145 
AMMONITES fimbriatus. 
TAB. CLXIYV. 
Srec. Cuar. Discoid; volutions cylindrical, inter- 
nal ones exposed; lines of growth undulated, 
and in some parts fimbriated ; mouth orbicular. 
== 
Ty should appear from what remains in the specimen 
figured, that the mouth in a full grown shell, is fur- 
nished with an undulated reflected lip or ruffle, and the © 
more or less perfect formation of this at various periods, 
produces either undulating lines of growth, some of 
which are obtuse and others acute, or thin annular fim- 
briz, surrounding the volutions at certain intervals: the 
obtuse lines of growth are indented at their backs, but 
straight towards the mouth, and indicate that the undu- 
lation of the lip is strongest at the back of it. The 
whorls do not appear to have been very numerous ; the 
shellis thin, and the margins of the septa have rounded 
lobes. 
I could not refrain from publishing this curious Am- 
monite, although the fragment, for the loan of which I am 
indebted to the Rev. W. Buckland, is apparently so im- 
perfect ; however, it exhibits every essential character: 
itis from the Blue Lyas, at Lyme Regis, Dorsetshire. 
