KONGL. SV. VET. AKADEMIENS IIANnLINGAK. BAND 26. N:0 2. 149 



Var. amphileptu Eiib. (1843). — L. O, o v to 0,i; B. 0,oi5 to O, o 2 mm. Struc and punrta IH 

 to 21 in 0,01 mm. — S. ampli. Ehb. Am. I: 2 f. 9? M. Gr. Pl. XIV f. 18? HÉiiiii. D. (rAuvergne 

 p. 77 Pl. III f. 18 (1893). S. gracUis W. Sm. B. D. XIX f. 186. S. lanceolata Grun. Verh. 1860 

 p. 563. S. boryana Pant. III Pl. V f. 78; 1893 (S. javanica?). 



Fresh water: Swedeii! Finland! Holstein! England (Sm.), Greenland! Australia, Murray River! 



Var. genuina Cl. — L. 0,i to 0, 15; B. 0,03 to 0, 04 mm. Strite 14 to 17, punuta about 12 

 in 0,01 mm. — S. plioenkenteron W. Sm. B. D. Pl. XIX f. 185. Grun. Verli. 1860 p. 563. V. H. 

 Syn. p. 67 Pl. IV f. 2. Pant. III Pl. VIII f. 134. S. Britnii Per. in Hérib. d'Auvergne p. 76 

 Pl. III f. 22 (1893). 



Fresh water: Sweden! Finland! England! Belginm (V. H.), Switzerlaud! North America 

 (Canada, Calif.)! Brazil! Argentina! New Zealand! 



Var. Baileyi Ehb. (1843). — L. 0, 15 to 0,2; B. 0,045 mm. Strite and puncta 12 to 14 in 

 0,01 mm. - S. Bail. Ehb. Am. p. 143. S. pteroidea Bail. (accord. to Ehb.) M. G. Pl. XIV f. 5. 



Fresh water: North America (Cherryfield etc. fossil)! 



19. S. (Pleurostauron) parvula Grun. (1878). — V. liuear-lanceolate, with obtuse or slightly 

 rostrate ends. L. 0, 02 to 0,025; B. 0, 005 mm. Stauros broad, pervious. Stria; 23 in 0, 01 mm. 

 radiate. — Grun. in Cl. M. D. N:o 139. 



Fresh water: Berlin! 



Var. prominula Grun. Ms. — Linear, with rostrate ends. L. 0, 02 to 0,04; B. 0, 004 to 0,oo8 

 mm. Strise 25 to 28 in 0,oi mm. 



Fresh or slightly brackish water: Greenland! Finmark, Tana Elf (Grun.), Gulf of Bothnia! 



Var. producta Grun. (1880). — V. linear lanceolate, with rostrate ends. L. 0, 03 to 0, 04; 

 B. 0.008 mm. Strise 18 to 20 in 0,oi mm. — Stauron. producta Grun. in V. H. Syn. Pl. IV f. 12. 



Fresh water: Sweden Skåne! Holstein! (Grun.). 



As S. parviila Janisch has described, but not iigured, a form from Angamos Guano (Charac. 

 d. Guano II p. 14), which cannot be identitied, for which reason Grunow's name may be 

 retained. — S. parvula Grun. differs from S. prod^icfa only by its smaller size and finer strise, 

 and they may be united. The var. producta is nearly akin to, and seenis to graduate into 

 S. Legumen. 



20. S. (Pleiirostaiirou) oblougii Grun. (1867). — V. linear, with broad, rounded ends. 

 L. 0,038 to 0,05; B. 0,0122 mm. Stauros linear, reaching to the margin. Strise transverse, 15 in 

 0,01 mm. — Grun. Nov. p. 20 Pl. I f. 15. 



Fresh water: Java, foss. (Grun.). 



I have not succeeded in finding this form in the edible earth from Java, and cannot say 

 anything about its affinities. 



21. S. (Pleurostauron) obtusa Lägst. (1873). — V. linear-Ianceolate, with broad, obtuse, 

 not rostrate ends. L. 0, 06 to 0,07; B. 0, 01 mm. Stauros broad, reaching to the margin, where it 

 becomes somewhat broader. Strise 19 to 21 in 0, 01 mm. — Lägst. Spitsb. D. p. 36 Pl. I f. 11. 



Fresh water: Spitsbergen (Lägst.). 



A similar form from Australia (Blue Mountains) has slightly rostrate ends. Another similar 

 form, but with narrow, subacute ends, is described by Lbwis (Proc. N. Se. Philad. 1865 Pl. II 

 f. 14) as a variety of S. Legumen. 



22. S. (Pleurostauron) Legumen Ehb. (1843). — V. elongated, biconstricted. Median infla- 

 tion not larger than the others. Ends rostrate. L. 0,o3 to 0,035; B. 0,oo8 mm. Stauros reaching 

 nearly to the margin and not dilated outwards. Strise 27 in 0,oi mm., slightly radiate. Frustules 

 coherent in short bands. — Sfauroptera Legumen Ehb. Am. p. 135 Pl. I: 2, f. 5 (fide Kiitz.). Stauro- 

 neis Leg. KtJTZ. Bac. p. 107 Pl. XXIX f 11. Greg. M. J. IV Pl. I f. 9. V. H. Syn. p. 69 

 Pl. IV f. 11. 



