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When a clufter is already in good part ftripped 
of its Polypi* the branches are no longer able to 
contract with the fame quicknefs and readynefs as 
before. When there remain but a very few Polypi, 
none but thofe branches to which Polypi are ftill 
fixed continue to exert this power $ which they 
alfo lofe as icon as they are ftripped of their few 
remaining ‘Polypi, after which they (hew no further 
capacity of moving. 
From all which particulars it feems to refult, that 
this motion in the ftem and in the branches of a 
clufter, is entirely derived from the Polypi, which 
are fixed upon the branches. Notwithftanding 
which it rauft be acknowledged, that an obferver, 
attending to the appearance only of this motion, 
can hardly help perfuading himfelf at the firft, that 
they are the branches, which draw and give motion 
to the Polypi . 
The refemblance and the analogy, which the fi- 
gure of a clufter of Polypi bears to the figure of a 
plant, would induce any obferver, for fome time to 
imagine, that the Polypi which he fees fixed to the 
branches of the clufter, do really proceed and fpring 
from thofe branches, in the fame manner as the 
leaves, the flowers, and the fruits of a vegetable, 
fpring from the branches of the fame. 
It is neverthelefs the contrary of all this, that is 
true. The branches, compofing the clufters of the 
Polypi , fpring from the Polypi which are at their 
extremities. Thefe Polypi, which at the firft appear 
to be the fruits of the clufters, may more properly 
be confidered as their roots : and of the truth of 
this any one may eafily fatisfy himfelf, who will 
be 
