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



area narrow, widened in tlie middle to a broad, transverse fascia. Strise 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. 

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



35. P. subsolavis G-eun. (1882). — V. linear-lanceolate, with obtuse ends. L. 0,065 to 0,o7; 

 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 suborbicnlar space. Strise 10 to 11 in 0,oi mm. strongly diver- 

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

 Nav. Legmnen vix undulata V. H. Syn. Pl. VI f. 17. Nav. {decciirrens Ehb. var.?) subsolaris 

 Grun. Foss. D. Öster. Ung. p. 143. Nav. scythica Pant. III 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. hrevistriata Grun. (1882). — Area broader. Strise less radiate. — Nav. subs. var. br. 

 Foss. B. Österr. Ung. p. 143 Pl. XXX f. 38. 



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



Var. anstraliensis Cl. — L. 0,096; B. 0, 012 mm. Strise 14 in 0, 01 mm. 



Fresh water: Rieva Lagoons, Australian Alps! 



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

 B. 0,017 mm. Strise 10 in 0, 01 mm. 



Fresh water: Finland (Loj o)! 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 iiliform, slightly oblique, with approximate central 

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

 widened in the middle to an elliptical space. Strise 11 to 14 in 0, 01 mm. strongly divergent in 

 the middle, convergent at the ends. — Am. p. 134 Pl. 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. mesogongyla Ehb. (1870). — V. linear, gibbous in the middle and gradually tape- 

 ring to the subcapitate, broad ends. L. 0,o6 to O, os; 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. StriiB 11 in 0, 01 mm. strongly divergent in the middle and 

 convergent at the ends. — Ber. 1870 II f. 16. Cl. D. of Finland p. 25 Pl. 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! 

 Utali (Ehb.). 



Var. interrupta, Cl. (1891). — L. 0,o6; B. O, ni mm. Strise 12 in 0, 01 mm. interrupted by 

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

 Fresh water: Finland! 



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

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

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

 latter is too insufHciently figured to admit of Identification. P. decurrens seems to be a form of 

 P. stauro]ttn-u,. 



38. P. Silliiiiaiioriim Ehb. (1843). — V. lanceolate, with large, capitate ends. L. 0,i4 to 

 0,1.'^,; H. (),n:t4 to (),o;).'^> 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 riigosities. Strise 10 in 0,oi mm., strongly divergent in the middle, and there alternately 



