BIVALVIA. 153 



this species has been very rarely met with, it may possibly have been more abundant in 

 that part of the Crag whence his shells were taken, but now long since washed 

 into the sea. 



C. ecUnatum, Dubois, ' Wolhyn. Pod.,' pi. vi, figs. 13, 14, does not appear from the 

 figure to correspond with our shell. 



2. Cardium nodosum, Montague. Tab. XIII, fig. 4 a — c. 



Cakdium nodosum. Mont. Test. Brit., p. 81, 1803. 



_ _ Turt. Brit. Biv., p. 186, t. xiii, fig. 8, 1822. 



— — Hanleij. Recent Shells. Supp., pi. xvii, fig. 44. 



— — Reeve. Conch. Icon. Cardium, pi. xxii, fig. 128. 



— — Loven. Ind. Moll. Scandia, p. 36. 



— — Alder. Catal. Moll. North, and Durh., p. 83, 1848. 



— — Forbes and Hani. Hist. Brit. Moll., vol. ii, p. 22, pi. xxxii, fig. 7, 1849. 



— DiscREPANS? Brown. lUust. Brit. Conch., pi. xxii, fig. 9, 1827. 



— scABRUM. Phil. En. Moll. Sic, vol. ii, p. 38, vol. xiv, p. 16, 1844. 



— — Hanley. Rec. Shells. Supp-, pi. xvii, fig. 43. 



Spec. Char. Testa parvd, ovato-orbiculari, parum convexd, sub-aquilaterali, antice 

 rotundatd, postice truncatd ; costis circa 2Q planulatis, nodulosis ; interstitiis jjunctatis. 



Shell small, somewhat orbicular, slightly convex, a little inequilateral, anterior side 

 rounded, posterior truncated ; ribs about 26, flattened, and ornamented with tubercles ; 

 interstices narrow and punctated. 



Length, \ an inch nearly ; height, f ths do. 



Localdy. Cor. Crag, Sutton. 



Red Crag, Sutton, Alderton, Bawdsey. 



Recent, Mediterranean, Britain, Scandinavia. 



This species is particularly abundant, more especially in the Coralline Crag, at Sutton, 

 where the larger specimens are generally much altered by the loss of all the outer 

 coating of the shell, and with it, of course, its tubercles ; but in the younger state it 

 may be obtained plentifully in high perfection, and in some specimens the tubercles are 

 very deciduous, while in others they cover the entire surface. The diameter is in general 

 greater from the anterior to the posterior side, than from the umbo to the ventral 

 margin : it is not so in all. It may be very well distinguished by its contour, which is 

 slightly angular on the hinder side, but less so than in C. exigimm. The ribs are very 

 flat and broad, and the interspaces so narrow, that it is only occasionally the ridges or 

 punctated surface of those furrows can be seen. On the anterior and central portion 

 of the shell, the nodules, when remaining, are broad and obtuse, reaching across the 

 ribs, while on the posterior side, the ribs are more convex, and only ornamented in the 

 centre with sharper or smaller tubercles. 



