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



Ar.tificiol Vcij. 



% 



j Keel with decussating rows of puncta .-1. (/igantea Grun. 



■ I — without — — — 2. 



„ ( Keel with double rows of large marginal puncta ^ .... A. Temperei Cl. 



\ — without — — — — 3. 



j Keel not separate from the lower part of the valve 4. 



I — separate — ■ — • — — • 5. 



, ) Valve siliceous A. consjncun Grey. 



) — membranaceous ^1. Duseni Cl. 



^ j Keel and valve separated by a row of puncta A. niarginr punctata Cl. 



\ — — — ■ — ■ — junction-line 6. 



„ I Valve membranaceous 7. 



'• \ — solid 8. 



I Junction-line with several denticulations A. ornatn Bail. 



1 — — one or no — A. paludo.sa W. Sm. 



^ j Margin of the valve crenulated A. cvenulata Temp. 



\ - ~ not - 9. 



„ j Striae of the keel obsolete A. Brchissoniana Grev. 



" t — — distinct 10. 



[ Striae on the keel wider than on the valve A. Kjellnianii Cl. 



10. — — closer — — A. kryophila Cl. 



I • — — and the valve equidistant 11. 



.. ) Keel strongly sigmoid .4. alata Kltz. 



■ \ — slightly — 12. 



.,„ j Striae G in 0,0 1 mm. . •. A. Meneghiniana Grey. 



""■ to 12 — A. lata Grey. 



j Striae b 

 I - 11 



1. A. Paliulosa W. Sm. (IX5;3). — Frustule membranaceous, in the zone-view deeply con- 

 stricted, with rounded to truncate ends. B. 0,o.s to 0,o5 mm. Junction-line sinuose (or not). 

 V. linear-lanceolate, with acute (or apiculate) ends. L. 0,05.5 to 0,i3 mm. Median line strongly 

 sigmoid. Strife 19 to 20 in 0,oi mm., some of them frequently coarser than the others. — W. Sm. 

 B. D. I. p. 44, PI. XXXI f. 2G9. V. H. Syn. p. 121, PI. XXII f. 10. 



Brackish water: North Sea (Sweden! England! Belgium!) Cape May! Barbados! 



Var. hahusiensis Cl. — Frustule strongly constricted. L. 0,08; B. 0,o4 mm. Junction-line not 

 sinuose and not punctate. Strise 22 in 0,oi mm., those on the zone and the basal part of the valve 

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



Marine: Sweden, Fiskebackskil! 



Var. africana Grun. (1879). — Frustule strongly constricted. L. 0,05 to 0,06; B. 0,o;} mm. 

 Junction-line not sinuose and not punctate. Strire 20 in 0,oi mm., those on the keel with coarse 

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



Brackish water: South Africa! 



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

 0,03 mm. Junction-line with a large sinus. Striai 23 in 0,oi mm. — PI. I f. 1. 



Brackish water: Artern, Saxony! 



Var. hyperhorea Grun. (1880). — Frustule slightly constricted in the middle. L. 0,o65 to O.o:; 

 B. 0,035 to 0,036 mm. Junction-line slightly sinuose. Stripe 27 to 28 in 0,oi mm. — A. pal. var.? 

 hyp. Grun. A. D. p. G2. PI. V f. 86. 



Brackish water: Sea of Kara (Grun.). 



Forma miniita Grun. (1884). — L. 0,o35 mm. — A. hyp. f. iiiiu. Grun. Franz Jo.sephs L. D. 

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



Marine: Franz Josephs Land (Grun.). 



