18 
from the remainder of the shell by a kind of step parti* 
eularly prominent near the beak ; the length is greater 
also ; the carinated form of the beak not so evident 
and the front edge has two or three waves in place of a 
regular curve. The shell seems to be very thin and not 
pearly. 
Casts of this in ferruginous indurated marl, with 
nearly ail the shelly remains worn off, have been for- 
warded to me by Miss E. Hill, who obtained them 
from Lantrissent near Cardiff. Similar casts occur at 
Osmington ; he plate contains two views of one of 
these that was given me by Miss Benett. Fig. 3 is from 
an imperfect cast in ferruginous sand, from Parkham 
Park, in Sussex : I received it from G. A. Mantel!, Esq* 
MODIOLA eequalis* 
TAB. COX.- — Fig. 2. 
Spec. Char. Oblong, convex, smooth, anterior 
lobe large, obscurely defined. 
The regular curvature of the margin which presents no 
angle, is a striking feature in this Modiola : the two ends 
are nearly equal in width, and the posterior lobe almost 
as large as the remainder of the valve, and very gradu- 
ally united with it. The length is about twice the width. 
A cast in loose ferruginous sandstone, from Parkham 
Park, in Sussex, by G. A. Mantel!, Esq- 
