— 25 — 



frontal plate with rostrum in a couple of specimens (var. 

 crassirostris H. J. H.) was described. In Sars 1 type, in all 

 specimens from the Swedish Antarctic Expedition, from 

 the northern part of the Indian Ocean, from the « Siboga » 

 and from Japan (U. S. Nat. Mus.) the third abdominal 

 segment has no free dorsal process, but first to third abdo- 

 minal segments each dorsally at the middle of the hind 

 margin with a small, produced and rounded part, while the 

 hind margin of the two next segments is straight. But 

 the Copenhagen Museun possesses 1 1 specimens taken at 

 two localities far South (lat. 40°g 1 S. and 3j 1/2 0 S.) and 

 very distant from each other in South Atlantic, from a loca- 

 lity at lat. 1 3° S., long. io3i/3° E., and from a locality 

 between New Zealand and Tasmania, and all these speci- 

 mens, most of them adult but differing much in size, agree 

 with the typical form in the eyes and the rostrum, in the 

 structure of the antennulas and the produced rounded part 

 of the hind margin of first and second abdominal segment 

 — this feature being an excellent spécifie character — but 

 their third abdominal segment is carinated posteriorly in 



F^ig. 7. Euphausia si- 

 milis G. 0. S., var. 

 armata n.var. Inner 

 and median lobe of 

 left copulatory or- 

 gan, from behind. 

 p 2 . terminal process; 

 p\ proximal process; 

 p' 1 . lateral process. 



the median line and produced into a compressed, some- 

 what short, but very conspicuous, acute process. That the 

 specimens with this process are only a variety, not a sepa- 

 rate species, is proved by the agreement in the other cha- 

 racters enumerated and by the copulatory organs (Fig. 7) 



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