



27 



Diastopora maeandrina, Wood. 

 Bowerbankia arctica, Busk. 

 Buskia nitens, Alder. 



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

 tegnelsen. Størsteparten af de ovenfor anførte arter er 

 heller ikke observeret ved Spitsbergen eller i Karahavet. 



Af de 7 arktiske former, som forekommer ved Queen 

 Charlotte Islands men ikke ved britiske kyster er den kun 

 én nemlig Cellaria articulata, som endnu ikke er indlemmet 

 i vor fauna. De øvrige 6 (Flustra membranaco-trancata, 

 Membranipora ardica, Myriozoum coarctatum, Bhamphosto- 

 mella plicata, Céllepora incrassata, Eetepora elongata) er 

 vel kjendte fra vor arktiske region. 



Da jeg sommeren 1894 udenfor Nordkvn i Finmarken 

 tog op en Laminaria hyperborea, som fra granden til 

 toppen (70 cm.) var tæt besat med Gemellaria loricata i 

 yppig vekst, blev jeg slaaet over denne tydelige tilkjende- 

 givelse af livskraft. Paa min reise forleden vinter havde 

 jeg anledning til at skrabe noget i trange dg 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 

 almindelige indtryk, at arktiske dyr i regelen er kraftige 

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

 legenhed i størrelse og ud vikling i det hele tåget fremfor 

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

 udtaler ogsaa om polyzoerne: „Sie fehlen nirgends vollig, 

 sind aber in den Tropen und den grossen Tiefen sparsamer, 

 dagegen in den kålteren gemåssigten Zonen am håufigsten 

 nåchstdem in den polaren Zonen am besten entwickelt". 

 Hvad kan granden være hertil? Jeg tror, at polyzoernes 

 rige udvivling i cle 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 lindes suspen deret i våndet**). Heraf synes at frem- 



*) 



Die niedere Tierwolt des antarktischen Ufergebietes. 

 Yed en enkelt anledning har jeg seet individerne i en polyzo- 

 koloni foretage bevægelser, som jeg opfattede som spisning. 

 Paa ruderne i et af akvarierne ved den biologiske station 

 havde nemlig fæstet sig kolonier af Membranipora membranacea, 

 ndentvil grundlagt af larver, som var indkomne med led- 

 ningsvandet. Jeg kunde da tydeligt se, hvorledes polypiderne 

 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 tillige 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 (Cucumaria frondosa) foretage 

 tentakelbevægelser, som ganske sikkert havde med ernæringen 

 at gjøre. Hos Cucumaria blev ikke hele tentakelkrans en trukket 

 ind samtidig, men hver enkelt af hovedgrenene blev afvekslende 

 puttet ind i munden. 



Diastopora maeandrina, Wood. 

 Bowerbankia 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 been observed in Spitsbergen 

 or the Kara Sea. 



Of the 7 arctic forms that occur in Queen Charlotte 

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

 only one, namely Cellaria articulata, that has not yet been 

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

 branaceo-truncata, Membranipora arctica, Myriozoum coarc- 

 tatum, Bhamphostomella plicata, Céllepora incrassata, Bete- 

 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 hyperborea that was covered 

 from top to bottom (70 cm.) with a luxuriant growth of 

 Gemellaria loricata, I was struck with this clear evidence 

 of vital force. During my expedition last winter, 1 had 

 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 strengthens the general impression that 

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

 words, arctic forms on the whole, exhibit 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 grossen Tiefen sparsamer, dagegen in den kålteren 

 gemåssigten Zonen am håufigsten nåchstdem in den polaren 

 Zonen am besten entwickelt". What can be the reason 

 of this? I 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 fixed 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 niedere Tiervelt des antarktischen Ufergebietes. 

 On one occasion I have seen the individuals in a colony of 

 Polyzoa going through movements which I took to be eating. 

 Colonies of Membranipora 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 incessantly 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- 

 ment, but I have no doubt whatever that in this way a 

 supply of nourishment was also taken 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 (Cucumaria frondosa) making tentacular movements 

 which were certainly connected with feeding. In Cucumaria 

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

 each of the main branches was put into the mouth in turn. 



4* 



11 



