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CEPHALOPODA Ammonites accipitris 
J. Buckman, 1844. 
Original description 
(1844. — Op. cit., p. 102). 
« Ammonites accipitris, Tab. 11, f. 6. — Back thin, not distinctly keeled, crenated ; 
volutions 4 or 5, one-third concealed ; ribs slight, irregular, curving forwards, sometimes 
one or two short intermediate ones between the longer pairs, mouth with a curved beak 
resembling that of the Falconidæ. Diameter 1 3/4 in., thickness 2 lines, aperture oblong 
ovate, about one-fourth the diameter. 
« LocaLrry. — Lias Shales from the Railway cuttings between Cheltenham and Gloucester, 
the village of Cleeve, etc. » 
OBSERVATIONS 
To the above description may be added : — that the periphery (back) is rounded and 
bears a slight line like a keel, until the last third of the whorl, where it is broader, flatter, 
coarsely crenated, without any sign of keel. The inclusion of whorl is nearly one-half at the 
aperture; and the umbilicus expands rapidly during the last half-whorl, so that the previous 
inclusion would be rather more. The small ribs are bowed somewhat on the lateral area, 
and are slightly projected on the periphery. There is some mistake in the dimensions, for 
the type-specimen is 1 in. (25mm) in diameter, and 2 3/4 lines (6mm) in thickness at the 
aperture. 
Characters from more than one specimen are combined in the original figure and in the 
description. The coarse ribs shown in the figure are taken from another example (T?) than 
that with « slight irregular ribs ». The « short intermediate ones [ribs] between the longer 
pairs » belong to another specimen (T#). Therefore T! and T? must be regarded as cotypes 
as if they had been separately figured, instead of their characters being contained in one 
figure. Of these T! is taken as a now-selected holotype. T? and T* would then become 
paratypes. 
There is no genus to which this species has been, or can be referred. 
Locazrry AND HorizON. — The record may be thus amplified : — Lower Lias, Upper 
Sinemurian, zone of Am. oxynotus, With À. cultellus (pars = oxynotus) and À. Colesi, cuttings 
on the Midland Raïlway near Cheltenham, Gloucestershire, for instance, Lansdown Station, 
Cleeve Village, and perhaps Swindon. 
Generic name. As no name can be assigned even provisionally, I propose the designation 
Cheltonia from the locality Cheltenham, with the following definition : — A dwarf Ammonite- 
series, a degenerate series of the 4rietidæ, Oxynotoceratan in character, but more umbilicate, 
with rounded, almost uncarinate, and later crenate, periphery. Aperture rostrate ; septal 
margins simple, like those of Am. lævigatus, globosus, etc. Type : À. accipitris, J. Buckman, 
the selected holotype (T1.). 
1904. S. S. Buchman. 
27 
