276 CARDIIDJE. 



runs from the beak to the lower part of the posterior margin; 

 there is no perceptible gape : beaks very small, not contiguous, 

 slightly inclining to the anterior side ; beneath them on this 

 side is a false lunule or smooth lozenge-shaped space with 

 slightly prominent lips : ligament cylindrical, yellowish-brown 

 with a golden hue : hinge-line curved : hinge-plate reflected, 

 occupying about one-fourth of the circumference : teeth, in the 

 right valve two triangular cardinals, the posterior of which is 

 much larger and higher than the other, besides two short an- 

 terior laterals also of unequal size, and one triangular and pro- 

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

 anterior of which is the larger, besides a single lateral on each 

 side, the anterior one being triangular and projecting : inside 

 bright and glossy, sometimes stained with purple or reddish- 

 brown towards the beaks and on the posterior side, fluted near 

 the margin only : pallial scar indistinct : muscular scars large, 

 roundish-oval, and equal-sized. L. 0-55. B. 0-6. 



Var. lactea. Shell milk-white. 



Habitat: In gravelly sand, at 15-20 fathoms, oft' 

 Guernsey and Sark, as well as thrown up on the beach 

 at Herm (Lukis and J. G. J.). It is at present one of 

 our most scarce shells, although I have a series from not 

 much larger than half a line to the full size. I shall 

 not be surprised if it is found on the Cornish coast. Its 

 exotic range is entirely southern. No writer on the 

 conchology of the North of France appears to have 

 noticed it. It inhabits every part of the Mediterranean, 

 and also the iEgean, as well as the Atlantic from Yigo 

 to the Canary Isles, at various depths from 6 to 75 

 fathoms. 



The appearance of punctures in this and the follow- 

 ing three species arises from the ribs being crowded or 

 squeezed together, so as to prevent the free development 

 of the interstitial striae. 



The late Dr. Lukis discovered the interesting and 

 remarkable species now described, to be an inhabitant of 

 our seas j and he most liberally sent me the finest of the 



