99 



nearly semicircularly curved. The median lobe has somewhat more than its proximal half very 

 broad, with the strong, much curved, proximally thick lateral process placed on the posterior 

 surface somewhat from the inner and considerably from the terminal margin, as this part of 

 the lobe terminates in a somewhat long, transverse margin, from the outer edge of which the 

 distal part of the lobe projects; this distal part is shaped about as a moderately long, somewhat 

 thick, distally a little expanded and obliquely rounded process which reaches beyond the end 

 of the setiferous lobe, is straight and stiff, though not consisting- of the hard, semitransparent 

 chitine as the real processes. The setiferous lobe without lateral setae, while its end is angularly 

 bent, with 7 seti-e. 



Length 13 — 13.5 mm. (some specimens from the Atlantic 15 mm.). 



Remarks. — S.\rs" type of E. gibba G. O. S. is from the Pacific. His figure of the 

 copulatory organs is of great value for the determination, as it shows a very long and strongly 

 curved proximal process; I have at hand specimens from the Pacific possessing such copulatory 

 organs. Sars states that the "Challenger" material of E. gibba comprises specimens from the 

 Atlantic, but these specimens are not in the British Museum, and I suppose that S.a.rs has 

 committed an error, as the specimens of the gibba-^xowy^ from the Atlantic hitherto investigated 

 by me belong to two other species, viz. E. pseudogibba Ortm. and E. hemigibba n. sp. — 

 Ortmann established his E. pseudogibba on Atlantic specimens from the Plankton-Expedition, 

 but as he gives a long list of localities I am nearly sure that he had both the Atlantic species 

 named among his material. Nearly all the differences pointed out by him between his E. pseudo- 

 gibba and E. gibba G. O. Sars are of no value — this is partly due to some inaccuracies in 

 Sars' figures — and under such circumstances I assign the name pseudogibba to the most 

 clumsy of the two Atlantic species, as Ortmann states that E. pseudogibba is more clumsy 

 than E. gibba, according to Sars' figure of the latter species. 



The best characters of the males of E. pseudogibba are some points in the structure of 

 the copulatory organs : the strongly curved, broad end of the proximal process is unique in the 

 gibba-grou^, and by the shape of the distal part of the median lobe it is instantly separated 

 from E. Jictnigibba n. sp. and E. gibba G. O. Sars (in the last-named species this median lobe 

 terminates in a very curved, slender process not found in any other species of Euphausia 

 examined by me), but agrees moderately with E. paragibba n. sp. ; however, in this latter species 

 the lateral process is armed on the outer margin, while it is unarmed in E. pseudogibba. — 

 The character from the keel on third antennular joint is rather good for separating females of 

 E. pseudogibba and E. hemigibba from each other, but less valuable for separating E. pseiidogibba 

 from E. paragibba, and the character afforded by the shape of sixth abdominal segment is poor. 



Finally it may be mentioned that E. pseudogibba in the living state probably is coloured 

 somewhat differently from E. hemigibba and E. paragibba, as several specimens of the first- 

 named form are darker, more brownish, than specimens of the two other species found in the 

 same bottle (from "Siboga" Stat. 148); specimens of E. pseudogibba and E. hei7iigibba in the 

 same bottle of the Monaco-collection show similar differences. 



Distribution. — I have at hand this species from stations in the northern subtropical 

 part of the Atlantic, but I have not seen any specimen from the Pacific. 



