SEASONAL CHANGES IN ZOOPLANKTON 



267 



but each were either fairly well represented or abundant in December, March and also 

 in May. We have already noted that Rustad and Wheeler have demonstrated that 

 Euphausia superba lives for two years, and Clark (19 19) has shown how abundant it may 

 be in the Antarctic winter. In view of the small number of stations taken in November 

 little significance should be attached to this month's results unless confirmed by later 

 work. 



Reference has already been made on pp. 203 and 214 to the different stages in the 

 development of Euphausian larvae in different seasons. 



Limacina helicina, as far as our observations go, would appear to be an early summer 

 form, being abundant in December but absent in March and May with only a few taken 

 in November, and L. balea an autumnal form which was only present in fair numbers in 

 May, being absent in November, December and March. Salpa fusiformis was abundant 

 in November and December, but poorly represented in March and May. 



Table XLIX 



Showing the temperature in ° C. at stations taken at different times of the year at approxi- 

 mately the same position 45 miles off the north-east coast of South Georgia (except St. 151 

 which is 60 miles off the coast) 



