66 AXEL OHLIN, ARCTIC ORUSTACEA. 



Strangely enongh, it was not obtained either on the 

 Challenger Expedition or on the German Plankton Expedition. 



Gr. O. Särs says^: »May be the British form, Tlnjsaiwpoda 

 Couchii, observed by Bell, is identical with the present spe- 

 cies.3> Norman has, however, clearly proved that Nycti- 

 plianes Couchii is a very distinct species, nearly related to 

 Nyctiphanes australis G. O. Särs from Bass' Strait, Australia. 



Length 37 mm. 



Rhoda Sim 1872. 



(= Boreophausia G. O. Särs 188.3). 



Stebbing is the first who, in his :^History of Crnstacea», 

 pointed ont that two Northern Euphausiids, viz. the well- 

 known Thysanopoda inermis Kröyer and a closely-allied form 

 Thysannpoda Raschii M. Särs, ought strictly to be referred 

 to the gemis Ehoda, established in 1872 by G. Sim in his 

 paper on »Stalk-eyed Crnstacea N. E. Coast of Scotland», 

 pnblished in »the Scottish Naturalist». The genus was ere- 

 ated to receive a species, viz. lihoda Jordincana^ which Norman 

 identities with Thysanopoda Raschii. Särs, in his »Prelimi- 

 nary Notices on the Schizopoda of H. M. S. »Challenger.> Ex- 

 pedition», established for Kröyer's Thysanopoda inermis a new 

 genns, viz. Boreophausia., but without giving any generic 

 diagnosis. Two years afterwards he added^ to this genus 

 Thysanopoda ncglecta Kröyer and Tltysanopoda Raschii M. 

 Särs and, with some hesitation, Thysanopoda longicaudata 

 Kröyer. Of these .species, Thysanopoda Raschii is the only 

 one that ought properly to be referred to Boreophausia, the 

 other two belonging, according to Hansen and Norman, to 

 the genus Tliysanotssa, established by Brandt in 1851. Since 

 Rhoda Jardincana has proved to be identical with Borro- 

 phausia Raschii, Särs' genus must yield priority to the much 

 older name Rhoda. The genus thus includes Rhoda inermis 

 (Kröyer) and Rhoda Raschii(M. Sars). 



1 1. c. p. 12. 



2 Norweg. North Atlant. Exp. 11, p. 13. Rep. Challenger Exp., p. 04. 



