64 



CRETACEOUS LAMELLIBRANCHIA. 



Pteria (Pseudopteea) anomala (Sotverby), 1836. Plate IX, figs. 2a-d, 3a, b, 4a,b. 



1836. 



AviCTTLA 



? 1846. 



- 



? 1842. 



GERVILLIA 



? 1845-6. 



AviCTTLA 



? 1850. 



— 



1854. 







1868. 



— 



1869. — 



1871. 

 ? 1873. 



1893. — 



, /. de C. Sowerby. Trans. Geol. Soc, ser. 2, vol. iv, pp. 



240, 342, pi. xvii, fig. 18. 

 A. E. Retiss. Die Verstein. der bohm. Kreideformat., 



pt, 2, p. 22, pi. xxxii, figs. 1—3. 

 H. B. Geinitz. Char. d. Schicht. u. Petref. des siiehs. 

 Kreidegeb., pt. 3, p. 80, pi. xx, fig. 38. 

 Grundriss d. Verstein., p. 459, pi. xx, 



fig. 5. 

 Das Quadersandst. oder Kreidegeb. in 

 Deutschland, p. 170 (partini). 

 J. Morris. Cat. Brit, Foss., ed. 2, p. 163. 



A. Briart and F. L. Cornet. Descript, Mineralog. Geol. 



et Pal. de la Meule de Bracquegnies (Mem. 



cour. et Mem. des Sav. etrangers, vol. xxxiv), 



p. 52, pi. iv, fig. 7. 



F. J. Pictet and G. Campiclie. Foss. Terr. Cret. Ste. 



Croix (Mater. Pal. Suisse, ser. 



5), p. 71. 



F. Stoliczka. Palaeont. Indica, Cret, Fauna S. India, 



vol. iii, p. 398. 

 H. B. Geinitz. Das Elbthalgeb. in Saclisen (Palseonto- 

 grapbica, vol. xx, pt. 1), p. 207, pi. 

 xlvi, figs. 5, 6. 



B. Michael. Zeitschr. der deutscb. geol. Gesellscb., vol. 



xlv, p. 233. 



Non 1846. 



— 1850. — 



? — 1877. — 



1883. 



A. d'Orbigny. Pal. Franc. Terr. Cret., vol. iii, p. 478, pi. 



cccxcii, figs. 1 — 3. 

 d'Orbigny. Prodr. de Pal., vol. ii, p. 167. 

 A. Fritsch. Stud, im Gebiete der bobm. Kreideformat. : 

 II, Weissenberg. u. Malnitz. Schicht., p. 

 128, fig. 108. 

 Ibid., Ill, Iserschicbt., p. 109. 



Description. — Shell rather large; outline (without the ears) triangular, very- 

 oblique ; anterior margin convex, forming a rounded angle with the sinuous postero- 

 ventral margin. Umbo of left valve pointed, acute, near the anterior extremity. 

 Apical angle about 45°. 



Left valve very convex, with a strong, rounded ridge extending from the 

 umbo to the postero-ventral extremity. In front of this ridge the shell curves 

 rapidly downwards, and becomes nearly vertical to the plane of the valves near 

 the anterior margin and near the anterior ear. Behind the ridge the valve is 

 flattened and slopes dorsally (fig. 2 a) ; but this part is sometimes divided into two 



