13 



ItriiHiiis-. — Buec'k lias rel'piTcd tliis toi'in tn the yi'ims ritidl/iciiiis/o, 

 because in tlie figure given by (irdes the 3 jiosterioi' pairs fif pereiopoda are 

 represented as being of uniform longtli. In realit}', however, tiie ;5d ]iair are, 

 at least in full-grown specimens, distinctly longer than the 2 succeeding 

 ones, althougli the difference in this species is not nearly so great as in the 

 2 succeeding species. Moreover the powerft;! structui'c of the 2 anterior 

 pairs of perein])oda, as also the mutual length of the antennie, shows this form 

 to be a true JEnfhemisfo. As to the form named by Dr. Bovallius E. his])/nosa 

 Boeck, at least the habitus-figure given would seem more projierly to relate 

 to the present than to Boeck's species. 



Occurrence. — Off the coa.st of Norway I have only observed tiiis 

 form in a single locality, viz., at Hasvig in west Finnia,i-k. It occurred 

 here rather sjiaringly in deej) water together with Piirril]irnii><to ohiiriti. 



Bistrilmticm. — Arctic Ocean: Davis strait, east coast of Greenland, 

 Jan Mayen at Stat. 225 of the Norwegian North Atlantic Expedition. 



6 Euthemisto libellula, (Mandt) 

 (I'l. (i, lig. ]). 



Gdiiimariis libellula, Mandt, Obsevvationes in Historiam naluralem et Anatomiam 



comparatam in itiiiere gronlandico facta;, p. :!2. 



Syn : Thcmisto arctica, Kreyer. 



Body very slender, with the back rounded, not carinated. Ceplialon 

 scarcely more deep than long, obliquely rounded in front; eye-pigment rather 

 large, obliquely oval. Superior antenna' with the Hagellum scarcely curved. 

 Gnathopoda having the propodal joint shorter than the carpal one, car])al 

 IDrocess of the 2nd pair nearly reaching the tip of the propodal joint, dactylus 

 very small. Carpal joint of the 2 anterior pairs of pereiopoda broadly ovate, 

 slightly expanded towards the extremity and provided, on the posterior edge, 

 with a regular series of rather elongated setae. Tliird pair of jiereiopoda very 

 elongated, basal joint expanded, with the anterior edge 1)ulging out on the 

 middle and provided with short bristles, propodal joint about the length of 

 the carpal, anterior edge with a regular series of rather strong setae placed 

 at regular intervals and increasing in length towards the extremity, outer 

 part of the edge densely spinnlous, dactylus slightly Hexuous, with a dense 

 tuft of fine spinules at the base. Urosome vei'y slender, about half the 

 length of the metasome. Uropoda likewise very slender, rami of the last jiair 

 subequal in length. Body densely ornamented with dark purplish pigmentary 



