INTRODUCTION. 



Of the zoological collections brought home from the Norwegian North 

 Polar Expedition, those relating to the marine invertebrate animals have been 

 placed in my hands for examination and description, and I now propose to 

 report on the results of my investigations as far as the Crustacea are con- 

 cerned. Indeed, by far the greater number of the animals collected belongs 

 to this extensive class, and there is comparatively little to report of other 

 animals. As, however, all knowledge of the fauna in this far remote, and 

 hitherto unexplored part of the North Polar Sea may be of considerable interest, 

 it is my intention in a subsequent paper also to give a short account of the 

 other marine invertebrates found during the Expedition. 



The collection in question consists of several tubes and bottles from 

 different localities, each, as a rule, labelled with date, depth and mode 

 of preservation. I have carefully gone through the contents of all the 

 samples, in order to gain both a general view of the character of the fauna, 

 and more special information about the several species. Only one of the 

 bottles contained true bottom-animals taken up by the aid of the trawl; all 

 the other samples have been procured by the aid of the tow-net, and of 

 course contain exclusively pelagic animals, chiefly Crustacea. Of these 

 again Copepoda, chiefly belonging to the Calanoid group, are predominant, 

 having been taken in nearly every haul and in considerable numbers along 

 the whole route of the "Fram". This peculiar character of the collections 

 is due to the unexpected physical conditions found in the Polar Sea trav- 

 ersed. As is well known, it has until recently been the general assumption 

 of geographers, that the Polar basin, north of Siberia and Franz Josef Land, 



