133 
AMMONITES complanatus. 
TAB. DLXIX.- -fig. 1. 
Spec. Char. “ Fiat, volutions wholly inserted, the 
inner half marked with numerous indistinct 
transverse undulating striae, the outer portion 
plicated ; umbilicus very small, almost con- 
cealed ; carene slightly convex, its margins 
crenated by the angular terminations of the 
plicae ; aperture sagittate/' 
u The longest diameter is about 8 inches, greatest thick- 
ness 1*8 inch, width of the outer volution 5 inches. 
u The volutions are thickest near the middle, and gra- 
dually contract into a narrow keel, which at the aperture 
does not exceed 4-tenths of an inch in width, and has an 
elevation or ridge down the centre. . . .The septa are nu- 
merous, and very foliaceous. 
“ Locality, Hamsey.” 
With Mr. Mantell’s kind permission we have figured 
the specimen from which the above description, copied 
from his Geology of Sussex, pages 1 18 and 1 19, was taken. 
We know of no other example of the species : it is twice 
the diameter of the figure. The plicae do not occur upon 
the outer volution. 
