M 



82 p. T. CLEVE, SYNOPSIS OF THE NAVICULOIl) DIATOMS.- 



StrisB <j in 0,oi mm P. Thorax Bkun. 



13 — — P. lignitica Oh. 



I Valve narrow lanceolate P. subsolaris Grun. 



{ 



I Central area broad P. stnurnptern Grun. 



Valve large. L. 0,1 to 0,2 mm 10. 



— smaller. L. 0,05 to 0,08 mm 11. 



^ J Axial area very narrow P. luculenta A. S. 



\ — — ''3 as broad as tlie valve P. Tahellaria Ehb. 



I Central area small P. gibhn Ehb. 



' \ — — large P. mesogongyla Ehb. 



^„ j Striffi parallel P. spifsbergensis Cl. 



linear 7. 



_ . Ends subcapitate 8, 



rounded _ 12 



narrow 9 



M 



\ — radiate 13. 



{ 



^., . Striae 8 to 10 in 0,ui mm P. rangoonensis Grun. 



I — 13 in — — P. hogotensis Grun. 



27. P. spitsber^ensis Cl. N. Sp. — V. linear, with parallel margins and ronnded ends. 

 L. 0,058 to 0,007; B. 0,007 to 0,008 mm. Median line filiform with somewhat distant, bayonet- 

 shaped, terminal fissnres. Axial area distinct, less than '/j of the breadth of the valve, linear, 

 slightly widened aronnd the central nodule, or transversely dilated to a fascia. Strise 16 to 17 

 in 0,01 mm., almost parallel. — PI. I f. 13. 



Fresh water: Spitsbergen (Cl. M. D. N:o 159), Jenissey! 



Var. stomatophora Cl. — Central area with a linear marking on each side of the central 

 nodnle. — Fresh water: Spitsbergen. 



28. P. luculenta A. S. (1876). — V. linear, slightly gibbous in tlie middle and at the ends. 

 L. 0,1; B. 0,0 14 mm. Median line filiform, with approximate central pores, and bayonet-shaped 

 terminal fissures. Axial area very narrow; central area small, orbicular. Striai 13 in 0,oi mm. 

 strongly divergent iu the middle and convergent at the ends. — Nav. Incuhnta A. S. Atl. XLIII f. 12. 



Fresh water: Bengal (Kyan-Zoo, Atl.). 



29. P. gibbil (Ehe.?) W. Sm. (18.')3). — V. linear, gradually tapering from the middle to 

 the subcapitate ends. L. O,ori to 0,o8; B. 0,oo7 to 0,oo8 mm. Median line filiform, with approxi- 

 mate median pores and slightly ciirved terminal fissnres. Axial area narrow, linear, slightly 

 dilated in the middle. Striae 10 to 11 in 0,oi mm. slightly divergent in the middle and convergent 

 at the ends, frequently interrupted in the middle. — Stmiroptera gibba Ehb. Am. I: 2 f. 3 (1843)? 

 P. gibba W. Sm. B. D. I PI. XIX f. 180. Nav. Proserpime Pant. Ill PI. XVIII f. 260 (1893). 

 Nav. appendiculata Pant. Ill PI. Ill f. 46 (1893)? 



Fresh water: England (Cornwall)! Scotland (W. Sm.), Ireland (Mourne Mountains)! Ai;stra- 

 lia (Blue Mountains)! N. America (Waterford, Maine)! Brazil (Caldas)! 



30. P. stauroptera Grun. (1860). — V. slender, gradually tapering from the middle to 

 the subcapitate ends. L. 0,oy to 0,12; B. 0,012 to 0,oi3 mm. Median line filiform, with approxi- 

 mate median pores and slightly curved terminal fissures. Area wide, about a thii'd of the breadth 

 of the valve. Stria; 9,5 to 10 in 0,oi mm. strongly divergent in the middle and convergent at 

 the ends. — Nav. stauroptera Grun. Verb. 1860 p. 516. Nav. gibba Donk. B. D. p. 70 PI. XII 

 f. 3. A. S. Atl. XLV f 48 to 50. Nav. gibba var. hyalina H^rib. a. Perag. D. d'Auvergne p. 92 

 PI. IV f. 14. 



Fresh water: Iceland! Sweden! Norway (Stavanger, foss.)! Finland! Holstein! Australia 

 (Murray River, Blue Mountains)! N. America (Canada, Massachusetts, New Hampshire, Sierra 

 Nevada)! Brazil! 



