428 Birge—Vertical Distribution of Pelagic Crustacea . 
hanging the weight-hangers on the weight-pins—• which occu¬ 
pies hardly a second for each weight. 
The bucket . -—The bucket consists of three parts, the bucket 
proper and the two pieces by which it is attached to the bag. 
(Plate VII, figs. 2, 3.) Each is made of thin spring brass. The 
two attaching pieces are cylinders. The upper one fits into the 
lower, and is about 6 cm. in diameter and 5 cm. deep. It has a wire 
to stiffen it in the upper edge. This and all of the parts are lap- 
soldered, so as to avoid a seam. The second or lower cylinder is 
large enough to fit over the upper one, and to permit the net to 
come between them. Each is provided with three equidistant 
loops of wire, by which they may be fastened together, and 
the lower one has two pins on opposite sides which fit into the 
bayonet catches of the bucket. The dredge net is drawn down 
inside the upper cylinder and turned up over its exterior; the 
lower cylinder is slipped over it and fastened to the upper one. 
The mouth of the net is thus held firmly between the cylinders, 
and at the same time no projections are left to hold back its 
contents, nor are there any longitudinal folds, if the dredge-net is 
properly fitted to the cylinder. The bucket proper is a cylinder 
•of thin brass 6 cm. in diameter and 7-J- cm. high, with four 
windows in its lower part, each 3|- x 4 cm., covered with brass 
wire gauze of .01 inch mesh. The opening of each mesh is 
about 0.17 mm. (.007 in.) in diameter. In the upper edge are 
cut notches for a bayonet catch, by which it is attached to the 
middle cylinder. It slips over the middle cylinder for a dis¬ 
tance of 3 cm., thus securing a tight joint, so far as the Crust¬ 
acea are concerned. The bottom is slightly conical, and leads 
to a conical tube filled by a rubber stopper, which is put in by 
a wire handle from the inside. There are three legs upon which 
the bucket may stand. In Pig. 2 the upper cylinder is sup¬ 
ported by blocks upon the second one. 
The dredge as described abovt. is not to be considered as an 
attempt at a universal self-closing dredge. It was designed to 
meet the conditions of the special problem which we had pro¬ 
posed and was found to meet those conditions admirably. 
The advantages of the dredge appear to me to be as follows: 
(1) It is simple, easily worked, and reliable. 
