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HISTORY OP BRITISH CRUSTACEA. 
are excessively amusing. The middle part of their long 
body is destitute of limbs, having, instead of legs, two pairs 
of oval clear vesicles; but the hinder extremity is furnished 
with three pairs of legs armed with spines and a terminal 
hooked blade like that already described. With these hind- 
most legs the animal takes a firm grasp of the twigs, and 
rears up into the free water its gaunt skeleton of a body, 
stretching wide its scythe-like arms, with which it keeps up 
a seesaw motion, swaying its whole body to and fro. Ever 
and anon, the blade is shut forcibly upon the grooved haft, 
and woe be to the unfortunate Infusory or Mite or Rotifer 
that comes within that grasp ! The whole action, the pos- 
ture, the figure of the animal, and the structure of the 
limb, are so like those of the tropical genus Mantis among 
insects, which I have watched thus taking its prey in the 
Southern United States and the West Indies, that I have no 
doubt passing animals are caught by the Crustacean also in 
this way, though I have not seen any actually secured. The 
antennse too, at least the inferior pair, are certainly, I should 
think, accessory weapons of the animal's predatory warfare. 
They consist of four or five stout joints, each of which 
is armed on its inferior edge with two rows of long, stiff, 
curved spines, set as regularly as the teeth of a comb, the 
