COPEPODA 149 



Clausocalanus furcatus (Brady). Only recorded at four stations between South 

 Georgia and the Falkland Islands. 



St. WS 67 ... 37 at 1000-750 m. St. WS 69 ... 1 $ at 50-0 m. 



St. WS 68 ... 1$ at 250-100 m. 12 at 1000-750 m. 



St. WS 70 ... 15 at 250-ioom. 



St. WS 67 is only just inside the Antarctic Zone, and here it was taken in the warmer 

 intermediate zone. It is not recorded elsewhere from the Antarctic Zone. 



Ctenocalanus vanus, Giesbr. This species was abundant throughout our region, except 

 at St. 9 far to the north of the Antarctic Convergence on the Tristan-South Georgia line, 

 and in somewhat reduced numbers at St . WS 70 towards the Falkland Islands. The reduc- 

 tion on these lines is clearly shown in Fig. 72. That we should find it abundant beyond 

 the line of Convergence at Sts. WS 68 and WS 69 is not surprising after reading 

 Farran's (1929) account of the species in his report on the Terra Nova collections. He 

 writes that it was "taken in abundance off Rio de Janeiro and continuously in large 

 numbers from off the north of New Zealand to the most southerly point reached". 



The complete record of its occurrence is tabulated in Appendix II. For the December- 

 January SouthGeorgia survey, 1926-7, the average number per 50 m. haul with the N 70 V 

 net in the top 250 m. of water was 288. It was more abundant over deep water than in the 

 shallow coastal regions. The maximum number per 50 m. haul was 4029. Its general 

 distribution is shown in Fig. 70. At the "control" St. 41 (see p. 265) the maximum 

 number per 50 m. was 1 445 and the minimum number 260 ; with this degree of irregularity 

 in occurrence our charts can serve no more than to indicate its very general distribution. 

 It is distributed equally in water of Bellingshausen Sea and Weddell Sea origin. 



Its seasonal distribution, together with other forms, is discussed on p. 266 ; it occurred 

 more abundantly in our samples taken in March 1926 than in those of November or 

 December of the same year or of May in the following year. 



Its vertical distribution round South Georgia is shown in Fig. 71, and that 

 approaching South Georgia from the north-east in February 1926, and between South 

 Georgia and the Falkland Islands in Fig. 72. It was most abundant in the top 100 m., 

 but it has occurred in small numbers in waters as deep as 2000 and 1000 m. There 

 is evidence of vertical migration, upwards at night; this, with the vertical migration 

 of other forms, is discussed further on p. 236. 



Its mean vertical distribution at deep water stations is shown in Fig. 55. 



In addition to the Terra Nova, referred to above, the Belgica, 1 the National 

 Antarctic (Discovery), 2 and the Gauss 3 Expeditions have recorded the species in 

 large numbers in the Antarctic. 



Microcalanus pygmaeus, G. O. Sars. Of general distribution but never abundant. It 

 rarely occurred in shallow water, being as a rule confined to stations beyond the edge of 

 the continental shelf. It occurred in the largest numbers at depths between 750 and 

 250 m., but was also taken between 2000 and 1000 m. See Fig. 55. 



A complete record of its occurrence is tabulated in Appendix II. 



1 Giesbrecht (1902). 2 Wolfenden (1908). 3 Wolfenden (191 1). 



