PHYTOPLANKTON OF SOUTH GEORGIA 



49 



was typical of old western Weddell Sea surface water, with Corethron valdiviae nowhere 

 important. Eiicampia antarctica formed nearly 15 per cent of the countable forms at 

 St. 512, and Thalassiothrix antarctica was most important relatively at the inshore 

 station. Of the less numerous forms it will be seen that Chaetoceros atla?itictis, Ch. 

 dichaeta, Dactyliosolen laevis and Nitzschia seriata were not so plentiful as on the 

 Undine South line, while on the other hand Biddiilphia striata reached its maximum 

 for the survey on this line and small numbers of Rhizosolenia styliformis were again 

 encountered. 



The line worked eastwards from Cape Vakop (Fig. 4) completes this account of the 

 second survey. The phytoplankton was still very rich, though it will at once be seen that 

 there was a big falling off in numbers at the oifshore stations. Table XV gives the full 

 analyses of the material collected on this line, and from it the reason for this falling off 

 in numbers, although the catches did not by any means show a proportionate decrease 

 in bulk, will at once be apparent. The inshore half of the line was evidently worked in old 

 surface water of western Weddell Sea type, with the forms mentioned on the previous 

 two lines strongly dominant. Farther out the line cut into the cold tongue of eastern 

 Weddell Sea surface water sweeping up the north-east coast of South Georgia some 

 50 miles out from the land, where the characteristic plankton association, with one 

 or two large species very strongly dominant, was encountered. The proportions of the 

 leading forms on the Vakop line are indicated in Table 11. 



Table 1 1 



Excluding uncountable colonies. f Excluding gelatinous colonies. 



