ZOOPLANKTON IN THE SOUTHERN OCEAN 



215 



Table 5. The variation according to latitude of the mean total volume (i.e. the sum of the measurements 

 of all hauls between 1000 m. and the surface), and the mean volume in the upper 100 m. (i.e. the sum of 

 the 50-0 m. and 100-50 m. measurements) in winter and summer. Numbers of observations are given in 



brackets 



[Note. Two groups of 15 interval cover the range 0-30° S; all other groups are in intervals of 5 .] 



O 20 



o 



> 



WINTER (mAY-OCt) O 

 SUMMER (nOV-APRIL) • 



15 



25 



•i 



8 



• • ♦* 



o »o 



.o°y »o * o . 





60 



LATITUDE 



DEGREES SOUTH 



Fig. 11. 



Individual total volumes (i.e. 1000-0 m.) at each station plotted according to the latitude of the station. 

 A few observations have had to be omitted for clarity. 



extended from equator to ice-edge by the inclusion of the results from Sts. 2886-2895 in the Indian 

 Ocean. It is apparent from the diagram that the greatest variation in volume occurs between 50 

 and 55 S, the highest latitudes being remarkable for the smallness of the catches and the lowest 

 latitudes for the lack of variation in the individual volumes. In spite of the fact that there are so few 

 observations north of 35 S, their difference from those in higher latitudes is most striking. Unfor- 

 tunately, these are the only N70V tropical observations available, and it may be that they cover a 



