K0NG1>. SV. Viyr. AKADEMIKNS IIANUI.INOAK. ItAND 27. N:() 3. 



11 



B. 



7. 



8. 



0. 

 10. 

 11. 

 12. 

 13. 

 14. 

 15. 

 16. 

 17. 

 18. 

 li). 

 20. 

 21. 

 22. 

 23. 

 24. 

 25. 

 2(3. 

 27. 

 28. 

 29. 

 30. 

 31. 

 32. 

 33. 

 34. 



Valve with undulate margins iV. Sancti Thomoc Cl. 



— — non — — 7. ' 



Fresh water habitat iV. lucUoviana A. S. 



Marine 8. 



Stria; not reaehiug to the margin iV. subalata Grun. 



— reaching [). 



Ends obtuse 10. 



— acute 14. 



Ends broad, rounded 11. 



— not very broad 12. 



Axial area graduallj' dilated to the middle (V. jmnalinensis Cl. 



— — abruptly — — a central area N. opima Grdn. 



Size small. L. about 0,05 mm 13. 



— large. L. about 0,1 mm N. distnns W. Sm. 



Axial area lanceolate A^. Nicwensis Pek. 



— — abruptly dilated into an orbicular central area N. salva A. S. 



Striae radiate throughout N. Platessa Cl. 



— transverse in the ends 15. 



StriaB crossed by a blank band N. Bricchii Grun. 



— • not — — — iV. Amicorum Grun. 



Striae radiate 17. 



— parallel 82. 



Terminal striae parallel or convergent 18. 



— — radiate 54. 



Terminal stria; ci'ossed by a lunate band N. annulata Grun. 



— — not — — — 19. 



Terminal striie genuflexed N. oblonga KiJTz. 



— — not — 20. 



Striffl crossed by lateral areas or by narrow blank bands 30. 



— not — — — — — — 21. 



Median stride of unequal length 22. 



— — equal — 3(5. 



Valve lanceolate, rostrate-capitate 28. 



— — not — — 23. 



Valve acute 24. 



— obtuse 25. 



Median striae alternately longer and shorter iV. Salinarum v. intermedia. 



— — shorter than the others N. notabilis Pant. 



Striae line, 20 in 0,oi mm N. hottnica Grun. 



— coarse, 8 to 9 mm 26. 



Stria coarsely lineate 27. 



— finely — N. digito-radiata Greg. 



Striae 6 in 0,0 1 mm N. peregrina Ehb. 



— 9 — — N. Reinhardtii Grun. 



Terminal striie strongly convergent iV. WilczeJcii Grun. 



— — parallel 29. 



Length 0,025 to 0,037 mm N. Salinarum Grun. 



— 0,115 mm N. Bho Cl. 



Striae crossed by a lateral area 31. 



— — — two or more blank bauds 34. 



Valve obtuse 32. 



— acute 33. 



Valve linear, with rounded ends N. obtusa Cl. 



— lanceolate iV. Haneri Grun. 



Lateral area unilateral N. Anthracis Br. a. Cl. 



— areas bilateral N. Bruchii Grun. 



Longitudinal bands two on each side 35. 



— — several — N. Tuscula Ehb. 



Conf. iV. basaltw proxima Br. and N. aquitanUe Br. (additional) 



