SUPPLEMENT 
ON 
THE ACALEPH . 
In our supplementary observations on this class, we must 
chiefly confine ourselves to the Acalephe simplices, which 
are mostly comprised in the great genus MEDUSA of Linnzus, 
and to which M. de Lamarck has given the name of Me- 
dusarie. 
These animals are extremely: numerous in all seas, but 
more particularly in those of warm climates, have been re- 
marked at all times by the inhabitants of the sea shore, and 
by all authors of natural history, from Aristotle down, though 
they are scarcely of any utility to the human race. But the 
singular property which they possess of being luminous to a 
great degree in darkness, or obscurity, and that of producing 
a painful sensation similar to the sting of nettles, when any 
of them are touched, must have occasioned them to have 
been observed early. Accordingly all maritime people have 
particular denominations to designate them. ‘These names 
almost always indicate one of these two properties, such as 
knide, acalaphe, urtica marina, sea-nettle, &c. 
These acalephe have a regular form, very circular, hemis- 
pherical, more or less convex above, and concave underneath, 
VOL, XII. 00 
