122 
AMMONITES cinctus. 
TAB. DLXIV.—fg. 1. 
Spec. Cuar. “ Discoidal, subumbilicate ; volutions 
depressed, half inserted, transversely radiated ; 
radii annular, distant, bifurcated, undulated ; 
umbilicus expanded, sides smooth, with a mar- 
ginal row of oblique tubercles ; ambit convex, 
embraced by the radii ; aperture ovato-sagit- 
tate. 
en a 
Tue volutions, although compressed, have a slight de- 
gree of convexity, and are ornamented by transverse ra- 
diations that arise from a row of small tubercles on the 
inner margin. Each radius divides into two branches, 
which pass with a gentle sweep across the ambit, and 
unite with the corresponding undulations of the oppo- 
site side; small oblique tubercles are placed on each ra- 
dius at the point of bifurcation. 
It is scarcely necessary to remark, that although this 
species approaches to A. varians in having bifurcating 
radiations and a row of tubercles on the inner margin, 
yet it is widely separated from it by the rounded form of 
the back (front) and other obvious differences. 
Longest diameter 3°8 inches; width of the outer volu- 
tion two-fifths of the diameter; transverse diameter of 
the aperture 1-1 inch. 
Locality, Middleham.”’ 
The above description is copied from the Geology of 
Sussex, pp. 116 and 117. It appears that only one indi- 
vidual has been found; and the permission granted by 
Mr. Mantell to figure that, is the more valuable, because 
it had not been figured before. It is a cast in Chalk 
Marl; the edge of the aperture seems to have been per- 
fected, as it was evidently somewhat thickened. 
