80 



ed from it, by having three teeth beneath the apices, 

 like those of the G. Venus, in addition to the callous 

 lengthened tooth or ridge. Shell marine, equivalve, 

 inequilateral, obliquely or transversely elongated; 

 valves finely striated, never ribbed; hinge with three 

 teeth beneath the umbo, and one lateral elongated 

 tooth, or callous ridge. 



Cypricardia Guinaica Cypricardia rostrata 



angulata coralliophaga. 



[Three fossil species.] 



HIATELLA. 



Chem.6, t. 6,/ 51,52. 



A genus established by Daudin and unknown to La 

 Marck, who is of opinion, from the type given, that it 

 more nearly approximates to the Carditae, (although the 

 shell gapes), than to the Solenes, with which Linnaeus 

 had classed it. Shell very inequilateral, transverse, and 

 gapiiig at the upper part. Hinge with a small tooth 

 on the right valve, and two rather larger oblique teeth 

 on the left, ligament exterior. 



Hiatella arctica. 



