of Scandinavia, and to iirove tliis it was necessury only to niake sonie casts 

 witli one of Hensen' s »quantitative« plankton nets in varions piaces and coni- 

 ])are tlie weight or volnnie of tlie plankton I i'onnd with that from the opon 

 waters. If tliis gathering took placo from ontside the western moutli of tlie 

 Limfjord, tiirongh the fjord, and ending in the Cattegat, I shonld see also 

 whether the plankton of the Limfjord agreed with that of the Cattegat or with 

 that of the North Sea at this moment, and thus learn whether it had eome hy 

 the cnrrent from the east or from the west. 



The result of such au investigation , undertaken onljoard the guu-hoat 

 »Hauch'< in the days from 22. — 3L October 1896, is seen iu table L The 

 Diutoinaceæ and Feridinieæ are here determined by Mr. H. Gran, whom I 

 thank with all my heart for doing tliis work, a work which I valne so mucli 

 the higlier, as I know that he is one of the greatest authorities on this 

 snbject. The letter r in tlie tables indicates that the organism in qnestion is 

 rare, c that it is common, cc and ccc that it is very common, and -f^ t'bat it 

 is neither rai'e nor common. Mr. (h-an has hitherto used these marks iu this 

 way, but I confess that they are only of a very relative signification ; and here 

 particularly, where the question is of somewliat quautitative determinations 

 of the whole mass of the plankton, other designatious ought to be used in 

 future, which do not speak of »rare« or »common« without further determina- 

 tion and, indeed, without our knowing whether they mean »common« or »rare« 

 in the specimens ivliicli hare heen gafhered or in the rolmne of water in which 

 they have been taken. I could imagine that we, by future investigations of 

 tilis kind, preferred to determine the occurrence of the plankton organisms 

 in the volume of water from which they are taken, only by the weight, in 

 gram, of the plankton, and confiued ourselves, in our work with the specimens, 

 to give information of how great a proportion (in weight or volume) of the 

 whole mass that is gafhered the varions species form ; one species forms abont 

 half of it, one nearly the whole, one c. 74^ oi^^ c. 7ioi oi^c c. Yiool li^re is 

 something, at any rate, in which the thought eau rest, and I should think it 

 is as easy to do so, as it is to nse the present designations. 



For the prelimiuary orientatiou which I here wish to give, the designa- 

 tions used by Mr. Gran may be employed however, whon we remeraber that 

 CC and ccc indicates an occurrence which is perhaps 100, nay 1000 times 

 greater than r. 



As the table shows we made one e.rcursion through the Limfjord in Octo- 

 ber — November 1891), anothcr in April 1897 in the -Sca-eaglc , and finally a 



