DISTRIBUTION OF YOUNG STAGES OF EUPHAUSIA SUPERBA 117 



Ruud (1932, p. 33) says: "We only find larvae in any quantities in our samples at the 

 stage when they begin to feed, i.e. the first Calyptopis stage (Taube, 1915). The younger 

 larvae would naturally be found with the eggs." With respect to the last statement the 

 present observations on the vertical distribution of the Metanauplius furnish very 

 favourable evidence for the hypothesis that the eggs are to be found in deep water rather 

 than at the surface. 



TIME OF OCCURRENCE 



All the Metanauplii were taken during the months of February, March and April and, 

 while it is possible that about the middle of April may be the latest time for the occur- 

 rence of this form, the range in the other direction must be extended considerably be- 

 yond the date of the earliest record. It will be seen presently that there is an isolated 

 record of a 2nd Calyptopis in the first half of November, which would indicate a period 

 for the production of Metanauplii prolonged to at least five and a half months. But if 

 this 2nd Calyptopis be regarded as an unusual exception — and that this may be so is 

 indicated by there being no record of 2nd Calyptopis again until two and a half months 

 later — then the normal time of occurrence of Metanauplii may be reduced to a period of 

 about three months, extending from mid-January to mid-April in the second half of the 

 southern summer. 



CALYPTOPIS STAGES, FURCILIA STAGES 



AND ADOLESCENTS 



REGIONAL DISTRIBUTION 



It has been mentioned in the Introduction to this paper that the 70-cm. vertical nets 

 yielded the main supply of earlier developmental forms and the i-m. nets older larvae 

 and adolescents. In discussing the distribution of stages subsequent to the Metanauplius 

 it is convenient to classify the material examined in three divisions as follows: 



Material caught in the 70-cm. nets. 



Material obtained during the circumpolar cruise. 



Material caught in the i-m. nets. 



Of these three divisions the first is concerned mainly with first season larvae, that is to 

 say larvae taken during the summer season in which they were hatched ; and the third 

 division deals with second season forms, including late Furcilia and adolescents, hatched 

 in the summer previous to that in which they were caught. The circumpolar cruise was 

 made chiefly in the winter months and only material from the i-m. nets was examined. 

 As regards both time of year and state of development the larvae in the second of the 

 above sections are placed intermediately between those of the other two sections. 



Material caught in the 70-CM. nets 

 In the discussion of the 70-cm. net catches the stations have been divided into the 

 following areas: 



(i) Falkland Islands to South Georgia. 

 (2) South Georgia surveys. 



