THRACIA. 243 
difficult. especially without the opportunity of comparing specimens, to establish 
the identification. Professor Boule informs me that the type is a poorly preserved 
specimen, but that its outline is satisfactorily represented in d’Orbigny’s figure ; 
the specimen is now in the Natural History Museum, Paris. 7’. Robinaldina is 
allied to 1’. neocomiensis (VOrbigny),'’ but is said to differ from the latter by the 
ereater curvature of the ventral margin and by its relatively shorter shell. 
Distribution.—Lower Greensand (Perna-bed and Crackers) of Atherfield. 
Atherfield Beds of Redhill, Reigate. 
Turacta Sancta-Crucis, Pictet and Campiche, 1865. Plate XL, figs. 4—6. 
1865. Turacta Sancrm-Crucis, I. J. Pictet and G. Campiche. Foss. Terr. Crét. 
Ste. Croix (Matér. Pal. Suisse, ser. 4), 
p- 117, pl. eviii, fig. 8. 
1870. = — F. Stoliczka. Palzeont. Indica, Cret. Fauna 8. 
Tudia, vol. iii, p. 72. 
Description.—Shell oblong, compressed, imequilateral. Anterior margin 
rounded; ventral margin shghtly curved; posterior margin truncated, slightly 
convex, forming an angle with the postero-dorsal margin. <A carina extends in a 
curve from the umbo to the postero-ventral angle and cuts off a concave postero- 
dorsal area. he surface of the shell is ornamented with growth-rings. 
Measuremeits : 
(1) (2) 
Length 43 : 39 mm. 
Height 20 ; N62 Se 
(1) Gault, Folkestone. 
(2) Gault, Black Ven. 
Affinities.—It seems doubtful whether this species is distinct from 7’. simplex 
(VOrbigny), of which casts only are figured by d’Orbigny? and by Pictet 
and Campiche’; but the latter authors state that it differs from 7’. simplew by the 
absence of an internal rib, the presence of a carina, and by the more acuminate 
anterior end. 
Type.—F rom the Upper Gault of Ste. Croix. 
Distribution.— Gault of Folkestone and Black Ven. 
MiRACiw cp eelate Uh. nes. 7——o. 
Some examples of Thracia, usually of rather large size, appear at first sight to 
be distinct from 7’. Sancte-Crucis on account of their relatively greater height and 
1 «Pal. Franc. Terr. Crét.,’ vol. 11 (1845), p. 381, pl. ceclxxu, figs. 3, 4. Pictet and Campiche, 
op. cit., p. 115, pl. eviii, figs. 3, 4. 
2 Op. cit., p. 382, pl. ccclxxii, figs. 5, 6. 
3 «Foss. Terr. Crcét. Ste. Croix’ (‘ Matér. Pal. Suisse,’ ser. 4, 1865), p. 116, pl. eviii, fig. 7. 
