List of Crustacea Cladocera from Madison, Wis. 397 



THE CONE-DEEDGE. 



The dredge which I have used for collecting seems worthy of special 

 description. It consists of four parts: the body, the cone, the net, and 

 the screw-top. The body is a cylinder of stout tin, strengthened by a 

 wire at each end, four inches long, and four inches in diameter. On 

 top of this is placed a cone of brass netting, five inches high. This is 

 attached below to a circle of tin so that it fits into the top of the body 

 like the cover of a tin pail. The bail of the body is of stout brass wire; 

 the ends passed through the side of the body and enlarged, and the 

 loop of wire shaped so as to fit within the cone and project through a 

 hole in its top with an eye into which the dredge-line can be fastened. 

 To the end of the line is attached a snap-hook larger than the hole in 

 the top of the cone, so that the cone can not come off the body when 

 in use. There are two cones provided for my dredge, one of one-tenth 

 inch mesh, and the other of one-twentieth inch. 



The ¥ V inch mesh is coarse enough unless it is desired to secure very 

 large forms. For ordinary shallow water collecting it is the best size. 

 The cone can easily be removed for work at night in the open water. 



The net is of fine cheese cloth, eighteen to twenty -two inches long, 

 conical, large enough at the base to slip over the dredge body, to which 

 it is tied. It is faced with stout muslin for a distance of two or three 

 inches at each end. At the smaller end it is small enough to fit the 

 screw-top, a tin cylinder one inch in diameter and one and one-quarter 

 inches in length, with a wire in one end and on the other a zinc 

 screw-top, such as are used on kerosene cans. 



The seam along one side of the net is so made as to leave a sort of a 

 loop in the cloth, through which a string can be run. One end of this 

 string is tied about the dredge body; to the other end can be attached 

 a weight, when desired, without having the pull of the weight come on 

 the net. 



This dredge is very useful for collecting small animals in shallow or 

 weedy water. It can easily be thrown from the shore to a distance of 50 

 feet or more, thus permitting much more extensive collecting from 

 shore than does the ordinary hand net. It can be drawn through weeds 

 and over muddy bottoms, straining large amounts of water without 

 becoming filled with mud or clogged with weed. If it is desired to col- 

 lect from water close to the bottom without obtaining mud, a weight 

 fastened to the end of the cord spoken of, so as to drag behind the 

 dredge will cause the dredge to lift at each pull and so exclude most of 

 the mud, except in very deep water. If a band of cloth is fastened 

 about the base of the cone, leaving only the upper part free it will ad- 

 mit the water just above the bottom without scraping up mud. An old 

 rake or other irregular piece of iron fastened to the dredge-line in front 

 of the dredge will stir up the bottom and thus samples of bottom ani- 



