140 p. T. CLEVE, SYXOPSIIS OF THE NAVICULOID DIATOMS. 



central areas indistinct. Strise about 16 in 0,oi mm. the median stronger and more distant, very 

 slightly radiate, at the ends parallel, all finely punctate. — Stauronein Cruciciila W. Sm. B. D. 

 1 p. 60 PI. XIX f. 192. Ldt. Spitsb. D. p. 37 PI. II f. 14. N. cruc. Donk. B. D. p. 44 PI. VI 

 f. 14. V. H. Syn. p. 96 PL X f. 15. Stauroneis dilatata W. Sm. B. 13. 1. c. f. 191? 



Brackish water: Spitsbergen! Baltic! Coasts of the North Sea (Sweden! England! Belgium 

 V. H.), Atlantic coasts of North America! 



Var. obtusata Grun. (1880). — Smaller, broadly lanceolate, with rounded obtuse ends. L. 

 0,025 to 0,05; B. 0,01 to 0,oi6 mm. Striae 17 in 0,oi mm. — Nav. Crude, oar. obt. Geun. A. D. 

 p. 35 PL II f. 37. 



Brackish water: Grun. 



Var. minuta Grun. (1860). — V. broadly lanceolate, with slightly rostrate ends. — L. 0,o2; 

 B. 0,01 mm. Strife 19 in 0,oi mm. — Staur. Crucicula var. minuta Grun. Verb. 1860 p. 567 

 PL VI f. 15. 



Marine: Adriatic (Grun.). 



7. N. gibbula Cl. N. Sp. — V linear, slightly gibbous in the middle, with broad, truncate 

 ends. L. 0,033 to 0,043; B. 0,oo85 to 0,oi mm. Axial area indistinct. Central area very small, 

 rounded. Strise 16 (middle) to 21 (ends) radiate in the middle, where they are of equal length, 

 slightly radiate in the ends, distinctly punctate, puncta (about 22 in 0,oi mm.) forming longi- 

 tudinal rows. — N. gibberula Lagst. Spitsb. U. p. 30 PL I f . 7 (1873). — N. gibbula Icon. n. PL V f. 17. 



Fresh water (moist earth etc.): Spitsbergen! Beeren Eiland (Ldt.). 



Var. oblonga Lagst. (1873). — V. linear not gibbous in the middle. — Nav. gibberula var- 

 oblonga Lagst. 1. c. p. 31. 



Fresh water: Spitsbergen (Lagst.). 



Var. capitata Lagst. (1873). — V. strongly gibbous in the middle, with dilated, rounded 

 truncate ends. — N. gibberula car. capitata Lagst. 1. c. p. 31 PL I f . 7 «'. 



Fresh water: Spitsbergen (Lagst.), Beeren Eiland (Lagst.). 



8. N. Lundstromii Cl. (1880). — V. linear-lanceolate, with subrostrate, broad ends. L. 0,o34 

 to 0,05 1; B. 0,0 11 to 0,013 mm. Median line with the terminal fissures in the same direction. 

 Axial area narrow, slightly dilated around the central nodule. Strife 16 (middle) to 20 (ends) in 

 0,01 mm., radiate throughout, finely punctate, in the middle of equal length. — Cl. A. D. p. 13, 

 36, PL II f. 39. 



Brackish water: Sea of Kara (Jamal)! 



Var. Frieseana Grun. (1879). — V. with broad rostrate-capitate ends, slightly asymmetrical. 

 L. 0,032 to 0,048; B. 0,oi2 to 0,015 mm. Strife 16 to 18 in 0,oi mm. (middle) or 20 to 22 in 0,oi 

 mm. at the ends, in the middle radiate and of eqiial length, at the ends radiate, distinctly punctate, 

 puncta (about 20 in 0,oi mm.) forming undulating longitudinal rows. — Gymbella Frieseana Grun. 

 in Cl. M. D. N:o 261. Icon. n. PL V f. 18. 



Brackish water: Finmark (Tana Elf)! 



9. N. protracta Grun. (1880). — V. linear, with rostrate and truncate ends. L. 0,0 2 2 to 

 0,035; B. 0,008 to 0,01 mm. Axial area very narrow; central very small. Strise 12 (middle) to 20 

 (ends) in 0,oi mm., slightly radiate in the middle, transverse at the ends, coarsely punctate, puncta 

 about 17 in 0,oi mm. — N. Cruc. car.? prot. Grun. A. D. p. 35 PL II f. 38. V. H. Syn. p. 96 

 Suppl. PL B f. 27. Foss. D. Oster. Ung. p. 146 PL XXX f. 47. N. Troglodytes Pant. II p. 54 

 PL XI f. 184 (1889)? 



Brackish water: Salines of the mainland of Europe (Grun.), Belgium (V. H.), Hungary, 

 foss. (Pant.) — Cameroon! 



Var. maxima Cl. — L. 0,o8; B. 0,oi6 mm. Strise about 14 to 15 in 0,oi mm. 

 Fresh water: Rio Purus, Brazil (Deby Coll.)! 



