250 POPULAR HISTORY OF THE AQUARIUif. 



are generally rounded at the top, and flattened at tlie base, 

 with an aperture which the Spider sometimes seems to find 

 with considerable difficulty, by feeling with its feet before 

 inserting the body. AVhen placed in a jar with water, the 

 Argyroneta fixes his bell sometimes to the edge of the jar, 

 and at other times to the stones placed in it, or the aquatic 

 plants growing in it; but when the objects are wanting, he 

 will hang his nest upon cross filaments carried from one side 

 of the jar to the other. 



Professor Bell has recently communicated the following 

 very interesting observations to the Linnsean Society respect- 

 ing our insect and his subaqueous habits, in a series of ex- 

 periments. They were made in consequence of Mr. Gosse 

 having denied the fact of the Argi/roneta ever filling his cell 

 with air brought from the surface: — 



" ^0. 1. Placed in an upright cylindrical vessel of water, 

 in which was a rootless plant of Stratiotes, on the after- 

 noon of November 14. By the morning it had constructed 

 a very perfect oval cell, filled witli air, about the size of 

 an acorn. In this it had remained stationary up to the pre- 

 sent time. 



"No. 2. November 15. In another similar vessel, also 

 furnished with a plant of Stratiotes, I placed six Argi/roneta. 



