During the expedition of the Vega Mr. Kjelhnan collected a 

 number of samples containing diatoms, which with the per- 

 mission of Prof. Nordenskiold were delivered to me for exami- 

 nation. 



The gatherings were the following: 



1. Five bottles with diatoms collected on the ice near 

 Cape Wankarema. 



2. Diatoms washed from alga3, collected near Pitlekaj, 

 Cape Deschnew (East Cape). 



3. Surface diatoms from the Behring Sea. 



4. Fresh-water diatoms from Japan. 



5. Diatoms from algae collected on the Island of Labuan 

 near Borneo. 



6. Diatoms washed from algae collected near Point de 

 Galle, Ceylon, and coarse bottom-mud, dredged in the same 

 locality. 



7. Mud from the bottom between Aden and Bab-el-Mandeb. 

 Besides there w^ere taken several samples of mud from 



the bottom of the North Siberian sea, which all proved free 

 from diatoms. 



For the examination of several of these samples, sufficiently 

 clean slides could not be prepared by the usual cleaning pro- 

 cess, so that the specimens must be selected and mounted. 

 In this difficult work I had the good fortune to be helped by 

 the german microscopist Mr. Weissflog, who prepared for 

 me, with the most exquisite skill, slides containing diatoms 

 from Labuan, Ceylon and Bab-el-Mandeb. For this consider- 

 able assistance, without which I should hardlv have found 

 so many species, I render him my best thanks. 



I. Diatoms of the Arctic Sea. 



The first notices about the diatoms of the Arctic Sea 

 have been given in 1841 by Ehrenberg, who examined some 



