Zooplankton — Bary 
51 
been confined to surface waters in this study. 
It is applicable, however, to determining re- 
lationships between plankton and water 
masses in a vertical direction. David (1955), 
and others, have been concerned with the 
vertical distribution of species on an ocean- 
wide scale, but the method equally applies to 
much more limited areas. It should prove of 
value also in studies of plankton-water rela- 
tionships near convergences, areas of up- 
Fig. 20A, B. The distribution of the four planktonic groups in relation to salinity for A. January 1951: 
Stations 1-6. B. March 1951; Stations 320-343. 
INSET: November 1951; Stations 795-921. 
The position of the subtropical convergence in B is suggested by the dashed isohalines near Station 330. 
The symbols for the planktonic groups, and the scale of abundance, are as in Figures 10-21. 
