27 



Diastojjora maeandrina, Wood. 

 Bowerhankia arctica, Busk. 

 Buskia nitens, Alder. 



Disse udgjor omtrent 14 pct. af samtlige arter i for- 

 tegnelsen. Størsteparten af de ovenfor anførte arter er 

 heller ikke oliserveret ved Spitsbergen eller i Karahavet. 



Af de 7 arktiske former, som forekommer ved Queen 

 Charlotte Islands men ikke ved britiske kj'ster er den kun 

 éa nemlig Cellaria niiiculata. som endnu ikke er indlemmet 

 i vor fauna. De øvrige G (Flustra menihranaco-truncata, 

 Me))ilraiiipora arctica, Myriozoum coarctafitm, Wiampliosto- 

 mella pJicata, Cellepora incrassata, Retepora elongata) er 

 vel kjondte fra vor arktiske region. 



Da jeg sommeren 1894 udenfor Nordkyn i Finmarken 

 tog op en Laminaria Jiyperhorea. som fra grunden til 

 toppen (70 cm.) var tæt l)esat med Gemellaria Joricata i 

 yppig vekst, blev jeg slaaet over denne tydelige tilkjende- 

 givelse af livskraft. Paa min reise forleden vinter iiavde 

 jeg anledning til at skrabe noget i trange og strømsterke 

 sund i Finmarken, og det viste sig ogsaa der, at enkelte 

 arter som Gemellaria, Menipea, etc. havde en enestaaende 

 kraftig vekst. Studiet af polyzoerne bekræfter saaledes det 

 almindclige indtryk, at arktiske dyr i regelen er kraftige 

 og velfødde. Med andre ord, arktiske former viser over- 

 legcnhed i størrelse og ud vikl ing i det hele tåget fremfor 

 sin nære slegtninge blandt de boreale dyr. Dr. Pfefler*) 

 udtaler ogsaa om polyzoerne: „Sie fehlen nirgends vdllig, 

 sind aber in den Tropen und den grøssen Tiefen sparsamer, 

 dagegen in den kalteren gemiissigten Zonen am haufigsten 

 nachstdem in den polaren Zonen am be.sten entwickelt". 

 Hvad kan grunden være hertil? Jeg tror, at polyzoernes 

 rige udvivling i de polare have hænger sammen med de 

 selvsamme haves store planktonrigdom. Ifølge sin bygning 

 og sit fastsiddende voksesæt er polyzoerne udelukkende 

 henvist til at leve af plankton eller af organiske rester, 

 som tindes suspenderet i våndet**). Heraf synes at frem- 



*) Die medere Tierwult des antarktischen Ufergebietes. 

 **) Yed en enkelt anledning har jeg seet individerne i en pol\-zo- 

 koloni foretage bevægelse.r, som jeg opfattede som spisning. 

 Paa ruderne i et af akvarierne ved den biologiske station 

 havde nemlig fæstet sig kolonier af Menibranipora inemhranacea, 

 udentvil grundlagt af larver, som var indkomne med led- 

 niugsvandet. Jeg kunde da tydeligt se, hvorledes polypideme 

 uophørligt skjøv sin tentakelkrans sammenlagt i form af et 

 rør ud af mundingen, derpaa sprede kransen ud i tragtform 

 for saa efter en liden stunds forløb at trække den ind. Det 

 er muligt at dette ogsaa var en aandedrætsbevægelse, men at 

 der paa den maade tilMgc skede en tilførsel af næring, synes 

 mig utvilsomt. Egentlig talt kan man neppe tænke sig nogen 

 anden maade at spise paa for disse dyr. I det samme akva- 

 rium har jeg seet en sjøpølse (Cueumaria frondosa) foretage 

 tentakelbevægelser, som ganske sikkert havde med ernæringen 

 at gjøre. Hos Cueumaria blev ikke hele tentakellvransen trukket 

 ind samtidig, men hver enkelt af hovedgrenene blev afvekslende 

 puttet ind i munden. 



Diantopora maeandrina, Wood. 

 Bowerhankia arctica, Busk. 

 Buskia nitens, Alder. 



These amount to about 14 per cent of the total 

 number of species in the list. The greater number of the 

 above-named species have not ])een observed in Spitsbergen 

 or the Kara Sea. 



Of the 7 arctic forms that occur in Queen Charlotte 

 Islands, but not on tiie shores of Great Britain, there is 

 only øne, namely Cellaria articidafa, that has not yct been 

 incorporated in our fauna. The other 6 (Flustra mem- 

 hranaceo-trnncata, Memhranipora arctica, Myriozoum coarc- 

 tatiim, Bliamphostomella plicata, Cellepora incrassata, Rete- 

 pora elongata) are well known from our arctic region. 



In the summer of 1894, when, off Nordkyn in Fin- 

 mark, I drew up a Laminaria hypcrhorea that was covered 

 from top to liottom (70 cm.) witii a luxuriant gi'o\vth of 

 Gemellaria loricata, I was struck with this clear evidence 

 of vital force. During my expedition last vvinter, I bad 

 occasion to dredge a little in narrow channels in Finmark 

 where the current was strong, and it proved that there 

 too, certain species, such as Gemellaria, Menipea. etc. 

 were of an exceptionally strong growth. The study of 

 polyzoans thus strongthens the general impression that 

 arctic animals as a rule are strong aml thriving. In other 

 words, arctic forms on the whole. exhiliit a superiority as 

 to size and development, to their near relations among 

 the boreal animals. Dr. Pfeffer*) also says of polyzoans: 

 „Sie fehlen nirgends vollig, sind aber in den Tropen und 

 den grøssen Tiefen sparsamer, dagegen in den kalteren 

 gemiissigten Zonen am haufigsten nachstdem in den polaren 

 Zonen am besten entwickelt". What can be the reason 

 of this? 1 believe that the luxuriant development of the 

 Polyzoa in the polar sea is connected with the great 

 abundance of plankton in that sea. From their structure 

 and their tixed manner of growth, polyzoans are compelled 

 to live exclusively on plankton or organic remains that 

 are found suspended in the water**). From this it would 



*) Die niedcre Tiervelt des antarktischen Ufergebietes. 

 **) On one occasion I have seen the individuals in a colouy of 

 Polyzoa going through movements which I took to be eating. 

 Colonies of Memhranipora membranacea had fastened them- 

 selves to the glass in one of the aquaria in the biological 

 station, without doubt growing upon larvæ. that had come 

 in with the water-supply. I could distinctly see how the 

 polypides inoessantly pushed out their circlet of tentacles 

 folded together in the form of a tube, and then spread them 

 out in a funnel-shape, only to draw them in again in a little 

 while. It is possible that this was also a respiratory move- 

 meut, but I have no doubt vrhatever that in this way a 

 supply of nourishment was also tåken in. Strictly speaking, 

 it is hardly possible to imagine any other way for these ani- 

 mals to eat. In the same aquarium, I have also seen a sea- 

 cucumber {Cueumaria frondosa) making tentacular movements 

 which were oertainly connected with feeding. In Cueumaria 

 the whole circlet of tentacles was not drawn in at once, but 

 eaeh of the main branches was put into the raouth in tm-n. 



4' 



