BIGELOW: EXPLORATIONS OF THE COAST AVATERS. 



309 



along the southern slope of Georges Bank, in the northeastern and 

 southeastern corners of the Gulf; and generally south and southwest 

 of Halifax. In the northwestern, central, and eastern parts of the Gulf 

 as a whole, on the northwestern part of Georges Bank, in the Eastern 

 Channel, and over the whole breadth of the continental shelf off Shel- 



FiG. 91. — Volumes of plankton per square meter of sea area, July-August, 1914. 

 6, very rich, 170 + cc. per square meter. 



4, rich, 100 + cc. 



3, intermediate, 30 - lOOcc. 

 1, scanty 30 — cc. " 



burne. Nova Scotia, plankton volumes were intermediate between 

 these extremes. 



The volume of plankton, however, is no index to its regional density, 

 which is after all the most important question before us, because the 

 amount of water filtered varies with the depth at various stations; a 

 better criterion is the volume per cubic meter. 



