[ 42 ] 
contain the fame in fome very fmall, in others fcarce 
or not at all vifible”. — But I flatter myfelf, that it 
will be found upon enquiry, that thefe are only cir- 
cumftances, which are common to other teftaceous 
bodies, that have been accidentally broken or decayed 
by time, when forfaken by their inhabitants. For no 
teftaceous body can be formed without an inhabitant 5 
nor does it appear to me, that any Belemnite was 
ever formed without an alveolus, or concamerated 
fhell. 
The conical cavity and its nucleus are always pro- 
portioned to the bulk of the Belemnite, but not to 
its length : fome are four times longer in proportion 
to the alveolus than others. The apex of the conical 
cavity, where the alveolus is firft formed, in fome runs 
up about half the length of the whole Belemnite ; 
in others not a fixth part of the whole [£] : but the 
aperture, or upper chamber [/] is equally proportionable 
to the bulk, or circumference of the Belemnite, of 
whatfover lize or ftiape; and is the feat [m] or dwell- 
ing-place of the animal, that forms the Belemnite. In 
what manner this work is executed, I fhall now endea- 
vour to explain. 
A conflderable part of marine bodies, efpecially 
thofe of the teftaceous tribe, are generally buried in 
mud or fand, except fome few, which ftick to rocks, 
&c. as the limpets and periwincles ; by which means 
we are prevented from making thofe remarks upon 
the feveral ftages of their growth, which an accurate 
enquirer would defire. We muft therefore have re- 
ly] Fig. 8. [/] Fig. xiii. b. 
[r«] We never find a Belemnite with part of the alveolus, 
hut the veftigia or marks of the remainder appear in the cavity, 
and are continued to the verge of it, 
courfe 
