METHODS OF COLLECTING AND PHOTOGRAPHING 



71 



in. 14. Triangle dredge 

 ds used by the writer. 

 For description see 

 text. (From an orig- 

 inal photograph.) 



net four pieces of half-inch band iron extend radially for about 

 three inches and then turn and run parallel to one another for some 

 distance beyond the tip of the net. 

 Here they are bent inward and 

 riveted at the center. 



To collect organisms that live 

 in the bottom it is necessary to 

 use some form of dredge that will 

 bring up the bottom material. 

 To bring up the superficial ooze 

 the weight attached to the townet 

 line or cone dredge line may have 

 the form of a rake, or be other- ' 



. , 1 . . Tig. i^. Townet on 



wise irregular, so that it stirs up runners, designed 



, ^ by the writer. For 



the ooze and drives animals from description see 



text. (Fromanong- 



it to be caught in the net. For inai photograph.) 

 animals that cannot be thus dislodged the writer has used a 

 triangle dredge (Fig. 14). This consists of a bag of one-fourth- 

 inch square mesh netting, or burlap, or other coarse material, 

 lined at the bottom with muslin and hung from a wrought-iron 

 frame which may be made by any blacksmith. The frame 

 consists of an equilateral triangle, twelve to fifteen inches on 

 each side, of heavy band iron, and of three stout iron rods, 

 one extending from each angle of the triangle at right angles 

 to its surface, to a distance of about three feet. The edge of 

 the triangle is formed into large saw-teeth bent slightly out- 

 ward so that they tend to dig into the bottom. An eye at each 

 corner serves to attach a rope which extends to the hauling line. 

 The rods serve to keep the triangle upright when the net is drawn 

 along the bottom, so that the mouth of the bag is open and the 

 teeth plow into the bottom. 



Another useful type of dredge has the form of a triangular or 

 quadrangular pyramid, whose side and slant height are each about 

 six inches. A number of stout steel wires, about six on each side, 

 are soldered together so as to form the apex of the pyramid, while 

 their opposite ends are bent slightly outward beyond its base, so 

 that they project like the teeth of a comb. The framework thus 



