CARDIUM. 279 



larger, besides two anterior laterals of unequal size and one 

 posterior lateral ; in the left valve two cardinals, the anterior 

 being much larger than the other, besides a single lateral on 

 each side ; all the lateral teeth, except the front anterior one 

 in the right valve, are triangular, and, although short, project 

 considerably : inside bright and glossy, occasionally iridescent, 

 and sometimes of a yellow hue and more or less stained with 

 purplish- or chocolate-brown in front and on the posterior 

 side, fluted near the margin only : pallial scar indistinct : mus- 

 cular scars oval, large, nearly equal-sized, and deeply im- 

 pressed. L. 0-55. B. 0-55. 



Var. subquadrata. Shell rhomboidal, in consequence of the 

 posterior side being more expanded than usual and of the 

 dorsal margin being quite straight ; furrows slightly striated, 

 instead of being punctured. 



Habitat : Oozy ground in the laminarian zone on 

 most parts of our coasts, at from 3 to 15 fathoms. The 

 variety is rare, and has only occurred to me at Scal- 

 loway in the mainland of Shetland, and at Sark, one of 

 the Channel Isles. As an upper tertiary fossil this 

 species has been noticed by Mr. Grainger at Belfast, by 

 Mr. James Smith in the Clyde beds at Dalmuir and 

 Bute, and by Mr. Godwin- Austen in the Sussex de- 

 posits. Finmark and Bergen (Sars) ; Sweden, 15-20 

 fathoms (Malm) ; Cherbourg and Granville (De Ger- 

 ville); Vigo (M' Andrew) ; Gulf of Lyons (Martin); 

 Algeria (Weinkauff); Corsica (Bequien) ; Adriatic 

 (Chiereghini) ; Sicily (Philippi) ; ^Egean, 7-30 fathoms 

 (Forbes) ; and Sebastopol in the Black Sea (Midden- 

 dorff). Many intermediate localities have also been 

 recorded by other authors. 



Turton says that these shells are "sometimes imbedded 

 in hard clay; and both Mrs. Griffiths and ourselves have 

 taken them from the interior of the hardest stones in 

 Torbay." They may have found their way into such 

 places for the sake of shelter, but (like Sterne's star- 



