592 



With regard to the greater part of the samples, I have been 

 able to give the temperature of the water, and mostly also its 

 salinity, but the latter is nol of any greal interest as regards the 

 area in question. 



1. The Plankton of the Atlantic Ocean, off the Færoes. 



(Tables I— V.) 



In my papers on the plankton of the North Atlantic Ocean of 

 the years 1897, 1898, 1899 I have pointed out the main features of 

 the changes occurring in the plankton of this region. 



Taking the eastern part, which touches the Færoes, more parti- 

 cularly into consideration they may briefly be summed up as fol- 

 lows: — During winter (Dec. — April) a poor Discoplankton 1 oc- 

 curs, consisting mostly of species of Coscinodiscus, intermixed with 

 a great many other species which occur singly; during spring a 

 rich Chætoplankton and frequently a Nit z se hia plankton are 

 met with ; the former is characlerized by the presence of , e. g. 

 Chaetoceras atlanticum and decipiens and the latter by Nitzschia 

 seriata and delicatissima and the small Chaetoceras Schuttii ajf. and 

 pelagicmn. Later in the summer these planktons are succeeded by 

 Scolica plankton, consisting mainly of the species of Ceratium; 

 sometimes the Peridiniaceae are replaced by Rhizosolenia stgliformis 

 and several other species, and a Sty li plankton is produced. To- 

 wards autumn Halosphaera viridis is met with in these associa- 

 tions, and it holds out beyond autumn, and after the other forms 

 have disappeared it occurs as a Sphæraplankton which during 

 the winter occurs together with the Discoplankton or is replaced 

 by it. Sometimes during the summer a boreal association of Peri- 

 diniaceæ, viz. Longipesplankton occurs in the area between the 

 Færoes and Iceland. 



In what follows we shall see how the plankton of the Færoes 

 harmonizes with the developing process in the open ocean sketched 

 above. 



1897, Table I. During March — April Coscinodiscus is the most 

 common form, i. e. Discoplankton. Thcn comes in Mav Chaeto- 

 ceras decipiens and Nitzschia seriata, i. e. Chæto- and Nilzsehia- 

 plankton. In the samples of July — August there is a greal diffe- 

 rence between the poor sample (No. 5) taken off Syden") in which 



1 A closer characteristic of the different plankton-associations mav be had in 

 the above-mentioned works by Cleve, by Gran and by the author of this paper. 



