KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 123 



Var. amphipleuroides Gtrun. (1880). — L. 0,13; B. 0,02 mm. Central nodule elongated; median 

 line slightly excentric. Transverse strise 23, longitudinal striae 18 to 19 in 0,oi mm. — Van- 

 heurchia rhomb, var. amphipl. Gtrun. A. D. p. 47 PI. Ill f. 59. 



Fresh water: Finland (Russian Lapland, Ladoga)! Mouth of Jenissey! Vancouver Island 

 (Grove Coll.)! 



Var. saxonita Rabh. (1851). — V. lanceolate, with rostrate ends. L. 0,05 to 0,07; B. 0,oi3 

 to 0,02 mm. Strife fine, 34 to 35 (V. H. Syn.). — Frusfulia saxonica Rabh. (Bac. exc. N:o 42. 

 Fl. E. Alg. p. 227). Grun. Banka D. PL I f. 13. Nav. crassinervia BriSb. in W. Sm. B. D. p. 47 

 PL XXXI f. 271 (1853). Grun. Verh. 1860 p. 548 PL V f. 12. Donk. B. D. p. 42 PL VI f. 12. 

 VanheiircMa crass. Bb^b. Ann. Soc. phyto. et microgr. de Belgique Vol. I p. 204 (1868). 



Fresh water: Spitsbergen (Lagerst.), Beeren Eiland (Lagerst.), Sweden! Finland! Germany! 

 Australia (Blue Mountains, Daintree River)! New Zealand! Bengal! 



Var. viridula Brj^b. (1849). — Frustules in gelatinous tubes. V. elongated, with broad, obtuse 

 ends. L. 0,08 to 0,ii; B. 0,oi5 mm. Strife 28 to 30 in 0,oi mm. (V. H.). — Colleton, viridulum 

 Be^b. in Kiitz. Sp. A. p. 105. VanJieurckia virid. Br]&b. Ann. Soc. phyt. et micr. de Belgique 

 Vol. I p. 203 (1868). V. H. Syn. p. 112 PL XVII f. 3. Frustulia torphacea A. Br. in Rabh. Alg. 

 Sachs. N:o 761 (1858). 



Fresh water: Germany! France (Breb.). 



4. P. interposita Lewis (1865). — V. linear-elliptical, with broad, rounded ends. L. 0,i2 

 to 0,13; B. 0,025 to 0,027 mm. Central nodule small, terminal nodules small, approximate to the 

 endsi Transverse strise 20, longitudinal 18 in 0,oi mm. — Nav. interposita JjEwis 'Proc. Ac. Fhilad. 

 1865 PL II f. 19. Nav. Martonfii Pant. Ill PL XVII f. 247 (1893)? 



Brackish water: Sierra Leone! Bombay (Grove Coll.)! Savannah Ga.! Oakland, Calif.! South 

 America (Lewis), Hungary, Tallya fossil (Grun.). 



Var. lahuensis Cl. (1883). — Narrow elliptic-lanceolate with obtuse ends. L. 0,0 6 5 to 0,072; 

 B. 0,015 mm. Transverse striae 17; longitudinal 18 to 21 in 0,oi mm. — Nav. O'M. var. lab. 

 Cl. Vega p. 496. " 



Marine: Labuan! 



Var. incomperta Lewis (1865). — Transverse strise about 27, longitudinal 22 to 23 in 0,oi 

 mm. — Nav. incomperta Lewis 1. c. f. 20. 



Brackish water: Atlantic coasts of U. States (Lewis). 



Var. Julieni Brun a. H;6rib. (1893). — L. 0,o7; B. 0,012 to 0,oi7 mm. Transverse striae 

 about 28, longitudinal 20 in 0,oi mm. — N. Jul. Brun a. H^rib. D. d'Auvergne p. 199 PL VI f. 8, 9. 



Brackish water: Auvergne, fossil! 



5. F. Lewisiana Gbev. (1863). — V. linear, with broad, rounded ends. L. 0,i9 to 0,21; 

 B. 0,035 to 0,038 mm. Central nodule small, terminal nodules elongated and linear, at some distance 

 from the ends. Transverse striae parallel in the middle, convergent at the ends, 24 in 0,oi mm. 

 Longitudinal striae 25 in 0,oi mm. irregularly undulating. — Nav. n. sp. Lewis Proced. Ac. Nat. 

 Sc. PhU. PL II f. 3 (1861). Nav. Lewis. Grev. T. M. S. XI p. 15 PL I f . 7 (1863). Vanheurckia 

 Lewisiana Br:6b. Ann. Soc. phytol. et microgr. Belgique Vol. I p. 202 (1868). 



Brackish water: Sierra Leone! Cameroon! India (Wallich), Batavia! Sendai, Japan, fossil! 

 Brazil (Brun Coll.)! Florida and Georgia (Lewis). 



Stenoneis Cl. N. Gen. 



Valve narrow, with rounded ends. Central and terminal nodules very small. Median line 

 indistinct, bordered by two strong linear silicious ribs. Structure: fine, transverse, striae. Axial 

 area indistinct. 



