BIVALVIA. 155 



Length, f ths of an inch. ; height, -|ths of an inch. 



Locality. Cor. Crag, Sutton. 



This elegant species is one of the most abundant shells, though very rarely found 

 with the valves united. 



It much resembles the figure of C. elongatum, Turt. Judging from that alone, it 

 was imagined to have been the same, and inserted under such name in my Catalogue. 

 The great peculiarity of our shell is the very broad furrow, or intermediate space be- 

 tween the ribs, and the intersecting of these furrows by regular, sharp, elevated ridges 

 at right angles to the ribs. It is very inequilateral, and rather tumid, with a somewhat 

 prominent umbo ; the ribs are thickly studded with elevated and vaulted scales, ex- 

 tending about three quarters across the depressed but not quite flattened rib ; and 

 when the specimen is in good condition, the entire surface of the rib is covered with 

 these prominent half-tubular spines. 



On the posterior portion they are more prominent and sharp, the spaces between 

 the ribs are nearly as broad as the ribs themselves, and filled with the regular ridges, 

 giving it a somewhat cancellated appearance ; the ribs are seldom less than twenty-two 

 or more than twenty-four in number, and these are distinctly visible within the shell. 



In the very infant state of this species (fig. 5 c\ the ribs are not more than half 

 in number ; after which, an additional one is interposed between each, so that only 

 every other rib terminates or converges to the beak. The margin of the shell is deeply 

 indented by the ribs, more especially on the posterior side, where they project in a 

 somewhat ragged or jagged manner beyond the margin. 



5. CARDIUM EDULE, Linnaeus. Tab. XIV, fig. 2 a g. 



Lister. Hist. Conch, pi. 334, fig. 171. 



Vale. Hist, and Antiq. of Harwich, p. 293, pi. xii, fig. 5. 1730. 



CARDIUM EDULE. Linn. Syst. Nat., ed. 12, p. 1124, No. 90, 1767. 



Don. Brit. Shells, vol. iv, t. 124, fig. 1, 1803. 



Phil. En. Moll. Sic., voL i, p. 52, t. iv, fig. 16. 



Loven. Ind. Moll. Scand., p. 35, 1846. 



Midden. Malac. Rossic., p. 548, t. xv, figs. 10-22. 



Basterot. Bord. Foss., p. 81, 1825. 



VULGARE. Dacosta* Brit. Conch., p. 180, pi. xi, fig. 1. 



EDULE. Chemn. Conch. Cab., t. vi, p. 198, t. xix, fig. 194, 1/82. 



PECTINATUM. Desk. 2d edit. Lam., t. vi, p. 405. 



ARCUATUM, Reeve. Conch. Icon. Cardium, pi. xxii, fig. 133. 



ZONATUM. Brown. Illust. Brit. Conch., t. xxii, fig. 8, 1827. 



TENUE. Id. t. xxii, fig. 4. 



CRENULATUM. Reeve. Conch. Icon., pi. xx, fig. 112. 



RUSTICUM. Chemn. Conch. Cab., t. vi, t. xix, fig. 197. 



Eichwald. Fauna Caspio-Caucasia Nouv. Mem. dela Soc. Imp. des Nat, 



de Mosc., t. vii, t. xxxvii, figs. 24-27. 

 Phil. En. Moll. Sic., vol. i, t. iv, figs. 12-14. 



EDULINUM. J. Sowerby. Min. Conch., t. 283, fig. 3, 1821. 



