DISTRIBUTION OF YOUNG STAGES OF EUPHAUSIA SUPERBA 109 



larvae to the stock — it is exclusively a period of growth. The third division of the graph 

 coincides with the depth of the southern winter when conditions for growth will be 

 unfavourable, and although the June average depends on one sample it may be taken 

 that it represents, roughly at any rate, what actually happens at that time of year. With 

 the coming of spring, environmental conditions become favourable again and growth 

 and development go ahead. The larvae pass from Furcilia 6 to the adolescent phase, so 

 that by the end of the year the former stage of development is no longer encountered in 

 the samples. 



This curve of average length corresponds fairly closely with the comparable portion 

 of Ruud's Total Growth Curve (Ruud, 1932, p. 45, fig. 10), but in the present figure the 

 first period referred to above is continued for at least a month longer than Ruud's figure 

 indicates. The period of rapid growth prior to winter covers the period April-June, as 

 compared with February-March depicted in Ruud's figure. This last difference affects 

 the length of the winter period of reduced rate of growth. On the whole, however, the 

 results are in fair agreement, and what differences there are probably originate from the 

 widely separated sources from which the present material was obtained. 



The distribution of records throughout the year with the exception of the month of July 

 helps toward a better understanding of the development and growth of this euphausian 

 than was hitherto possible, and although many of the results cannot be regarded as final 

 and conclusive, they at any rate furnish a basis for future corroboration or contradiction. 



DISTRIBUTION 



EGGS 

 REGIONAL DISTRIBUTION 



In the samples examined there are forty-eight records of eggs from twenty-eight dif- 

 ferent stations. Most of the catches are of small numbers of eggs, but at one station, 

 St. 540, relatively enormous numbers were obtained, of which the maximum occurred 

 in the 500-250-m. net. 



In the Falkland sector, from which all the data relating to eggs have been obtained, 

 they were found in great abundance near Graham Land and the South Shetlands or in 

 the path of currents which have a component towards these places (Fig. 31). They 

 were also found near the South Orkney Islands and South Georgia and above the 

 Scotia Arc in the vicinity of the South Shetlands. They were also found close to the 

 continental shelf west of Graham Land in the south of the Bellingshausen Sea. 



The area of greatest abundance of eggs is near the northern end of Graham Land, 

 particularly in the Bransfield Strait; at each group of stations made there between 

 November and February eggs were found in greater or less abundance. 



There are probably two main reasons why eggs occur in the regions described. 

 Along the west coast of Graham Land and the Scotia Arc, as far as the South Sandwich 

 Islands at all events, the temperature and salinity are roughly the same (vide Deacon, 

 1933, figs. 12, 13, 24), and these conditions are probably the optimum for eggs to be laid. 



