1 24 INVERTEBRATA. 



more distinct than upon the shell itself. The umbo is pointed. 

 Pallial line simple. 



Our shell has considerable resemblance to some forms of C. angu- 

 lata, rostrata (Sby.) ; their hinges are similar ; but C. Sedgwickii is a 

 smaller species, with a more globose shell, and less expanded in front. 

 The posterior angle is not nearly so well developed, though it is 

 faintly seen. 



The distinct cordiform lunule, marked off by a definite groove, 

 is an important character, serving to separate off a small group of 

 cretaceous shells from the true Cyprina. It is seen in C. regularis, 

 as described and figured by D'Orbigny, and this author states 

 that the same structure occurs in the shell which he refers to 

 C. rostrata, Fitton ; I have not detected it in British specimens of 

 that species. 



Localities. Upware, Potton. 



N. Europe. Hils Thon (in Hildesheim Museum as " Mac- 

 tromya nicht bestimmt.") 



CYPRINA SEDGWICKII, Walker, var. 



A rounded, inflated variety of C. Sedgwickii, Walker, ap- 

 proaching the gault species C. regularis. 



CYPRINA ANGULATA, var. ROSTRATA, Sby. 

 Cyprina angulata, Sowerby, Mineral Conchology, pi. 65, var. 

 Cyprina rostrata, Sowerby, Geol. Transactions, vol. IV., p. 341, 



pi. 17, f. 1. 



C. Ervyensis, Pictet and Roux. 



We only know of one specimen, and that an internal cast, of 

 this species from Upware. It agrees with Sowerby's typical C. ros- 

 trata from Blackdown. 



Localities. Upware, Potton (Coll. J. F. Walker), Blackdown, 

 Sandgate, Hythe. 



N. Europe. Perte du Ehone, Saxonet, Mortran. 

 Range. Lower Greensand, Aptien, and Lower Gault. 



CYPRINA OBTUSA, n. sp. 

 (Plate vi., fig. 13, a c.) 



Shell subtriangular, inflated, very inequilateral, the surface 

 marked with delicate concentric striae. Umbones prominent 



