AMMONITES fimbnatus, 
TAB. CLXIY. 
Spec. Char. Discoid; volutions cylindrical, inter- 
nal ones exposed; lines of growth undulated,, 
and in some parts fimbriated; mouth orbicular* 
It 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- 
briae, 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 
shell is 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 : 
it is from the Blue Lyas, at Lyme Regis, Dorsetshire. 
