64 CRETACEOUS LAMELLIBRANCHIA. 
Remarks.—Most of the English specimens have only a portion of the shell 
preserved. I have collected examples from the Cenomanian of St. Catherine, near 
Rouen (the locality of the types), which agree exactly with English specimens. 
Types.—Specimens from Rouen, but not the types, are in the d’Orbigny 
Collection at the Museum of Natural History, Paris. 
Distribution.—Chalk Marl of Pinhay Cliff, Lyme Regis. Base of Chalk Marl 
(zone of WNSchlenbachia varians) of Chard, Maiden Newton, Eggardon Hill, 
and Titherleigh near Chard. Chloritic Marl of Maiden Bradley. Rye Hill Sand 
of Warminster. Upper Greensand of Plush. 
CucuLtza, sp. Plate XIII, figs. 6a, d, ¢. 
Cf. 1844. Arca Gurraneert, A. d’Orbigny. Pal. Frang. Terr. Cret., vol. iii, p. 228, 
pl. eeexviii, figs. 1, 2. 
— 1850. — — — Prodr. de Pal., vol. ii, p. 164. 
— 1866. — — F J. Pictet and G. Campiche. Foss. du Terr. Crét. 
Ste. Croix (Mater. Pal. Suisse, ser. 4), pt. 3, p. 474. 
— 1871. — — F.. Stoliczka. Palwxont. Indica, Cret. Fauna 8S. India, 
vol. iii, p. 848 (ZLrigonoarca). 
Description.—Shell oval or rhomboidal, high, convex. Anterior and ventral 
margins curved. Posterior margin oblique; postero-ventral angle rounded ; 
antero-dorsal angle sharp. Umbones rather small, close together, placed near 
the anterior third of the shell. Carina rounded. Hinge-area narrow. Orna- 
mentation consists of very fine radial ribs crossed by lines of growth. 
Measurements : 
Length . . . : : : : , 2) oo mm. 
Height . ; : ; , : : : <) Al =; 
Remarks.—The only example I have seen of this is a right valve in Mr. Meyer's 
collection. It is similar to Arca Guerangeri, d’Orbigny, but is less inflated. 
Only a small part of the hinge is seen. 
Distribution.—Chalk Marl (Meyer’s Bed 10) of Dunscombe, 
