EOLIDID. 125 
there are closely packed a vast multitude of clear 
oblong capsules, within each of which a narrow 
body is discerned running through its length. At 
the will of the animal, a number of these oblong 
capsules are ejected from the aperture, and at the 
same instant each capsule shoots forth with great 
force from one end a long thread or hair. These 
thread capsules are found in the Actiniw and Coral 
animals, as also in Medusw ; and there can be little 
doubt that they are weapons of defence, and that 
the propulsion of the thread is the immediate cause 
of the stinging power possessed by many of these 
animals; probably, indeed, by all, though not 
appreciable by us. 
The structure of the mouth and of the tongue 
with its numerous teeth has been already described. 
PAPILLZ OF EOLIS, 
A short gullet leads into a large membranous 
stomach, sending off on each side branches which 
subdivide and lead by smaller tubes into the canals, 
which I have already mentioned as running through 
the branchial papille. 
