THE WATER SPIDER. 231 



* No 2. Nov. 15. In another vessel, also furnished with 

 Stratiotes, I placed six Argyronetrae. 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 from 

 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 

 size and nearly the form of half an acorn cut transversely, the 

 smaller and rounded part being uppermost. 



* No. 3. The only diiference between the movements of this 

 and the former was, that it was rather quicker in formmg 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 

 two hinder legs, which are crossed at an acute angle near their 

 extremity, this crossing of the legs taking place at the instant 



