FRESHWATER DIATOMS 



ERNST OSTRUP. 



THE following notes on tlie freshwater Diatoms of Ihe Færoes 

 are based on the freshwater Algæ material — 135 gatherings, 

 four of which contained Plankton — coUected by Mr. Borgesen, 

 Mr. Jensen, Mr. Ostenfeld and Prof. Warming on the Danish Ex- 

 peditions to the Færoes in 1895 — 1899. 



Placochromaticæ. 



AMPHIPRORA Ehr. 1843. Cl. Syn. I, p. 13. 



1. Amphiprora paludosa W. Sm. var. hyperborea Grun., Cl. & 

 Grun. arc. D. tab. V, fig. 86. 



Plankton from »the mouth of Sandsvatn« ^Sando). 



PLEUROSIGMA W. Sm. 1852. Cl. Syn. I, p. 32. 



2. Pleurosigma angulatum Quekett var. finmarchica Cl., Cl. & 

 Grun. arc. D. tab. III, fig. 67. 



Plankton from the mouth of Sandsvatn« (San do). 



CALONEIS Cl. Syn. I, p. 46. 



3. Caloneis lepidula Grun., V. H. Syn. tab. XIV, fig. 42. 

 Not rare in a gathering from Hojefjæld on Bor do. 



4. C. bacillaris Grun., V. H. Syn. tab. XII, fig. 27. 

 Nolso. 



5. C. fasciata Lgst., Lgst. Spetsb. tab. II, fig. 11, V. H. Syn. 



tab. XII, figs. 31—34. 



Here and there. 



I agree with Cleve (Syn. I p. 50) in including Nav. fonticola, fonti- 

 nalis and Laciinarum under Nav. fasciata Lgst. 



