24 Hjalmar Ostergi'en. [No, 9 



It is quite different witli regard to the species, which princi- 

 pally belong to the less depths. Amongst them are four, which 

 are common to the Arctic and Boreal regions : Cucumaria froiiclosa, 

 Phyllophorus jÆucidus, Ph. driimmondii and Psolus phantapus. 

 These appear also in the north as well as in the south of Norway. 

 Bnt in the south of Norway one meets besides with a whole series 

 of Holothurians (Dendrochirotæ and Synaptidæ), which have their prin- 

 cipal distribution at a small depth: Cucumaria hyndmani (Thomps.), 

 C. elongata DiJB. & Kor., C. Jadea (Foeb.) Thyone fiisus (0. F. 

 Mull.) Thyone raphamis DiJB. & Koe., Pseiidocucumis mixta 

 OsTEEGR.^), Synapta inhærens (0. F. Mull.), as well as several 

 new species belonging to the genera Psolus, Synapta and Lahidoplax. 

 Of all these none but Synapta iniiærens is found north of the Arctic 

 cu^cle, and this only in one specimen. 



As regards the pure arctic fauna, we can altogether pass over 

 those species of Holothurians, which exclusively belong to the grea- 

 ter depths. These species are not . found on the Norwegian coast. 

 Beside the four species which have been mentioned as common 

 to the arctic and boreal districts, there are a considerable number 

 of Holothurians at less depths on the coasts of the Arctic lands. 

 Amongst them there live, as before mentioned; five species on the 

 most northerly coasts of Norway: Trochostoma boreale, Anlijro- 

 derma jeffreysii, Chiridota lævis, Myriotrochiis rinkii and Trochoderma 

 elegans. In the high arctic regions, as the Sea of Kara, Spitzber- 

 gen and Greenland must further be added: Cucumaria yninuta 

 (Fabe.), C. glacialis Ljungm., C. calcigera (Stimps.) Psolus fabricii 

 (DuB. & Koe.) 2) and Eupyrgus scaher Lutk. Even Eljyidia glacialis 



^) Also this species is omitted b}' LuDWia (1900). I liave now before me 

 specimens even from. tlie Faroe Islands and from ISTormandy. Some of the spe- 

 cies here mentioned are sometimes found at a depth of more than 100 m., bnt 

 ver}- seldom deeper than 200 m. Thyone raphamis has been found at 64^ 48' N., 

 none of the other Dendrochirotæ north of the Trondhjem Fiord. Cucumaria 

 elOngata is found near Christiansund, 63^ 10' N. (Danielssen 1859). but not 

 further north. Jarzynsky's C. iJentactes from the Murman Coast can therefore 

 hardh' be identical with C. elongata (cf. Ludwig, 1900 p. 48). Possibly this 

 C. pentades as Avell as ,.Perdacta Koicaleivskii Jaij'" (Wagner, 1885 p. 36) are some 

 of the pure arctic species of the genus Cucumaria. 



-) According to Bell Ps. fabricii is found in Japan and Shetland. Pro- 

 fessor Bell has kindly let me see his specimens, which circumstance occasions 

 the following remarks. The specimen from Japan (Bell 1882) belongs to a 

 species described by me (1898 a) as Psolus jajmnicuST \^-hich. although it certainly 



