PHYTOPLANKTON OF SOUTH GEORGIA 



47 



were the feature of the line worked in a direction slightly east of south from Undine 

 South Harbour (Fig. 4). The general character of the phytoplankton was similar to that 

 described at the two inshore stations of the previous line, the influence of western 

 Weddell Sea surface water being marked throughout. The full analyses of the phyto- 

 plankton catches on this line are to be found in Table XIII. The proportions of the 

 leading forms are shown, so far as is possible, in Table 9. 



Table 9 



* Excluding uncountable colonies. \ Excluding gelatinous colonies. 



It will be seen that Chaetoceros socialis and Thalassiosira antarctica were dominant 

 throughout, accompanied by Chaetoceros neglectus inshore and with lesser numbers of 

 Fragilaria antarctica farther south. A very large number of species were recorded, this 

 line being surpassed only by that oft' Annenkov Island, where, as we have seen, a certain 

 amount of mixing with old Bellingshausen Sea surface water had probably taken place. 

 It will be noted that Chaetoceros atlanticiis and Ch. dichaeta here reached their maximum 

 both in numbers and importance for the survey, while Corethron valdiviae, as on the 

 Annenkov Island line, was comparatively scarce. This is in strong contrast to the hauls 

 taken at this time in water originating in the eastern Weddell Sea, to the east and 

 north of South Georgia. Encampia antarctica again reached its maximum inshore, as 

 on the Annenkov Island line. It will be noted also that at the two southernmost stations 

 on the Undine South line the phytoplankton was somewhat scantier than at those 

 worked nearer the island, though the hauls were still very large. 



Thus the general character of the phytoplankton on this line closely reflected the 

 western Weddell Sea origin of the surface water. There is a possibility of slight mix- 

 ture with old Bellingshausen Sea water away to the south-west, which is perhaps 



