30 



DISCOVERY REPORTS 



to the very great range in total phytoplankton content of the water, it has been impossible 

 to show the phytoplankton totals on the same scale for each line, but in each case the 



Fig. 4. Chart showing the positions of the stations worked on the two surveys round South Georgia, 

 January-February 1930 open circles, and November 1930, black dots. 



scale adopted is shown at the left-hand margin. Charts showing the distribution of each 

 of the principal species, and also the total diatoms, are also given (Figs. 12-17) in an 

 attempt to build up a picture of the conditions over the whole area. It may be men- 

 tioned that most of the lines consisted of eight stations worked at approximately lo-mile 

 intervals. 



The main features of the Larsen line (Table II, Figs. 4, 5) were the almost complete 

 absence of diatoms at the inshore stations, where the dinoflagellates Peridinium ant- 

 arcticum and Ceratium pentagonum i.grandis were dominant, and the relative abundance 

 of diatoms, principally Corethron valdiviae in the spineless chain form, and Thalas- 

 siothrix antorctica at the next two stations. The outermost stations on this line (Sts. 357 

 and 358) were perforce worked much later than the others when conditions were 

 obviously different. The temperatures were higher, and the two large dinoflagellates 



