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a decree of adhesion, that, whilst the animal secured this vacuum, no 
removal of it from that spot could take place, unless accompanied by 
destruction of the parts of which it was composed. On the other 
hand, whenever the animal was disposed to submit itself, with its 
dwelling, to the direction of the waves, it would only be necessary to 
contract the perpendicular fibres terminating on the edge of the infe- 
rior surface, by which that edge would necessarily be raised ; and by 
continuing this process through each successive circle towards the cen- 
tre, the air would gain access to the vacuum, and the animal would 
be immediately loosened. Whilst affixed by its inferior surface to any 
other substance, the whole of its circumference would be formed into 
as many fixed points as there are fibres proceeding up its superior 
surface. These fibres, thus fixed at their inferior part and terminating 
in the sides of the longitudinal cavity on the upper part, would, by 
their contraction, draw downwards the whole alcyonic mass, and at 
the same time widen the central longitudinal opening, by which ac- 
tion the contents of the ventricular cavity must have necessarily been 
expelled. The relaxation of these fibres would of course be accom- 
panied by the refilling of the cavity, and by the alternate conti action 
and relaxation of these fibres, the alternate filling and emptying of the 
ventricular cavity would be effected. 
The probability that the animal possessed this power of thus form- 
ing a vacuum, and of fixing itself, like the remora, or sucking-fish, is 
rendered exceedingly probable, by both the specimens which I pos- 
sess, as has been already observed, having on their inferior surface 
concavities, not only differing in their magnitude, but also in their 
form, arising from different circles of the series having been more or 
less acted upon, by which corresponding risings and depressions have 
been left. From the rarity of the fossils, I was not disposed to insti- 
tute any examination of them which should, either chemically or me- 
chanically, injure their surface. 
