During the expedition of the Vega Mr. Kjellman collected a 
number of samples containing diatoms, which with the per- 
mission of Prof. Nordenskiöld 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 alge, collected near Pitlekaj, 
Cape Deschnew (East Cape). 
3. Surface diatoms from the Behring Sea. 
4. Fresh-water diatoms from Japan. 
3. Diatoms from alge collected on the Island of Labuan 
near Borneo. 
6. Diatoms washed from alge 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 were 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 hardly 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 
