244 



bulletin: museum of comparative zoology. 



boreal animals. The only important variation from this general 

 plankton type was on German Bank (Station 10244) where we encoun- 

 tered the Pleurobranchia swarm which appears to characterize that 

 locality (p. 249; 1914a; 1915); and these same copepods formed the 

 bulk of the plankton over the continental shelf off Marthas Vineyard, 

 and on. the eastern part of Georges Bank, while they were one of its 



Fig. 79. — Predominant types of macroplankton, July-August, 1914. 



1, Copepod and Sagitta; 2, Sagitta swarms; 3, Euphausiid; 4, Copepod; 5, Cope- 

 pod and amphipod; 7, Amphipod; 8, Amphipod and euphausiid; P, Pteropod 



swarm; ^^'^^, offshore limit to copepods as an important factor: , 



Northern limit to predominant tropical plankton. 



important constituents off Shelburne (Fig. 79). But very few were 

 taken in the waters over the continental slope; in the Eastern Channel 

 or off Halifax. 



Sagittae (p. 294) were as important, faunally, as copepods, over the 

 central part of Georges Bank and in the Northern Channel ; amphipods 

 near the land off Shelburne and Cape Sable (p. 286, Fig. 79) ; and 



