128 
menta, ex monte Heimburgensi, quae evidentur arguunt, lapidem ejus- 
modi, si integer esset, octo uncia fore longiorem, cum interim summa 
crassities in ambitu quatuor uncias cum dimidia omnino expleat.” 
Oryctogr. JVoric. 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 circumference, in the thickest part, is five inches and a half, and 
the concamerated 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 state 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 necessaiy 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. V alch ; 
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 ap- 
pears in support of its existence. 
