PLANKTON OF 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. 



FlQ. 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 



