DISTRIBUTION OF ANTARCTIC MACROPLANKTON 



127 



superba. Column 3 in Table V, however, shows how greatly the warm-water species 

 were reduced at Sts. 365 and 369. On leaving the South Sandwich Islands the ship 

 started a line of stations to the west (Sts. 372, 373, etc.) and here we see the plankton 

 was again of the warm type. Column 4 in the table shows a very striking contrast 

 between Sts. 365 and 369, and Sts. 372 and 373. Fig. 41 shows the relative positions 

 of the "warm" and "cold" plankton. 



In the 1 930-1 season a number of stations were taken to the east and south-east of 

 South Georgia (see Fig. 14, p. 82). In October the ' Discovery II ' sailed from Capetown 

 to South Georgia via Bouvet Island and the journey from Bouvet Island to South 

 Georgia was mainly along or through the outskirts of the pack-ice (see Fig. 42). As these 

 stations are in the form of an extended line they are not separated into groups and shown 

 in Table V. The stations at the east end of this line had not perhaps a very "cold" 

 plankton, but Diphyes antarctica was present at all of them, Dimophyes was taken at 

 St. 453, and Haloptilus ocellatus appeared at St. 460. At Sts. 462-9 the plankton was of 



40 



Fig. 42. Distribution of warm- and cold-water plankton between South Georgia and Bouvet Island. The 



edge of the pack-ice is indicated. 



a warmer type. There was a single specimen of Eusirus at St. 466 and of Auricularia 

 at St. 469, but at all of these stations there were large numbers of Limacina balea, 

 reaching a maximum at St. 466, and comparatively abundant Euphausia frigida (both 

 warm- water species). At St. 470 there were three specimens of Eusirus and at Sts. 471 

 and 472 Diphyes antarctica reappeared and the numbers of L. balea and E. frigida became 

 suddenly reduced. When the ship reached South Georgia the November survey was 

 begun, and as already noted revealed here a very cold-water plankton. It seems there- 

 fore that in the early summer of 1 930-1 there was a cold-water plankton in the neigh- 

 bourhood of Bouvet Island and South Georgia, but between the two a rather " warmer " 

 plankton. 



When the ship reached South Georgia the pack-ice was lying close up to the island, 

 but at the end of November, when the survey was finished, the ice-edge had receded 

 some way to the south-east. In December the 'Discovery II' sailed in this direction, 

 and, on meeting the ice, followed its edge in a south-westerly direction, taking Sts. 528- 

 33 in the positions shown in Fig. 43. Here the constitution of the plankton was still 

 very " cold " (see column 5 in Table V, p. 1 25), even more so than around South Georgia 



