124 



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 Mr. 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 concamerated 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 

 siphuneulus, 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 belem- 

 nite, but which in general is destroyed. Monument des Catastrophes* 

 Tome III. p. ii. 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. Vol. LIV. 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 observes), 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 whole belemnite ; in others, not a sixth part of the whole : 



