Fig. 46. Changes in the position of the ice edge during the season 1930-1. Note the recession of the ice 

 as the season advances. The position of the ice in October 1928-9 is shown for comparison. 



Fig. 47. Relative positions of warm- and cold-water plankton at different times in the vicinity of South 



Georgia and the South Sandwich Islands. 



9-2 



