86 
those of the two proceeding orders, are, according to Farr ( ? 
tnhidar with terminal apertures. _ . 
Tlie month, which is powerfully muscular, is situated in l ’ 
centre of the oral disc, and opens into a long, large, ^ 
canal which terminates either in a gizzard or the ston) a “ 
This canal, which may be called an oesophagus, is powerfu ^ 
muscular and very easily excited into action. When a polyi 
has succeeded in capturing its food, it is conveyed into W 
oesophagus, which instantly contracts on it, and by a sen 1 
of graduated contractions and relaxations forces it onwat 
under great pressure, to the gizzard or stomach. 8 , [3 
marked in different parts of its length, especially i° ' 
superior portion, by numerous closely arranged circular sp° 1 "^ 
at each extremity it seems more opaque than at any oy 1 
part, as if its two openings were guarded by circular muscl ’ 
which is probably the case. In some species this eaDal op®, 
into the stomach ; but in others it terminates in a powei 
organ which has been called a gizzard. This gizzard, > r ° j 
its inequalities of light and shade, appears to be of uneq 
thickness ; but there are always two dark spots, or °' rCll t | ie 
scribed bodies, placed opposite each other. Sometimes , 
circumference of each of these spots is plain; at others 11,8 ,,, 
with radiating lines, apparently formed of folds. Aft® 1 ' , tt 
merous examinations it seems to me most probable 1 ^ 
muscular fibres radiate from these points over the w 
organ, and consequently when they act, these points . 
brought into close approximation, and in their motions g 1 '!^ 
the food down to a pulp fitted for digestion; and such 8 “jy 
tribution of fibres would also produce the folds occasion® 
seen. This organ opens inferiorly into the stomach, " qi, 
is a long, large muscular sac extending to the base, of the®® j 
It is semi-opaque, and very irritable; its surface is niaj ' j, 
with minute irregular spots, which appear lo be gastric h’ j s 
eles for the secretion of a coloured fluid for digestion. 1 s 
an organ, however which is liable to considerable vari** 1 a t 
in size, depending probably on the quantity of food in 1 ^ 
the time. It is fixed in its proper situation bv tb |D :il , 
muscles attached to different parts of its surface. This ° r b |j 
seems to perform the functions of the stomach and s jt 
intestines in higher animals; for the food remains 10 j 
longer than in any other organ, is digested there, g 
afterwards passes with great rapidity through the ren,a, l ( J( >(' 
tube. From the upper edge of the stomach arises an® 
canal which, ascends between the sides of the polype and 
oesophagus, and terminates in a small orifice near th® tf 
of the tentacula. In some species the gizzard is 8 5 ^ 
in which case the first tube, or oesophagus opens int° 
stomach. 
