130 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



nets, tow nets, and dredges. Besides these there were some forms of nets not in com- 

 mon use. The ordinary form of deep-sea dredge was found to slip over the hard clay 

 bottom or over the thick matting of characese which covers this bottom, so that it 

 usually came up empty. In its place was used a dredge made as follows: An iron 

 baud 2 inches broad, g of an inch thick, and 4 feet inches long, is cut along one edge 

 into a row of triangular teeth, each an inch broad and an inch high. These teeth are 

 sharpened and bent so as to form an angle of about 15 degrees with the rest of the 

 band, which is provided with holes into which a net may be laced. The band is then 

 bent on the broad side into the form of an equilateral triangle, with the teeth inclined 

 outward. To each angle is welded a stout ring for the dredge rope, and also an iron 

 rod, 2£ feet long, which projects at right angles to the plane of the triangle and from 

 the edge of the band opposite the teeth. A liat net of inch mesh is suspended from 

 the triangle, and its bottom is lined for about a foot with coarse cotton cloth. The 

 whole net frame has thus the form of a triangular prism and when dragged along the 

 bottom always rests upon one side, so that the teeth at the edge of the frame act with 

 great effectiveness in loosening objects imbedded in the hard clay bottom. This net 

 is modeled from one exhibited among the apparatus of the plankton expedition in 

 the German University exhibit at the World's Fair. 



Another piece of apparatus of great value is the net designed by Prof. E. A. 

 Birge for collecting cladocera, and described in Trans. Wis. Acad., vol. vin, 1891. It 

 is indispensable on weedy bottom or shores. 



The ordinary tow net when weighted to be used on the bottom is apt either to run 

 at an unknown distance from the bottom, or, if it reaches the bottom, to foul in the 

 weeds or till with mud and sand. We therefore made use of a tow net supported on 

 four flat iron runners which are welded to the iron net ring. These runners extend 

 for about 30 inches at right angles to the plane of net ring and are then bent toward 

 one another and riveted together at a point opposite the center of the net ring and 3 

 feet from it. The net thus hangs within the frame formed by the runners, and its 

 mouth is held about 2 inches from the bottom. This proved an excellent device for 

 collecting bottom forms free from weeds or mud. 



For quantitative work we used a vertical net which is more fully described in 

 auother place. 



Six persons worked in the laboratory from July 15 to September 15. They were — 



Prof. J. E. Iteighard, director; quantitative work, Crustacea, and vertebrates. 



Dr. H. B. Ward, associate professor of biology, University of Nebraska, Lincoln, 

 Nebr. ; worms. 



Mr. Frank Smith, instructor iu zoology, University of Illinois, Champaign, 111. ; 

 protozoa and mollusca. 



Dr. Robert Wolcott, Ann Arbor, Mich.; insecta and hydrachnida. 



Mr. H. S. Jennings, assistant in animal morphology, University of Michigan; roti- 

 fera, sponges, and bryozoa. 



Mr. A. J. Pieters, assistant in botany, University of Michigan ; plants. 



Each had charge of that portion of the subject set opposite his name. These gen- 

 tlemen worked enthusiastically, aud without compensation, in the interest of science, 

 so that whatever results have been reached are largely due to their unselfish devotion. 



Two employes of the fish commission, Mr. Dwight Lydell and Mr. Jesse Marks, 

 rendered valuable service in collecting, fishing, aud otherwise furthering the interests 

 of the laboratory. 



