EARLY RECORDS AND RECENT LITERATURE 45 



only six, constitutes perhaps his most important contribution (see also Fraser, 1937) to our knowledge 

 of euphausian life-history. He is the first to show that spawning is a long drawn out phenomenon, 

 lasting in the Falklands sector of Antarctica from November to March, and not the ' spontaneous ' 

 outburst of Ruud, and the first too to suggest, from the deep occurrence of the Metanauplius, that 

 the early larval development must take place at great depths and could not be the surface phenomenon 

 postulated by that author. John (1936) places it in his ' southern group ', concluding from the observa- 

 tions of 'Discovery II ' in the summer, autumn and winter of 1932 that its normal range is from the 

 Antarctic coastline northwards to the northern edge of the pack-ice and a little beyond. He remarks 

 on the concentration of larval and early adolescent krill encountered at the ice-edge by ' Discovery II ' 

 during her circuit of Antarctica in 1932-3, and is the first to record how the larvae in some measure 

 of abundance may be carried far to the north of the ice in cold water deflected from the south by the 

 submarine ridge connecting Gaussberg with Kerguelen. Matthews (1937, 1938a, 19396) makes the 

 first definite reference to this species as the food of the humpback, right and sei whales on the South 

 Georgia whaling grounds. Bargmann (1937) describes the development of the male and female 

 reproductive system, distinguishing seven clearly marked stages in each, and in a later paper (Barg- 

 mann, 1945) uses these stages to work out the composition and growth-rate of the euphausian popula- 

 tion as a whole. Extending the work of Ruud (1932) she shows that the females are consistently 

 smaller and take longer to reach sexual maturity than the males and that the total period of growth from 

 the egg to the adult occupies a minimum of 22 months in the male, and 25 in the female. She gives 

 an excellent coloured plate of the adult male and female. Barkley (1940) gives a detailed description, 

 with admirable figures, of the filtering mechanism by which E. superba ingests its food, and from an 

 examination of some 1300 krill stomachs demonstrates conclusively that by far the most frequently 

 occurring and abundant remains are those of the chain-forming diatom Fragilariopsis antarctica, 

 although other organisms, of which he gives a long list, the more important of them small, spineless 

 ('glatten') diatoms, are also ingested. Hart (1942) gives an excellent diagram showing the overriding 

 importance of Euphausia superba in the Antarctic food chain and again refers to Fragilariopsis 

 antarctica as an important constituent of its diet. Nishiwaki and Hayashi (1950) report that the blue 

 and fin whales taken by the Japanese whaling fleets near the Balleny Islands and on the northern 

 outskirts of the Ross Sea in 1947-8 were feeding, for all practical purposes exclusively, on Euphausia 

 superba. Nishiwaki and Oye (195 1) studied 1640 krill samples collected from blue and fin whales' 

 stomachs in the Ross Sea-Balleny Islands area in 1948-9. They call attention to the predominance 

 of 'small' whale food (see p. 140) in these high latitudes and note that of 392 stomachs examined in 

 December, 40 % were empty, and that of the stomachs with food in them 68 % contained little or 

 scarcely any krill at all. The December scarcity of feeding-stujff these figures suggest, however, is not 

 altogether surprising, for the Japanese were operating then in the West Wind drift, a region recently 

 shown (Marr, 1956) to support only a meagre population of krill. Perhaps the most interesting of 

 Nishiwaki and Oye's findings was that the stomachs of night-flensed whales were often empty, and 

 they suggest tentatively that, since most of the whales worked up at night are those that are caught 

 the afternoon of the day before, these animals in the main are early morning feeders and that possibly 

 they feed only once a day. Dell (1952), working from Bargmann's plate, gives an admirable line 

 drawing of the adult male. Sheard (1953), discussing the larval development of the Euphausiacea as 

 a whole, defines the Furcilia phase as that part of the development during which 'the abdomen is 

 differentiated in detail to act as a locomotor organ'. Thus for all euphausians he proposes that this 

 particular phase, on the precise definition of which there has for so long been such widespread dis- 

 agreement, should now include only three stages, Furcilia i in which the pleopods develop as non- 

 functional rudiments, Furcilia 2 in which the pleopods, with their musculature, develop as functional 



