[49 J FISHERIES OF THE UNITED STATES. 561 



ter, of the United States Fish Commission. It consists of a rectangu- 

 lariron frame, 3 feet long by 9£ inches wide, the iron measuring 2£ inches 

 in breadth and one-half inch in thickness. The two longer sides of the 

 frame are each furnished on the outer side with six stout, rake- like, iron 

 teeth, 7 inches long, which curve forward toward the tips, where they 

 are sharply pointed. At their bases they are of the same size as the 

 iron of the frame, and their front edges are sharpened. The handles 

 are similar in shape to those of the common dredge, but measure over 

 3 feet in length ; they fasten into eyes at the corners of the frame. 

 Back of the rake frame there is attached one of the ordinary Blake 

 dredges, which measures 4 feet in width, and, therefore, projects 6 

 inches on each side of it. This is intended to receive the loosened 

 materials as they are plowed up by the teeth. The rake dredge is 

 simple in its working, but requires considerable power to drag it along, 

 especially through compact sand and mud. Many species of animals, 

 previously unknown, have been recently obtained by its use. The first 

 rake frame employed by the Fish Commission was planned by Prof. A. 

 E. Yerrill, in 1871, and continued in use up to 1881. It consisted of a 

 triangular frame of flat bar-iron, with straight teeth projecting from both 

 sides of one of the bars, the drag rope being attached to the opposite 

 angle. The net which followed it was fastened into a light rectangu- 

 lar frame of round iron. Another style of rake dredge, invented by 

 Captain Chester in 1881, has the teeth attached directly to the scrap- 

 ing edges of an enlarged dredge frame of the ordinary pattern. 



Benedict Rake Dredge, for collecting small forms of invertebrates in 

 moderate depths of water. 



United States Fish Commission. 

 This dredge consists of a double rake, and a cylinder of galvanized 

 sheet-iron, 30 inches long by 11 inches in diameter, containing an elon- 

 gate tapering strainer, and supported in an iron frame-work, having six 

 runners of five-eighth inch round iron, about 4 inches high. These run- 

 ners extend the entire length of the cylinder, and project behind it a 

 distance of about 5 inches. They are arranged at equal distances apart 

 around the cylinder, so that on whichever side it falls it is supported 

 by two of them. The strainer is made of No. 40 brass wire cloth, is 

 elongate, truncate- conical in shape, and has the same diameter in front 

 as the cylinder, to which it is attached at the mouth. It tapers to a 

 width of about 6 inches at the hinder end, where it rests against a 

 coarse wire netting, forming the bottom of the cylinder. The mouth of 

 the cylinder is furnished with a funnel-shaped collar of sheet-iron, open- 

 ing inward, and with a short conical strainer, of coarse wire netting, 

 projecting from in front. A bail of round iron, with a loop for the at- 

 tachment of the dredge-rope, is fastened to the front end of the cylinder 

 frame. The rake, which drags in front of the cylinder, is constructed of 

 an oak bar, with two series of teeth^on each side and a handle in front. 

 2444— Bull. 27 36 



