i66 DISCOVERY REPORTS 



SUMMARY 



1. The egg, Nauplius, Metanauplius and Calyptopis stages of Eiiphaiisia stiperba 

 have been described — Nauphus 2 for the first time (p. 17). 



2. The nature of Furciha stages in Euphausiacea has been discussed. The suggestion 

 is advanced that, in the Hght of the data supphed by the present material and the in- 

 terpretation of known larval histories in conjunction with these results, the actual 

 number of stages in early Furcilia development is much smaller than previously 

 acknowledged (p. 32). 



3. A division is made of larvae with all pleopods setose and seven terminal spines on 

 the telson into two Furcilia stages: (a) those that on moulting are again seven-spined, 

 (b) those that on moulting are five-spined (p. 41). 



4. Reasons are given for abandoning the term Cyrtopia (p. 50). 



5. Later larval development is diffuse and ill-defined and individual variation is 

 great (p. 51). 



6. Anatomical descriptions of Furcilia stages are given to indicate the general trend 

 of development (p. 68). 



7. The term adolescent as used in this report is defined and the indistinctness of this 

 phase emphasized (p. 99). 



8. Anomalous length frequencies are discussed and reasons suggested why some of 

 the larvae in their second season are so much larger than the majority. A correlation 

 between large size and phytoplankton distribution is given, but doubt is expressed 

 whether the correlation is a direct one or due to a community of conditions affecting 

 phytoplankton in abundance and euphausians in length (p. 103). 



9. The average lengths of earlier larvae indicate that the young euphausian reaches 

 a length of about 10 mm. by the end of its first summer season (p. 106). 



10. In the first year or fourteen months E. stiperba reaches a length of over 24 mm. 

 Growth is not regular, being slowed down during the winter months (p. 107). 



11. The distribution of eggs, Nauplii and Metanauplius shows that these stages are 

 found in deep rather than shallow water. Regionally the majority of the eggs have been 

 found in the Bransfield Strait, but Metanauplii are widely spread throughout the Scotia 

 Sea. The second half of the summer season is the time when eggs, Nauplii and Meta- 

 nauplius are to be found (p. 109). 



12. The distribution of Calyptopis and Furcilia stages is described, and the general 

 impression obtained is that in the Falkland sector at any rate no well-defined predilec- 

 tion for the immediate vicinity of ice can be demonstrated (p. 1 17). 



13. The ice-edge distribution of Furcilia 6 and adolescents is made clear, especially 

 by the results obtained from the circumpolar cruise stations and a line of stations 

 from Bouvet to South Georgia early in the summer season (p. 137). 



14. The vertical distribution and migrations of young E. superba are described and 

 the distinction made between early stages which have a well-defined diurnal vertical 

 migration and the adolescents which remain continuously at the surface (p. 151). 



