82 P. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



( Striae 6 in 0,oi mm P. Thorax Brun. 



' \ — 13 — — P- lignitica Ol. 



( Valve narrow lanceolate P. suhsolaris Geun. 



■ \ — linear 7. 



( Ends subcapitate 8. 



— rounded 12. 



8. |C-^ 



Central area broad P. stauroptera Grun. 



— narrow 9. 



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



i 



( — smaller. L. 0,05 to 0,08 mm 11. 



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



■ \ — — Vs !is broad as the valve P. Tabellaria Ehb. 



( Central area small P. gibba Ehb. 



' \ — — large P. mesogongyla Ehb, 



.,„ j StriiB parallel P. spitsbergensis Cl 



X/S 



i' 



\ — radiate 13. 



Striae 8 to 10 in 0,01 mm P rangoonensis Geun. 



12 in — — P. bogotensis Grun. 



13. \^'^ 



27. P. spitsbergensis Cl. N. Sp. — V. linear, with parallel margins and rounded ends. 

 L. 0,058 to 0,067; B. 0,007 to 0,008 mm. Median line filiform with somewhat distant, bayonet- 

 shaped, terminal fissures. 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 0,0 1 mm., almost parallel. — Pl. I f. 13. 



Eresh vpater: Spitsbergen (Cl. M. D. N:o 159), Jenissey! 



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

 nodule. — Fresh water: Spitsbergen. 



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

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

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

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



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



29. P. gibba (Ehb.?) W. Sm. (1853). — V. linear, gradually tapering from the middle to 

 the subcapitate ends. L. O, os to 0,08; B. 0, 007 to 0,oo8 mm. Median line filiform, with ajoproxi- 

 mate median pores and slightly curved terminal fissures. Axial area narrow, linear, slightly 

 dilated in the middle. Strise 10 to 11 in 0, 01 mm. slightly divergent in the middle and convergent 

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

 P. (jibba W. Sm. b. D. I Pl. XIX f. 180. Nav. Proserpince Pant. III Pl. XVIII f. 260 (1893). 

 Nav. appendiciilata Pant. III Pl. III f. 46 (1893)? 



Eresh water: England (Cornwall)! Scotland (W. Sm.), Ireland (Mourne Mountains)! Austra- 

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



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

 the subcajntate ends. L. 0,o9 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 third of the breadtli 

 of the valve. Strife 9,5 to 10 in 0,01 mm. strongly divei-gent in the middle and convergent at 

 the ends. — Nav. .itatiropfera Grun. Verh. 1860 p. 516. Nav. gibba Donk. B. D. p. 70 Pl. XII 

 f. 3. A. S. Atl. XLV f. 48 to 50. Nav. gibba var. hyalina Hérib. a. Peraq. D. d'Auvergne p. 92 

 Pl. IV f. 14. 



Fre.sh water: Iceland! Sweden! Norway (Stavanger, foss.)! Einland! Holsteiil! Au.stralia 

 (Murray Rivei-, Blue Mountains)! N. America (Caiiada, Massachusetts, New Hampshire, Sierra 

 Nevada)! Brazil! 



