THE WATER SPIDER. 
231 
‘ No. 2. Nov. 15. In another vessel, also furnished with 
Stratiotes, I placed six Argyronetrse. The one now referred to 
began to weave its beautiful web about five o’clock in the after- 
noon. After much preliminary preparation, it ascended to the 
surface, and obtained a bubble of air, with which it immediately 
and quickly descended, and the bubble was disengaged front 
the body and left in connexion with the web. As the nest was, 
on one side, in contact with the glass, inclosed in an angle 
formed by two leaves of the Stratiotes, I could easily observe 
all its movements. Presently it ascended again and brought 
down another bubble, which was similarly deposited. 
‘ In this way, no less than fourteen journeys were performed, 
sometimes two or three very quickly one after another; at other 
times with a considerable interval between them, during which 
time the little animal was employed in extending and giving 
; shape to the beautiful transparent bell, getting into it, pushing 
' it out at one place, and amending it at another, and strengthen- 
; ing its attachments to the supports. At length it seemed to be 
satisfied with its dimensions, when it crept into it and settled 
itself to rest with the head downwards. The cell was now the 
1 size and nearly the form of half an acorn cut transversely, the 
smaller and rounded part being uppermost. 
4 No. 3. The only difference between the movements of this 
and the former was, that it was rather quicker in forming its 
cell. In neither vessel was there a single bubble of oxygen 
evolved by the plant. 
‘The manner in which the animal possesses itself of the bubble 
of air is very curious, and, as far as I know, has never been 
exactly described. It ascends to the surface slowly, assisted by 
a thread attached to the leaf or other support below and to the 
surface of the water. As soon as it comes near the surface, it 
turns with the extremity of the abdomen upwards, and exposes 
a portion of the body to the air for an instant, then with a jerk 
it snatches, as it were, a bubble of air, which is not only attached 
to the hairs which cover the abdomen, but is held on by the 
I two hinder legs, which are crossed at an acute angle near their 
extremity, this crossing of the legs taking place at the instant 
