W hile tlie Biological Station was at work iu tlie Limfjord, at Nykøbing 

 011 Mors, in 1895 and 96, the Plankton was often examiued, and I was aston- 

 ished at the great difference in its appearance at the various times, a differ- 

 ence which was found also by a closer microscopic examinaiion. In both these 

 years I had, in the autuinn, observed an unquestionable immigration of Nodihica 

 together with Filema octopus (Ehizostoma Cuvieri), the latter in large, beauti- 

 ful specimens, and the former so numerous that, when it died and drifted 

 ashore, it would cover the coast with a red coating which looked like tomato- 

 soup. There can be no doubt that the two said organisms had drifted into the 

 fjord from the North Sea (in the Cattegat they are not so common); ordinarily 

 they do not live liere: during tlie whole rest of the year they are not to be 

 found iu the Limfjord. Wheu we see the rapid current which at times, parti- 

 cularly with a westerly wiud, runs through the whole fjord from the west to 

 the east, in some piaces almost like a river, we can easily understand such 

 au immigration ; nor did I doubt that the changes which I found from time to 

 time in the finer plankton, particularly among the Dialoniaceæ, must be ex- 

 plained in the same way, bj' au immigration with the current from the west or 

 from the east. It would be a good thing, however, to prove that this was really 

 the case, and I seized the opportunitj' to do so with so much the gi-eater 

 pleasure, as anothcr question iu which I was interested miglit be solved at the 

 same time. This question concerued the density of the planldon in our fjorde, 

 compared to its density in the Swedish and Norwegian fjords and in our more 

 open waters. By seeing Professor Otto Pettersson carry out some plauktou- 

 gatheriugs in the Gidlmare fjord (later on also while travelling in Norway), I had 

 got the idea that our fjords werc evidently much richer in plankton than those 



