92 



CRETACKOrS LAMET>LI liHAXrHIA. 



Types. — From tlic Neocomian of Soignelay, near Auxerre. The type of 

 P. Fittoni is from the Pen^a -bed of the Isle of Wiglit. 



Distribution. — Lower Grecnsand (Pcj-)m-bed) of Atherfield. Tcalby Liiiu'stone 

 (zone of Bdemnites hrunsvicensis) of Nortli AViningliam. 



Fio. 18.—Pcrna Ricordeana, d'Orbigny. Tcalby Limestone, North Willingham. Sedgwick Museum. 

 Loft valve, x J. 



Perna Rauliniana, (VOrUgmj, 1846. Plate XII, figs. 6, la, h, 8, 9. 



1846. Pkena Rauliniana, A. d'Orhujny. Pal. Pran9. Terr. Crct., vol. iii, p. 497, 



pi. cccci, figs. 4, 5. 

 1850. — — d'Orbigny. Prodr. de Pal., vol. ii, p. 138. 



1852. — — F. J. PicM and W. Bona: Moll. Foss. Grcs verts de 



Geneve, p. 497, pi. xli, fig. 4. 



1854. — — J. Morris. Cat. Brit. Foss., ed. 2, p. 179. 



1855. — ~ G. Cottcav. Moll. Foss. de I'Youne, p. 107. 



1869. — — F. J. Pictet and G. Campichc. Foss. Terr. Crtt. Ste. 



Croix (Mater. Pal. Suisse, ser. 

 5), ]). 100, pi. clx, figs. 1, 2. 



Description. — Shell of moderate convexity, valves nearly equal, compressed 

 posteriorly, snb-rhomboidal, oblique, much higher than long; postero-ventral 

 margin rounded, anterior margin slightly concave, posterior margin slightly convex, 



