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CARDIUM. 

 cardium. — Linn. 

 Mawes Linnaus, plate 7. 

 This beautiful and interesting family has been so well 

 defined by Linnaeus, that La Marck has not separated 

 any of them. Similar to the G. Venericardium and 

 G. Pecten, the convexity of their valves is furnished 

 with numerous longitudinal ribs, more or less elevated, 

 armed with spines, hollow scales, or marked with 

 striae; the interior partly smooth and only grooved at or 

 near the margin. In all the species, the connecting li- 

 gament of the valve is exterior, very short, and the two 

 muscular impressions but slightly marked. Shell equi- 

 valve, subcordiform; apices protuberant; hinge with 

 four teeth on each valve, the two primary ones oblique 

 and near together, articulating with the correspond- 

 ing teeth on the other valve; two lateral inserted dis- 

 tant teeth. They inhabit the sea shore, concealed at 

 a small depth in the sand. La Marck makes two di- 

 visions of them: the first is distinguished by having 

 the anterior side as large or larger than the posterior, 

 and no distinct angle at the apices ; the second, by 



