KONGL. SV. VET. AKADEMIENS HANDLINGAE. BAND 27. N:0 3. 91 



( Valvi 



„ . Valve large. L. 0,15 to 0,2 mm . . . P. cardinalis Ehb. 



small L. 0,08 to 0,12 mm 3. 



„ 1 Striae 7 to 7,5 in 0,oi mm . . ... P. (Bstuarii Cl. 



\ — 9 to 12 — — P. isostauron Ghcn. 



Valve giblions in the middle and at the ends . 5. 



not — — — — — — .6. 



Stria) 4,5 to 5 in 0,0-1 mm .... .P. nobilis Ehb. 



7 in 0,01 mm. . . . P. gentilis Donk. 



„ ( Striae parallel or slightly radiate . . 7. 



I — strongly radiate .... . . P. distinguenda Cl. 



Valve with parallel margins . . . . P. streptoraphe Cl. 



convex — .... . ' . . 8. 



Striae 4,5 to 5 in 0,oi mm P. flexuosa Cl. 



6,5 (to 15) in 0,0L mm P. viridis Nitzsch. 



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61. P. viridis Nitzsch (1817). — V. elliptic-linear, with parallel margins, attenuated to- 

 wards tte rounded ends. L. 0,i4 to 0,i7; B. 0,02 to 0,024 mm. Median line complex; terminal 

 fissures comma-shaped. Axial area linear, narrow, about '/j of the breadth of the valve, slightly 

 widened around the central nodule. Striae 6,5 to 7,5 in 0,oi mm. slightly divergent in the middle 

 and convergent at the ends, else almost parallel, crossed by a distinct band, about Vs of the length 

 of the striae. — Bacillaria viridis Nitzsch PI. IV f. 1 to 3. Pinnul. viridis Ehb. Inf. p. 182. Nav. 

 viridis Kt5Tz Bac. p. 97 PL XXX f. 12. A. S. Atl. XLII f. 11 to 14, 19, 21, 22, 23. V. H. Syn. 

 p. 73 PI. V f. 5. Pinnul. medioconstricta Rabh. A. Sachsens N:o 952 (1860). Nav. Gutvinskii Pant. 

 Ill PI. XIV f. 217 (1893)? 



Fresh water: Sweden (Lapland to Skane)! Norway! Finland (Russian Lapland to Ladoga)! 

 Belgium (V. H.), Germany (Franzenbad Dept.)! Hungary (Dubravica Dept. Grun.), Italy (Livorno, 

 Atl.), Australia (Talbot Hiver, Victoria)! New Zealand! America (Illinois, California, Ecuador, 

 Brazil)! 



Var. intermedia Cl. (1891). — V. linear. L. 0,o7 5 to 0,ii; B. 0,oi4 to 0,oi5 mm. Area 

 about V4 of the breadth of the valve. Striae 8 to 9 in 0,oi mm. divergent in the middle, conver- 

 gent at the ends, crossed by a narrow band. — Nav. major A. S. A. Atl. XLII f. 9, 10. Finn, 

 virid. var. int. Cl. D. of Finl. p. 22. Nav. viridis Pant. Ill PI. VII f. 119 (1893)? 



Fresh water: Sweden (Lapland, Smaland)! Finland! Scotland (Atl.), Congo (V. H. Coll.)! 

 Java! Australia (Blue Mountains)! 



Var. commutata Grcn. (1876). — V. linear. L. 0,05 to 0,09; B. 0,oi mm. Area narrow, 

 widened in the middle. Striae 10 to 12 in 0,oi mm. divergent in the middle, convergent at the 

 ends. Bands indistinct. — Pinnul. viridis W. Sm. XVIII f. 163 a'. Nav. commutata Grun. A. S. 

 Atl. XLV f. 35 to 37. Finn. Heufleri Pedicino Ischia PI. II f. 17 (1867). Finn, sudetica Hilsb 

 Rab. A. Eur. N:o 1023 (1861). Nav. decumana Pant. Ill PL XXXV f. 499 (1893)? 



Fresh water: Sweden (Upsala, Rosslangen in Smaland)! Finland (Russian Lapland to La- 

 doga)! England Sm., Scotland (Lock Canmor Atl.), Germany (Harz, Atl.), France (Lac Gerardmer, 

 Vosges)! Tasmania! America (Canada, Waltham Mass., S:ta Rosa Calif., Sierra Nevada, Rio Purus 

 Brazil)! 



Similar to Finn. vir. var. commutata is Finn, ohlongo-linearis Kostowset (Materialy 1888 

 p. 23 PI. XVII f. 5) but this form has wider striae, about 6 in 0,oi mm. 



Var. leptogongyla (Ehb.?) Grdn. (1876). — V. linear with parallel margins, or slightly 

 gibbous in the middle. Ends rounded. L. O.os; B. 0,oi mm. Area narrow, strongly dilated in 

 the middle to a rhomboid-orbicular space. Median line filiform. Terminal fissures semicircular. 

 Striae 10 in 0,oi mm., divergent in the middle, convergent at the ends. — Nav. leptogongyla G-rvs. 

 in A. S. Atl. XLV f. 26 to 28. Nav. Talellaria Donk. B. D. p. 70 PL XII f. 4? 



Slightly brackish water: Eger, Franzenbad foss. ! 



Var. fallax Cl. — L. 0,045 to 0,095; B. 0,oo9 to 0,oi6 mm. Area very narrow. Striae 10 to 

 12 in 0,01 mm., almost parallel, frequently uni- or bilaterally interrupted. — Pinnul. viridis § W. Sm. 



