H^droida. 



I Vaaren 18'jG blev elet raig overdraget at uudersøge 

 Hydroideniaterialet fra Den norske Nordliavsexpedition. og 

 jeg tillader mig herved at frembære min ærbødige Tak til 

 Redaktionskomiteen, de Herrer. Professorerno Moliu og G. 

 0. Sårs, fordi dette interessante Hverv blev mig anbetroet. 



Materialet indeholder 45 Arter, hvoraf 16 er nye for 

 Videnskaben; og deriblandt er tiere Former, hvis Anatomi 

 er af stor Interesse, og som tildels kommer til at have 

 Indvirkning paa Opfatningen af Hydroidernes Systematik. 

 For at faa Anledning til at sætte mig grundig iud i de 

 tidligere kjendte Formers Bygning, og derigjennem sættes 

 istand til at faa et selvstændigt Syn paa Sammenhængen 

 mellem Arterne og paa Grundlaget for Systematiken, har 

 jeg faaet overladt til Undersogelso Hydroidesamlingerne fra 

 Kristiania Universitet og fra Tromso Museum, ligesom jeg 

 ogsaa har gjennemgaaet private Samlinger fra Konservator 

 Appelløf og Kand. Nordguard i Bergen. Jeg tillader mig 

 herved at rette en Tak til de nævnte Herrer og til Sam- 

 lingsbestyrerne Prof. E. Collett i Kristiania og Konservator 

 Sparre-Sdineider i ^'roraso, for den Hjælp de gjennem sit 

 værdifulde Materiale har ydet mig under mit Arbeide med 

 Hydroiderue. Specielt har Samhngen i Kristiania været mig 

 af stor Nytte, da den indbefatter alle de af Prof. J/. og 

 G. 0. Surs fuudne Hydroider og saaledes ogsaa Orginal- 

 exemplarerne for de mange Beskrivelser af nye Arter, som 

 de begge har leveret. Herigjennem er jeg sat istand til, 

 dels paa enkelte Punkter at supplere disse Beskrivelser, og 

 dels at klargjøre Tvivlspørgsmaal, der senere er opstaaede 

 dem angaaeude. 



Mit Materiale har tilsammen omfattet 5 — GOO Exem- 

 plarer af Hydroider, der kau henføres til ca. 150 Arter, og 

 jeg antager, at det representeier saagodtsom alle Norges 

 Hydroider, idet Universitetets Samling indbefatter Arter 

 fra hele Landets Kyststrækning, medens af de tidligere 

 nævnte Specialsamlinger, Apiwllofs er fra Bergenskanteu, 

 Xordf/aards fra Lofoten og Egnen omkring Nordkap og 

 Tromso Museums fra dette Sted. 



Den norske Xiinljiavse-xpeilitinn. Kiistinc Bonnevie: Hydroida. 



Hydroifla. 



In the spring of 1896, I was commissioned to examine 

 the collection of Hydroids from the Norwegian North Athiu- 

 tic Expedition; and I here beg to offer my grateful thanks 

 to the editorial committee. Professors fiolin aud G. O. Sårs, 

 for having entrusted this iuteresting task to me. 



The collection comprises 45 species, of which 16 are 

 new to science; and among them are several forms whose 

 anatomy is of great interest, and whicb will. to some extent, 

 affect the present views with rcgard to the systematisation 

 of hydroids. In order to become thoroughly acquainted 

 with the construction of the forms already known, and thus 

 be enabled to look with an unprejudiced eyc at the affinity 

 between the species, and on the foundation for the .systema- 

 tisation, I obtained permission to examine the collectiuus 

 of hydroids from the Kristiania University and ft-om Tromsø 

 Museum, and I have also gone through the private collec- 

 tions of Curator Appdlnf and Hr. Nordgaard in Bergen. 

 I beg here to tender my tlianks to these gentlemen, and 

 to Prof. P. Collett and Curator SjHirre-Schiudcr, the res- 

 pective directors of the Kristiania and Tromso coUections, 

 for the help they trough their valuable material have given 

 me in my work. The collection in Kristiania, in particu- 

 lar, has been of great use to me. as it comprises all the 

 hydroids found by Professors J/. and G. 0. Sais. and 

 thus the original specimens for the numerous descriptions 

 of new species which they have fui-nished. By this means, 

 I have been enabled, partly to supplement t!u'se descrip- 

 tions in certain points, and partly to elucidate doubtful 

 questions which have subsequently arisen concerning them. 

 The material which I had to work upon contained. in 

 all, between 5UU and 6UU specimens of Hydroids, referrable 

 to about 150 species; and I imagine that it includes repre- 

 sentatives of very nearly all the hydroids of Norway, as 

 the University collection contains hydroids from the entire 

 line of coast, while the previously-mentioned private coUec- 

 tions, Appelløf s and Nordguard's, are respectively from tlie 

 Bergen district and from Lofoten and the region round 

 the North Cape, and tiiat of the Tromso Museum from 

 Tromsø. 



