228 



Ernst Østiu p. 



(2) From W. Greeiil. only, and from nowhere else 



in the Arctic districts 10 (5.5 "/o) 



— E. Greenl. -L E. of Greenl. only, and from 



nowhere else in the Arctic districts. . 15 (8.2 °/o) 



— East Arct. S. only, and from nowhere 



else in the Arctic districts 19 (10.4 "/o) 



(3) From W. Greenl. + E. Greenl 53 (29.1 "/o) 



— W. Greenl. + Eastward 90 (49.5 "/o) 



— Eastward on the whole 149 (81.9 ^lo) 



These three percentage tables show, that there is a rise in the 

 percentages as regards the eastern districts, and therefore the Diatoms 

 found in the material at hand indicate an easterly tendency as 

 regards their Arctic distribution. 



As the material examined consists partly of Alga-samples, partly 

 of ice-samples, I have in the following table given an account of 

 the occurrence of the genera in these samples. 



Predominant in 



the Alga-samples 

 are the genera 



ii .4> 



<U -3 



Z -r 





Predominant in t^ u 



1 . o « 



the ice-samnles i- > 



are the genera -^ = 



SI 



In hoth Alga- and 

 ice-samples oc- 

 cur the genera 



ce O. 



< (S 



^ ^"H 



1 Achnanthes .... 



2 Amphipleura. . . 



3 Amphora 



4 Auricula 



5 Biddulphia .... 



6 Campylodiseus . 



7 Cocconeis 



8 Grammatophora 

 y H^'alodiscus. . . . 



10 Licmophora. . . . 



11 Plagiogramma. . 



12 Pleurosigna .... 



13 Podosira 



14 Rhalidonema. . . 



15 Rhoicospenia. . . 



16 Surirella 



17 Synedra 



18 Trachyneis 



19 Tropidoneis . . . . 



6 

 2 

 15 

 1 

 4 

 1 

 9 



Actinocyclus . . 

 Amphiprora . . 

 Rhizosolenia . . 

 Stauroneis . . . . 

 Stephanopyxis 

 Thalassiosira . . 



10 



1 Caloneis 



2 ! Chætoceros . . 

 8 Coscinodiscus 

 4 Diploneis .... 



Fragilaria. . . . 

 Gomphonema 

 Gjrosigma . . . 

 Hantzscliia. . . 



Melosira 



Navicula 



11 I Nitzschia .... 



12 i Pinnularia . . . 



