BIVALVIA. L'l 



Slicll suborbicular ; lower valve convex, and irregularly laminated ; upper valve 

 ornamented with fine, longitudinal, and divaricating stria* ; margin of the valve crenulated 

 above on each side of the hinge. 



Dimensions, 5 inches by 4. 



Localities. Bracklesham (Edwards). 



France, Valmondois et Senlis (Deshayes). 

 This species is not abundant, and it is confined, I believe, to Bracklesham. The 

 peculiarity of this shell, whence I presume it received its name, is the elevation of the 

 centre of the upper valve. This arises from an adherence of the animal to some cylin- 

 drical body, by which a considerable indenture is given to the outside of the lower valve 

 and an elevated ridge to the inside ; this is communicated to the upper valve, in order to 

 give room to the animal inhabitant, and thus an elevated, semi-cylindrical ridge is on the 

 outside of the upper valve, corresponding with the body adhered to. Specimens sometimes 

 occur which have been attached by the greater portion of the lower valve to a flat surface, 

 and the upper valve in this case has no elevation, but its favorite habit was apparently to 

 select a cylindrical stem for support. The upper valve is covered with fine striae, and 

 the interior has the margins crenulated near the hinge ; but M. Deshayes figures a specimen 

 (pi. 64, fig. 3) in which the crenulations have extended round the entire margin of the 

 upper valve. This is not so in the British specimens which have come under my inspection. 

 The ligamcntal area is large and broad. 



8. OSTREA ELEGANS? DesItayCS. 



Ostrea elegaxs. Desk. Coq. Foss. des Env. de Par., p. 361, pi. 50, figs. 7 — 9. 



— — J. Sowerby, in Dixon's Geol. of Sussex, p. 174, 1 850. 



— — J. Morris. Catal. Brit. Foss., p. 174, 1851. 



" This is intermediate in several respects between 0. radiosa and O.jlabellula, but has 

 more plaits than the latter. I much doubt the propriety of separating it as a species. 5 ' — 

 /. Sowerby. 



I am inclined to think with Mr. Sowerby that the English fossil called eleyans is only a 

 variety. There is not any fossil in Mr. Edwards's collection that deserves to be called 

 eleyans, in specific contradistinction to radiosa, Sow., Jlabellala, or eymbula ; and as the 

 above name is given upon the authority of Mr. Edwards's specimens, it is introduced here 

 without a figure, and with considerable doubt. 



9. Ostrea flabellula, Lamarck. Tab. Ill, fig. 4, a — d. 



Chama plicata. Solander, in Brander, Foss. Hant., pi. viii, figs. 84, 85, 1766. 

 Ostrea FLABELLULA. Lam. Ann. du Mas., t. viii, p. 164, No. 16; and t. xiv, pi. 20, 



fig. 3, a, b, 1806. 



