90 



CKETAt!E()LiS LAMELUBRAXfTITA. 



Pehna HicoRDiiANA, iV Orb i(j hi/, IS-l'O. Text-figures lG-1 8. 



184(J. 



1850. 

 1854. 

 1855. 

 1858. 



18(iy. — 



181)9. 

 1883. 



1900. 



Perna Kicoedeana, a. d'Orhiijmj. Pal. Fiiiui;. Terr. Crct., vol. iii, p. VJ-i, 



pi. cccxcix, figs. 1 — 3. 



— — d'Orbigny. Prodr. de Pal., vol. ii, j). 82. 



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



— G. Coiteau. Moll. Foss. do I'Youue, p. 107. 



— — F. J. Pictet and E. Benevier. Foss. Terr. Aptien (Mater. 



Pal. Suisse, ser. 1), p. 125. 



— F. J. Pictut and G. Campiche. Foss. Terr. Crct. Ste. 



Croix (Mater. Pal. Suisse, ser. 

 5), p. 93, pi. clvii, fig. 1. 



FiTTONi, Pictet and Camjiiche. Ibid., p. 95, pi. clvii, fig. 2. 

 RicouDiANA, W. Keeping. Foss., etc., Neoc. Upware and BrickJiill, 



p. 150. 

 RicoEDEANA, A. WoUevHinn. Die Biv. u. Gastrop. d. deutsch. u. 



hoUiiud. Neocoms (Abliaudl. d. k. 



preussisch. geol. Land., N. F., pt. 



31), p. 61. 



Fio. 10. — Pcma Rifordcana, trOrbigny. Lower Cireousaml (Penta-bud), AtliL'i-fiuld. BIiiSL'iim of Practical 

 Geology, No. 12351. Left valve, x J. 



Descriftion. — Shell large, tliick, sub-quadrate, compressed; left valve more 

 convex than the riglit. Posterior margin sligiitly convex or nearly straight and 

 forniiiig with the hingo-line an angle which is rather greater than a right-angle. 



