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bulletin: museum of comparative zoology. 



As a whole the water was richer in plankton above 100 meters than 

 below that depth, the mean volume of all the catches taken above 

 100 meters (909 ccm.) being almost three times the mean of all the 

 deeper hauls (350 ccm.); while it was only above 100 meters that 

 exceptionally large catches (2000 ccm. or more) were taken. Con- 

 sequently, the volumes per cubic centimeter as calculated from the 

 quantitative hauls must be used with discrimination. They repre- 

 sent the actual density fairly well at stations where no stratification 

 is apparent from the horizontal hauls {c. g. Stations 10225, 10232); 

 and approximate the truth in shallow waters, particularly where 

 mixed vertically by tidal currents. But they greatly understate the 

 actual maximum density in deep water where the plankton is stratified, 

 making such regions appear much less prolific, as feeding grounds for 

 pelagic fishes than they actually are, while crediting to their barren 

 layers a richness which they do not possess. 



