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



^„ ( Valve bioonstricted ... ... 19. 



not — . 20. 



1 Small (L. 0,03 to 0,04 mm.) . S. Legumen Ehb. 



\ Large (L. 0,2 mm.) . . . . . S. Fulmen Btw. 



( Valve fusiform .... .S". Frauenfeldtiana Grun. 



20. I — rhombic-lanceolate . . . ... . . ■ S. acuta W. Sm. 



I — lanceolate or linear-lanceolate .... SI. 



( Large (L. 0,12 to 0.2 mm.) ... . ... S. javanica Geun. 



1 Small (L. less than 0,0 7 mm.) . 22. 



f Striae about 15 in 0,0 1 mm. ... . . . . 8. oblonga Geun. 



\ — fine 23 — . 23. 



s rostrate .... . .... S. parvula Gkun. 



non-rostrate . . . . . S. obtusa Lagst. 

 „ . ( Branches of the stanros parallel 



19. 



21. 

 22. 

 23. 



f End 



2:'! 



1^ — — divergent 



( Freshwater habitat . 



\ Marine ... 

 j)„ J Ends rostrate . . 

 "1 — non-rostrate 

 „_ ) Valve lanceolate, subrostrate 



\ — broadly elliptical . 

 _„ ( Stauros with very divergent branches 



. . S. Sagitta Cl. 



25. 



26. 



.... 27. 

 8. Crucicula Geun. 

 . . . 8. andicola Cl. 

 1.9. Reichardtiana Geun. 



28. 



. 8. Lindigiana Geun. 



\ — — less — — . . . . . . . 8. ovata Geun. 



„n J Median line sigmoid or with the terminal fissures in contrary directions 30. 



' \ — — not sigmoid . . . the same — or indistinct 31. 



., j Median line sigmoid . . N. tumida BKis. 



' \ — — straight ... . .... N. auklandica Gbun 



31 P"^ 



• \ — without — . ... 32. 



32. 



Ends with diaphragms ... . N. inelegans Grove & Stuht. 



— without — . ... 32. 



( Median line flexuose N. plicatula Geujj. 



\ — — straight 33. 



„„ ( Frustule arcuate ■ N. Garkeana Geun. 



'^^^ \ - not 34. 



I Strise very fine (28 to 30 in 0,oi mm.) . 35. 



\ — 15 to 20 in 0,01 mm 37. 



„, ( Zone broad N. Hyalosira Cl. 



' ' ( — narrow 36. 



(Ends acute N. aponina KtJTZ. 



I — rostrate-capitate . N. Bulnheimii Grun. 



Valve linear, obtuse .... .... N. Scopulorum Beeb. 



— — lanceolate . . . 38. 



37. ( — rhombic — . . . 39. 



— elliptic — N. suavis Cl. & Grove. 



— rostrate ... . . . ..... iV. Jimboi Pant. 



„„ ( Zone broad . . N. complanata Grun. 



narrow . . ... . . . N. plicata Donk. 



Frastules in gelatinous tubes . _ . i\^. Grevillei Ao. 



— free 40. 



Obtuse • N. Weissflogii Geun. 



^ Acute or subacute .... . . . . . .41 



■I 



... I Median line reaching to the ends ... ... N. Libellus Geeo. 



\ — — not — — 42. 



.„ ( Terminal fissures indistinct N. rhombica Greg. 



hook-shaped . . N. hamulifera Geun. 



I Terminal fissnr 



1. S.? pellucida Cl. (1883). — V. elliptical, with broad, rounded ends, thin and convex. 

 L. 0,053 to 0,06; B. O.oie to 0,023 mm. Median line with the terminal fissure.s indistinct because 

 the convexity of the valve. Central nodule transversely dilated to a short stauros. Axial area 

 indistinct; central small. Strise 16 to 21 in 0,oi mm. obscure, punctate. 



