52 CRETACEOUS LAMELLIBRANCHIA. 



Cucull;ka Fittoni (Pictet and Campiche), 1866. Plate X, figs. 4 a — d, 5 — 7. 



1857. Arc a. Robinaldina, F. J. Pictet and E. Renevier (non d'Orbigny). Foss. 

 Terr. Aptien, &e. (Mater. Pal. Suisse, ser. 1), 

 p. 105, pi. xv, fig. 4. 

 1866. — Fittoni, F. J. Pictet and G. Campiche. Foss. Terr. Cret. de Ste. 



Croix (Mater. Pal. Suisse, ser. 4), pt. 3, pp. 455, 471. 

 1871. — — F. Stoliczka. Palseont. Indica, Cret. Fauna S. India, vol. 



iii, p. 343 (? Trigonoarca). 



Description. — Shell more or less oblong, rather inflated, equilateral or slightly 

 inequilateral. Anterior margin evenly rounded, passing gradually into the ventral, 

 which is parallel to the dorsal margin, but curves toward the postero- ventral angle. 

 Posterior margin nearly straight, oblique. Umbones moderately large, nearly 

 median, separated by only a small space, with a very sharp carina, curved, and 

 passing to the postero-ventral angle. The postero-dorsal area is sharply de- 

 pressed, and near its ventral third bears another carina. Hinge-line rather short ; 

 area small, with many ligament-grooves. Ornamentation consists of many fine 

 concentric grooves, and on the antero-dorsal part of the shell of a few radial ribs; 

 postero-dorsal area with many radial ribs. Central teeth (about ten) transverse ; 

 lateral teeth longitudinal. Interior not seen. 



Measurements : 



(i) (2) 



Length . . . 19*5 . . 14 mm. 



Height ... 15 . 11-5 „ 



Thickness . . 12'5 . . 9'5 „ 



Affinities. — This form is probably only a local variety of Area Robinaldina, 

 d'Orbigny ; it differs from that in being less elongate posteriorly. In d'Orbigny's 

 figure of A. Robinaldina the ventral margin has a greater curvature than in any of 

 the specimens which I have seen in the Paris museums. Area Comueliana, 

 d'Orbigny, is distinguished from G. Fittoni by the absence of the sharp carina. 

 Area zequilateralis, Briart and Cornet, is very similar to 0. Fittoni, but it appears 

 to be proportionately shorter, and to have the anterior margin less curved. 

 Distribution. — Crackers of Atherfield. Atherfield Beds of East Shalford. 



CunuLL.KA vagans, Keeping, 1883. Plate X, figs. 8 — 10. 



1883. Cucull^a vagans, W. Keeping. Foss., &c, Keoc. Upware and Brickhill, 



p. 151, pi. viii, fig. 8. 

 1883. — eruans, Keeping. Ibid., pp. 33, 34, 36, 65 {nom. nud.). 



