88 p. T. OLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



0,01 mm. parallel, convergent at the ends. — Nav. modesta Grun. Foss. U. Oster. Ung. p. 143 

 PI. XXX f. 39. 



Fresh water: Hungary, foss. Grun., Ecuador (Riobamba)! 



VII. Majores. 



Artificial hey. 



Terminal fissures in contrary directions ... ... . . 2. 



— — — the same — . . 3. 



Ends broad, ronnded . ... P. Flamma A. S. 



— snbcapitate P. Flammula A. S. 



Striae parallel or slightly radiate .... 4. 



— radiate 5. 



( Area broad P. macilenta Ehb. 



\ — narrow . . . . P. secernenda A. S. 



{Band across the striae broad 6. 

 — — — narrow or indistinct . . 7. 



I Elliptic-lanceolate P. Dactylus Ehb. 



I Linear with broad, rounded ends . . . P. latevittata Cl. 



{Area very narrow 8. 

 — moderately broad . 9. 



„ J Striae slightly radiate . P. conspicua A. S. 



M 

 H 

 '{ 



— strongly — P. oregonica Cl. 



■ Valve with undulate margins P. Esox Ehb. 



1 Margins not undulate 10. 



..„ f Ends triangular P. trigonoeephala Cl. 



— rounded or subcuneate P. major KtJTZ. 



50. P. macilenta (Ehb. 1843) Cl. — V. linear, with broadly obtuse ends. L. 0,i i to 0,1 5; 

 B. 0,017 to 0,02 mm. Median line broad, oblique, not complex; its central pores approximate and 

 the terminal fissures comma-like. Axial area wide, less than a third of the breadth of the valve, 

 linear, scarcely widened in the middle. Strife parallel, 8 to 9 in 0,oi mm. crossed by a narrow 

 band. — Ehb. Am. 21 f. 23? M. G. I f. 7; I: 3 f. 13. Cl. Diat. of Finland p. 24 PL I f. 27. 



Fresh water: Sweden (Lake Wenern, Lake Rosslangen in Kalmar Ian)! Finland (Nyland, 

 Pudasjarvi)! Hungary (Bory, fossil)! America (Pine spring, Hermico Co, Va, Deby Coll.)! 



51. P. secernenda A. S. (1876). — V. linear, with broadly rounded snbcapitate ends and 

 slightly gibbous middle. L. 0,17; B. 0,o2i mm. Median line oblique with approximate central 

 pores. Axial area narrow, not dilated around the central nodule. Strise 7 to 8 in 0,oi mm. almost 

 parallel. - Nav. sec. A. S. Atl. XLIII f. 13. 



Fresh water: Laconia U. S. A. (Atl.). 



52. P. trigonoeephala Cl. N. Sp. — V. linear, gibbous in the middle and at the broadly 

 cuneate, subcapitate ends. L. 0,i7 to 0,2; B. 0,o2 6 mm. Median line narrow, its central pores 

 approximate. Terminal fissnres comma-shaped. Axial area riarrow, linear, slightly dilated in the 

 middle. Striae 7 in 0,oi mm. slightly divergent in the middle and convergent at the ends. Bands 

 not visible. — PI. I f. 21. 



Fresh water: America (Waltham Mass., Hudson River, Deby Coll., Big Lake S. Calif. 

 Deby Coll.)! 



53. P. conspicua A. S. (1876). — V. linear, gibbous in the middle and at the ends. L. 0,ii 

 to 0,13; B. 0,018 to 0,019 mm. Median line filiform, with approximate central pores and semi- 

 circular terminal fissures. Area very narrow, slightly dilated around the central nodule. Striee 

 11 in 0,01 mm. slightly divergent in the middle, elsewhere almost parallel. — Nav conspicua 

 A. S. Atl. XLIII f. 10, 11. 



Fresh water: Demerara River! 



