1 2 F. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. ~ 



„. I Central area small or iailistiiict N. mnltiscriata Grun. 



' ) — — orbicular — N. maculosa Donk. 



., j Size small. L. 0,015 to 0,04 mm 37. 



\ — large. L. 0,0.5 mm. and more 43. 



„- j StrisB 14 ill 0,oi mm 38. 



\ — 6 to 10 mm ' 40. 



„ I Median strise stronger N. cinda Ehb. 



-^^^ \ - - not 39. 



f Ends obtuse N. Beckii Pant. 



39. < — acute N. ammophila Geun. 



I — subcapitate N. cryptocephala Kutz. 



, J Strise coarsely lineate 41. 



I — apparently smooth 42. 



... j Valve rhomboidal N. Raphoneis Grun. 



\ — elliptic-lanceolate N. Formentera Cl. 



1^-, j Terminal strise strongly marked N. hungarica Grun. 



"I — — not — — N. cosUdata Gkun. 



,„ j Ends protracted 52. 



■ I — not — 44. 



. , I Central area distinct 46. 



\ — — not — 45. 



,. ( Marine habitat N. spuria Cl. 



\ Fresh water — N. radiosa KtJTZ. 



. , j Stria; coarsely lineate 47. 



I — finely — 49. 



,_ ) Marine habitat 48. 



\ Fresh water — N. vulpina KtiTZ. 



, j Valve narrow lanceolate, not very convex N- pinnata Pant. 



— broadly — convex N. fortis Greg. 



,„ J Valve not very convex N. avenacea Breb. 



\ — convex, with conical ends 50. 



,,. j Ends very elevated and compressed N. compressicauda A. S. 



^^- i - not - - - 51. 



.. J Central area small N- cancellata Donk. 



' \ — — large N. Centraster Cl. 



( Ends subrostrate, obtuse N. viridnla KtiTZ. 



^'1 — non-rostrate 53. 



Ends subcapitate N. rhtjnchocephala Ktixz. 



acute N. gotlandica Grun. 



_ , ) Frustule arcuate 55. 



' \ — non — 56. 



j.^ j Strise about 18 in 0,oi mm X. genvflexa KCtz. 



' ' \ — — 10 - — iV. Bolleana Grun. 



,,, I vStrise crossed by lateral areas or blank bands 57. 



^^- \ - not - ■ - - - - 64. 



^^ J Strise crossed by a single, narrow area 58. 



' \ — — — several longitudinal bands 60. 



j-o j Apiculate N. Galea Brun. 



I Non-apiculate 59. 



J. j Axial i)art of tlie valve elevated N . superimposita A. S. 



■^^ ■ i - - - - not - N. Phi Cl. 



. ( Blank lines straight N. arata Grun. 



' \ — undulating 61. 



.^ j Axial area unilateral 62. 



^ — areas bilateral 63. 



.... \ Valve slightly convex N. imperfecta Cl. 



I — very — N. monodon Grun. 



.„ j Valve slightly convex iV. censors A. S. 



' I — very — N. guttata Grun. 



53. I 



