PHYTOPLANKTON OF SOUTH GEORGIA 



51 



Turning to individual species, reference to the list given on p. 65 shows that the most 

 important of these were : 



Chaetoceros socialis 

 Thalassiosira antarctica 

 Chaetoceros neglectus 

 Ch. criophiliim 

 Corethron valdiviae 

 Fragilaria antarctica 



in that order of total abundance. 



Fragilaria antarctica f. bouvet 

 Nitzschia seriata 

 Eiicampia antarctica 

 Thalassiothrix antarctica 

 RJiizosolenia styliformis 

 Dactyliosolen laevis 



Fig. 18. General distribution of Diatomales (totals per loo-o m. haul), South Georgia survey, November 

 1930. This chart is based on catches made at the positions indicated in Fig. 19. 



The distribution of Chaetoceros socialis is shown in Fig. 19. It will be seen that it was 

 taken at fourteen stations only, all of which were grouped round the southern extremity 

 of the island, some close inshore, and the others in the neighbourhood in which the 

 pack-ice lingered longest during this spring, and all in water which from the general 

 nature of the phytoplankton as a whole, almost certainly originated in the western 



Weddell Sea. 



7-2 



