103 
ASTARTE planata. 
TAB. CCLYIL 
Spec. Char. Transversely obovate, gibbose, with 
small obtuse concentric ridges ; edges crenu- 
lated ; lunette concave ; shell thick. 
JL he ridges upon the surface are small, obtuse, close 
together, and lost near the margin ; the edge is often 
very broad, flat, and crossed by sulci formed of extend- 
ed crenulations, which are visible even when the valves 
are close. The anterior side is slightly truncated. 
This is a plain* looking shell, in consequence of the 
smallness of the ridges ; it is nearly two inches wide, 
and above one inch and a half long when full grown : 
the whole of the broad crenulated margin being visible 
when the valves are close has a curious appearance. 
Found in indurated Marl at Gunton, by the Rev. G. 
R. Leathes ; and at Roydon by — Smith, Esq. 
