PLANKTON OF THE GULF OF MAINE 



179 



not to the deep water off the southeastern slope of Georges Bank. The numerical fre- 

 quency of A. longiremis likewise rose by April to a maximum of 2,S00 per square meter 

 off Cape Cod, 1,300 per square meter in the northern channel, and 863 per square 



Portland C aO 



r 6 



o 



a«A*« 41 



w mm. 





Fiq . 61 .—Numbers of the copepod Acartia longiremis per square meter of sea area, April, 1920, as calculated from the vertical 

 hauls. O, none in vertica lhaul; X, taken in surface haul. The hatched curve incloses the area where it was plentiful 

 enough to be taken regularly in the verticals 



meter north of Georges Bank, though on the average it was still only about 2J^ per 

 cent of the total copepods (0-14 per cent). In 1920 it reappeared in Massachusetts 

 Bay in May, when it occurred at all the stations there and along the line from Cape 



