16 ARKIV FÖR BOTANIK. BAND 14. NIO 9. 



Naviculae Microstigmaticae Cl. 



Stauroneis (Pleurostauron) parvula Grün. var. promi- 

 nula Grun. — Cleve, Syn. Nav. D. I, p. 149. 0str., Danske 

 D. Tab. 2, f. 33. 



Foss.: Ab. Hindersmossen. 



Distr. {fresh or slightly brack, w.): Greenland, Finmark, 

 Gulf of Bothnia, Danmark. 



Stauroneis septentrionalis Grun. Franz-Jos. L. D. Tab. 

 1, f. 48. 



Foss.: Kk. Knjäsha. 



Distr. {mar.): Franz- Josefs land. 



Some minute specimens, only 15 »j. in length and 2 |j- in 

 breadth, with about 18 distinct, smooth, subradiate striae 

 in 10 |J.. 



Navicula (Schizonema) Grevillei Ag. var. apiculata (Ag.) 



— V. H. Syn. Tab. 16, f. 4—8. 



Foss.: Ab. Hindersmossen. 



Valve 24 [x in length, 6 [j. in breadth. 



Though Cleve (Syn. Nav. D. I, p. 153) does not distin- 

 guish this small form from Navicula Grevillei, I think it 

 preferable to do so, as it is notably smaller than the main 

 species, for which Cleve states a length of 30 — 70 [j. arid a 

 breadth of 16 ^^.. Van Heurck's figures of Schizonema api- 

 culatum are equally drawn from very small forms. 



Navicula (Libellus) rhombica Greg. M. J. IK. Tab. 4. 

 f. 16. Cleve, Syn. Nav. D. I, p. 152. 



Foss.: Kk. Knjäsha. 



Distr. {mar.y. Greenland, North Sea, Sumatra, Japan (foss.). 



Navicula Libellus Greg. D. of Clyde, Tab. 14, f. 101. 



— Siin. Navicula rhombica Donk. B. D. Tab. 9, f. 1. 



Foss.: Kk. Knjäsha. 



Distr. {mar.): North Sea; ubiquist, though not recorded 

 from the Arctis. 



Libellus? septentrionalis östr. Mar. D. Öst-Gr0nl., p. 

 439, Tab. 8, f. 97. 



