8 Illinois State Laboratory of Natural Histpry. 



Keighard buckets after which it is very hirgely modeled. Its 

 advantages are its stability, the drip-point, and the band 

 clamp, the latter permitting readily the renewal of the silk in 

 the bucket. 



Previous to the adoption of the bucket just described, the 

 net in which the collections at Havana were made was closed 

 by a circular piece of silk clamped on the end of a brass 

 cylinder screwing into the head-piece (Plate L, Fig. 1, k. p.). 

 The clamp used for this purpose is similar to that 

 employed to fasten the net to the head-piece. (See Plate 

 I., Fig. 1, and Plate II., Fig. 3, ;/. c.) When a collection 

 had been made the silk circle was removed and, with the plank- 

 ton condensed upon it, transferred to the killing fluid. This 

 form of plankton bucket was used by Apstein ('92) on his 

 qualitative plankton net, and was afterwards described by 

 Borgert ('96) for a net to l)e towed behind steam-vessels. 



c. The head of the net (Plate I., Fig. 1) is a truncated 

 cone, at whose upper and lower ends are rings 10 and 25 cm. 

 in diameter respectively {ii. r. and /. r.). These rings are 

 made of No, 5 (American Standard Gauge) brass wire. The 

 side of the cone {e. b. I.) is made of heavy linen, known in the 

 trade as " butchers' linen." Its lower edge is joined to the 

 silk net at the seam (Plate I., Fig, 1, sin.), where it also 

 meets the cover-strip {c. s.) — a narrow band, made of the 

 same cloth — which extends over the lower ring (/. r.). In the 

 upper edge of the cone is bound a heavy cord [cd.) which, in 

 turn, is fastened to the upper ring {ti. r.) by a series of loops 

 of strong thread (///.). The upper ring and the cone are sup- 

 ported by three equidistant wire stays (zc. s.). These are 

 made of No. 8 l)rass wire and are provided with an eye at 

 each end. The lower eye (/. c.) embraces the lower ring and 

 is held in place by small hips soldered upon each side. The 

 upper eye {u. c.) is attached to the cord {^cd.) by a small cloth 

 strap {st.) and also serves as a point of attachment for a stay- 

 line {s. I.) which runs from the bucket to the lower end of 

 the wire stay {iv. s.) to which it is fastened, passing from 

 this to the upper eye (//. e.) and then to the draw-line (Plate 

 III., Fig. 6, d. /.). 



