KONGL, SV. VKT. AKADEMIENS HANDLINGAH. HANI) 27. N:() 3. 21 



24. N. obliinga Kiixz (1833). — V. linear-lanceolate, with truncate ends. L. 0,07 to 0,2; 

 B. 0,0 14 to 0,024 mm. Axial area very narrow. Central area suborbicular. Stria; 7 to 8 in 0,oi 

 mm., very finely lineate, the median more distant and strongly radiate, the terminal convergent 

 and angularly bent. — Frustulia ohJonga KtJTZ Dec. N:o 71 (accord, to Lagst.). N. ohlonqa Kt'nz 

 Bac. p. 97 PI. IV f. 21. Grun. Verh. 18()0 p. 523. A. S. Atl. XLVII f. 63 to 68. V. H. Syn. 

 p. 81 PI. VII f. 1. Pant. Ill PI. VIII f. 142. Pinmd. oblouc/a W. Sm. B. D. XVIII f. 165. 



Fresh or very slightly brackish water: Sweden! Finland! Saxony! Belgium (V. H.), Eng- 

 land! Switzerland (Brun.), Illinois! Fossil: Dubravica, Hungary (Grun.), Mexico and Guatemala! 



Var. lanceolafa Grun. (1860). — Shorter and broader lanceolate. — Verh. I860 p. 523 

 PL IV f. 25. 



Var. acuminata Grun. (1860). — Almost linear, with cuneate, obtuse ends. — 1. c. 



Fresh water: Austria (Grun.). 



Var. nodulosa Grun. (1860). — As the var. acuminata, but with triundulate margins. — 1. c. 



Fresh water: Frankfurt am Main. 



25. N. falaisiensis Grun. (1880). — V. narrow, lanceolate, with subrostrate, obtuse ends. 

 L. 0,02.5; B. 0,00.5 mm. Axial area indi.stinct. Central area small, rounded. Striae about 20 in 

 0,01 mm., slightly radiate throughout. — V. H. Syn. PI. XIV f. 5. 



Fresh water: Greenland! England (V. H. T.), Belgium (V. H.). 



Var.? Lanceola Grun. (1880). — V. linear with more distinctly rostrate ends. L. 0,o3; 

 B. 0,004 mm. Striae 23 in 0,oi mm. more radiate — V. H. S. PL XIV f. 6 B. 

 -A^ falamens'is is according to Grunow nearly related to N. Bulnheimii. 



26. N. areiiicola Grun. (1882). -- V. linear, frequently slightly gibbous in the middle, 

 with broad, rounded ends. L. 0,02; B. 0,oo5 mm. Axial and central areas indistinct. Striai 13 

 or 14 (middle) to 21 (ends) in 0,oi mm. very finely lineate, slightly radiate throughout. — Amphi- 

 prora arenaria Br^b. in Rab. A. E. N:o 2150. N. arenicola Grun. F. D. Ost. Ung. p. 149 

 PL XXX f. 76, 77. 



Marine (aestuaries) : Coasts of France and England (Grun.). Firth of Tay! 



27. N. dicephala (Ehb. 1836?) W. Sm. (1853). — V. linear to linear-lanceolate with capi- 

 tate-rostrate ends. L. 0,o25 to 0,04; B. 0,oi to 0,oi25 mm. Axial area indistinct. Central area 

 large, transverse and rectangular. Strise 9 to 11 in 0,oi mm. radiate throughout. — Pin. dicej)h. 

 Ehb. Inf. p. 185. Am. 11: i f. 29? N. dicephala W. Sm. B. D. I p. 87 PL XVII f 157. Grun. 

 A. D. p. 34. V. H. Syn. p. 87. PL VIII f. 33, 34. Strose Klieken D. f 4. 



Fresh water: Sweden! England! Saxony! Switzerland (Brun.), Hungary, Dubravica, fossil 

 (Grun.), Kamtchatka! Japan! Illinois! Ecuador! 



Var. elginensis Greg. (1856). — L. 0,024 to 0,o3; B. 0,oi to 0,0105 mm. Strife 12 to 14 in 

 0,01 mm. transverse at the ends. — Pinn. elginensis Greg. M. J. IV PL I f. 33. Grun. A. D. p. 35. 



Fresh water: Scotland, Ben Lawers fossil (Grunow), Finland, Pudasjarvi, fossil! 



Var. suhcapitata Grun. (1882). — V. with broadly truncate ends. — F. D. Ost. Ung. p. 156 

 PL XXX f. 54. 



Fresh water: Hungary, fossil (Grun.). 



N. dicex>hala is very nearly connected with the Cymbellfe, which, besides its great resem- 

 blance to Cym. anglica, is proved by its cell-contents (see A. S. Atl. PL LXXII f. 29 — 33; Grun. 

 F. D. Ost. Ung. XXX f. 55). There is only one chromatophore-plate, in the middle separated 

 by a plasmatic mass from the zone, and on the dorsal side deeply cloven by a linear fissure. 



28. N. laiiceolata (Ag. 1827?) Kutz (1833). — V. lanceolate. L. 0,o3 to 0,05; B. 0,oo8 to 

 0,01 mm. Axial area indistinct. Central area distinct, orbicular. Stria? 12 (middle) to 15 or 16 

 (ends) in 0,o 1 mm., strongly radiate throughout. — Frustulia lanceolata Agardh Flora X p. 626? 



