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been discovered on the outside of some of these fossils, and by the 
marks having been seen of such a laminated structure, as is frequently 
observed in shells, whilst in a state of decomposition. 
Targioni Tozzetti, as well as M. Fermin, both conjectured, that 
they had seen an animal which might be considered as the recent ana- 
logue of the belemnite. But the animals which have been described 
by these naturalists differ materially from each other, and neither of 
them appears sufficiently to agree with the belemnite to allow us to 
consider it as being analogous with it. 
The opinion formed by M. Walch respecting the nature of this 
fossil, or rather of its original state, displays a considerable degree of 
ingenuity. According to his opinion, the larger and exterior part of 
the belemnite was a shell containing a viscous and gelatinous fluid, 
now rendered a spathose body ; that to the superior part of this 
conical shell was attached the exterior part of the shell of the con- 
camerated alveolus, in the upper chamber of which the animal lived, 
as in the Nautilus and Cornu ammonis. Through the septa dividing 
the chambers passed a siphunculus, which was connected with a 
small tube passing through the centre of the fluid contained in the 
external shell, and terminating in a small round projection, which 
existed at the point of the belemnite, but which in general is 
destroyed. Monumens des Catastrophes , Tome III. p. n. p. 212. 
Some very ingenious conjectures on the growth of the belemnite 
were proposed by a very ingenious and active promoter of these 
inquiries, Mr. Joshua Platt, of Oxford, Philos. Trans. Yol. LIY. 
p. 38, in a paper which he named, “ An Attempt to account for the 
Origin and Formation of the extraneous Fossil, commonly called the 
Belemnite.” The conical cavity and its nucleus, (Mr. Platt ob- 
serves,) are always proportioned to the bulk of the belemnite, but 
not to its length : some are four times longer in proportion to the 
alveolus than others. The apex of the conical cavity, where the 
alveolus is first formed, in some, runs up about half the length of the 
