DISCOVERY REPORTS 



Fig. i. Contour chart of the ocean floor showing the position of South Georgia on the Scotia Arc, based 



For a full discussion of the hydrological conditions round South Georgia and of the 

 South Atlantic generally, reference should be made to the hydrological reports by 

 Mr H. F. P. Herdman, Mr A. J. Clowes and Mr G. E. R. Deacon, which will be pub- 

 lished soon after the present paper. But since a knowledge of the hydrological condi- 

 tions is essential to the understanding of the plankton distribution, the authors have 

 kindly placed at our disposal provisional sections of their forthcoming paper from which 

 the following information is abstracted together with direct quotations. 1 



The South Atlantic Ocean may be divided into four zones, each with well-marked 

 characters : the Antarctic, the sub-Antarctic, the sub-Tropical and the Tropical Zones. 



1 Since this section of the report was written Deacon (1933) has published a general account of the 

 hydrology of the South Atlantic Ocean. 



