DR. MANTELL ON THE BELEMNITE. 
397 
it is important to preserve faithful representations taken whilst the speeimens are 
fresh from the stratum, for when the clay contracts by drying, the delicate shelly 
structure of the phragmocone but too frequently shrivels and flakes off; 1 know of 
no means by which this decomposition can be prevented, and am therefore desirous of 
adding to the illustrations of this communication the accompanying drawing, by 
Mr. Mounsey, of the beautiful fossil above mentioned, in which are shown the elon- 
gated processes of the phragmocone in their natural position on each side the dorsal 
line ; the interval between them is occupied by a thin pellicle of a dark integument 
marked with very fine diverging parallel strise ; this substance is probably the inner 
lining of the capsule of the sepiostaire in a carbonized state, a condition in which 
animal tissues so often occur in argillaceous deposits. 
I likewise annex a drawing of another specimen (Plate XXIX. figs. 9, 10) of the 
distal termination of the osselet of the Belemnoteuthis, in which the alveolus or hol- 
low occupied by the chambered shelly cone is exposed ; the cavity is filled with cal- 
careous spar, and is surrounded by a dense fibrous radiated structure, analogous to 
that of the osselet of the true Belemnite ; an additional proof that in the Belemno- 
teuthis this investment is the osselet or guard of the phragmoeone. After this evi- 
dence, the presumed generic identity of the Belemnite and Belemnoteuthis must, I 
conceive, be abandoned by every accurate observer; consequently the form and struc- 
ture of the body and arms, and other soft parts of the Cephalopoda to which the 
Belemnites belonged, have yet to be discovered. 
Description of the Plates. 
PLATE XXVill. 
Fig. 1. Outline of a remarkably fine specimen of a Belemnite with the phragmocone 
and its elongated processes, from the Oxford Clay, Wilts. In the British 
Museum. The length of the original is 22 inches. 
Fig. 2. Represents the basilar or upper portion of the above fossil of the natural size, 
e. The right, and f. the left process. 
X, a?, X. The base of the process spread over the conical shell of the 
ph ragmocone. 
PLATE XXIX. 
Fig. 3. Part of the phragmocone of a Belemnite from the Lias, in the collection of 
John Morris, Esq. 
3®. Lateral view of a portion of the same, showing the remains of one of the 
longitudinal processes on the shell of the phragmocone. 
Fig. 4. Outline exhibiting all the known pai ts of the Belemnite in their relative 
position, the osselet being split asunder longitudinally, and one side re- 
moved to show the situation of the alveolus, &c. 
