^'ii^^Sii^ 



Fig. 4. 



1. The vertical closing net: (a) hauling the net vertically, {b) the messenger on its way to trip 

 the closing mechanism (c). The triple bridle is then released and the net is throttled (rf) and 

 hauled the rest of the way closed. 



2. The Clarke-Bumpus net: a small net mounted on a special frame incorporating opening and 

 closing mechanisms. These rotate a close-fitting metal disc about a pivot at the mouth of the 

 cylinder which opens and closes the entrance. 



3. The Bossanyi net: for samphng the plankton close to, but not actually on the bottom. The 

 doors are kept shut by springs except when the arms drag along the bottom. The net lies on a 

 frame to prevent chafing on stones and shells. 



