124 



DISCOVERY REPORTS 



(P- 115) that the larvae later in development than the Metanauplius, undergo a vertical migration 

 diurnally through a column of water greater in depth than 250 m. That they should be absent from 

 water shallower than 250 m. in this survey argues that for reasons connected with light intensity 

 it is essential for them to have greater depths to recede to in the daytime. This will be dealt with in 

 the section on vertical migration. 



(e) Survey of February-March 1928 (Sts. WS 144-195). Fig. 44. 



Very few larvae were taken during this survey; one Calyptopis 2 at St. WS 173 just beyond the 

 shallow water on the Vakop Line and two Calyptopis 1 and 2 at St. WS 182 in the first deep-water 

 station on the Clarke Rocks Line. It was noted above that one egg was taken at St. WS 147 in the 

 250-100 m. net. This station was on the edge of the continental shelf with a sounding of 274 m., but 

 the previous station (WS 146), taken in almost the same position three days before, gave a sounding 

 of 1096 m., so that both must have been on the very edge of the continental shelf. 



38" 



53 



54 



55 



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■ W5 1 79 



I 



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wsiai 



53 



55 



38° 



36" 



3-t" 



Fig. 44. Distribution of young Euphausia superba, South Georgia survey 

 (70-cm. net hauls), February-March 1928. 



(/) Prince Olaf lines, March 1931 (Sts. WS 567-575). Fig. 45. 



Two lines of stations to the northward from Prince Olaf Harbour were made in March 1931, and 

 at two stations, both in deep water, one Calyptopis i and one Furcilia 6 were recorded. 



{g) South-west side of South Georgia, April 1929 (Sts. WS 417-426). Fig. 46. 

 No larvae were taken at any of the stations. 



(/?) East side of South Georgia, May 1930 (St. 393). 



At this station four flights of nets, each from 300 m. to the surface, were made, but only one larva, 

 a Furcilia 5, was taken. 



Two points are made apparent by these surveys; first that Calyptopis and early 



