128 



ex monte Heimburgensi, quae evidentur arguunt, lapidem ejusmodi, si 

 integer esset, octo uncia fore longiorem, cum interim summa crassi- 

 ties in ambitu quatuor uncias cum dimidia omnino expleat" Oryctogr. 

 Noric. p. 35. 



A specimen which I possess, in two fragments, the superior of which is 

 represented Plate VIII. Fig. 8, measures nearly twelve inches, and must 

 have been, when perfect, upwards of fifteen inches in length : its cir- 

 cumference, in the thickest part, is five inches and a half, and the Oon- 

 camerated cone is nearly six inches in length. 



Frequently, on one side of the belemnite, a slight and narrow groove 

 is observable, as in Fig. 13 : and in some specimens two, and even 

 three of these grooves, are seen. How far these may be considered as 

 giving a claim to specific distinctions, or whether they should be 

 regarded as only the marks of varieties, cannot perhaps be at present 

 determined. 



The structure of the concamerated part of the belemnite leaves 

 not a doubt that, like the nautilus, it was sunk or raised in the water 

 by the different modifications of an appropriate organization. But 

 it yet remains to endeavour to determine the original stale and nature 

 of that organization, and particularly of that spathose body of which 

 the belemnite is chiefly constituted. 



The opinion of M. Walch, that it was originally a gelatinous fluid, is 

 the only conjecture that I am aware of, which has been hitherto 

 hazarded respecting the nature of the substance of which it was com- 

 posed originally. To confirm this opinion, it would be necessary to 

 show that there had existed a shell, or some covering, by which this 

 fluid had been inclosed and kept together. This circumstance has 

 been supposed by several, and has indeed been assumed by M. Walch; 

 but a close attention to the several statements which have been made 

 on this subject, and a careful examination of every specimen which has 

 come within my reach, has convinced me that no solid reason appears 

 in support of its existence. 



