34 ASTRID CLEVE, ON RECENT FRESHWATER DIATOMS. 



f. elongata. 



Valve elongated, slightly rostrate, O, o 8 to 0,i mm. in 

 length. 



Kv. 34, Nu. 2, S.-K. 'l^l. — Somewhat rare. 



Var. bidens Grun. — V. H. XXXIV, 20—22. 

 Striae 12 in 0,oi mm. Elevations low. 

 Kv. 9, 28, 32, 34, Nu. 3, 5, 11, 14, 17, 18, 25, 37, 39, 41, 

 Ll. 21, Km. 30, Gl. 43. — Frequent. 



Var. bigibba Ktixz. — V. H. XXXIV, '2^. 

 Striae 10 to 12 in 0,oi mm. Elevations high, protracted. 

 Nu. 14, 17, 18, 25, 41, Ll. 21, S.-K. 22, 33, Kv. 32. — 

 Rather frequent. 



Var. laticeps Grun. — V. H. XXXIV, 25. 



Striae 12 in 0,oi mm. 



Kv. 1, 28, 32, Nu. 14, 18, 37, 41, Kk. 48. — Somewhat 

 frequent. 



E. gibbosa Grun. — V. H. XXXV, 13. 



Nu. 17. — Rare. 



Pseudo-Eunotia Grun. 



P. hemicyclus (Ehb.) Grun. — V. H. XXXV, 23. 



Jm. 6. — Rare. 



Ceratoneis Ehb. 



C. arcus (Ehb.) Kutz. — V. H. XXXVII, 7. 



Kv. 9, 32, Nu. 17, 18, Km. 30, Tr. 38, Ke. 49. — Rather 

 frequent. 



Synedra Ehb. 



S. Ulna Ehb. — V. H. XXXVIII, 7. 



Km. 30, Nu. 41. — Somewhat rare. 



Var. amphirhynchus Ehb. — V. H. XXXVIII, 5. 



Kv. 9. — Rare. 



Var. danica KtJTZ. - V. H. XXXVIII, 14. 



Jm. 6. — Rare. 



