2 oS Of the frefh Water Polyps . 
the Ikin of the body is reverfed. The plume which is 
upon the bafe c, enters with it, and appears, wEen all 
inclofed, like A B. After it is thus inclofed, it will foon 
come out again if it be left quiet. 
When it is out of the cafe, you may fee a tendon fixed 
by one end g, to the inferior extremity of the ftomach; 
and the other at o, the bottom of the cafe. There is 
alfo another of thefe tendons fixed to the bafe of the- 
plume at a, and the other end of the fame to the bottom 
of the cafe at o ; it is by the help of thefe two tendons 
that the animal draws itfelf into the cell. 
Thefe plumed polypes are feldo.m alone, but many of 
them placed together one by the fide of the other; and 
there are feveral of them that come out of the fame cafe, 
but by different orifices, which is the way they multiply. 
At firft there is a little elevation upon the fuperficies 
of the cafe of an old one, after which the body and plume 
s t begin to appear; or when a young one begins to 
fhoot the bafe of the plume and points of its arms uuu, 
fhew themfelves and increafe as the body enlarges. 
They can only eat very fmall animals, but of thefe 
they devour great numbers in a day. 
The quick motion of the plume, or rather the fe%- 
ther-like arms thereof, form a kind of whirlpool, into 
which moil of thefe little animals that are fwimming 
near it are precipitated. 
Every inffant one or two of its arms fuddenly bend 
into the plume, and immediately replace themfelves into 
their firff: fituation ; the fame arm feldom bends twice to¬ 
gether, nor do they touch the prey but by their rapid 
and continued motion caufe a turning hi the water, 
which conducts thofe minute animals into the plume, al¬ 
though they make feveral efforts to efcape, • the - fudden. 
inflection of one arm, adds a new degree of rapidity to 
the 
