30 MOLLUSCA FROM THE CRAG. 



This is quite distinct from any of the varieties of P. iigrinus, the larger or more 

 rounded form of the rays, as well as less inequality in the auricles, will distins^iish 

 it ; and in all the varieties of that species, strongly marked divaricating striae, or 

 cun'cd lines radiating from the umbo, may easily be observed, but I have been unable 

 to detect such markings upon my specimens of this species, although individuals of 

 tiffrinus, much less in size, exhibit them distinctly ; and it seems also to be specifically 

 different from P. Dumasii, in which the rays are larger, fewer, and more prominent, 

 and the auricles of our shell are comparatively larger than those in that species. In 

 the recent state, this is, probably, a deep water species, as PajTaudeau speaks of his 

 specimens having been obtained by means of the dredge. 



6. Pecten danicus, Chemnitz. Tab. IV, fig. 2. 



Pecten Danicus. Chem. Concb. Cab., t. xi, p. 265, pi. 207, fig. 2043, 1/95. 



— — G. Sow. Thesaur. Concb., vol. i, p. 01, pi. 12, figs. 16 & 187. 



— — For/j. and Hani. Hist. Brit. Moll., vol. ii, p. 288, pi. 52, figs. 1, 2, 7—10. 



— GL.\Bais. Brown. 111. Brit. Concb., pi. 32, figs. 3, 4, 1827. 



— DuM.\sii. Payr. Cat. Moll, de I'lle de Corsi., p. 75 pi. 2, figs. 6, 7, 1826. 



— — l)esh. Append. LyeU's Princ, vol. iii, p. 15, 1833. 



— — Forbes. Kept. /Egeau Invert., p. 183, 1843. 



— — Jeffreys. Ann. Nat. Hist., vol. six, p. 313. 



— ASPERSUS. Besh. 2d ed. Lam., t. vii, p. 136, 1836. 



— — Phil. En. Moll. Sic. vol. i, p. 82. 1836; and vol. ii, p. 57, 1844. 



— Jamesoxi. Smith. Mem. Wern Soc., vol. viii, p. 58, pi. 2, fig. I, 1838. 



— — Brown, inust. Concb. Gr. Brit., 2d edit, p. 73, pi. 25, fig. 7. 



— SEPTEMRADiATLs. Loven. Ind. Moll. Scand., p. 31, 1846. 



— TRiiiADiATUS. Miitl. Zool. Dan., vol. ii, p. 2.», pi. 60, figs. 1, 2, (fide Loven and Desk.) 

 OsTREA UYBRIDA. Gmel. Syst. Nat., p. 3318, 1788 (fide Loven). 



— — W. Wood. Ind. Test., p. 48, pi. 10. fig. 10, 1825. 



— TuiKADiATA. Turt. ed. Linn., vol. iv, p. 268, 1806. 



— — W. Wood. Ind. Test., p. 50, pi. 10, fig. 39, 1825. 



— SEPTEMRADIATA. Id. - - p. 268, 1806. 



— INFLEXA. Poli. Test. Sicil., vol. i, p. 160, t. 28, figs. 4, 5. 



— CLAY ATA. Id. - - - p. 161, t. 28, fig. 17. 



Pecten Pseud-Amusicm. Desk. E.xped. Scient. de Morea, p. 231, pi. 2, figs. 9—11, 1833. 

 Ency. Metb., pi. 212, fig. 6. 



Sjjec. Char. Testa suhrotundatd, (equilateruli, radiis 5 — G rottindatis inaqualihm, 

 striatis ; auriculis inccqttalibus. 



Shell subcircular, equilateral, thin, with rounded or convex rays varying in number 

 from 5 to 6 striated ; auricles unequal. 



Diameter, 1 inch. 



Local it I/. Clyde Beds. Recent, .'Egean, and Scandinavia. 



Although this species, in the recent state, has been obtained in the .Egcan, as 

 we 11 as in the Mediterranean Sea, and is quoted also by Philippi as an abundant fossil 



