KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND 



27. 



n:o 



13 



64. 

 65. 

 66. 

 67. 

 68. 

 69. 

 70. 

 71. 

 73. 

 73. 

 74. 

 75. 

 76. 

 77. 

 78. 

 79. 

 80. 

 81. 

 82. 

 83. 

 84. 

 85. 

 86. 

 87. 

 88. 

 89. 

 90. 

 91. 

 93. 

 93. 



/ Valve rostrate .... .65. 



\ — non — . . . . . 73. 



{Median striae alternately longer and shorter 66. 

 — — not — _ _ _ ... 69. 



/ Striae coarsely lineate 67. 



\ — finely — 68. 



(Central area with stigmas N. dementis Grun. 

 — — without — . N. leptostigma Ehb. 



I Striae aboiit 9 in 0,oi mm N. Qastrum Ehb. 



\ — — 17 — — N. platystoma Ehb. 



I Valve linear .... .... . . . . N. falaisiensis Gedn. 



I — lanceolate to elliptical . . 70. 



{Valve very convex 

 — not — . . . 



{Striae coarsely lineolate . 

 — finely — 



J Central area small 



( — — large ... 



I Median striae alternately longer and shorter 



( Size small. L. O.oa mm 



. N. erucifera Gbun. 



71. 



. N. Placentula Ehb. 



73. 



N. anglica Ralps. 

 . N. dicephala W. Sm. 



76. 



74. 



N. arenariceformis Pant. 



I — larger. L. 0,06 to 0,i mm 75. 



f 3,5 to 4 times longer than broad N. valida Cl. a. Gbun. 



\5to6 — — — — N. Hasta Pant. 



( Central area small or indistinct 77. 



\ — — medium sized or large 80. 



J Ends conical . . . N. inflexa Geeg. 



\ — not — . . 78. 



{Striffi slightly radiate N. arenicola Geun. 

 — strongly — ... 79. 



( Fresh water habitat .... N. lanceolata Kutz. 



\ Marine . N. Solaris Geeg. 



{Striae coarse 5 to 6 in 0,oi mm. . . .81. 



— finer 10 in 0,oi mm N. oviformis Cl. 



( Striae coarsely lineate . . . . . ■ N. pennata A. S. 



\ — finely — . . . . N. consanguinea Cl. 



/ Size small, L. less than 0,03 mm. . ... ... .83. 



\ — larger. L. more — . . . 86. 



{Striae 15 in 0,0 1 mm 84. 

 — 32 to 33 mm. 85. 



{Lineolae forming longitudinal striae . . . . . . . . . . N. mollis W. Sm. 



— not — — — ... . . . N. incerta Grun. 



f Frustules in gelatinous tubes N. corymbosa ka. 



1 — — the interior of algae ... . . ... . . N. nidulans Cl. 



Frnstule arcuate N. sibirica Geun. 



not - .... 87. 



j Frnst 



I Striae crossed by lateral areas or blank bands . . 

 \ — not — — — — — 



{Striae coarsely lineate 

 — finely — 



j Lineolae forming oblique or longitudinal fine striae 



\ — not .... 



f Valve very convex 



97. 



N. 



S. 



\ — not — 



I Valve asymmetrical 



\ — symmetrical ... 



{Frustule arcuate . ... 

 — not — . . 



( Valve linear 



\ — lanceolate or rhomboidal 



Satura A, 

 89. 

 . . 103. 

 .90. 

 91. 

 ... 93. 

 N. Scoliopleura A 

 .... 93. 

 N. Cubitus Be. a. Temp 

 N. Northumbrica Donk. 

 ■ • N. jejuna A. S. 

 94. 



S. 



