HYDRA. 183 
of the glass, with its body and its tentacula extended, in 
which position it is ‘‘ as vigilant as a spider in the centre of 
its web, fully intent on prey, and will seize a worm with as 
much eagerness as a cat catches a mouse.”—“‘ I have often 
seen them thus situated, extending and waving their arms 
in the water, several inches long, and so exquisitely slender 
as not to exceed the thickness of the finest cobweb; yet 
their sense of feeling is so delicate, that if a worm touches 
even the utmost extremity of these very slender arms, they 
immediately lay hold of it, and, contracting themselves to 
about the middle length, by clasping their arms about it, 
they envelope and fetter it in so many places, and to such a 
degree, that notwithstanding it be much larger, and seem- 
ingly stronger, it is soon rendered incapable of struggling 
to any purpose.” “Tis a fine entertainment to behold the 
dexterity of a polype in the mastering its prey, and observe 
with what art it evades and overcomes the superior strength 
or agility thereof. Many times, by way of experiment, I have 
put a large worm to the very extremity of a single arm, 
which has instantly fastened on it with its little invisible 
claspers. Then it has afforded me inexpressible pleasure to 
see the polype poising and balancing the worm, with no 
less seeming caution and judgment than a skilful. angler 
