XV'l 
INTRODUCTION. 
touched with iustrunients without much effort at con- 
traction. 
The gular tube is remarkably corrugated longitudinally, 
the folds being so full, that a transverse section would 
present a series of figures 8. In the present state of con- 
, traction there were horizontal corrugations also. At a 
short distance below the mouth the stomach ends abruptly, 
the edge, thin and delicate, hanging freely like a much 
folded curtain into the cavity. At each angle of this 
flattened sac the gonidial groove was conspicuous from top 
to bottom, inclosed by two slender columns of the firm 
cartilage-like muscle. 
The diameter of the digestive tube is, when at rest, not 
greater than that of the mouth ; indeed, the walls are in 
contact; nor, so far as my observation extends, are they 
ever separated except for the reception of food. 
It has been customary to represent the stomach as a sac 
pierced at the bottom “ by one or more valvular openings 
which communicate with the cavity of the body.”* But 
the case is as I have stated it : the free folded membrane 
hangs perpendicularly ; nor is there any thickening of the 
edge, nor any structure which at all resembles a sphincter. 
In tall specimens, I have observed, through the semi- 
transparent integuments, food pass into the stomach, and 
have marked that the morsel is invariably retained, never 
passing through to the general cavity ; but I am persuaded 
that this is effected by the common contractility of the 
walls, and not by a sphincter. 
'When morsels of food, such as fragments of butchers’ 
meat, are swallowed by Anemones, they are retained for 
some hours, and then vomited ; and because little change 
has passed upon the solid parts it has been rashly concluded 
that no process of digestion takes place in these animals. 
On this foolish hypothesis it is difficult to see why food 
should be swallowed at all, or what need the animal has of 
mouth or stomach. Their ordinary food, however, is not 
mammalian muscle, but the far softer and more fluid flesh 
ot Crustacea^ Mollusca, and Annelida. Nothing is more 
common than to find large specimens of A. mesemhryan- 
themum or T. crassicornis discharge, soon after their capture, 
• Siebold’s Comp. Anat. § 37. “ The stomach with its circular aperture 
at the ease ” (Teale). Johnston, indeed, denies it any aperture at all : — 
" There is no — other visible exit from the stomach than the mouth.” 
