[ 43 ] 
‘them in a much more perfeCt date [w] than the for- 
mer, with the alveolus in many of them j but that 
part is commonly crufhed [x] by the incum- 
bent matter. 
The fiphunculus of the Belemnite is always upon 
the verge of the chamber, or cell ; and in the fip- 
hunculusis a little gutt or duCtus, proceeding from the 
body of the animal, by dilatingor contracting of which 
the animal, it fhould l'eem, may go out or into its cell 
atpleafure. Thisis theonly ftay, which the animal has 
to fecure its retreat : but I cannot agree with the learned 
dodtor Hooke [«], that the gut or dudtuspajjes through all 
the cells to the end of the fpiral cone , either in this Hiell or 
the nautilus. His difcovering ofafpiramentum in the 
centerof the latter was merely conjectural; for the ends 
of the fpiral cone of concamerated fhells are fhut 
up in the fame manner with thofe of the turbinated 
kind : and it is common for all turbinated fhell-fifh, 
as they increafe in bulk, and enlarge their fhells, 
to leave their bottom or firft-formed convolutions. 
Therefore I make no doubt but the fame is done by 
the concamerated tribe ; for if the gut go through 
only one or two valves, it will be a fufficient ftay to 
the animal, and, being contracted or dilated, will 
ferve all the purpofes above mentioned. How far 
this is practicable by our little inhabitant, cannot abfo- 
lutely be determined; but if it be conftantly fixed 
by the gut to the fiphunculus, it has a furprifing 
power of contracting and dilating its body, to ex- 
tend fo far as the bottom or point of the Belemnite, 
'[«/] Fig. [*] Ibid, at y. 
[%] Hooke’s poithumous works publiihcd by Derham 8®. 
p. 306. 
[a] See the little pearly cornu-ammonis {hell. 
which 
