44 
longitudinal low ridge extending from the cen- 
tral beaks ; ventral margin arched. 
Syn. Thracia convexa, 5. V. Wood, Annals, %c. 
v. 6. 245. (non auctorum.) 
'I HRACIA convexa , a recent species, is a convex nearly 
heart-shaped shell, with a straight ventral margin, and 
beaks nearest the posterior extremity; but still so much is 
the shell before us like it, that imperfect specimens may 
easily be mistaken for the same; and Mr. Wood observes 
in the i Annals,’ that his “ specimens are compressed and 
broken ; too imperfect for identification.” Specimens since 
collected at Sudburn Hall and Ramsholt by the Rev. R. 
Wilson and Mr. S. V. Wood have enabled us to determine 
the difference and to give nearly complete figures. A spe- 
cies more nearly allied to T. convexa is found in the newest 
tertiary beds of Sicily. 
THRACIA sulcata. 
TAB. DCXXXII — fig .3. 
Spec. Char. Transversely elongated, oval, largely 
truncated, compressed, concentrically furrow- 
ed ; truncated extremity separated by an ob- 
tuse ridge ; beaks rather nearest to the pos- 
terior extremity, hinge callus lanceolate. 
The surface of this is composed of granules, like several 
others of the same genus; it is otherwise so distinctly 
marked that it is easy to recognise it. The specimens 
figured are in the cabinet of F. E. Edwards, Esq., who 
discovered them at Bracklesham. 
