42 ASTRID CLEVE, ON RECENT FRESHWATER DIATOMS. 



r. Epithemia Zebra KtJTZ. 



o. Eunotia Clevei Grun. 



r. Stephanodiscus astraea Grun. 



o. Melosira arenaria Moore. 



Thiis only 8 of these 22 forms occur at all in Lule Lapp- 

 mark, and only 2 in any abundance. 



If now the flora of the Ancylus-sea be compared witli 

 that of a country enjoying a temperate climate, as for in- 

 stance southern Sweden, and Belgium, of which the diatoma- 

 ceous flora is comparatively well known, the result obtained 

 is as follows: (f = frequent, r — rare, o = absent in Belgium). 



f. Navicula tiiscula Ehb. 



r. Galonets latiuscula KuTZ. 



f. Pleurosigma atte^iuaium W. Sm. 



o. Diploneis domhlittcncnsis GrRUN. 



f. elliptica KtJTZ. 



f. Cocconeis Fediculiis Ehb. 



f. Cymhella aspcra Ehb. 



f. Ehrenhergii KtJTZ. 



f. lanceolata Ehb. 



f. prosfrafa Ralfs. 



o. Gomphonema geminattim Ag. 



f. Ampliora ovalis KtJTZ. 



f. Surirella spiralis KtJTZ. 



f. Cymatopleura elliptica W. Sm. 



f. Campylodiscus hihernicus Ehb. 



f. noricus Ehb. 



f. Epitliemia tiirgida Ktixz. 



r. Hyndmanii W. Sm. 



f. Zebra Kutz. 



o. Eunotia Clevei (tRUN. 



o. Stephanodiscus astraea GtRUN. 



f. Melosira arenaria Moore. 



This list shows that there is a great resemblance between 

 the diatomaceous flora of the Ancylus-sea and that of Belgium. 



Finally, some statistical statements may be permitted, 

 though the percentages will probably be somewhat altered 

 when further investigations have increased the number of 

 diatom-forms known as living in Lapland. 



