KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 32. N:0 3. 



Surface-plankton. 



In the following account of the plankton, gathered by the Swedish expedition to 

 Spitzbergen in 1898, I distinguish, as nsually, with c coinmon, cc very common, ccc the 

 principal mäss, with -|- neither common nor rare, with r rare, and rr some few specimens 

 only. In case of scarcity of the plankton I enclose the sign by one or two parentheses and 

 where no plankton was found I use 0. 



1. Lindesnäs— Lofoten. 



May 27th to June Ith. 



Temperature varying between 7° and 9°. Salinity 33 — 35 p. m. 

 The plankton is of great uniformity, being a mixture of tripos- and northern neintic 

 plankton (Tjj, iVs). 



The most important species are the following: 



Of triposplankton : Of northern neritic plankton: 



Åcartia Clausii -\-, Acartia longiremis c, 



Microsetella atlantica r, Ceratium tripos var. longipes cc, 



Oithona similis -\-, Peridinium depressuni -\-, 



Evadne Nordmannii c, Coscinodiscus ocidus iridis rr. 



E. spinifera c, 

 Podon intermedius r, 

 Halosphcera viridis r, 

 Ceratium furca -{-, 

 C. fusus -\-, 

 C. tripos r, 



C. trip. v. macroceros c, 

 Rhizosolenia styliformis rr. 



Common to both: 



Calanus finmarchicus -\-, 



Temora longicornis -)-■ 



One sample only (63°13'N 5°15'E.) contained Leptocylindrus danicusm abundance. 



The plankton of this region agrees completely with that of June 1896.^ If com- 

 pared with the plankton of May 1897 in the same region, we mark that the tripos- 

 plankton occurred in 1898 in greater abundance. This corresponds with the lower tem- 

 perature (5,45 — 9,72) and salinity (28,o5 to 34,ii) in the year 1897. 



VBih. till K. Sv. Vet.-Akad. Handl. XXIIl, 2, N:o 4. 



K. Sv. Vet. Akad. Handl. Band 32. N:o 3. 2 



