50 



CRETACEOUS LAMELLIBRANCHIA. 



Affinities. — GucuUsea Forhesi is closely related to C. Gabrielis, Leymerie, 1 but 

 differs from it in the presence of strong radial ribs on the adult shell. In G. 

 Gabrielis (of which I have seen three or four very perfect specimens) these ribs 

 are found on the young parts only, and are but faintly marked. Gucullgea tumida, 

 Matheron, is perhaps related to G. Forbesi ; it was founded on an internal cast. 

 C. Forbesi is distinguished from Area Moreana, d'Orbigny, 2 by its strong carina 

 and more widely separated umbones. 



The form figured by Coquand 3 as Area dilatata (from the Aptian of Obon, 

 Arcaine, &c.) is very near to G. Forbesi; but the shell is longer posteriorly, and 

 the radial ribs are not seen. A. Gresslyi, de Loriol, 4 is, perhaps, closely allied to 

 G. Forbesi, but is at present imperfectly known. 



Types. — From Atherfield. I have not seen the original of Forbes' figure 

 (1845). 



Distribution. — Pema~bed of Atherfield. Also, according to Fitton, in Beds iii, 

 vi, ix, and xiii of Atherfield. 



Cucull^a Cornueliana (d'Orbigny), 1844. 



Plate VIII, figs. 11—13; Plate X, 

 figs. 1 a — c, 2 a, b, 3. 



1844. ArcA Cornueliana, A. d'Orbigny. Pal. Fran?. Terr. Cret., vol. iii, p. 208, 



pi. cccxi, figs. 1 — 3. 



— — E. Forles. Quart. Journ. Geol. Soc, vol. i, p. 246. 



— — A. d'Orbigny. Prodr. de Pal., vol. ii, p. 80. 



— — J". Morris. Cat, Brit. Foss., ed. 2, p. 185. 



— — G. Cotteau. Moll. Foss. de l'Yonne, p. 86. 



— — P. de Loriol. Aoiin. Invert. Foss. du Mont Saleve, 



p. 86, pi. x, fig. 7. 



— — F. J. Pictet and G. Campiche. Foss. Terr. Cret. de 

 Ste. Croix (Mater. Pal. Suisse, ser. 4), pt. 3, 

 pp. 445, 469. 



— — P. de Loriol. In A. Favre, Eecherch. geol. dans 

 Savoie, &c, vol. i, p. 380, pi. c, fig. 9. 



— — F. Stoliczka. PalaRont. Indica, Cret. Fauna S. India, 



vol. iii, p. 342 {? Trigonoarcd). 



CuculL-EA subnana, W. Keeping. Foss., &c., Upware and Brickhill, p. 115 



pi. v, fig. 10. 



1845. 

 1850. 

 1854. 

 1855. 

 1861. 



1886. 



1867 



1871. 

 ? 1883 



1 ' Mem. Soc. Geol. de France,' vol. v (1842), p. 6, pi. vii, fig. 5 ; d'Orbigny, ' Pal. Franc. Terr. 

 Cret.,' vol. iii (1844), p. 198, pi. cccviii. 



2 D'Orbigny, ibid., p. 200, pi. cccix, figs. 1—3. 



3 ' Mon. de Pelage Aptien de l'Espagne ' (18G5), p. 139, pi. xxii, figs. 1, 2. 



* ' Anim. Invert, foss. Neoc. du Mt. Saleve' (1861), p. 87, pi. xi, figs. 1—3. 



