26 









de skiftende tider paa de store dyb i vore fjorde. Disse 

 fjorddyb udmerker sig ved en stor stabilitet i de fysiske 

 forhold. Temperaturen er 6 — 7° C. og saltge halten 35 °/ 00 

 eller lidt over. Det ligger da nær at antage, at saadanne 

 forhold ogsaa maa egne sig vel for former af sydlig oprin- 

 delse. Selv saa langt mod nord som i Vestfjordens dyb- 

 bassin har Gr. 0. Sårs fundet bundfaunaen at være væsent- 

 lig sydlig, mens nævnte fjords littoralfauna havde et arktisk 

 præg. Littoralfauna ens større afhængighed af den geogra- 

 fiske bredde bunder sandsynligvis i hydrografiske forhold, 

 idet vandlaget fra — 200 å 250 meter staar under direkte 

 inclfly deise af de meteorologiske faktorers aarlige variation. 



I Vestfjordens største dyb (Tranødybet) tog jeg 16de 

 marts 1899 ved trawling i en dybde af en dybde af ca. 600 

 meter 3 eksemplarer af Kinetoslrias smittii. Temperaturen 

 var 6.3° O., saltgehalten 35.06 °/ 00 , den aarlige forandring er 

 for intet at regne. Kinetoskias arborescens i Sognefjorden, 

 og smittii i Vestfjorden le vede saaledes under omtrent de 

 samme hydrografiske forhold, men det er aabenbart stor 

 forskjel paa deres zoogeografiske karakter. Den første 

 er arktisk, og den maa i Sognefjorden betragtes som en 

 relikt form, mens Kinetoskias smittii baade af andre og af 

 mig er tåget i en flerhed af eksemplarer i de vestlandske 

 fjorde, Trondhjemsfjorden, o. s. v., men den er ikke tåget 

 i egentlig arktiske farvand, følgelig maa den være boreal 

 og ved sin optræden i Vestfjorden, Ty sfj orden etc. betegnes 

 som en sydlig emigrant. Denne betegnelse kan uden tvil 

 ogsaa anvendes paa Bicellaria alderi ved dens forekomst 

 paa St. 315 (74° 53' N. Br.). Havde Golfstrømmen ikke 

 været, vilde visselig ogsaa denne polyzo have manglet paa 

 dette sted. Derimocl er Flustra abyssicola en arktisk og 

 gammel form, sandsynligvis den ældste af de recente flu- 

 straer. 



Den norske polyzoverdens stærkt arktiske karakter 

 giver sig blandt andet tydeligt tilkjende ved sammenligning 

 med Grønlands. At Vanhøffens fortegnelse*) (30, p. 233) 

 har jeg noteret følgende, som endnu ikke er fundne ved 

 norsk kyst: 



Cellaria articidata, Fabr. 

 Flustra serrulata, Busk. 

 Schizoporella biaperta. Michelin. 

 Hippoihoa expansa, Dawson. 

 Porella acutirostris, Smitt. 



? , perpusilla, Busk. 

 Cellepora ivhiteavesi, Norman. 

 Stomatopora penicillata, Fabr. 



„ diastoporoides, Norman. 



*) Denne fortegnelse er, saavidt jeg kan forståa, meget fuldstæn- 

 dig. Idetmindste én art er dog udeglemt, nemlig Cribrilina 



scutulata, Busk. 



many of an arctic form having remained through changing 

 periods in the great depths in our fjords. These fjord- 

 depths are remarkable for a great stability in their phy- 

 sical conditions. The temperature is 6° or 7° C, and the 

 salinity 35 °/ 00 or a little more. It is then natural to sup- 

 pose that such conditions must also be well adapted for 

 forms of southern origin. This, too, has proved to be the 

 case. Even as far north as in the deep basin of the Vest- 

 fjord, G. O. Sars has found the bottom fauna to be essen- 

 tially southern, while the littoral fauna of the same fjord 

 was arctic in character. The great dependence of the 

 littoral fauna upon the geographical latitude, probably rests 

 upon hydrographical conditions, as the water-stratum from 

 to 200 or 250 metres, is under the direct influence of 

 the annual variations of the meteorological factors. 



In the Vestfjords greatest depth (Trano depth), on 

 March 16th, 1899, I caught, when trawling in a depth of 

 about 600 metres, 3 specimens of Kinetoskias smittii. The 

 temperature was 6.3° C, the salinity 35.06 °/ 00 , the annual 

 variation cannot be reckoned as anything. Thus Kine- 

 toskias arborescens in the Sognefjord, and smittii in the 

 Vestfjord, lived under almost the same hydrographical con- 

 ditions; but there is evidently a great difference between 

 their zoogeographical characters. The first is arctic, and 

 in the Sognefjord it must be regarded as a relict iorm; 

 while a number of specimens of Kinetoskias smittii have 

 been found by myself and others in the west-country fjords, 

 the Trondhjem Fjord, etc., but it has not been found in 

 truely arctic waters. It must therefore be boreal, and in 

 its appearance in the Vestfjord, Tysfjord etc., be designated 

 a southern emigrant. This designation may also without 

 doubt be used for BiceUaria alderi, from its occurrence at 

 Station 315 (74° 53' N. Lat,). Had there been no Gulf 

 Stream, this polyzoan would certainly not have been found 

 in this place. On the other hand, Flustra abyssicola is 

 arctic, and an early form, probably the earliest of the 

 recent Flustra species. 



The extremely arctic character of the Norwegian Po- 

 lyzoa is clearly seen, among other things, by a comparison 

 with that of Greenland. I have noted down the following 

 species from Vanhoffen's list*) (30, p. 233), which have 

 not been found on the Norwegian coast: 



Cellaria articulata, Fabr. 

 Flustra serridata, Busk. 

 Schizoporella biaperta, Michelin. 

 Hippothoa expansa, Dawson. 

 Porella acutirostris, Smitt. 



„ perpusilla, Busk. 

 Cellepora whiteavesi, Norman. 

 Stomatopora penicillata, Fabr. 



., diastoporoides, Norman. 



: ) As far as I am able to jndge, this list is very complete, but 

 one species at least, has been omitted, namely, Cribrilina scu- 

 tulata, Busk. 



wmw 



*^*mm 



