41 
AMMONITES annulatus. 
TAB. CCXXII. 
Spec. Char. Discoid,, with numerous, close, very 
prominent radii, which are often divided as 
they pass over the rounded front ; volutions 
from 5 to 7, exposed ; aperture roundish. 
T he numerous radii at first sight distinguish this from 
A. communis, (tab. 107 ;) the volutions are also more 
numerous than in that species. In some specimens the 
sides of the whorles are slightly depressed ; in others 
gibbose. The radii are, externally, very prominent 
round ridges placed so near together as to form a deep 
sulcus between each, some of them are divided in their 
passage round the front, so that they appear equally 
distant over all parts. When the outer surface of the 
shell, which adheres strongly to the stone, is broken orf, 
the ridges are much diminished ; and instead of convex sur- 
faces, like wires wound about the shell, they are flat, as if 
they were formed of square wire. The cast, when all the 
shell is removed from it, is also marked by slightly ele- 
vated rounded radii. 
This species of Ammonite occurs along with A. com- 
munis, at Whitby, in Yorkshire. It is also met with in 
the lower sandy beds of the inferior Oolite, which ap- 
proach the Lias at Cropredy, near Banbury, in Oxford- 
shire. Near Ilminster it is found, but with hardly any 
of the shell remaining. 
Fig. 1. represents a specimen lent me by the Rev. 
W. D. Conybeare : it is in a grey porous limestone : its 
