D. 



'et var oprindflig iiiiii liensigt at udgive en forteg- 

 nelse over de iiorsJie synascklier baseret paa vore museums- 

 samlinger. Til iværksættelsen af denne plan gjennemgik 

 jeg universitetsmuseets og Bergens museums synascidiesam- 

 linger, der af bestyrerne velvillig stilledes til min disposition, 

 hvorfor jeg herved frembærer min eriijendtligste tak. 



Kun faa af disse samlingers talrige species var be- 

 stemte og ialmindelighed blot genus. Artsangivelse forekom 

 næsten blot ved prof. M. Sars's type-exemplarer fra hans 

 reise i Lofoten og Finmarken 1849. Hvad der forefandtes 

 bestemt udenfor dette refererede sig til gamle usikre be- 

 skrivelser. Det viste sig derfor snart, at nogen fortegnelse 

 over vore synascidier uddragen af disse samlinger alene 

 ikke lod sig udarbeide, sa a meget mere som materialet knn 

 i de færreste tilfækle tillod nogen revideret bestemmelse i 

 sin daværende forfatning. Synascidierne med sin blode 

 consistens kræver nemlig en meget omhyggelig præparation 

 og nogen saadan var sjelden foretagen, saaat den nødven- 

 dige detaillerede undersøgelse af dyrenes anatomi her ikke 

 lod sig foretage. Ligeledes var farven gaaet tabt uden at 

 være noteret. Denne spiller hos Uere familier en meget 

 fremtrædende rolle. Naar hertil kommer skrumpning og 

 forandringer frembragte ved muskelcontraction i dødsøie- 

 blikket, vil vanskelighederne ved bestemmelsen blive ioine- 

 faldende, især naar man ikke raader over en typesamling 

 til sammenligning. En saadan har jeg derfor først maattet 

 anlægge, hvorved jeg har kunnet undersøgc dem i frisk 

 tilstand og conservere dem paa en passende maade. 8aa- 

 ledes har jeg kunnet bestemme meget af museernes materiale 

 ved at referere disses species til mine egne. 



Den oprindelige j)lan blot at give en fortegnelse over 

 de norske synascidier med beskrivelse af de nye arter har 

 jeg fraveget, for saa vidt som jeg ogsaa har behandlet en- 

 kelte genera mere indgaaende, naar materialet dertil har 

 givet mig anledning. Ialmindelighed har jeg anført de 

 vigtigste karakterer for disse, og hvor der herskede nogen 

 uklarhed i definitionen, en kort begrundelse af slægtens 

 optagelse. 



Den norske Nordhavsexpedition. H. Huitfeldt-Kaas: Synascidiæ. 



I. 



Lt iiad originally been my intention to pul)lisli a list 

 of the Norwegian Synascidiæ, based upon the collections 

 in our museums. In order to carry out this plan, I went 

 through tiie collections of these animals in the University 

 Museum, and the Bergen Museum, these collections being 

 freely placed at my disposal by their respective directors, 

 for whose courtesy in so doing, I would iiere express my 

 most grateful acknowledgements. 



Only a few of the numerous specimens in these col- 

 lections have been determined at all, and most of these 

 only as to genus. Any statement of the species was found, 

 alraost without exception, only in Prof. M. Sars's type- 

 specimens from his journey in Lofoten and Finmark, in 

 1849. Whatever others were determined had reference to 

 old, uncertain descriptions. It was therefore soon evident 

 tiiat it was not possible to prepare a list of our Synascidiæ 

 tåken from these collections alone, tiie more so as, in most 

 cases, the specimens, in their present condition, did not 

 allow of a revised definition. Synascidians, with tiieir soft 

 consistency, require very careful preparation, and this they 

 have rarely received, so that tbe necessary particular exa- 

 mination of the anatomy of the animals was not possible 

 here. The colour had also disappeared without liaving been 

 recorded; and this. in many families, plays a very important 

 l)art. Wiien to this is added the shrinl<ing and changes 

 l)rought about by nniscular contraction at tlie moment of 

 death, the difficulties of determination will be apparent, 

 especially wiien there is no type-collection at one's disposal 

 for comparison. I have therefore first been obliged to 

 make a collection, by means of which I could examine the 

 animals in a fresh condition, and preserve them properly. 

 I have tluis been enabled to determine many of the museum 

 specimens l)y comparison with my own. 



I iiave departed from the original i)lan of only giving 

 a list of tiie Norwegian Synascidians witii descriptions of 

 the new species, in as far as I have also given a more 

 detailed account of some few genera, where the material 

 for so doing has given me the opportunity. Of these I. 

 have generally stated the most important characters, and 

 where any uncertainty in definition was apparent, a short 

 argument for the admission of the genus. 



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