163 
AMMONITES restrains, 
TAB. CLXXXIL 
Spec. Char. Depressed, carinated, tuberculated ; 
tubercles three or four upon each radius, 
largest towards the front; volutions exposed ; 
aperture elliptical with a compressed reflected 
beak. 
T he aperture, exclusive of the beak, is somewhat less 
than a third of the diameter of the shell long ; the beak 
is a little reflected and flattened, the edges of it so pressed 
together, as nearly to close it : the tubercles are more 
divided upon the inner whorls than upon the outer ones, 
where they begin to run into one another, and form 
ridges that are curved forwards, towards a prominent in- 
sulated keel : volutions about four. 
So remarkable is the beaked mouth of this Ammonite, 
that I have named it from that character. The figure is 
taken from a specimen lent me with a valuable collection 
of the same Genus by the Rev. Mr. Buckland ; it was 
found in Chalk Marl at Roak Village, near Benson, Ox- 
fordshire. The terminal chamber or that in which the 
animal is supposed to have resided, being preserved 
entire, renders the specimen particularly valuable, as it 
is commonly broken off. 
