BIVALVIA. 29 



5. Pecten Bruei, Payraudeau. Tab. V, fig. 3, a — b. 



Pecten Bruei. Payr. Cat. Moll, de l'lle de Corse, p. 78, pi. 2, figs. 10—14, 1826. 



— Desk. Append. Lyell's Princ., vol. iii, p. 14, 1833. 



— — G.B. Sow., Jr. Thesaur. Conch., vol. i, p. 70, pi. 20, figs. 241-2, 1847. 



— — Chenu. Illust. Conch. Pecten, pi. 39, fig. 6, a — c. 



— Pictus. Gold/. Pet. Germ., vol. ii, t. 97, fig. 4, a— c, 1830 (not Da Costa). 



— striatus ? Gold/. Pet. Germ., vol. ii, t. 96, fig. 3, a — b. 



— Lamalii. Nyst. Coq. Foss. de Belg., p. 305, pi. 22, fig. 5, a — b, and pi. 24, 



fig. 5, 1844. 



— Pandora? Desk. Exped. Scient. de Morea, pi. 2, figs. 12—14, 1833. 



Spec. Char. Testa sudor biculari, cequivalvi ? aquilaterali, convexiuscidd ; radiatim 

 costatd, costis 18 — 20 convexis incequalibus, longitudinaliter tenuissime lineatis, in juvenfd 

 nodosis vel subimbricatis ; auriculis alteris minimis, radiantibus. 



Shell suborbicular, equivalve ? equilateral, slightly convex ; costated with 1 8 to 20 

 unequal rounded ribs, finely striated longitudinally ; and nodose or imbricated in the 

 young state ; auricles unequal and rayed. 



Diameter, \ an inch. 



Locality, Coralline Crag, Sutton. Recent, Mediterranean. 



Five or six separated valves are all that I have obtained, and these appear to cor- 

 respond with the recent species above referred to. Four localities are given by 

 Payraudeau, of recent habitats, who says it is " peu abondant." The shell figured 

 by Nyst is presumed to be the same, from the disposition of the rays; but he speaks 

 of irregular and oblique striae upon the sides of the shell, like those upon tigrinus; 

 these I have not been able to detect in my specimens, which, however, may but ill 

 display such sculpture, as they are, probably, only young individuals, not measuring 

 more than half the diameter of the Belgian fossil ; but from the representation 

 there is a slight difference, the auricles of his shell are rather more rounded, and 

 more unequal, and approach nearer in that character to one of the varieties of 

 tigrinus. 



Our' shell may be further described as having rounded rays generally single, some- 

 times arranged in pairs, but in no regularity in either the right or left valve, while the 

 whole surface, as well on the costse as between them, is covered with radiating 

 striae, these appear like linear markings in the shell, and not upon it, the line being 

 alternately of a light and dark colour, that upon the centre of each rib, larger or 

 broader than the rest. 



In the young shell, the rays are ornamented with nodose protuberances, and the 

 interstices have then also a raised portion of the shell, so that, in its young state, the 

 surface is prettily cancellated. The auricles are unequal, the anterior one being the 

 larger of the two, though not displaying so great a disparity as in tigrinus ; they are 

 sharp and rectangular, and not the least rounded, covered with prominent rays, which 

 are strongly decussated by raised lines of growth : there is a small byssal sinus under 

 the anterior auricle. 



