BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 21. AFD. III. K:0 2. 15 



Frustulia (Ag.) Rabh. (Van Henrckia Bréb.) 



F. rhomboides Bréb. — V. H. XVII, 1. 



Kv. 1, 16, 28, 34, Nu. 5, 17, 18, 19, 37, 41, Jm. 6, 31, 

 Ks. 15, 20, Km. 10, 30, Na. 35, Tj. 42, S.-K. 7, Ol. 43, 47, 

 Ll. 21. — Very frequent. 



Var. crassinervia Bréb. — V. H. XVII, 4. 



Nu. 25, Ks. 20. — Rare. 



Var. amphipleuroides Grun. — A. D. pl. Ill, 59. 

 Ke. 49. — Rare. 



F. ynlgaris Thwaites. — V. H. XVII, 0. 

 Kv. 32, Ke. 49. — Rare. 



Caloiieis Cleve. 



C. Silicnla Ehb. — Nav. limosa KtJTZ., Cl. Syn. Nav. p. 51. 



Var. genuina Cl. 1. c. — V. H. XII, 18. 



Kv. 32, 26, Ke. 49. — Somewhat rare. 



Var. alpina Cl. 1. c. — V. H. XII, 21, Lägst. Spitsb. pl. I, 6. 



Kv. 32, Nu. 2, 18. — Rather rare. 



I have in pl. I f . 9 figured a forna, whieli I tliink Le- 

 longs to this variety, though somewhat difFerent in outline. 

 It is gibbous in the middle and lias slightly clavate ends. 

 It occurs in Kk. 48. 



Var. infläta Grun. — V. H. XII, 20. 



Ke. 49. — Rare. 



Var. ventricosa Donk. — V. H. XII, 24. 



Kv. 26. — Rare. 



Var. Jenisseyensis Grun. — A. D. pl. I, 18, p. 29. 



To this variety I refer the slightly gibbous forms with 

 rounded ends and 21 striae in 0,oi mm., measuring 0,0 3 3 mm. 

 in length, that occur in Kv. 1, 28, Jm. 6, Km. 30, Ll. 21. — 

 Somewhat rare. 



C, bacillaris Grég. — V. H. XII, 27, Cl. 1. c. p. 50. 



A form belonging to this sjiecies occurs in Kv. 1. The 

 valve is 0,023 mm. in length, 0,oo7 mm. in breadth, with 23 



