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arms by its violent struggling, and so make its escape " 
(p. 68). But be remarks in another place , — “I have some- 
times forced a worm from a polype, the instant it has been 
bitten (at the expense of breaking off tbe polype's arms), 
and have always observed it to die very soon afterwards, 
without one single instance of recovery." He seems to 
have thought the hydra was possessed of teeth. “ It is 
surprising to behold how soon a polype kills a vigorous, 
nimble worm; except by crushing, no way can put it to 
death more speedily. But there is no certainty what kind of 
weapons this is effected by, though probably it may be armed 
with sharp teeth." It is usual to attribute to the thread- 
cells, which characterize the whole of the sub-kingdom 
Gcelenterata , the power of stinging, which unquestionably 
belongs to some of the members, as to certain of the Medusae. 
But I think that this opinion needs more decided verification 
than it has yet received. If it be a fact that the thread-cells 
(or “ cnidge " as they are technically called) are the cause of 
the stinging power in the tentacles of Gyancea capillata , for 
instance, then it is fair to surmise that they have a kindred 
property, varying in degrees, in other members of the sub- 
kingdom. The experiments of Mr. Gr. H. Lewes are sufficient 
to throw considerable doubt upon the benumbing properties 
of the hydra. This observer noticed that small entomostraca 
dropped suddenly to the bottom of the vessel, and remained 
motionless there for a minute or two, after having been held 
by the arms of a hydra; but he found that if he touched 
a water-flea ( cypris ) with the point of a pin, precisely the 
same thing occurred. He considers that this sudden motion- 
lessness of the water-flea is analogous to what we often 
observe in numerous other animals, viz., the practice of 
“ shamming dead," in schoolboy phraseology. The larva of 
an Ephemera having been “ thrice caught by three different 
hydrge, tore itself away without any visible hurt." A nais 
that had been held by the embraces of a Hydra viridis for 
some time, struggled itself free.* Hot only was it apparently 
unhurt by this contact, but three days afterwards it was as 
lively as ever. “ With two other naids the same result was 
observed. From experiments I have myself made with 
regard to this question, I am inclined to doubt altogether 
the paralysing power ascribed to the hydra. I have re- 
peatedly seen small worms, gnat-larvse, and other aquatic 
creatures, alive and apparently quite uninjured from the 
effects of the hydra's embrace, some time after they had freed 
themselves or been released by the point of a needle." 
* “ Seaside Studies,” p. 137. 
