56 



DISCOVERY REPORTS 



Ch. flexuosus, Mangin, was found at the following stations: St. 137, 3000 (5) ; WS 40, 

 18,000 (3); WS 43, 96,000 (16); and WS 46, 300 (2). 



Ch. neglectus, Karsten, was found at St. 133, 7200 (12); WS 38, 5600 (28); WS 44, 

 204,000 (38) and WS 63, 1200 (4). 



Ch. radiculum, Castr., was found at St. 161, 54,000 (9) ; WS 40, 12,000 (2) and WS 43, 

 6000 (1). Mangin (1922) regards this species as a variety of Ch. schimperiamis, Karsten. 



Ch. schimperiamis, Karsten, occurred most abundantly at the southern end of the 



Fig. 26. Distribution of Chaetoceros criophilum round South Georgia in the December-January 1926-7 



survey. For full explanation see legend of Fig. 16. 



island, but was also found at a few outlying stations on either side. Its distribution is 

 shown in Appendix I and Fig. 27. 



Ch. socialis, Lauder. This species, which is so abundant at times in the northern 

 hemisphere, is recorded by Mangin (1922) as being rare in the Antarctic, except for a 

 limited area at the South Orkneys where it was abundant in December and January, 

 1903-4; Karsten did not record it at all. In our survey it proved to be the most im- 

 portant species, occurring in enormous numbers on both sides of the island, but 

 particularly upon the western side where it formed a dense zone. Here at two stations 

 over 500 million were recorded in single hauls from 100 m. to the surface; there can be 



