pr af de paa den norske Nordhavsexpedition 
fundne Asteroidea har været forbunden med ikke faa 
Vanskeligheder. 
Dels har Materialet været ringe, stundom kun | Ex- 
emplar, dels have vi savnet et tilstrækkeligt Sammenlignings- 
material, dels er den derhen hørende Literatur saa over- 
ordentlig spredt 1 fast alle Jordens Tidsskrifter, og endelig 
er Beskrivelsen af mangfoldige Arter ufuldstændig og uden 
at være ledsaget af Tegninger, saa det ikke har været os 
muligt, uagtet al anvendt Møie, at kunne med Sikkerhed 
diagnostisere dem, hvorfor det ogsaa tør hænde, at en eller 
anden af de i denne Afhandling som nye opførte Arter 
falder sammen med enkelte af de saa ufuldstændigt beskrevne 
Arter. Men om saa skulde være Tilfældet, trøste vi os 
med, at den Beskrivelse, vi levere ledsaget af Afbildninger, 
skal for andre Forskere blive en Veiledning til at undgaa 
de Skjær, vi have stødt paa. 
Paa den følgende Side findes Tabeller over de Sta- 
tioners geografiske Beliggenhed, hvilke ere omtalte i Ar- 
beidet over Asterozdea.. 
Bergen, 29de April 1882. 
Den norske Nordhavsexpedition. Danielssen og Koren: Asteroidea. 
he revision of the Asteroidea discovered on the Norweg- 
ian North-Atlantic Expedition, has been atttended with 
no little difficulty. 
Various causes have prevailed, to make it impossible 
for us to diagnose our specimens with certainty; notwith- 
standing our utmost efforts to do so. Our difficulties have 
arisen, partly, from the paucity of material met with; con- 
sisting at times, of only a single specimen; and, partly, 
from the absence of sufficient supply of subjects for compar- 
ison. It also happens, that the literature relating to the 
subject is vastly spread through journals from almost all 
quarters of the globe; and the descriptions contained in 
these, are aften insufficient, from being unaccompanied by 
illustrative drawings. It may consequently occur, that one 
or other of the species presented in this memoir as new, 
may coincide with one or other of these insufficiently de- 
scribed ones. Should this prove to be the case; we comfort 
ourselves with the reflection, that our memoir, accompanied 
as it is, by illustrative drawings, will serve other investi- 
gators as a guide, enabling them to overcome the diffi- 
culties which we have met with in our researches. 
On the two following pages will be found, tables of 
the geographical position of the stations which are referred 
to in our memoir on Asterozdea. 
Bergen 29" April 1882. 
