DISTRIBUTION OF ANTARCTIC MACROPLANKTON 133 



were not taken, Parathemisto and Euphausia frigida had increased very greatly (see 

 columns 2 and 3). The surveys in the Bransfield Strait in 1929-30 and 1928-9 show a 

 marked contrast. At the former, which was in November, plenty of " cold " species were 

 taken, and Limacina balea and some Chaetognatha were the only warm-water species. 

 At the latter, which was in February, none of the very "cold" species was present and 

 only one or two of the moderately "cold", while Parathemisto and Euphausia frigida 

 appeared in quite large numbers for this locality (see columns 1 and 4). It may be 

 mentioned here that the Chaetognatha, as a group, are not to be relied on as a warm 

 element in the plankton, especially in such places as this where Eukrohnia hamata is not 

 necessarily the dominant species. 



In the region between the South Shetlands and the South Orkneys there was a large 

 element of cold-water species in December 1 930-1. In February in the same season 

 there was little, if any, diminution in the very cold-water species, but there were fewer 

 of the moderately "cold" group and more of the warm-water species. In March there 

 were definitely fewer of the "coldest " species, and the warm-water species on the whole 

 were stronger than in February (see columns 6, 7 and 9). Single stations are unreliable, 

 but the one taken in November 1929-30 (column 5) suggests a " colder" plankton than 

 was found in February 1928-9 or April 1927-8. 



Table VI provides an interesting example of the unusual coldness of the 1 930-1 

 season. The catches in February of this season can be compared with those of February 

 1928-9 both in the Bransfield Strait and farther east (columns 3, 4, and 7, 8). It will 

 be seen that a much "colder" plankton was present in 1930-1 than in 1928-9. 



THE BELLINGSHAUSEN SEA 



The Bellingshausen Sea has been visited only twice, each time in the middle of the 

 summer, so that we have not the material for a comparison of the conditions in different 

 months, but there is some interest in a comparison between the plankton taken by the 

 ' William Scoresby ' in 1929-30 and the ' Discovery II ' in 1930-1. Table VII shows the 

 average number of warm- and cold-water species taken during these two cruises. It has 

 been seen in a previous section that a much richer plankton was taken in the more 

 westerly part of the Bellingshausen Sea than in the eastern part, and these further 

 stations are therefore treated separately in the table. 



The principal conclusion to be drawn from these figures is that, at any rate in the 

 western Bellingshausen Sea, the plankton of 1930-1 was not of a colder type than that 

 of 1929-30, although everywhere to the west of the South Shetlands exceptionally cold 

 conditions were met with in the former season, while in the latter season the conditions 

 were unusually mild. The dates on which the 'William Scoresby' took observations 

 in the western Bellingshausen Sea in 1929-30 were about three weeks later than those 

 of the corresponding stations of the ' Discovery II ' in 1930-1, and yet at the former the 

 very " cold " species were on the whole more numerous than at the latter. It is true that 

 in the eastern part of the Bellingshausen Sea a slightly "colder" plankton was taken in 

 1 930- 1 than in 1929-30, but the difference is not nearly so great here as it was for 



