84 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



area narrow, widened in the middle to a broad, transverse fascia. Striae 12 in 0,oi mm. strongly 

 divergent in the middle and convergent at the ends. — Nav. bogotensis A. S. Atl. XLIV f. 30 to 32. 

 Fresh water: New Grenada (Atl.), French Pond, Maine (Atl.). 



35. P. subsolaris Geun. (1882). — V. linear-lanceolate, with obtuse ends. L. 0,o65 to0,07; 

 B. 0,0 1 to 0,0 14 mm. Median line with bayonet-shaped terminal fissures. Axial area narrow, 

 widened in the middle to a large suborbicular space. Strise 10 to 11 in 0,oi mm. strongly diver- 

 gent in the middle and convergent at the ends. — Nav. decurrens? A. S. Atl. XLV f. 29, 30. 

 Nav. Legumen vix undulata V. H. Syn. PI. VI f. 17. Nav. (deccurrens Ehb. var.?) subsolaris 

 Grun. Foss. D. Oster. Ung. p. 143. Nav. scythica Pant. Ill PL XXIII f. 335 (1893). 



Fresh water: Norway (Stavanger, foss.)! Scotland! Hungary (Dubravica Dept. Grun.), New 

 Zealand! Canada! Dana's Pond (Grun.), Demerara River! 



Var. brevistriata Gbun. (1882). — Area broader. Striae less radiate. — Nav. subs. var. br. 

 Foss. D. Osterr. Ung. p. 143 PI. XXX f. 38. 



Fresh water: Hungary (Dubravica Dept. Grun.). 



Var. australiensis Cl. — L. 0,o96; B. 0,oi2 mm. Striae 14 in 0,oi mm. 



Fresh water: Rieva Lagoons, Australian Alps! 



Var. linearis Cl. — V. linear, with parallel margins and broad, subtruncate ends. L. 0,12; 

 B. 0,017 mm. Striae 10 in 0,oi mm. 



Fresh water: Finland (Lojo)! Rangoon! New Zealand! 



36. P. Tabellaria Ehb. (1843). — V. slender, gibbous in the middle and at the ends. 

 L. 0,1 to 0,2; B. 0,0 15 to 0,02 mm. Median line filiform, slightly oblique, with approximate central 

 pores and bayonet-shaped terminal fissures. Axial area linear, less than '/g as broad as the valve, 

 widened in the middle to an elliptical space. Striae 11 to 14 in 0,oi mm. strongly divergent in 

 the middle, convergent at the ends. — Am. p. 134 PI. II: 1 f. 26. M. G. II: 3 f. 6. Nav Tab. 

 A. S. Atl. XLIII f. 4. 



Fresh water: N. America (Cherryfield, "Waltham Mass., Bemis Lake, White Mountains, 

 Crane Pond) S. America, Brazil, Caldas! South Africa, Ombika (Brun Coll.)! 



37. P. meso^ongyla Ehb. (1870). — V. linear, gibbous in the middle and gradually tape- 

 ring to the subcapitate, broad ends. L. 0,o6 to 0,08; B. 0,oi3 mm. Median line filiform, with 

 somewhat approximate central pores and slightly curved terminal fissures. Area narrow, widened 

 in the middle to an orbicular space. Striae 11 in 0,oi mm. strongly divergent in the middle and 

 convergent at the ends. — Ber. 1870 II f. 16. Cl. D. of Finland p. 25 PI. I f. 11. Nav. (without 

 name) A. S. Atl. XLV f. 45. Nav. decurrens Cl. Vega XXXVI f. 20. Nav. gibba V. H. Syn. 

 Suppl. A f. 12. 



Fresh water: Iceland! Scotland, Lock Canmor (Atl.), Finmark! Norway, Dovre! East Cape! 

 Utah (Ehb.). 



Var. interrupta Cl. (1891). — L. 0,o6; B. 0,oi mm. Striae 12 in 0,oi mm. interrupted by 

 a broad, transverse fascia. — Cl. D. of Finland p. 26 PL I f. 10. 

 Fresh water: Finland! 



P. mesogongyla of Ehrenberg comprises several different species, among which are P. no- 

 bilis and P. major. As the forms figured in Ber. 1870 seems to be the same as ours, I have 

 adopted Ehrbnberg's name. Grunow believes this form to be P. decurrens of Ehrenberg, but the 

 latter is too insufiiciently figured to admit of identification. P. decurrens seems to be a form of 

 P. stauroptera. 



38. P. Sillimanorum Ehb. (1843). — V. lanceolate, with la,rge, capitate ends. L. 0,i4 to 

 0,1.5; B. 0,034 to 0,035 mm. Median line filiform with distant median pores and bayonet shaped 

 terminal fissures. Axial area large, dilated around the central nodule, on both sides of which 

 are some rugosities. Striae 10 in 0,oi mm., strongly divergent in the middle, and there alternately 



