BIVALVIA. 23 
Prcren maximus. Chenu. Ilust. Conch. Pecten, pl. 2, figs. 1—3, and pl. 29, figs. 1—18. 
— — Loven. Ind. Moll. Scand., p. 30, 1846. 
= — Alder. Cat. Moll. North., p. 76, 1848. 
<= — Forb. and Hanl. Hist. of Brit. Moll., vol. ii, p. 296, pl. 49, 1849. 
— — Sismond. Syn. Meth. An. Invert. Pedem. Foss., p. 13, 1847. 
— —_ G. B. Sow. Jr. Thesaur. Conch., vol. i, p. 45, pl. xv, figs. 98-100, 1847. 
— yuucaris. Da Costa. Brit. Conch., p. 140, pl. 9, fig. 3. 
— compianatus. J. Sow. Min. Conch., t. 586, 1828. 
— —_—- S. Wood. Catalogue, 1840. 
— — J. Morris. Cat. Brit. Foss., p. 114, 1843. 
_— —_— Nyst. Coq. Foss. de Belg., p. 285, pl. 22 bis, fig. 1, 4, b!, 1843. 
—  srrmis. G. B. Sow. Jr. Thes. Conch., p. 46, pl. 16, figs. 116, 117, 1847. 
— mepius. Chem. Conch. Cab., t. vii, p. 272, t. 60, figs. 586, 587, 589. 
— — Desh. 2d ed. Lam., t. vii, p. 130, 1835. 
— — Phil. En. Moll. Sic., vol. ii, p. 59, 1844. 
= — Chenu. Must. Conch., pl. 4, figs. 2—6. 
= — Sismonda. Syn. Meth. Ped. Foss., p. 13, 1847. 
—  GRanpis. J. Sowerby. Min. Conch., t. 585, 1828. 
= — S. Woodward. Syn. Tab. Brit. Org. Rem., p. 19, 1830. 
— — S. Wood. Catalogue, 1840. 
— — J. Morris. Catal. Brit. Foss., p. 114, 1843. 
— — Nyst. Coq. Foss. de Belg., p. 284, pl. 21, fig. 6, 6, 6, and pl. 22, 
fig. 1, a, 6, 1844. 
Ency. Meth., pl. 209, fig. 1, a, 0. 
Spec. Char. Testd ineguivalvi, suborbiculari ; valvd dextrd vel inferiori convera, 
superiore planulata ; radirs magnis, \3—14 rotundatis, longitudinaliter striata ; marginibus 
lati-crenulatis ; auriculis equalibus. 
Shell inequivalved, suborbicular; right or inferior valve convex ; left or upper 
valve flat, or very slightly inflated; ornamented with 13 or 14 large, rounded, and 
striated ribs or rays; margin broadly indented ; ears equal. 
Length, 54; height, 43 inches. 
Locality, Cor. Crag, Sutton, Aldbro’, Ramsholt, Gedgrave. 
Red Crag, Sutton, Bawdsey. 
Northern Drift, Ireland (Forbes). 
Recent, Britain and Northern Seas, Mediterranean ? Red Sea: 
This is very abundant in some localities of the Coralline Crag, and particularly 
variable in its exterior ornament. The peculiar arrangement of the striated portion of 
the rays, which some of the specimens have assumed, induced authors who have 
described the Crag shell, to consider it as wholly distinct from the recent British 
species, and I was long of the same opinion ; but the examination of numerous speci- 
mens in the cabinets of my Crag collecting friends, has shown a union between the 
extremes of sculpture, as represented in the variety grandis, and that which is commonly 
exhibited in the generality of recent specimens, by small and almost imperceptible 
variations, so as to prevent a distinct line of demarcation to be drawn between 
