658 MANUAL OF NATURAL HISTORY. 



breadth ; parallel with their lower edges, fourteen 

 holes are pierced equidistant from each other, to 

 receive the laces of the bag. These two plates, or 

 scrapers, are joined by means of two cross-bars, so 

 as to form an angle of about forty-five degrees with 

 the plane of this position ; each bar is five inches in 

 length by three-and-a-half-eighths in diameter. The 

 arms are each sixteen inches in length by three 

 eighths-and-a-half in diameter, and play upon the 

 cross-bars by means of double swivel-joints. Their 

 anterior extremities are beaten flat, so as to meet 

 closely and vertically, and are pierced, for the recep- 

 tion of the bolt, which at the same time passes 

 through the extremities of what may be termed the 

 bridle-ring, to which the rope is affixed/' By draw- 

 ing the bolt and folding the arms inwards the 

 dredge is readily stowed away. " In no case should 

 the bag exceed eighteen inches in depth ; one may 

 be best made of twine, with meshes half-an-inch 

 apart, and another of cheese-cloth or serge for fine 

 work/' The net may also be formed of a raw hide, 

 with holes punched in it. The strength of the rope 

 must be regulated by the depth at which the dredge is 

 used, but in all cases a fourteen pound weight should 

 be attached to the rope at the distance of six inches 

 from the dredge. 



Small hand-nets made of cheese-cloth and fixed to 

 an iron ring with a socket, for a walking stick, will 

 be useful, or a circular tin spoon pierced with holes, 

 will answer the same purpose, namely, for scraping 

 the bottoms of pools for small delicate shells. 



