MODIOLA. 103 
M. pedernalis, Romer,! is a larger species with finer ribs, and the anterior part 
of the shell nearly smooth. 
Distribution.—Perna-bed of Redcliff. Crackers of Atherfield. Atherfield Beds 
of Kast Shalford, Peasmarsh, Sevenoaks, and (ferruginous nodules) Littleton Pit, 
near Guildford. 
Moptota (Bracuyponves) srriavto-cosrara (@’ Orbigny), 1844. Plate XVIL, fies. 9a, b, 
10a, b, 11 w—e. 
1844. Myrinus srrraro-cosratus, A. d’Orbigny. Pal. Franc. Terr. Crét , vol. iii, 
p. 281, pl. ccexlii, figs. 4—6. 
1848. Moproua srriaro cosrara, H. G. Bronn. Index Paleont., vol. i, p. 739. 
1850. Mrryuus srrraro-cosratus, A. d’Orbigny. Prodr. de Pal., vol. ii, p. 166. 
1867. Moproua srrraro-cosratus, F. J. Pictet and G. Campiche. Foss. Terr. 
Crét. Ste. Croix (Matér. Pal. Suisse, ser. 4), 
p. 510. 
1871. ~- stRIATO-cosTavTA, E. Stoliczka. Paleont. Indica, Cret. Fauna 
8. India, vol. i, p. 373. 
Description.—Shell small, oblong or ovate-oblong, short, inflated, somewhat 
expanded, and also rounded and compressed posteriorly, ventral margin slightly 
sinuous. Umbones not quite terminal. No carina; dorsal and ventral to a line 
between the umbones and the posterior extremity the valves are sharply com- 
pressed. Ornamentation consists of numerous fine radial ribs separated by narrow 
grooves and covering the entire surface; the ribs curve toward the dorsal margin. 
The radial ribs are crossed at tervals by concentric ridges. 
Measurements : 
(1) (2) (3) (4) (9) 
Leneth . ; ; an) 8 8 7 5°) mm. 
Height . : F cad 5 es) 25 Ba eee 
Thickness ; ; ._— I ve) 5 — ,, 
(1) to (5) from Blackdown. 
Affinities.—The relation of this species to M. vectiensis is given above. It 
seems to approach closely the form described by Pictet and Campiche* as Litho- 
domus prestensis. 
Distribution —Blackdown Greensand. 
' «Tie Kreidebild. von Texas’ (1852), p. 58, pl. vii, fig. 11. 
2 « Boss, Terr. Crét. Ste. Croix” (‘ Matcér. Pal. Suisse,’ ser. 4, 1867), p. 522, pl. exxxvi, figs. 2—4. 
