- 239 - 



form of which I give a figure (fig. 10) must be the D. cylindricum 

 Imhof 1 ). We have then recorded from the Færoes three forms of 

 Dinobryon, viz. D. divergens Imh. from 

 Vaagö, D. cylindricum Imh. and D. sociale 

 Ehbg. from Strömö. 



In the sample from Velbestad I found 

 when I examined it in living condition in 

 Thorshavn, 3 or 4 colonies of Uroglena 

 vol vox, which has hitherto not been 

 known from the Færoes; also some spe- 

 cimens of Pandorina morum (0. F. Müll.) 

 Bory were seen. 



The four samples from Kirkebörejn do not 

 contain other plant organisms (excepted a few 

 bottom forms of desmids and diatoms) than 

 Peri din i um Wille i and the above men- 

 tioned Dinobryon species; it is an inter- 

 sting fact, which also is evident with regard 



to the samples examined by Mr. Börgesen ir > , 



r J ° rig. 10. Dinobryon cylm- 



and myself, that the plankton from the dricum Imhof. ( 450 /i). 

 Færoese tarns contain but very few 



diatoms — at least in the height of the summer. If we compare the 

 samples from the Færoes with the sample from Iceland treated above, 

 it is striking to see the difference in that point; specially, we miss 

 in the Færoes the numerous chains of Melosirae. In 

 common for both countries we may mention the want of the 

 Myxophyceae; and by this fact the plankton of these countries 

 differs, as mentioned above (p. 235), from that of the lowland lakes 

 of Northern Central Europe, with which it otherwise agrees rather 

 well, much better than with the plankton of the alpine lakes. 



J ) Gfr. Brunnthaler, I., in Verhandl. zool.-bot. Gesellsch. Wien, 1901, 

 p. 299, fig. 2. 



Lern m ermann, E., in Ber. Deutsch. Bot. Gesellsch. 1900, p. 516, 

 Pl. XIX, tigs. 1-5. 



