily 

 indicate the genus. The Isocardia lives usually in the 

 sand within reach of the waves, and is found in Europe, 

 the East and West Indies, China, and New Holland. Mr. 

 Reeve, in his monograph of this genus, says that /. cor. is 



Isocardia cor. 



5 species f ; also 



Forbes' S British Moll. 



f lieeve's Icon. 



