68 AXEL OHLIN. AKCTIC CRUSTACEA. 



Jllioda inermis bas more or less the same distribution as 

 tbe preceding species, whicb it rivals also in number of spe- 

 cimens. It is restricted to the boreal parts of the North At- 

 lantic and its continuation northwards. It occurs ofF the 

 British Isles, West- and North-Norway, Kära Sea, Spitz- 

 bergen, Jan Mayen, East- and West-dreenland, and the coast 

 of New England as far south as Vineyard Sound and Massa- 

 chusetts Bay. 



It does not attain such a size as Nyctiphanes norvegica. 

 My largest specimen measured 29 mm. 



Thysanoessa Brandt 1851. 



This genus was establisbed by Brandt in Middendorff'.s 

 kSibirische Reise with the following diagnosis. Pedum maxil- 

 larium par externum reliquis pedibus longius. It included 

 Thysanopoda {Thysanoessa) longipcs Brandt which has proved 

 to be identical with Thijsatiopoda ncgJccfa Kröyer. Another 

 species figured but not described by Kröyer, in »Voyage en 

 Scandinavie etc», is also referred to this genus, viz., Thysa- 

 nopoda longicaiidata. In 1882 Särs described two more spe- 

 cies from the coasts of Norway, viz. Thysanoessa borealis and 

 Thysanoessa tenera, but Hansen, who has examined Kröyer's 

 type-specimens, preserved in the Museum of Copenhagen, comes 

 to the conclusion that Thysanoessa borealis must be identified 

 with Thysanop)oda neglecta, and Thysanoessa tenera with Thy- 

 sanopoda longicaudata. In the vChallenger reports». Särs has 

 added two new species to the genus, viz. the cosmopolitan 

 Thysanoessa gregaria and Thysanoessa macrura from the Ant- 

 arctic and South Atlantic Oceans. The genus which is close- 

 ly allied to Ncmatoscelis G. O. Särs and Stylocheiron Gr. O. 

 Särs is, in its present restriction, distinguishable, according 

 to Särs, by the following characteristics: first pair of legs 

 greatly produced and rather strong, the two last joints armed 

 with spiniform bristles on both margins. 



During the Swedish Arctic Expeditions of the last three 

 sumraers onlv the following species was obtained, viz. 



