Polychæta from Ihe cruises of the 
Danish Research-steamer ‘‘Dana“ 1922 and 23. 
Contribution towards the knowledge 
of the distribution of the Polychæta in Danish waters. 
By 
Hjalmar Ditlevsen. 
Zoological Museum of the Uiiiversity, Copenhageii. 
This paper mainly deals with collections brought home by the 
research-steamer “Dana“ in 1922—23 from Danish waters, that is 
to say from the North Sea, the Skagerrack, the Kattegat, the Belts, 
the Sound and the Baltic. Besides some material taken by the Da¬ 
nish investigation-steamer “Sallingsund“ (now “Japetus Steen- 
strup“) and kindly forwarded to our museum by Dr. Blegvad 
has been withdrawn. Also some species, taken by the author on a 
trip in 1912 with the same steamer and, as the species forwarded 
by Dr. Blegvad, mainly new to our fauna, have been dealt with on 
this occasion. 
I beg also here to express my best thanks for the courtesy shown 
me by the Director of the Danish Biological station, Dr. C. G. J ohs. 
Petersen who was kind enough to invite me to this trip. 
The material at my disposal was for the greater part well pre- 
served and, as it was only a short time after the capture when I 
began the working out, there was generally no difficulty in dealing 
wijh the single species. 
No species with certainty new to science was found but one 
problematic, namely the Glycera sp. with branched giils, taken in 
the northern part of the Sound; not few however were new to the 
Danish fauna. On working out the material it was my aim, regar- 
ding the literature from the later years, to give as far as possible 
a general view of the distribution of the single species in our 
waters, which has, however, proved to be practicable merely in 
outlines, at any rate for the present. 
It has not been possible to learn something certain about the 
behaviour of the different species to the hydrographical lines, viz. 
Darsserort-Gedser and Gniben-Djursland which was not to be ex- 
