TO DEPRESSOR. 

 \ 



Fig. 3. Some types of nets, etc., for catching plankton. 



1. The simple townet: it can be kept below the surface by a weight (a) or a depressor 

 (fo); the bucket (c) retains the catch in good condition. 



2. The paravane net: the diving plane acts as a depressor and the opening is not obstructed 

 by bridles. 



3. The Nansen net, rigged for vertical hauls, as used by the research ship Discorery. 



4. The Gulf III high-speed plankton sampler. 



