BIVALVIA. 23 



Pecten maximus. Chenu. Illust. Conch. Pecten, pi. 2, figs. 1—3, and pi. 29, figs. 1—18. 



— — Loven. Ind. Moll. Scand., p. 30, 1846. 



— — Alder. Cat. Moll. North., p. 76, 1848. 



— — Fori, and Hani. Hist, of Brit. Moll., vol. ii, p. 296, pi. 49, 1849. 



— — Sismond. Syn. Meth. An. Invert. Pedem. Foss., p. 13, 1847. 



— — G. B. Sow. Jr. Thesaur. Conch., vol. i, p. 45, pi. xv, figs. 98-100, 1847. 



— vulgaris. Da Costa. Brit. Conch., p. 140, pi. 9, fig. 3. 



— complanatds. 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, pi. 22 bis, fig, 1, b, b' , 1843. 



— similis. G. B. Sow. Jr. Thes. Conch., p. 46, pi. 16, figs. 116, 117, 1847. 



— medius. Chem. Conch. Cab., t. vii, p. 272, t. 60, figs. 586, 587, 589. 



— — Desk. 2d ed. Lam., t. vii, p. 130, 1835. 



— — Phil. En. Moll. Sic, vol. ii, p. 59, 1844. 



— — Chenu. Illust. Conch., pi. 4, figs. 2 — 6. 



— — Sismonda. Syn. Meth. Ped. Foss., p. 13, 1847. 



— gkandis. J. Sowerby. Min. Conch., t. 585, 1828. 



— — £. 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, pi. 21, fig. 6, b, b, and pi. 22, 



fig. 1, a, b, 1844. 

 Ency. Meth., pi. 209, fig. 1, a, b. 



Spec. Char. Testa incequivalvi, suborbiculari ; valvd dextrd vel inferiori convewd, 

 superiori planulatd ; radiis magnis, 13 — 14 rotundatis, longitudinaliter striata ; marginibus 

 lati-crenulatis ; auricidis aqualibus. 



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, 5 1 ; height, 4f inches. 



Locality, Cor. Crag, Sutton, Aldbro', Ramsholt, Gedgrave. 

 Red Crag, Sutton, BaWdsey. 

 Northern Drift, Ireland (Forbes). 



Recent, Britain and Northern Seas, Mediterranean ? Red Sea r 



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 



