C 180 ] 
but (low, whereas k becomes afterwards very quick in 
thofe that are entirely perfected. 
The Polypi of the other Species that I have ob- 
fefved, are yet lefs than the lad : they are fhorter, 
but more open and hollow’d at their anterior Ends. 
Thefe have a Character that fufficiently diftinguifhes 
them from all the other Species : their Stems and 
Branches have a Motion that is not to be found in 
thofe of the other Polypi. Thefe Stems draw thern- 
fdves up, and fhorten all at once, taking the Form 
of a fpiral Wire or Screw ; and a Moment after they 
again refume their former Shape, ftretching them- 
felves out ftrait as before. 
Thefe feveral Species Polypi I have been fpeak- 
mg of, all multiply in vaft Abundance j but they have 
alfo Enemies that deflroy immenfe Numbers of them, 
and that in a very little time. 
I have alfo this Summer obferved regularly other fmall 
Polypi , of a different Sort from thofe that are found 
in Clutters. Thefe are nearly in Shape like a Tun- 
nel, pretty long in proportion to the Opening of 
their larger Ends. For this Reafon, Mr .^De Reau- 
mur has thought proper to diftinguifh them by the 
Name of Tunnel-like Polypi. 
I am acquainted with three Species of thefe laft 
Polypi., which are refpe&ively, green, blue, and 
white. 
Thefe mull: alfo be obferved often, and in various 
Attitudes, in order to obtain a tolerably exaft No- 
tion of their proper Structure. 
Their anterior End particularly, is of a far more 
compounded Shape, than one would atfirft imagine. 
There 
