EUPHAUSIA SUPERB A 219 



On the inner and front margin of the median lobe, beyond the end of the lateral process, 

 there is always a small additional process ; in one specimen there were two additional 

 processes. 



I have seen a very small spine-shaped process on the inner lobe in one or two speci- 

 mens of E. siiperba (cf. p. 205). 



Remarks. This species, the largest, most interesting and most important of the 

 genus, has been studied more closely by other members of the Discovery staff than by 

 me. Hardy and Gunther (1935, pp. 208-15) have written of its great importance in 

 the ecology of Antarctic seas and more particularly of its economic importance as the 

 only food of Blue and Fin whales in the south ; of its peculiar habit of swarming in 

 dense shoals so that it becomes accessible to the whales in numbers large enough 

 to satisfy them ; and of its occurrence as larvae and adults in different seasons on the 

 South Georgia whaling grounds. Eraser (1936) has published a very full description 

 of all the larval stages — more complete, and based upon far larger numbers of specimens, 

 than any previous account of the development of a Euphausiid. Dr H. E. Bargmann 

 will shortly be publishing a description of the internal anatomy of the species and an 

 account, based upon the enormous collection of specimens now available, of its life 

 history beyond the larval stages and of its distribution throughout the Antarctic Zone. 



Dr Bargmann has already examined a very large number and I am indebted to her 

 for the following facts : females are usually a little larger than males but both may reach 

 a length of 60 mm. ; the smallest female with spermatophores that she has seen was 

 32 mm. long, the smallest ripe male 41 mm. 



Distribution. I shall not attempt to give a full account of the distribution of 

 E. siiperba here : Dr Bargmann will give a better one, based on far larger collections than 

 I am considering, in her forthcoming report (see above). 



The stations at which it was taken in the commission of 193 1-3 are shown in Figs. 13 

 and 14. It was found on every one of our visits to the ice-edge, whether in summer or 

 winter, and at the majority of the stations made far into the drift- and pack-ice of the 

 Weddell Sea in January, including the southernmost of them. 



In the Falkland Sector, where our observations were for the most part made in 

 summer, E. superba was found scattered throughout the Antarctic Zone nearly as far 

 north as the convergence. It may be similarly distributed in other parts of the Antarctic 

 in summer ; we did not find it to be so in winter on our circumpolar cruises east-about 

 from S. Africa to S. America (Fig. 14). To the south-east of Africa, approaching Enderby 

 Land, small numbers of larvae and adults were found at Sts. 851-4, far away from the 

 ice-edge ; large numbers of adults and very large numbers of larvae were found at the 

 ice-edge itself (St. 855). This was in April. At and near the ice-edge to the south of 

 Australia, in May (Sts. 887-8), a few adults and many larvae were taken. At the ice- 

 edge to the south of the sea between Australia and New Zealand, in June, many larvae 

 but no adults were found (St. 912). The next catches were made in September at the 

 ice-edge to the south-east of New Zealand ; there were larger numbers of larvae and 



adolescents but no adults (Sts. 952-5). 



4-2 



