AND STRUCTURE OF THE BELEMNITE. 411 



The means I employed was to dilute muriatic acid with 

 four or five waters, and perhaps this was too rough an applica- 

 tion for the very delicate and minute fibres which were often 

 exposed to it, as I found in too many instances, that, after the 

 specimens were dried, the flinty arborisations would sometimes 

 fall to pieces. This extreme delicacy rendered an exhibition 

 of these specimens impracticable, which is to be the less re- 

 gretted, as I am indebted to the elegant and elaborate pencil 

 of Mr Greville for the most faithful representations of them ; 

 and which I have now the honour of submitting to the So- 

 ciety. 



No. 1. (Plate XXV.) the first drawing is a portion of a large 

 belemnite, selected to shew the nature and situation of the 

 alveolus, and the concamerated cone by which it is occupied. 

 This specimen was sent me by Dr Fitton from Northamp- 

 ton. 



No. 2. Is a flint from which the belemnite separated of its 

 own accord, and is selected on account of the indication of 

 a serpula, which seems to have been attached to the surface 

 of the animal. In several of the specimens, the external 

 surface seems to have been rough, and covered with minute 

 protuberances, corresponding depressions being observable 

 on the flint. 



No. 3. In this specimen the cone fills up entirely the base of 

 the belemnite ; the trace of its circle being lost in the sub- 

 stance of the flint. At its apex there is a delicate capillary 

 process appended. This is the process, which proceeds from 

 the apex of the cone, to that of the belemnite. I have found 

 it always extremely delicate, and it sometimes fell to pieces 

 by its own weight. There are also some of the little branches 

 of flint, which have occupied the pores or perforations allu- 

 ded to. 



No. 



