14 P. T. CLEVE, SYNOPSIS OF THE NAVICULOIH DIATOMS. 



Äriificml key. 



\ Keel with decussating rows uf puni^ta A. gigantea Gbus. 



I — witliout — — — ■ 2. 



„ I Keel with double rows of large marginal puncta .4. Temperei Cl. 



\ — without — — — — 3. 



( Keel not separate from the lower part of tlie valve 4. 



1 — separate — — — — • 5. 



, j Valve silieeous A. conspicua Geev. 



) — niembranaceous .4. Duseni Cl. 



^ f Keel and valve separated by a row uf puncta ^4. marginc ptmctata Cl. 



\ — — — — — junetion-line 6. 



P ) Valve niembranaceous 7. 



■ \ — solid 8. 



I Junetion-line with several dentieulations .4. ornata Bail. 



' \ — — one or no — A. paludosa W. Sm. 



o I Margin of the valve crenulated .4. crcnnlata Temp. 



'- \ - ~- not - 9. 



(, ) Striae o£ the keel obsolete A. Brebissoniana Grev. 



"I — — distinct 10. 



f Stria; on the keel wider than on the valve ^4. Kjelhnanii Cl. 



10. I — — doser — — A. krynphila Cl. 



\ — — and the valve ;equidistant 11. 



_,.. ) Keel strongly sigmoid -4. alata Kutz. 



■ \ — slightly — 12. 



.,„ I Stris 6 in 0,0 1 mm A. Meneghiniana Grev. 



\ — 11 to 12 — -4. lata Grev. 



1. A. Paliulo.sa W. Sm. (1X53). — Frustule membranaceous, in the zone-view deeply con- 

 stricted, with roniided to trnncate ends. B. O, o 3 to 0,o.'> mm. Junetion-line sinuose (or not). 

 V. linear-lanceolate, with acnte (or apiculate) ends. L. 0, 05 5 to 0, 13 mm. Median line strongh' 

 sigmoid. Striee 19 to 20 in 0, 01 mm., some of them freqnently coarser than the otliers. — AV. Sm. 

 B. D. I. p. 44, Pl. XXXI f. 2(39. V. H. Syn. p. 121, Pl. XXII f. 10. 



Brackish water: Xorth Sea (Sweden! England! Belginm!) Cape May! Barbados! 



Var. hahitsiensis Cl. — Frustule strongly constricted. L. O, os; B. 0, 04 mm. Junetion-line not 

 sinitose and not punctate. StritB 22 in 0, 01 mm., those on the zone and the basal part of the valve 

 more marked. Strite of the keel faint, ending at the median line in very small puncta. 



Marine: Sweden, Fiskebäckskil! 



Var. africana (tRUN. (1879). — Frustule strongly constricted. L. 0,o.t to O.oe; B. 0, 03 mm. 

 Junetion-line not sinuose and not punctate. Strite 20 in 0,ui ram., those on the keel witli coarse 

 puncta. — A. pal. v. afr. Grun. in Cl. M. D. N:o 196. 



Brackish water: South Africa! 



Var. snhsalina Cl. — Frustule very thin. strongly constricted in the middle. L. 0,04 : B. 

 0,03 mm. Junetion-line with a large sinus. Strite 23 in 0, 01 mm. — Pl. 1 f. 1. 



Brackish water: Artern, Saxony! 



Var. hyperborea Grun. (1880). — Frustule slightly constricted in the middle. L. O.oe 5 to 0,0 7; 

 B. 0,035 to 0,036 mm. Junetion-line slightl}^ sinuose. Stritf 27 to 28 in O.oi mm. — A. pal. var.? 

 hyp. Grun. A. D. p. Q-2. Pl. V f. 8(1. 



Brackish water: Sea of Kära (Grun.). 



Forma minuta Grun. (1884). — L. 0, 03.') mm. — .1. Jnip. f. min. Grun. Franz Josephs L. D. 

 p. 54 (106), Pl. I f. 51. 



Marine: Franz Josephs Land (Grun.). 



