230 DISCOVERY REPORTS 



and heavier in proportion to the shaft than that of E. spinifera (Fig. 28 c). The shaft is 

 bent a httle inwards immediately above the foot. On the front and inner side near the 

 distal end a short finger-like process, longer than that of E. spinifera, arises from it; 

 the short part of the main process beyond is less heavily chitinized than that before and 

 is often curled a little outwards. The proximal process is very similar to that of E. 

 spinifera but there are differences: the proximal part is a little heavier and the inter- 

 mediate part bent inwards at a greater angle to it ; the distal part is not bent at so sharp 

 an angle to the intermediate as in E. spinifera ; the lower (upper in the figures) portion 

 of the membranous expansion which curls backwards and upwards is considerably 

 bigger. I find these differences to be constant. The lateral process is hook-shaped ; it has 

 on the hind side of the bend a very small and low forked process. The median lobe has 

 an additional process. 



Three hundred and seventy-five specimens were measured. The largest male was 

 33 mm. long, the largest female 34 mm. The smallest sexually mature male, carrying 

 spermatophores and with fully formed petasma, was 20 mm. long, the smallest female 

 carrying spermatophores 21 mm. long; they were taken in September. 



A description of the larval stages from the second Calyptopis stage upwards is given 

 on pp. 285-294. The larval and post-larval stages described by lUig as E. longirostris are 

 actually E. spinifera; they are discussed on p. 294. 



Distribution. The stations at which E. longirostris were taken are shown in Figs. 20 

 and 22. All the previous records (they are summarized by Tattersall, 1924, p. 26) are 

 from positions within the sub-Antarctic Zone, and the same is true of mine but for two 

 south-east of the Cape. This is an exceptional region where sub-Antarctic water flowing 

 north-east mixes with water from the Agulhas Current flowing in the opposite direction, 

 and carries sub-Antarctic forms across the subtropical convergence. 



E. longirostris is sometimes absent from the coldest water of the sub-Antarctic Zone, 

 and it has never been taken in the Antarctic. 



Euphausia triacantha. Holt and Tattersall (Figs. 20, 22, 23, 28 d) 



E. iriacantha, Holt and Tattersall, 1906, p. 4; Tattersall, 1908, p. 12, pi. iv, figs. 1-3; Hansen, 

 i9i3,p. 34, pi. V, figs. 2fl-^; Zimmer, 1914, p. 428; Illig, 1930, p. 503; Rustad, 1930, pp.43, 

 54, figs. 35-37 ; Ruud, 1932, p. 54 ; Rustad, 1934, pp. 19^25 ; figs. 3-7, p. z^etseqq. ; Mackintosh, 

 1934, p. 76 et seqq.; Hardy and Gunther, 1935, many references. 

 Description. The carapace is expanded a little over each eye-stalk so that its antero- 

 lateral margins are convex, but there are no post-ocular spines. The rostrum is long, 

 strong and sharp, and reaches well beyond the eyes. The gastric area of the carapace has 

 a high and arched keel which is continued down the centre of the rostrum. On either 

 side of the carapace there is a low mound-like projection similar to but lower than those 

 of E. longirostris; no hepatic spine arises from it. The single lateral denticle on either 

 side of the carapace is placed very near the lower edge in which there is no incision. 



(Fig. 23 a, b.) 



The lobe of the first segment of the antennular peduncle is strong and bifid, the inner 



