20 ASTRID CLEVE, ON RECENT FRESHWATER DIATOMS. 



rostrate ends. Striae parallel, 15 in 0,oi mm. No isolated 

 puncta. 



Nu. 37. — Rare. 



Tliis little form occurs in moderate abundance in Nu. 37. 



— It seems akin to C. parva. 



C. parva W. Sm. — A. S. X. 14, 15, V. H. II, 14. 



Kv. 34, Ke. 49, Km. 30. — Somewhat rare. 



C. cymbifonnis Ehb. — V. H. II, 11. 



Kv 1, 26. 32, Ks. 15, Ke. 49. — Not rare. 



C. Cistula Hempr. — V. H. II, 12. 



Kv. 32. 34, Nu. 41, Km. 30. Tr. 38, Ll. 21, S.-K. 22. 

 Ke. 49. — Rather frequent. 



Var. luaculata KiiTZ. — V. H. II, 16. 

 Kv. 26, 32. — Somewhat rare. 



f. curta. — V. H. II, 17. 



Kv. 26. — Rare. 

 Var. arctica Lägst. — Spitsb. pl. II, 21, 22. 

 Ll. 21, Kv. 32, Km. 30. — Somewhat rare. 



C. helvetica KtlTZ. — \. H. IL 15. 



Km. 30, Tr. 38, Ke. 49. — Moder ately rare. 



C. aspera Ehb. — V. H. IL 8. C. gastroides KiJTZ. 



Kv. 19, 26, 32, Km. 10. 30. Ks. 15. 20. Nu. 17, S.-K. 22. 



— Rather frequent. 



C. lanceolata Ehb. — V. H. IL 7. 



Ke. 49. — Rare. 



1 have also observed in Nu. 17, 18, a Cymbella, that must 

 be either a sporangial form. or a new species. I give iigure 

 of it in pl. I, 12. The end-nodules are at some distance from 

 the ends; the striae are 12 to 14 in 0,oi mm., the valve is 

 0,04 mm. in length. O, os in breadth. 



Gomphouema Ag. 



a. parvulum KtJTZ. — V. H. XXV, 9, 10, 11, Cl. Syn. Nav. p. 180. 



Kv. 9, 26, 34. Nu. 2, 18, Ks. 20. S.-K. 22, 33, Gl. 43, 

 Gl. D. 44. — Frequent. 



Var. La^enula KtJTZ. — V. H. XXV, 8. 



Jm. 6. — Rare. 



