184 CONCHYLIA— />/THF/2^. 41. 



Tnrlon, Conch. Diet. p. 29. 



Chemnitz, vi. p. 16.5, tab. 15, fig, 1.58. 

 Pectunculus orbicularis. Lister, Concli. tab. 324. fig. 161. 

 Cardium ciliare. Linn. Syst. «&c. The young shell. 

 Mns. nosl. On most sandy coasts. 



Shell two inches in diameter, a little oblique, of a brown or 

 whitish color, clothed with numerous sharp white spines which 

 curve towards the cartilage side ; those on the opposite side 

 thicker and more obtuse. 



The young of this species, and of the Cardium aculeatum, are 

 in many respects so similar, that it is hardly possible to fix with 

 any decision, which of them should be considered as the Cardium 

 ciliare of Linne and subsequent authors. 



Both of them are thin and brittle, and have the spines lance- 

 •haped or longitudinally dilated at the base. 



The young of Cardium echinatum are entirely white, with the 

 grooves regularly striate transversely. They are abundant in 

 Dublin bay, where the Cardium aculeatum has never been found 

 to inhabit. 



The young of Cardium aculeatum are extremely fragile and 

 transparent, more dilated at the sides from the beaks, of a fine 

 glossy fawn-color, and irregularly striate in the grooves : they 

 are of rare occurrence, but found occasionally on the sands at 

 Paington. It is figured in Chemnitz, vi. tab. 17. fig. 171, 172. 



The young of Cardium tuberculatum are of a stronger con- 

 sistence, of a deeper chocolate brown with white blotches or rays, 

 and clothed with rather obtuse raised tubercles. 



