BIVALVIA. 29 
5. Pecten Brust, Payraudeau. Tab. V, fig. 3, a—é. 
Pscren Bruri. Payr. Cat. Moll. de I’Ile de Corse, p. 78, pl. 2, figs. 10—14, 1826. 
— Desh. Append. Lyell’s Princ., vol. iii, p. 14, 1833. 
—_ — G. B. Sow., Jr. Thesaur. Conch., vol. i, p. 70, pl. 20, figs. 241-2, 1847. 
—_ — Chenu. Illust. Conch. Pecten, pl. 39, fig. 6, a—e. 
— Prcrvs. Goldf. Pet. Germ., vol. ii, t. 97, fig. 4, a—c, 1830 (not Da Costa). 
—  srriarus? Goldf. Pet. Germ., vol. ii, t. 96, fig. 3, a—d. 
— Lamauit. Myst. Cog. Foss. de Belg., p. 305, pl. 22, fig. 5, a—é, and pl. 24, 
fig. 5, 1844. 
— Panporxz? Desh. Exped. Scient. de Morea, pl. 2, figs. 12—14, 1833, 
Spec. Char. Testé suborbiculari, equivalvi ? equilaterali, convexiusculd ; radiatim 
costatd, costis 18 —20 convewis inequalibus, longitudinaliter tenuissimé lineatis, in juventa 
nodosis vel subimbricatis ; auriculis alteris minimis, radiantibus. 
Shell suborbicular, equivalve ? equilateral, slightly convex; costated with 18 to 20 
unequal rounded ribs, finely striated longitudinally ; and nodose or imbricated in the 
young state; auricles unequal and rayed. 
Diameter, 3 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 striz upon the sides of the shell, like those upon “grinus; 
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 costz as between them, is covered with radiating 
strize, 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 /¢grinus ; 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. 
