KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 27. N:0 3. 17 



Var. leptocephala Br^b. (1880). — V. lanceolate, with sUghtly rostrate and obtuse ends. 

 L. 0,025; B. 0,006 mm. Striae 13 in 0,oi mm. — N. leptoceph. Br^b. in Ktitz Herb, accord, to Grun. 

 V. H. Syn. p. 82 PI. VII i. 16. 



Belgium (V. H.). 



Var. Cari Ehb. (1838). — V. narrow lanceolate. L. 0,046; B. 0,oo7 mm. Central area 

 distinct, transverse. Striae 17 in 0,oi mm. — N. Cari Ehb. Inf. p. 174. M. G. XII f. 20. V. H. 

 Syn. VII f. 11. 



Presb water: Habichtwalde, fossil (Ehb.), Australia, Daintree River! 



Var. angusta Grun. (1860). — V. linear-lanceolate, obtuse. L. 0,05 to 0,o65; B. 0,oo5 to 

 0,006 mm. Central area distinctly transverse. Striae 12 to 13 in 0,oi mm. — N. angusta Grun. 

 Verh. 1860 p. 528 PL V f. 19. N. Cari v. ang. V. H. Syn. PL Vn f. 17. 



Fresh water: Austrian Alps (Grun.), Vosges (Lac de Gerardmer)! Ecuador! 



N. Cari connects N. cincta with iV. radiosa and might as well be regarded as a variety of 

 the latter, distinguished principally by its somewhat transverse central area. 



10. N. radiosa Kutz (1844). — V. narrow, lanceolate, gradually tapering from the middle 

 to the subacute ends. L. 0,o45 to 0,09; B. 0,oi2 to 0,oi9 mm. Axial area indistinct. Central 

 area very small, rhomboidal. Striae 11 to 12 in 0,oi mm. strongly radiate in the middle and con- 

 vergent at the ends, finely lineate. — Bac. p. 91 PL IV f. 23. Finn, radiosa and P. acuta W. Sm. 

 B. D. p. 56 PL XVIII f 171, 173. N. radiosa Grun. Verh. 1860 p. 526. A. S. Atl. XLVII f. 50 

 to 52. V. H. Syn. p. 83 PI VII f. 20. Finn, acuta Strose Klieken f. 2. 



Fresh water: Spitsbergen (Lagerst.), Sweden! Norway! Finland! England! France! Switzer- 

 land! Saxony! Japan! South Africa! Illinois! Michigan! Brazil! Argentina! Ecuador! 



Var. dubravicensis Grun. (1882). — V. broadly lanceolate. L. 0,072 to 0,085; B. O,oii mm. 

 Striae 13 in 0,oi mm., more distant in the middle, distinctly lineate; lineolae 25 in 0,oi mm. — 

 F. D. Ost. Ung. p. 144 PL XXX f. 49. N. Duhrav. Pant. Ill PL XIX f. 281 (1893). 



Fresh water: Hungary, fossil (Grun.). 



Var. subrostrata Cl. — Linear with subrostrate, obtuse ends. L. 0,o85; B. O,oii mm. 

 Striae 10 in 0,oi mm. — Pinnul tenuis Greg. M. J. II PL IV f. 9 (1854)? 



Fresh water: Crane Pond (N. Am.)! 



Var. tenella Br^b. (1849). — Lanceolate with acute ends. L. 0,o3 to 0,o65; B. 0,oo5 to 

 0,006 mm. Striae 15 to 18 in 0,oi mm. — N. tenella Br^ib. in Klitz Sp. Alg. p. 74. N. radiosa 

 V. ten. V. H. Syn. p, 84 PL VII f. 21, 22. 



Fresh water: Sweden! Finland! Belgium (V. H.), Japan! Australia (Daintree River)! Tas- 

 mania! Greenland! Argentina! 



Pantocsbk describes as N. tenella var.? fossilis (II p. 54 PL V f. 91) a form with broad 

 axial area, which, if the figure be exact, cannot belong to N. radiosa. 



Var. minutissima Grun. (1882). — 0,o)7 to 0,027; B. 0,0035 to 0,oo4 mm. Striae 14 to 19 

 in 0,01 mm. — F. D. Ost. Ung. p. 144. 



Fresh water: Hungary, fossil (Grun.), Rostock, fossil! 



This var. seems rather to belong to N. cryptocephala v. veneta. 



11. N. gracilis Ehb. (1830). — V. almost linear, obtuse. L. 0,033 to 0,05; B. 0,oo65 to 

 0,01 mm. Axial area indistinct; central area distinct, transverse. Striae 11 to 12 in 0,oi mm., in 

 the middle slightly radiate, elsewhere almost parallel. — Ber. 1830 Inf. p. 176 PL XIII f. 2(?) 

 Grun. Verh. 1860 p. 526 PL IV f. 27. V. H. Syn. p. 83 PL VH f. 7, 8. 



Fresh water: Sweden! Finland! Denmark! Normandy! Arctic America! Argentina, Sierra 

 Famatina ! 



Var. schisionemoides V. H. (1880). — Frustules enclosed in unbranched, gelatinous tubes. 

 Central area somewhat smaller. — Colletonema neglectum Thwaites in W. Sm. B. D. II p. 70 PL LVI 



K. Sv. Vet. Akad. Handl. Band 27. N:o 3. 3 



