t 76 ] 
in a memoir relating to that fubjeCt *, juftly obferves, 
has been very improperly applied to this kind of 
animals i for it is certain, that not a fingle fpecies of 
them is poflefled of that flinging quality like a nettle 
(which the antients afcribed to them), and that only 
their tentacula feel rough and clammy, when touched 
with the finger. Even this roughnefs is not per- 
ceptible, but when the animal attempts to lay hold 
of the finger : it then throws out of the whole fur- 
face of the feeler a number of extremely minute 
fuckers, which, flicking fall to the fmall protu- 
berances of the fkin, produce the fenfation of a 
roughnefs, which is fo far from being painful, that 
it even cannot be called difagreeable. 
The proper genus, which thefe fea-nettles belong 
to, is that of the hydra of Linnaeus, commonly called 
the polype. This will evidently appear, from the fol- 
lowing characters : fir ft, from the gelatinous fub- 
flance, of which this whole tribe of animals confifls : 
fecondly, from their having only one opening in 
their bodies, which gives a paflage to the food, as 
well as to the excrements, of the animal : and laflly, 
from a fet of feelers, which furround this opening, 
and ferve thefe creatures for claws, to catch their 
prey with, and convey it to their mouths. As the 
lea-nettles agree perfeClly in thofe general characters 
with the hydra, fo do they alfo anfwer to many of 
its lefs effential, or merely accidental qualities : they 
live, for inflance, conflantly in the water, in which 
* Du mouvement progreflif et de quelques autres mouvemens 
de diverfes efpeces de coquillage, orties, et etoiles de mer. Me- 
myires de l’Academie Royale des Sciences, 171c. p. 439, &c. 
they 
