393 



Öfversigt af Kongl. Vetenskaps-Akademiens Förhandlingar 1900. N:o 4. 



Stockliolm. 



Microscopical examination of dust from drift-ice north 

 of Jan Mayen. 



By P. T. Cleve. 



[Communicated 1900, April 11.] 



During the Swedish Expedition under the direction of Pro- 

 fessor A. G. Nathorst to East Greenland in 1899 Mr. P. 

 DusÉN collected some saraples of dust, that were found on the 

 ice, which drifts with the E. Greenland current. Four such 

 samples, from 72° 30' N. 6° W., collected the 27^"^ of June, all 

 small, were delivered to me for examination. Of these saraples 

 two, labelled 173 and 176, proved very poor in silicious organisms, 

 but two, 174 and 175, very rieh. The last named samples were 

 identical, for which reason I treat of them in the following as 

 one sample. 



The number 173 contained some few specimens of the follow- 

 ing species: 



Fresh water forms: Brackish or marine: 



Caloneis Clevei Lagst. CluMoceros sp. spore. 



Cymhella ventricosa KÜTZ. Coscinodiscus lacustris Grun. 



Diatomella JBalfoureana Grev. Naviculaquadratarea A. S. var. 

 Ennotia proerupta var. curia Stuxbergii Cl. 



Grun. N. suhinßata Grun. 



Navicula gastrum var. Jenis- N. transitans Cl. 



seyensis Grun. Surirella minima Oestr. 

 N. pusilla W. Sm. 



