26 



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

 fjorddy]) udmerker sig ved en stor stabilitet i de fysiske 

 forhold. Temperaturen er 6—7» C. og saltgehalten 35 %o 

 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 G. O. Sårs fundet bnndfaunaen 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 

 indflydelse af de meteorologiske faktorers aarlige variation. 



' I Vestfjordens støi'ste dyb (Tranødybet) tog jeg 16de 

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

 meter 3 eksemplarer af Kinetnf];ius sutittii. Temperaturen 

 var fi.:^)" C. saltgehalten 35.06 " „„, den aarlige forandring er 

 for intet at regne. Kindoskias arhorcscens i Sognefjorden, 

 og smiff/i i Vestfjorden levede saaledes under omtrent de 

 samme hydrogratiske forhold, men det er aabenbart stor 



forskjel paa deres zoogeografiske karakter. Den første 

 er arktisk, og deu maa i Sognefjorden betragtes som en 

 relikt form, mens Kiiiefosk/ås smittii baade af andre og af 

 mig er tåget i en flerhed af eksemplarer i de vestlandske 

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

 i egentlig arktiske farvand, følgelig maa den være boreal 

 og ved sin optræden i Vestfjorden, Tysfjorden etc. betegnes 

 som en sydlig emigrant. Denne betegnelse kan uden tvil 

 ogsaa anvendes paa Bicellar/a ahléri ved dens forekomst 

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

 været, vikle visselig ogsaa denne polyzo have manglet paa 

 dette sted. Deiimod er Hustra ahysKtcola en arktisk og 

 gammel form. sandsynligvis den ældste af de recente flu- 

 straer. 



Den norske i)olyzoverdens 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 articulata, Fabr. 

 Flustra serrulata, Busk. 

 Scliizoporélki hiiqyerta. Michelin. 

 Hij^pothoa expansa, Dawson. 

 Porella acutirostris, Smitt. 



,. perimitiUa, Busk. 

 CelJepora wMteavesi, Norman. 

 Stomatopora penkillata. Fabr. 



diasfoporoides. Norman. 



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

 dig. Idetmindstc én art er dog udeglemt, nemlig CrihriUna 

 sciitulata. Busk. 



many of an arctic form iiaving remained through changing 

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

 depths are remarkalde for a great stability in their phy- 

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

 salinity 35 "/(.„ or a little more. It is then natura! to sup- 

 pose that sucli 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 tlie deep basin of the Vest- 

 fjord, G. 0. Sårs has found the bottom fauna to be essen- 

 tially Southern, vvbile the littoral fauna of tlie same fjord 

 was arctic in character. The gi'eat dependence of the 

 littoral fauna iipoTi the geographical latitude, probably rests 

 upon hydrographical conditions, as the water-stratum from 

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

 the annual variations of the meteorological factors. 



In the Vestf jordas greatest depth (Trana de])tli), on 

 March IGtli, 1899. I caught, when trawliug in a depth of 

 about 600 metres, 3 specimens of Khietusk/((S ,<iiiitti/. The 

 temperature was 6.3** C, the salinity 35.00 "/gg, the annual 

 variation cannot be reckoned as anything. Thus Kine- 

 toskias arborescens in the Sognefjord, and smiitii in the 

 Vestfjord, lived under almost the same hydrographical con- 

 ditions ; but there is evidently a great difference between 

 their zotigeographical characters. The first is arctic, and 

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

 w hile a number of specimens of Kindoskias smittii have 

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

 the Trondhjera 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 BiceVnria 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 al>yssicola is 

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

 recent Fhtstra 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 followiug 

 species from Vanh6flen's list*) (30, p. 233), which have 

 not been found on the Norwegian coast: 



CelJaria urticidata. Fabr. 

 Flustra serrulata, Busk. 

 Schizoporella biaperta, Michelin. 

 Hippothoa expansa, Dawson. 

 Porella acutirostris, Smitt. 



,, perpusilla, Busk. 

 Cellepora wJiiteavesi, Norman. 

 Stomatopora penicillata. Fabr. 



., diastoporoides, Norman. 



*) As far as I am able to judge, this list is very complete, but 

 one species at least, lias been omitted, namely. Cribrilina sm- 

 tidata, Busk. 



