8 MOLLUSCA FROM THE CRAG. 



This genus is found in the Secondary Rocks ; one species has been described by 

 Mr. Bean, from the Cornbrash ; 'Mag. Nat. Hist.' 1839. And some from the Green- 

 sand by Dr. Fitton. 



1. Anomia ephipium, Linnceus. Tab. I, fig. 3, a — d. 



Anomia ephippjum. Linn. Syst. Nat. ed. 12, p. 1150, No. 218, 1767. 



— squamula. Id. - - - p. 1151, No. 221. 

 _ _ Turt. Brit. Biv. p. 229, pi. 18, fig. 5-7, 1822. 



— — Broc. Conch. Foss. Subap., p. 461, 1814. 



— — Bekay. Nat. Hist. New York (Zool.), p. 168, pi. 12, fig. 209, 1843. 



— — Middendorff. Malacozoologia Rossica (Mem. de l'Acad. des Sc. Imp" 



de St. Petersb.), p. 519, t. 11, fig. 18-21, 1849. 



— sulcata. Poll, Test. Sic. vol. ii, p. 186, t. 30, fig. 12. 



— MARGARITACEA. Id. - - t. 30, fig. 11. 



— cffiPA. Id. - t. 36, figs. 1, 25-8. 



— lens 1 Gold/. Pet. vol. ii, p. 40, t. 88, fig. 8, a—e. 



— ephippium. S. Wood. Catalogue, 1840. 



— costata. Broc. Conch. Foss. Subap., p. 463, t. 10, fig. 9, 1814. 



— RADIATA? Id. - - - t. 10, fig. 10. 



— sulcata? Id. - - t. 10, fig. 12. 



Spec. Char. Testa polymorpM, crassd vel tenui, plerumque lavigatd, forma valde 

 irreyulari. 



Shell many shaped, thick and strong, sometimes thin and fragile, generally smooth, 

 form very irregular. 



Diameter, f ths of an inch. 



Locality, Cor. Crag, Sutton, Sudbourn. 



Recent, Mediterranean, Britain, Scandinavia, North America. 



The variety of this species, called squamula, is exceeding abundant in the Coralline 

 Crag, and like the recent shell, is subject to great distortion, depending upon the 

 body to which it has been attached ; a large number of these specimens have taken the 

 characters of the genus Pecten, to which, in the living state they were attached, but it 

 is only in the upper or free valve that I have been able to observe the costated form, the 

 lower or adherent one was probably much thinner, and less capable of preservation. 



A few specimens of the lower or perforated valve are occasionally met with, and in 

 all that I have seen, the valve is externally smooth, at least, free from striae or costae, 

 and its place of attachment was some smooth or even surface. This variety does not 

 appear to have attained the size of more than f ths of an inch in diameter, and the 

 majority of specimens have not reached above half those dimensions. In those 

 which have the upper valve quite flat and smooth, the place of attachment was 

 probably the interior of some shell, from which the lower valve would take the 

 convex form, giving room between the two for the occupation of its inhabitant. The 

 beak or umbo of this species, is almost immediately at the margin or projecting a 

 little beyond it. 



