326 THE MICROSCOPICAL NEWS. 
severed a tentacle (Fig. 78) from the head of one part, placing 
these very carefully in a watch glass which acted as a tank, that I 
might observe them the more easily under the microscope. 
Great was my surprise to find the tentacle which had been cut 
off holding on to Cycdops guadricornis, which struggled hard to 
make its escape, but was powerless to do so, the tentacle being 
carried about by the water-flea; a short time afterwards poor 
Cyclops was dead. =e 
This, I believe, is one of the clearest proofs of the stinging power 
of the Hydra. 
The cut portions, one hour after division, were simply curled up, 
or twisted upon themselves, and lay upon the bottom of the glass 
for three hours, no movement either of the body or tentacles being 
observed. The tentacle, however, which had been severed had 
made more progress. 
At first it simply contracted and expanded very slowly, and in 
one hour I could discern that in the expansion it was considerably 
shorter and thicker than before. I also noticed that it contained 
the protoplasmic fluid, the corpuscles floating about in it, and that 
it was much darker at the base or severed end. In one hour and 
twenty-five minutes it had assumed the shape seen in Fig. 79, 
the upper part representing the base, and the lower the free end of 
the tentacle. 
In twelve hours it was very much shorter and thicker at the 
lower part, and was perfectly healed at the upper portion, or what 
was formerly the attached end. (See Fig. 80.) , 
