KONGL. SV. VET. AKADEMIEXS IIANDLINGAR. HANI:) 27. N:<) 3. 17 



Var. leptocephala BriiIB. (1880). — V. lanceolate, with slightly rostrate and obtuse ends. 

 L. 0,025; B. 0,006 mm. Strite 13 in 0,oi mm. — N. leptoceph. Br^b. in Kiitz Herb, accord, to (Truii. 

 V. H. Syn. p. 82 PI. VII f. 1(5. 



Belgium (V. H.). 



Var. Cari EliiB. (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. 



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



Var. angusta Grun. (18B0). — V. linear-lanceolate, obtuse. L. 0,o.t to 0,o65; B. O.oos to 

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

 Verb. 1860 p. 528 PI. V f. 19. N. Cari v. ang. V. H. Syn. PI. VII f. 17. 



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



N. Cari connects iV^. cincta with JSf. 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 tapei'ing from the middle 

 to the subacute ends. L. 0,o45 to 0,09; B. 0,oi2 to 0,oi'.) 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 PI. XVIII f. 171, 173. X. radiosa Grun. Verb. 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. dubruficensis Grun. (1882). — V. broadly lanceolate. L. 0,o72 to 0,o85; B. 0,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 PI. XXX f. 49. ^Y. Bubrav. Pant. Ill PI. XIX f. 281 (1893). 



Fresh water: Hungary, fossil (Grun.). 



Var. subrostrata Cl. — Linear with subrostrate, obtuse ends. L. 0,o8.5; B. O,oii mm. 

 Striee 10 in 0,oi mm. — Pinniil tenuis Greg. M. J. II PI. 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,oo.t to 

 0,006 mm. Striae 15 to 18 in 0,oi mm. — N. tenella Br6b. in Klltz Sp. Alg. p. 74. N. radiosa 

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



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

 mania! Greenland! Argentina! 



Pantocsek describes as N. tenella var.? fossiUs (II p. 54 PI. V f. 91) a form with broad 

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



Var. minutissima Grun. (1882). — 0,oi7 to 0,027; B. 0,oo3.i 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. cryptoeephala v. veneta. 



11. N. gracilis Ehb. (1830). — V. almost linear, obtuse. L. 0,o33 to 0,0.5; 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 PI. XIII f. 2(?) 

 Grun. Verb. 18(i0 p. 526 PI. IV f. 27. V. H. Syn. p. 83 PI. VII f. 7, 8. 



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

 Famatina ! 



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

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



K. ,Sv, Vet. Akad. Handl. Band 27. N:o .-5. 3 



