133 
1 have possessed this specimen some years, it is Lime- 
stone from Derbyshire; it agrees in many respects with 
Mr. Martin’s description; his is more rapidly acuminated 
or conical, in his the dissepiments are approximate, 
concave, oblique, almost entire;” but in this the slight 
wave in the front which he speaks of is scarcely discern- 
ible, the oblique divisions of the sides are like the line 
fig. 5*, allowing it but little undulation. The sipliuncle 
placed between the centre and the edge agrees with ours. 
This species is said to vary considerably in size ; we hope 
this figure will give occasion to enquiry whether they 
are the same species or not, and as there is a furrowed 
species, O. Gesneri, it would be advisable also to look for 
that with the outer shell, Mr. Martin’s specimen being 
destitute of it. His figure of O. Breynii is destitute of the 
outer shell also. 
ORTHOCERA circularise 
T AB. L X*—Figs, 6 and 7 . 
Spec. Char. Shell smooth? gradually tapering* 
round; septa approximate* slightly concave 
with even edges; siphuncle placed about half 
way between the edge and the centre. 
Septa about three-sixteenths of an inch distant from each 
other. Diameter of the largest end in my specimen about 
in inch. 
