87 
. The food in the stomach lias a rapid rotatory motion while 
remains there, and is conveyed through the terminal tube 
‘ n >he same manner. Dr. Farre in an elaborate and excellent 
a fticl e on this subject says this rotatory motion is effected by 
''Oratory cilia, similar to those of the tentacula. 
. Even from this brief notice of the anatomy of the polypes 
w ill be seen that they are considerably elevated above 
'ose of the foregoing orders; and their activity and in- 
. diligence are equally superior. When fully expanded and 
search of prey, turning from side to side, with their len- 
' Hc ula in constant and graceful action, they seem like animated 
:‘°wrets ; but the suddenness of their disappearance is almost 
be\ ‘ ' 
Vlia 
Tl 
^Jond belief ; more resembling the visions of a fairy tale 
an any reality. How this is effected will now be explained. 
‘“e principle is alike in all the families, however widely 
. lo y may differ in external characters. For the sake of 
, 1 rev ity, it will, therefore, be described only as it occurs in 
' le Vesiculariadee, &c. The cells in this family for the most 
j? r t, resemble grains of wheat in shape. In these, the polype 
, u| es itself. The inferior portions of the cells are iullexibly 
£. 0r ny, while the upper parts are thinner and more membranous. 
11 the internal surface are distributed a few flat muscles, which 
( U| ' e attached to different parts of the polype; tints for instance, 
** is attached to the base of the stomach and the base of 
t) 7 cell ; others at the sides of the cell and to corresponding 
j^fts of the polype; their origins or fixed points always 
lj c | n g below their insertions. These are the muscles which 
0 ,°S to the polype; there are others which belong ex- 
tt «ively to the cell. The upper portion of tbo cell, being 
^'-'n branous and flexible, is operated on by muscles which 
m their origins on the upper part of the inflexible portion 
»r 
pper part i 
are insert* 
e crifice. Here then we see there arc two sets oi levers, 
tl! cell, then ascend and are inserted into the thin edge of 
|j ra »ged in the best possible manner for rapidity ot effect. 
t |^ Vhenj the polype can be instantaneously withdrawn, and 
'L.cpening drawn closely and tightly together, 
f *'e upper rim of the cell, when the polype is expanded, is 
to be surmounted by a coronet of long delicate bristles, 
are held together by a membranous connection ; and 
ill 6n Vbe polype is withdrawn, these remain closely compacted 
el"" Upright position at the entrance ot the cell. '1 ho mus- 
tli r are composed of simple fibres, ot nearly equal thiekness 
a t L 0u gfi°ut, and with but very slight attachments to each 
They are in fact the simplest form of muscle I ever 
t| le ' 'l hi* then is the mechanism of tlie rapid movements of 
c] e Puiype ; but th e way in which they protrude is not so 
*ela ^ lo be explained. The retractor muscles being lfl a 
Xetl state, the sides of the polype which are also said to 
