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the motion in queftion is not really what it at the 
firft appears to be, a rotatory motion round an axis. 
And I even know fome fpecics of Tolypi, in which 
this motion is, comparatively fpeaking, but flow : 
and in thefe it is diftinftly feen, that this motion, 
tho’ in general refembling that ohferved in the 
others, is not a revolving or rotatory motion : fuch, 
for example, is the motion which is taken notice of 
in that fpecics of Toly pi, which Mr heewenhoeck 
has deferibed in the 295th Number of thefe Tranf- 
aElions . This is one of thofe infe&s whofe motion 
is the mod to be admired, and it is belides ex- 
ceedingly curious upon many other accounts. 
I have already faid, in my paper above referred 
to, that the motion in queftion is very flow in the 
cluftering Tolypi , juft when they are opening again 
after their divilion, and I am greatly miftaken, if it 
may not then be feen very plainly that this motion 
is not a rotation. The fame remark may alfo be 
made on th| tunnel-like Poly pm, and that, almoft 
during all tne time that it employs in its repara- 
tion. 
I made ufe of an expedient, whilft I was obferving 
the cluftering Tolypi , whereby I was able to retard 
the quicknefs of their motion. I poured by little 
and little a ftnall quantity of fpirit of wine into 
the glafs wherein they were kept. This fpirit of 
wine immediately either abated the velocity of their 
motion, or took it quite away, according to the 
quantity of it that I poured in. That which fol- 
lows both in the one and in the other of thefe 
two cafes, is of ufe, and gives light to the prefent 
queftion. Sometimes the fpirit of wine forces the 
Polypus 
