1911] Kofoid: Self-closing Plankton Net. 331 



supporting rod works on an axle siiported in a slotted lug {lug, 

 pi. 25, fig. 15) on the rear face of the head-piece of the frame 

 (pi. 23, fig. 4) and can thus be bent downward during ascent 

 of the net and upward during descent. This makes possible a 

 more rapid heaving out or in of the net by reducing the area of 

 exposure of the bag and tends to protect the catch during the 

 handling of the net. As shown (pi. 23, fig. 4) the basal casting 

 into which this rod is seated also carries a short rod (ace. sup.) 

 curved upward, with two accumulator springs. During descent 

 the basal casting in the slotted lug rests firmly against a shoulder 

 or cushion (cush., pi. 25, fig. 15). 



The bucket is attached at the end of the net support (pi. 23, 

 fig. 4) whose distal end is bent downward to the level of the 

 bucket. Between the bucket and the tip of the carrier is a coiled 

 spring which affords play to the net in the horizontal direction 

 as the jaws open and close. The bucket bears two rings on one 

 side for attachment by wire hooks (but one in figure) to the sup- 

 porting rod above. 



The bucket (pi. 25, fig. 16) is made from spring brass tubing 

 10 cm. in diameter. Its total length is 12.5 cm. It consists of a 

 head-piece {hd. p.) which is encircled by a net clamp (n. cl.) 

 which binds the linen bucket bands at the lower end of the bag 

 to the top of the bucket. The clamp is a narrow band of spring 

 brass bearing two flanges {fl.) drawn together by a small bolt. 

 The head-piece is threaded on its inner face and the remainder 

 of the bucket may be unscrewed from it for removal of the catch, 

 without releasing the net from the clamp. The detachable part 

 is a plain cylinder with dished bottom formed of a casting 

 sweated into place with central outlet terminating in a drip- 

 point {dr. pt.) below. The outlet is closed by a removable plug 

 {pi.) of brass, ground in emery to fit closely and terminating 

 above in a shaft with a ring above the level of the top of the 

 bucket. This can easily be found and the plug removed or re- 

 placed through the silk bag without opening the net if desired, 

 and the contents of the bag removed without detaching the 

 bucket. 



On one side of the bucket there is a circular window 4 cm. in 



