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



Ärtificial Iceij. 



) Valve elongated, 3 to 6 times longer than broail 2- 



\ — broad, 2 to 3 7. 



f Margins parallel ■.-.... 3. 



2. ■; — convex ^■ 



I — undulating '^^■ 



{ Ends rounded N- bisidcdium Lägst. 



3. I — cimeate jV- anipMgomphus Ehb. 



I — rostrate jV. affine Ehb. 



f Ends rounded A'- Iriclis Ehb. 



A. ■ — subrostrate N. Iridis var. 



I — rostrate-capitate N. 2»-odicctu7n W. Sm. 



I Ends broad, rounded N. affine var. 



( — cnneate ^■ 



, I StriiE slightly oblique N- Hitclicoclrii Ehb. 



\ — strongly N. oblique-striatmn Å. S. 



j L. 0,03 to 0,04 mm jV. dnhium Ehb. 



I L. 0,06 mm ^- dilatatum Ehb. 



■ I L. 0,07 to 0,1 mm N. citreum Å. S. 



( L. 0,16 mm iV. tumescens Geun. 



1. N. bisulcatiim Lägst. (1873). — V. linear, with ronmled endy. L. 0, 04 to 0,u7; B. O.oos 

 to 0,009 mm. Strise 28 to 30 in 0,oi mm., distinctly jnmctate. — Navic. hisulmta Lägst. Spitsb. 

 D. p. 31 Pl. I f. 8. A. S. Atl. XLIX f. 15, 17. N. scita W. Sm. Ann. Mag. n. hist. XIX p. 10, 

 Pl. II f. 4 (1857)? 



Fresli water (alpine regions): Greenland! Spitsbergen! Beeren Eiland (Lägst.)! Dovre. Nor- 

 way! Sweden (Areskutan, Westerbotten etc.) I Finland! Lac Gerardmer (Vosges)! Argentina! 



2. N. affine Ehb. (1843). — V. linear, with rostrate ends. 



Var. loiujiceyis Greg. (1856). — V. small, frequently with nndulating margins. Ends broad, 

 rostrate or rostrate-capitate. L. 0,03; B. 0,oo5 mm. Striffi very fine. — Nea-, longiceps Greg. M. 

 J. IV Pl. I f. 27. 



Fresh water: Greenland! Scotland (Greg.)! 



Var. undulata Grun. (1860). — V. slightly triundnlate, with broad, rounded ends. L. O.or; 

 B. 0,0 13 ram. Strise. 24 in 0,oi mm. — Å^av. aff. var. undulata Grun. Verh. 1860 p. 544. Pl. V 

 f. 6. V. H. Syn. Pl. XIII f. 6. 



Fresh water: Sweden (Cl. M. D. N:o 103), Belgium (V. H.). 



Var. ampliirhynchi(.s Ehb. (1843). — V. with protracted, rostrate-capitate ends. 



Forma minor: L. 0,o4 to 0,o5; B. 0,oo8 to 0,0!3 mm. Strige 25 to 27 in 0,oi mm. 



Fresh water: Sweden (Upsala)! Astralia (Blue Mountains)! 



Forum major: L. 0,09; B. O.m mm. Stripe about 16 in 0, 01 mm. — Nav. affiuis Y^im. Am. 

 III: 1, i. 10 etc. N'av. amphirhijnchus W. Sm. B. D. XVI f. 142. Donk. B. D. p. 34 Pl. V f. 0. 

 A. S. Atl. XLIX f. 27 to 30. Nav. aff. var. ampMrh. Grun. Verh. 1860 Pl. Vf. 5. 11. Nav. Iridis 

 var. amphirh. V. H. Syn. Pl. XIII f. 5. 



Fresli water: Spitsbergen (Lägst.), Beeren Eilaud (Lägst.), Scotland! England! Belgium 

 (V. H.)! Sweden! Finland! New Zealand! 



Var. gennina Cl. — V. with rostrate, less protracted ends. 



Forma minor: L. 0,04.') to 0,o65; B. 0,oo8 to 0,oi3 mm. Strire 22 to 2'.» in (l.oi mm. — 

 Nav. affinis Ehb. Am. 11:2. f. 7; 4 f. 4. Kutz. Bac. XXVIII f. 65. Nav. affinis var. A. S. Atl. 

 XLIX fig. 20 to 23. Nav. bisulcafa var. turgidula Lägst. Spitsb. D. p. 32 Pl. I f. 9. 



Fresh water: Spitsbergen (Lägst.), Lappland! Finland (Tulomian Lappmark)! Italy (Atl.)! 

 Australia (Blue Mountains and Tasmania)! 



