10 



CRETACEOUS LAMELLIBRANCHIA. 



Sub-genus PLAGIOSTOMA, J. Sowerby, 1814. 

 ('Min. Conch,' vol. i, p. 175.) 



LIMA (PLAGIOSTOMA) SUBBIGIDA, Romer, 1836. Plate Til, figs. 5a, b, 69. Text- 

 figs. 1, 2, 3. 



1836. LIMA SUBKIGIDA, F. A. Romer. Ver stein, nord-deutsch. Oolithen-geb.,p.' 79, 



pi. xiii, fig. 16. 



PLANA, Romer, Ibid., p. 80, pi. xiii, fig. 18. 

 1841. STTBRIGIDA, R'dm&r. Die Verstein. d. riord-deutsch. Kreidegeb., p. 57. 



PLANA, .Roraer. Ibid, p.' 57. 

 1877. STJBRIGIDA, G. Bohm. Zeitschr. d. deutsch. geol. Gesellsch, vol. xxix, 



p. 235. 



1896. A. Wollemann. Ibid, vol. xlviii, p. 836. 



1900. Wollemann. Die Biv. u. Gastrop. d. deutsch. u. holland. 



Neocoms (Abhandl. d. k. preussich. geol. 

 Land., N.P., pt. 31), p. 30. 



PIG. 1. Lima (Plagiostoma) subrigida, Komer. Claxby Ironstone, Lincolnshire. Right valve. Natural size. 



Sedgwick Museum, Cambridge. 



Description. Shell convex, oval, height slightly greater than length ; antero- 

 dorsal margin nearly straight, postero-dorsal much shorter and nearly straight, the 

 remainder rounded and forming a regiilar curve. Apical angle rather more than a 



