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



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

 Pl. XXX f. 39. 



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



VII. Maj öres. 



Artificial key. 

 i Termi 



subcapitate P. Flammula A. S. 



( Strise paral 



\ — radiate 5. 



i Area broad P. maeilenta Ehb. 



.. . Terminal flssures in contrary directions 2. 



— — the same — 3. 



_ I Ends broad, rounded P. Flamm,a A. S. 



„ J Strise parallel or slightly radiate 4 



4 . 



\ — narrow P. secernenda A. S. 



j Band across the striae broad G. 



' \ — — — narrow or indistinct 7. 



„ J Elliptic-lanceolate P. Dactylus Ehb. 



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



_ ) Area very narrow 8. 



\ — moderately broad 9. 



_ ( Strise slightly radiate P conspicua A. S. 



( — strongly — P. oregonica Cl. 



( Valve with uudulate margins P Esox Ehb. 



not undulate 10. 



10. \ ™' 



Ends triangulär P trigonocephala Cl. 



rounded or subcuneate P major KtiTZ. 



50. P. maeilenta (Ehb. 1843) Cl. — V. linear, with broadly obtuse ends. L. 0,n to O,];,] 

 B. 0,0 17 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. Stripe parallel, 8 to 9 in 0,oi ram. crossed by a narrow 

 band. — Ehb. Am. 21 f. 23? M. G. T f. 7; I: s f. 13. Cl. Diat. of Finland p. 24 Pl. "l f. 27. 



Fre-sh water: Sweden (Lake Wenern, Lake Rosslängeii in Kalmar län)! Finland (Nyland, 

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



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

 slightly gibbous middle. L. 0,1?; B. 0,o2i ram. Median line oblique with approximate central 

 pores. Axial area narrow, not dilated around the central nodule. Strife 7 to 8 in 0,oi rara. alraost 

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



Fre.sh water: Laconia U. S. A. (Atl.). 



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

 cuneate, subcapitate ends. L. O, i? to 0,2; B. 0, 02 6 rara. Median line narrow, its centi-al pores 

 approximate. Terminal fissures comma-shaped. Axial area narrow, linear, slightly dilated in the 

 middle. Striai 7 in 0, 01 rara. slightly divergent in the middle and convergent at the ends. Bands 

 not vi.sibie. — Pl. 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,(11',] mm. Median line filiforra, with approximate central pores and serai- 

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

 11 in 0,01 ram. slightly divergent in the middle, elsewhere almost parallel. — Nar conspicua 

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



Fresh water: Demei'ara River! 



