17 



eastern Cattegat (tlie light-shiji ol' Fladen) iuto tlie Sound at tlie isle ol' Ilveen, 

 as far as the deep water goes. In the Cattegat it is covered by a dead plank- 

 ton, which howevcr, the fartber south we go, is mixed more and more witb 

 lildsosolenia alata, whose light colonrs resemble those ol' the dead plankton 

 very much. In the Sound, wliere the uppermost 3 fatboms have only a sali- 

 nitj' of 0,83 p. et., not even Ti. aliifa is t'ound in the snrface water, but only 

 in the middle parts (c. 2 p. et.), while the lowest water (3,^;; — 3,.2o p- et.) bas still 

 a rich Ch. horeale plankton. The uppermost 3 fatboms of water liere contaiu, 

 upon the whole, scarcely anj'thing but a few copepoda, and come certainl}' 

 directly from the Baltic Sea. The last column is plankton from Bornholm. It 

 contained perkliniete and of diatomaceæ only Chat. danicum. 



The sea from Sjællands Odde (Schultz's Grund) as far as the Great Belt 

 (Halskov) had very little plankton compared to the rest of the Cattegat. Is 

 this the rule? As 1 have said, the northern and the middle parts of the Catte- 

 gat have the greatest quautities of plankton ; but we cauuot conclude from this 

 that it is so always. The following table III from some weeks later shows, 

 however, nearly the same with respect to the Skager Rack. It was this 

 scarcity which in the autumn 1885 surprised V. Hensen so much that he sup- 

 posed something must be the matter with the filtering power of the nets. Tbere 

 can therefore scarcely be any dotibt that the Skager Rack and its deep fjords, 

 as a rule, have not the quantities of plankton which the Cattegat bas at cer- 

 tain times, whether calculated by surface-units or by cubics of water; the deeper 

 waters of the Skager Rack coutain but very little plankton. Whether the 

 Skager Rack in winter time has a denser plankton than the Cattegat, is not 

 known, but I doubt it very much. 



Table III, from the mouth of July 1897, in the Skager Rack aud the 

 northern Cattegat, shows that Bhkosolenia alata has now become common in 

 the upper water, and that Guinardia flaccida is very common in the bottom 

 water; as to the rest the plankton is uearly as it was in May 1897. 



In order to follow the composition of the plankton in the Limfjord during 

 the whole year aud so fill up the intervals between the 3 excursions described 

 above, we fished plankton the whole winter, while the Station remained at 

 Nykøbing on Mors, from October 189G till April 24th, 1897, with fitting inter- 

 vals. We made use of a Hensen' s »quantitative« bag, and when the Station 

 removed from tliis place, the matter was left in the bauds of a fisberman at 

 Nykøbing. He got an ordinary, small net for »qualitative« use, after it had 

 been proved by experiments that it caught only about 7i of Hensen's net. 

 With this net be has continuod the plankton fishery at the same place at N}'- 



