AND STRUCTURE OP THE BELEMNITE. 415 



to the ovarium of an animal, as already stated ; but this is a 

 pursuit I must leave to the comparative anatomist. He may 

 find in the threads by which these rounded masses are con- 

 nected, more uniformity than could be attributed to the acci- 

 dental perforations of a worm ; nor do I think the elegant and 

 delicate moss-like arrangement of the fibres with which they 

 are surrounded, seem likely to have accrued from any such 

 operation ; and as an organised connection has been point- 

 ed out, extending from the siphunculus to the apex of 

 the belemnite, perhaps more practised eyes may be able to 

 trace it farther in these or other specimens *. But as these 

 drawings shew, it is not the belemnites that are found in the 

 flint only that present this curious internal structure, for those 

 which occur in the chalk, when broken in the direction of 

 their axes, also exhibit the same phenomena, having the ca- 

 vities filled with white limestone, which, when contrasted with 

 the amber-coloured radiated spar of the belemnite, is exhibit- 

 ed with perfect fidelity. 



I have found several having these cavities filled partly with 

 chalk and partly with flint ; but this only when the belemnite, 

 by extending beyond the mass of the flint, was partly sur- 

 rounded by both. 



Now, under what circumstances was it possible, for either 

 the white limestone or the flint, to insinuate itself throughout 



VOL. IX. p. 11. 3 G the 



* Naturalists, having any connection with Ireland, will have no difficulty in 

 supplying themselves with specimens ; for although Mr Pakkinson mentions the 

 belemnite being found transfixed in flint as a circumstance of some rarity, the 

 north of Ireland affords an unbounded resource ; and it will be very interesting to 

 me to learn, that this fossil, found under similar circumstances in other places, 

 presents the same phenomena. 



