52 
but thicker and less pointed than the last: the hinge 
also appears to differ, as I have only been able to detect 
one central tooth in each valve; but the clayey stone is 
so hard, that it is difficult to clear the hinge. 
This fossil occurs in various parts of the Weald Clay 
and Hastings Sands, both in Sussex and on the Isle of 
Wight. See Dr. Fitton’s paper in the Annals of Phi- 
losophy above quoted. The specimen figured consists 
of indurated clay, and was collected at Chart. 
CYCLAS membranaceus. 
TAB DXXVII—fg. 3. 
Spec. Cuar. ‘Transversely obovate, depressed, 
smooth, very thin; anterior side small, pos- 
terior rather pointed. 
Syn. Cyrenamembranacea. Annals of Philosophy, 
Second Series, vol. 8. p. 376. 
Very much resembling the last, but it is extremely ~ 
thin. 
Occurs in slaty clay, accompanied by two other bi- 
valves and two univalves, which for the present are 
named Melania attenuata and M. tricarinata, but which 
are so much compressed and broken that they cannot be 
well defined. 
Found at Punfield by Dr. Fitton, in the Weald Clay. 
