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



„„ J Rows of puncta 7 to lU in 0,1 mm M. cribrosa Grun. 



''"■ t - - 14 to 15 - - 21. 



ij., j Loculiferous rim broad M. cocconeiformis Grun. 



~ \ — — narrow M. Horwnthiana Grun. 



I Valve elliptical 23. 



I — lanceolate 24. 



Valve with irregular large puncta M. oamariiensis Cl. 



- close striae M. orata Grun. 



Valve without axial or lateral areas 2;"). 



23. I '"'^ 



24. , 



with — — — 65. 



{ 



Striae crossed by several longitudinal furrows 2fi. 



not — — — — — -- 27. 



Valve elliptic-lanceolate or rhomboid M. qninquecostnta Grun. 



— lanceolate, acuminate M. seriata Ol. 



Puncta in straiglit longitudinal rows, stronger than the transverse 28. 



ransverse rows of puncta stronger than the longitudinal 31. 



25. 1^*"' 

 2(3. <j 



„ J Transverse strise 12 in 0,oi mm M. lineata Ol. a. Grove. 



"I — — 17 to 30 in 0,01 mm 29. 



oil j Loculiferous rim distant from the margin M. acuta Grun. 



' ' \ — — marginal 30. 



.-, I Central area distinct M. arata Cl. 



' \ — — indistinct M. exarata Cl. 



.,. j Valve with longitudinal lines parallel to the median line 



\ — without — — — — — — 



32. 



38. 



„.j I Longitudinal lines combined with the central area 33. 



' \ — — not — - — — 35. 



.,., j Small. L. 0,025 to 0,028 mm M. pnmila Grun. 



I Larger. L. 0,04 to 0,0 9.5 mm 34. 



„. j Loculi about 8 in 0,0 1 mm M. Dehyi Cl. 



' \ — — 5 — — M. Braunii Grun. 



„j. j Longitudinal lines close to the median line 36. 



' ' \ — — distant from — ■ — 37. 



Valve elliptic-lanceolate M. apiculata W. Sm. 



^ . , — linear with cuneate ends M. labuensis Cl. 



'I — broad, elliptical, rostrate M. Citrus Cl. 



( — lanceolate, rostrate M. baltica Grun. 



( Loculi 4 in 0,0 1 mm M. Pisciculns Cl. 



\ — 8 — - M. Peragnlli Cl. 



„„ ( Loculi of equal size 39. 



— — unequal — Gl. 



g„ ( Valve very small. L. 0,oi mm M. gallica W. Sm. 



\ — larger. L. 0,0 2 mm. and more 40. 



..^ i Loculi few 41. 



( — numerous 42. 



... ) Loculi 2 on each side M. capitate Brun. 



I — 4 — — M. exigua Lewis. 



. I Loculiferous rim inside tlie margin M. ixirndnxa Grun. [M. Smithii rar.). 



"' \ — — marginal 43. 



,„ ( Valve constricted in the middle M. coristricta Cl. 



^^- 1 - not - - - 44. 



( Valv 



.J. I Puncta forming almost straight longitudinal rows 46. 



\ - not — — - - — 48. 



.„ ( Median line strongly undulating M. nvdnlafa Grun. 



slightly — or straight 47. 



.„ I Ends rostrate-capitate M. Goesii Cl. 



.. I , .vlve rostrate or apiculate 45 



^*- ^ not - . 51. 



( Median line str( 

 \ — — slig 



Inds rostrate-ct 



— slightly rostrate M. fallax Cl. 



J Median line strongly Hexuose 49. 



• \ — — slightly — 50. 



