ITINERARY: FIFTH COMMISSION 305 



farther north, and one species at least extends southwards into our Northern Region 

 in abundance. 



After leaving New Zealand we made our way southwards through the ' special area ' 

 north of the Ross Sea, where the more southerly position of the Antarctic convergence 

 renders the distinction of Northern and Intermediate Regions impossible. Here the 

 phytoplankton in the middle of February was poor— almost certainly post-maximal. 

 Our eastward crossing of the Pacific during the latter half of February and the first 

 week in March was carried out in high latitudes. Most of the stations fell in the 

 Southern Region, where the main increase was evidently proceeding up to the end of 

 February, with slight falling off subsequently. Working northwards through another 

 'special area', the eastern South Pacific, a moderately rich phytoplankton was observed 

 at the two most northerly Antarctic stations, which may have represented the secondary 

 autumnal increase in this generally poor locality. Throughout the remainder of March 

 1938, however, when our work lay in the Scotia Sea, it was evident from the very small 

 quantities of phytoplankton observed that the post-maximal decrease was still in force, 

 and that any autumnal secondary increase would probably come later. 



The circumpolar cruise was completed by a line of stations from South Georgia 

 eastwards to the meridian of Greenwich, whence observations were continued south- 

 wards from the vicinity of the Antarctic convergence to 65° S, and after an eastward 

 zigzag, northwards from 67° S up the 20° E meridian to South Africa. This last portion 

 of the circumpolar cruise occupied the greater part of April 1938, and covered the same 

 area that was worked in detail throughout the following season. The results gave clear 

 indications of the secondary autumnal increase in the Northern Region. In the Inter- 

 mediate Region the quantities of phytoplankton were small, but slightly greater, on the 

 average, than those recorded in March and on other occasions. 



After refitting at Simonstown we again sailed south on i July 1938, on the first of 

 seven repeated series of observations between o and 20° E. On each of these cruises 

 our general procedure was the same. We aimed to reach the Greenwich meridian in 

 about 40° S, worked due south to the ice-edge, then turned to the north and east until 

 we reached the neighbourhood of 10° E, then turned south and east for the ice-edge, 

 and finally northwards in about 20° E. The extent of the north and south legs of this 

 W-shaped course necessarily varied with the influence of the weather and the position 

 of the ice-edge upon our fuel consumption. Throughout the winter and up to December 

 1938 the ice lay around 55-56° S, and it was possible to work north until we had nearly 

 reached the Antarctic convergence again in about 10° E on each of the first five cruises. 

 Later the ice-edge lay some hundreds of miles farther south. In February-March 1939 

 we reached the edge of the Antarctic continent itself between o and 4° E, and it became 

 necessary to cut out the middle zigzag altogether. This particular cruise gives a good 

 example of the enormous distances that have to be covered in this type of work. Pro- 

 ceeding from Cape Town to approximately 40° S in 0°, down to the Antarctic continent 

 and back up the 20° E meridian, the ship actually had to steam farther than she did in 

 her crossing of the South Pacific the previous season. 



