185 
BACULITES. Lamarck. 
Gen. Car. A straight lanceolate shell, a part of 
it internally divided by septa whose edges are 
sinuated : a siphuncle penetrates the septa near - 
their anterior margins. 
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A cenus very closely related to Hamites, differing only 
in being quite straight. Most of the species are very long 
and laterally compressed, so that the transverse section 
is elliptical; the apex has never been discovered, and 
we only know of one-instance of the opposite extremity : 
it is furnished with two elongated lobes, which, bending 
a little, seem to point out the anterior part; they turn 
from the siphuncle : the edge near these lobes is thicken- 
ed, and is only completed periodically, as appears from 
the successive impressions left upon the casts of many in- 
dividuals. The six principal lobes of the septa have a 
peculiar roundness of form, which helps to distinguish 
small specimens from Hamites. 
The first generic name was Homaloceratites, given by 
the Baron Hupsch. We are not aware of Lamarck’s 
reason for changing it; but his name is now come into 
general use, therefore we retain it. 
Lamarck describes three species ;—one from Diasuinicht; 
and two British: we regret that the latter have not fallen 
under our observation. One (B. anceps) is described with 
one sharp edge; in which it resembles a species very abun- 
dant in Normandy, which we have received as B. verte- 
bralis: the other may possibly prove to be a Hamites 
from Folkstone. 
All the species occur in the lower beds of Chalk or 
Chalk Marl and the es Greensand. 
$9 aes ae 
