M 



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



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



„ J Striae 7 to 7,5 in 0,oi mm P. astuarii Cl. 



1 — 9 to 12 — — P. isostauron Ghdn. 



. / Valve gibbous in the middle and at the ends 5. 



■ \ — not — — — — — — 6. 



^ I Stria) 4,5 to 5 in 0,01 mm P. nobilis Ehb. 



^- { - 7 



„ I Strise parallel or slightly radiate 7. 



b. ' 



in 0,01 mm P. gentilis Donk. 



i' 



\ — strongly radiate P. distinguencla Cl. 



_ j Valve with parallel margins P. streptoraphe Cl. 



( — — convex — 8. 



„ I Strise 4,5 to 5 in 0,01 mm P. flexuosa Cl. 



I — 6,5 (to 15) in 0,01 mm P. viridis Nitzsch. 



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

 wards the 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 '/, of ^^^ breadth of the valve, slightly 

 widened around the central nodule. Strise 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 '/s of the length 

 of the strise. — Bucillaria viridis Nitzsch Pl. IV f. 1 to 3. Finnul. viridis Ehb. Inf. p. 182. Nav. 

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

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

 III Pl. XIV f. 217 (1893)? 



Fresh water: Sweden (Lapland to Skåne)! Norway! Finland (Rnssian 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. 0,075 to 0, 11; B. 0,oi4 to 0,oi5 mm. Area 

 about V4 of the breadth of the valve. Striee 8 to 9 in 0, 01 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. III Pl. VII f. 119 (1893)? 



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

 Java! Australia (Blue Mountains)! 



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

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

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

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

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



Fresh water: Sweden (Upsala, Hosslängen in Småland)! 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. comniutata is Finn. ohlongo-linearis Kostowsky (Materialy 1888 

 p. 23 Pl. XVII f. 5) but this form has wider strige, about 6 in 0, 01 mm. 



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

 gibbous in the middle. Ends rounded. L. O, os; B. 0, 01 mm. Area narrow, strongly dilated in 

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

 Strise 10 in 0,oi mm., divergent in the middle, convergent at the ends. — Nav. leptogongyla G'r\]N. 

 in A. S. Atl. XLV f. 26 to 28. Nav. Tabellaria 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, 009 to 0,oi6 mm. Area very narrow. Strise 10 to 

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



v 



