236 DISCOVERY REPORTS 



proximal part, and expanded into a membranous plate which lies m a vertical plane. 

 The proximal part is widest near the base; there is a definite angle in the outer margm 

 at the widest point, whereas the inner margin is straight. 



The lateral process is hook-shaped with no secondary teeth or processes. There is a 

 small additional process on the median lobe. 



The largest specimens of E. similis seen, both male and female, were 33 mm. long; 

 the smallest female with spermatophores was 19 mm., the largest male with an m- 

 completely formed petasma 24 mm. long. 



None of the larval stages of E. similis has been described as such, but I think that the 

 "Furcilia larva— Stage i " described by Tattersall as of E. lougirostris (Tattersall 1924, 

 pp. 22-3, pi. i, fig. i) is really E. similis. I have taken one similar to it and specimens 

 of two later stages of the same species (see p. 286). 



Distribution. The stations at which E. similis was taken are shown in Fig. 26. It is 

 the most variable of the species described in this paper and has a much wider range 

 than any of the others. Its southern limit is in all meridians the Antarctic con- 

 vergence ; although it may occur immediately north of it it is usually absent from the 

 coldest part of the sub-Antarctic Zone. It is never found in the Antarctic. 



It has been recorded from just south and from north of the equator in the Atlantic: 

 Ortmann (1893) describes one specimen from the South Equatorial Current and Illig 

 (1930) two specimens from north-west of Cape Blanco. I have examined the latter; 

 one was about 5, the other between 5 and 6 mm. long and I could not recognize either 

 as E. similis, though I could not be sure that they were not. Illig records the species too 

 from west of Angra Pequena, about 26° S, in the east Atlantic ; I have seen some of his 

 specimens and found them to be similis. On the first of our two lines of stations in the 

 west Atlantic extending as far as 15° N, which are described on p. 228, E. similis was 

 found as far north in the subtropical Zone as 33° 47!' S, but no farther; on the second 

 line it was not found so far north. For these reasons I feel doubtful of Ortmann's record 

 from the South Equatorial Current. I cannot feel sure that the species has been shown 

 to extend farther north in the Atlantic than some way into the subtropical Zone. 



It has been recorded from farther north in the Indian Ocean and in the west Pacific: 

 Illig (1930) records it from near the Seychelles, the Amirante Islands, the Maldive 

 Islands, the Chagos Archipelago, Sumatra and Cocos Island in the Indian Ocean; 

 Hansen (191 5) from as far north as Japan and (1916) from near the Philippines in the 

 west Pacific. 



The other records of its occurrence are from the sub-Antarctic or subtropical regions 

 of the southern hemisphere. 



Euphausia similis var. armata, Hansen (Figs. 24 r, 25, 26) 



E. similis var. armata, Hansen, 191 1, pp. 24-6, fig. 7; Tattersall, 1924, p. 19; 1925, p. 7; Illig, 



1930, p. 498. 

 E. similis var. lohata, Zimmer, 19 14, p. 425, pi. xxvi, fig. 59. 



Description. Hansen described the variety armata as being distinguished from 



