102 



Side nær Basis af Endesegmentet og lige under den trian- 

 gulære Sidefortsats med en kort og tyk Stilk og kan ved 

 særegne Muskler slaaes til Siden ligesom de 2 Pløie paa 

 en Port. Ved Spidsen bærer de hver 2 korte ovale Ende- 

 grene, bvoraf den ene er særdeles liden og ganske dækket 

 af den anden (se Fig. 21) samt besat med korte Børster. 



Farven er i levende Tilstand ensformig skidden gul- 

 brun. Øinenes Pigment kulsort. 



Længden af de største erholdte Individer er, fraregnet 

 Følerne, 40""". 



Forekomst. Flere smukke Exemplarer af denne char- 

 acteristiske [sopode toges under Expeditionens Iste Togt i 

 Havet Ost af Island (Stat. 48) fra et Dyb af 300 Favne. 

 Qnder sidste Togt erholdtes endnu et Par Exemplarer af 

 samme Art udenfor Vestkysten af Spitsbergen (Stat. 359"), 

 Dybden 416 Favne. 



Udbredning. Arten er tidligere kjendt fra Færøerne, 

 Island. Spitsbergen, Grønland og Polarøerne, og maa be- 

 tragtes som en ægte arktisk Form. 



21. Arcturus tuberosus. Gr. 0. Sårs. n. sp. 



(Pl. IX. Fig. 2-1). 



Arcturus tuberosus, G. 0. Sårs, Prodromus descript. Crust. etc, No. 72 



(1876). 

 Arcturus bajfini, var. Feikleni. Miers, Report on the Crustacea collected 



l>y the Naturalists of the arctic Expedition in 187") — 70 (Ann. 



Nat. Hist. 1877), pg. 14. Pl. III, Fig. 1. 



Artscharacteristik. Legemet noget mere undersætsigt 

 end hos foregaaende Art, uden tydelige Haar og uden dorsale 

 Torner, men med uregelmæssig knudret ( )verflade. Epi- 

 mererne paa ile 3 bagerste Forkropssegmenter stumpt til- 



spidsede. Endesegmentet med jevnt bvælvet Overflade. 

 Øinene store, triangulært nyreformige. 2det Par Følere 

 betydelig hengere end Legemet, med 7-leddet Svøbe. Far- 

 ven blegt kjødfarvet. Længden .'55""". 



Findested. Stat. 18. 



Bemærkninger. Len her omhandlede Form staar 

 foregaaende saa overmaade nær, at jeg har været i stor 

 Tvivl om dens (iyldighed som distinet Art. især da der 

 blot forelaa til Undersøgelse et enkelt Exemplar. Jeg op- 

 førte den derfor i min Prodromus kun med Forbehold som 

 en ny Art og yttrede, at den muligvis kun vilde vise sig 

 at være en ganske tilfældig Varietet ai' foregaaende. Aaret 

 elter blev imidlertid den samme Form beskrevet af Miers 

 fra den Engelske Nbrdpolexpedition i 1875 — 7<i og angivet 

 at forekomme endog i Mængde paa en Localitet, uden at 



at the base of the terminal segment, and immediately be- 

 neath the triangular lateral projection. by a short and thick 

 pedicle. and admit. by the use of specially adapted museles. 

 of being pushed back. like the leaves oi' a folding door. 

 At the point, they have each 2 short. ovate terminal branches. 

 one of which is exceedingly small and completely covered 

 by the otber (see fig. 21), as also beset with short bristles. 



Colour. when alive. a uniform dirty yellowish-brown ; 

 ocular pigment a coal-hlack. 



Length of the largest specimens obtained — e.xcluding 

 the antennæ — 40""\ 



Occurrence. — Several fine examples of this charnc- 

 teristic Isopod were collected on the Ist cruise ol the Ex- 

 pedition. in the open sea. east of Iceland (Stat. 4«). from 

 a depth of 300 fathoms. On the last cruise two more 

 specimens of the same animal were tåken, off the west 

 coast of Spitzbergen (Stat. 359); depth 4Ki fathoms. 



Distribution. - - The species bad been previously 

 known from the Færoes, Iceland. Spitzbergen, G-reenland, 

 as also the Islands of the Polar Sea north of America, .-md 

 must. therefore, !»• regarded as a true Arctic form. 



21. Arcturus tuberosus. <i. <>. Sårs, n. sp. 



i Pl. TX. fig. 22). 



Arcturus tubei .-»... (J. O. Sårs, Prodromus desmptiOnis Crust etc. No. 



72 (1876). 

 Arcturus baffini, var. Feildeni, Miers, Report on the Crustacea collected 



by tlie Naturalists of the Arctic Expedition in 1sT."i — 76 (Ann. 



Nat. lii-t. 1-77 1, p. l-l. Pl. III. fig. i. 



Specifie Character. — Body a trille more thickset 

 than in the preceding species. without distinctly perceptible 

 hairs and without dorsal spines, but presenting an irregular 

 rugged surface. Epimera on the .'! posterior pedigerous 

 segments obtusely pointed. Terminal segment with uni- 

 formlv arcuate surface. Eves large, triangular- lvniform. 

 Second pair of antennæ considerahly longer than body. 

 with a scven-jointed Hagellum. Colour a hght pink. Length 



Locality. -- Stat. Is. 



Remarks. - • The form to be treated of here approx- 

 imates so closely the preceding. thatlhave felt verygreatly 

 in doubt conceming its title to specifie distinctness, and 

 the more so since but one specimen only lav before me 

 for examination. Heine. 1 recorded the animal in my "Pro- 

 dromus" with considerable reservation as a new species. 

 stating that it possibh vvould turn out to bi' a mere casual 

 variety oi' the preceding. Meanwhile, the year after the 

 same form vvas described by Miers from the English North 

 Pole Expedition in 1875 — 76, and said by him to occui' 



