178 
BULLETIN OF THE BUREAU OF FISHERIES 
During April it became so scarce in the Massachusetts Bay region and oven the 
northwestern part of the gulf generally that it did not appear there in the catches 
of the vertical nets, although the surface tows picked up a few at the localities marked 
Fig. 60. — Occurrence of the copepod Acartia longiremis, February to April, 1920, surface and vertical hauls combined. 
X, present; O, not found. The hatched curve incloses the areas where it occurred at every station 
on the chart (fig. 61 ); but, by contrast, it had spread generally over the whole eastern 
side of the gulf, with a rather definite line of demarcation between the areas where it 
did and did not occur in sufficient number for the vertical net to take it (fig. 61 ), but 
