1897] MICROSCOPICAL JOURNAL. 241 



The .sirn[»lest drag-net is a bag of silk-tissue fastened 

 to a brass or iron ring. The brim is provided with three 

 ringlets at an equal distance, in order to attach the line 

 to it (fig. 8.) If wo are on the open lake, our net may be 

 lowered unto the required depth and at the same time 

 towed by the advancing boat. During this operation the 

 water filling the net is strained, while the organisms in 

 it are retained by the fine tissue and may be secured in 

 the way formerly described. With this contrivance we 

 are enabled, provided our line is sufficiently long, to reach 

 the bottom of the lake and may even bring up mud from 

 the bottom. If we have no boat at our disposal and still 

 want to collect from parts which are a little distant from 

 the shore, then we put some stones, or other heavy 

 object into the bottom of the net, throw the latter into 

 the water and endeavour to get the desired material by 

 slowly pulling the net to the shore. 



Another kind of drag-net is due to the Bohemian Bio- 

 logical Institution. It reminds us in its general out-line 

 of the former, but is still different in many respects. 

 Like the former it possesses a brass or iron-ring with ring- 

 lets for tying on the line, but its bottom is open. Here 

 a glass-vessel is to be fastened as mentioned in descrip- 

 tion of the rod-net. This net, judging from its shape, 

 consists of two parts, viz., a larger cylindrical one and a 

 smaller funnel-like one, separated by a hoop of reed, 

 sewn in. In the middle of the cylindrical part is also 

 a hoop of reed. (fig. 4.) These hoops lessen the specific 

 weight of the apparatus. The Bohemian searchers em- 

 ploy still another, funnel-like, open net provided with a 

 reed-hoop, which is put in the space of the larger net 

 and is apt to prevent material already in the large net 

 from being washed away by the water flowing back. This 

 precaution is superfluous, though, if in dragging the net 

 necessary care is token and the required time is given to 

 strain the water. This implement is applicable only 



