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BELOPTERA. Deshayes. 
Gen. Char. Shell (bone?) internal, oblong, expand- 
ed, concave, thin : to its inner surface is at- 
tached a chambered cone, placed longitudi- 
nally; from the apex of the cone the shell is 
considerably thickened. 
This genus has been formed to receive those organic 
remains found in the Calcaire grossier of France, which 
resemble the bones of cuttle-fish (Sepia officinalis) ; but 
one of the species is (perhaps two may be) so nearly 
like the recent Sepia, that it does not seem necessary 
to remove it from that genus. We have modified the 
Gen. Char, of Beloptera so that it may only include such 
species as have a chambered cone resembling Belem- 
nite, that is, De Blainville’s 2nd section of the genus. 
We have given outlines of two of the species De 
Blainville refers to the genus; the third we have never 
seen. Fig. 1. is B. sepioidea (Sepia Cuvieri), which we 
would refer to Sepia; its septa being placed like the la- 
minae of that bone, and not crossing a conical cavity. 
Fig. 3 . is B. belemnitoidea, the only species in De Blain- 
ville’s 2nd section; the cone in it is completely divided 
by the septa into many narrow cells ; we know not whe- 
ther it had a siphuncle. The first appears to be a small 
portion only of the shell or bone, while this has rather 
the appearance of being nearly entire, the chambered 
cone filling half its length. We consider it as the type 
of the genus. Only one species is found in England, 
which is in the London Clay. 
