PHYTOPLANKTON OF LAKES IN THE FÆROES 



BY 



F. BORGESEN AND C. H.OSTENFELD. 



In Borgesen's listofthe Færoese freshwater algæ, and in Østrup's 

 list of the Færoese freshwater diatoms (Botany of the Færoes I) 

 wc see thai somc of the species enumerated in them have been 

 found in plankton-samples gathered by Ostenfeld in 1897. Aller 

 Borgesen had completed his investigations of the freshwater algæ, 

 hc gathered during a boating excursion to Bosdalafos on one of his 

 later journeys, a few plankton-samples, especially from Sorvaags- 

 vatn. Ostenfeld, happening to look through these samples, found 

 that they contained some points of interest, which gave rise lo the 

 idea of publishing jointly, a lisl of Ihe Færoese plankton-algæ ; the 

 co-operation seemed appropriate as Ostenfeld had also taken pari 

 in the investigations of the plankton-algæ gathered by him and enume- 

 rated in Borgesen's above-mentioned list. This also gives ns an 

 opportunity of correcting some of our earlier determinations, and of 

 making some additions to the list of the freshwater algæ as regards 

 the Chlorophgceae , but especially by including the Flagellata and 

 Peridiniaceae which have not hitherto been recorded (excepting Hy- 

 (Iriirus foetidus of the Flagellata which is mentioned in Borgesen's 

 list). With regard to the determinations, Borge sen has deter- 

 mined the Desmids, and Ostenfeld the Diatoms, Flagellata, and 

 Peridiniaceae; the rest of the algæ has been treated by ns jointly. 



The plankton-samples are obtained from the following localities : 

 Oste ro. Store Ejde So, leg. C. H. O, Aug. 22, 1897. Lille Ejde So, 



leg. C. H. O, Aug. 22, 1897. 

 Vaago. Sorvaagsvatn, leg. C. H. O., Aug. 2(>, 1897; Sorvaagsvatn, 



leg. F. B., July 5, 1899; Sorvaagsvatn, leg. F. B., July 5, 1899. 

 Sando. Grothusvatn, leg. C. H. O., Aug. 29, 1897: Sandsvatn, leg. 



C. H. O, Aug. 29, 1897. 

 Sydero. Kvanhaugevatn, leg. F. B., July 9, 1899: Lake in Kvalboejde, 



leg. C. H. ()., July 21, 1897; Vaagsvatn, leg. C. H. ().. July 25, 1897. 



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