PLANKTON OP THE GULF OF MAINE 
401 
these microscopic plants are flowering most intensively, volumes even as large as 
those noted (fig. 109) are but a pale reflection of the mass of vegetable matter actually 
present in the water. 
Fig. 109. — Volumes of phytoplankton (in cubic centimeters) per standard surface haul, April, 1920. The hatched curve 
incloses areas with more than 50 cubic centimeters; the stippled curve with more than 250 cubic centimeters 
The accompanying chart (fig. 109) for the last half of April is necessarily imper- 
fect, because records for the several stations ought to be taken simultaneously 
(which has not been practicable) . But the variations that appear there in the local 
