[ 77 ]• 
they never fwim, but always adhere to forne fixed 
body in it j and when they change their place, moft of 
them crawl along fo very (lowly, that their progreflive 
motions cannot be perceived with the eye to. This 
may be added, that they likewife bring forth their 
young ones alive, and that they grow again, after 
confiderable parts of their bodies have been cut off* 
all which proves hill farther, that thefe animal flowers* 
01 fea-nettles, are of the fame nature, have the fame 
chai afters, and do confequently belong to the fame 
genus, with the hydra. The polypes in general may 
be divided into two claffes, the one containing thofe 
polypes, that cannot conceal their feelers, though ever 
io much irritated 5 and the other, thofe, that,°at the 
leafl; imtation, contract themfelves, draw in their 
feelers, and frequently hide them under a membra- 
naceous cover made for that purpofe. The frit 
clafs, on account, of the fmall number of fpecies be- 
longing to it, needs no fubdiviflons; but to diftin- 
guifh properly the feveral forts of the fecond clafs, 
it is neceffary to divide it according to the various 
pofition of the feelers, which are inferted either in' 
the membranaceous cover itfelf, or into a flower- like 
production of the body, or laftly, in the very top 
part, or the difk of the polype : hence arife the three 
following fubdivifions of the fecond clafs : i. Hydra 
calyciflora. i. Hydra corolliflora ; and laftly, Hy- 
dra difciflora.- The reafon for which appellations 
will be. farther explained, in the defcriptions I am 
now going to give of every fort in particular. 
I he flrft clafs confifls but of a Angle, fort, whofe 
fpeciflcal character may be thus expreffed:- 
Hydra 
