60 NOTES ON 
the water, and suspend themselves thereon 
either by the arms or tail. 
They feed on small crustacea, worms, and 
larvee, but they do not refuse small pieces of 
raw meat, with which it is requisite to supply 
them, when there is a dearth of other food. 
When in search of prey they stretch out their 
arms and body to the utmost, and spread the 
former in various directions, thus presenting a 
large surface to entrap it. Figure 1 shewsa 
green polype extended for this purpose. As 
soon as an animal comes within their range, 
they entwine their arms about it, and after- 
wards, by contracting them, bring it to the 
mouth and devour it. It sometimes happens 
that the velocity with which their prey is mov- 
ing prevents the polype from securing its vic- 
tim. In such cases I have observed the little 
animal, after the attack, sink in the water ap- 
parently lifeless, and remain so for a few seconds 
before it resumed its wonted activity. From 
this singular fact, I am induced to imagine that ~ 
the polype possess the power of giving minute 
electric shocks, similar to some fish and insects; 
for in no other way can I account for the mo- 
mentary torpor of such active little animals as 
the water-fleas (Daphnia pulex) and the Cyclops, 
