VENTRICULITES. 
103 
to other bodies. Externally it was composed of a 
reticidated integument, which seems to have been 
capable of expanding and contracting according 
to the impressions it received ; and, internally, it 
possessed a surface covered with the apertures of 
numerous tubuli, in all probability the ojienings of 
vessels, by whicli nutrition was effected. 
These inferences naturally present themselves, 
even upon a slight ins])ection of the fossils above de- 
scribed. It has already been shown that the speci- 
mens occur in everv intermediate form, between 
that of a simple elongated cone, and a flat circular 
disk ; the thickness of the parietes of the cone being 
considerable when short, thinner when more ex- 
tended, and thinnest when completely expanded : 
hence it seems obvious, that the substance of the 
original must have been soft and elastic, susceptible 
of spontaneous expansion and contraction, or it 
could not have accommodated itself to such a 
variety of shapes, without fracture or laceration. 
The fibres composing the external integument are 
nearly straight in the expanded specimens, but are 
corrugated and moniliform in those which are con- 
tracted ; the thickness of the latter is also much 
greater than in the former examples ; — circum- 
stances that strongly corroborate the opinion here 
adv'anced. 
The expanded state of the animal might have 
been favourable for the discovery of the substances 
destined for its nutriment, and which, by the sub- 
sequent contraction, would be imprisoned in the 
funnel-like cavity. Whatever may have been the 
aliment, if must have undergone a certain degree 
H 4 
