1 50 p. T. CLEVE, SYNOPSIS OF THE NAVICULOID DIATOMS. 



Fresh or slightly brackish water: Sweden, Areskutan! Gulf of Bothnia! Lake Almten in 

 Smaiand! Scotland (Greg.), Belgium (V. H.). 



S. Legumen is nearly akin to S. parvula and may be regarded as a biconstricted variety of 

 that species. If so Legumen should be the specific name. 



23. S. (Pleurostauron) Smithii Grun. (1860). — V. rhomboid-lanceolate, with slightly 

 triundulate margins; the median inflation being larger. Ends apiculate. L. 0,02 to 0,03; B. 0,oo7 

 mm. Stauros narrow, reaching to the margins. Striae 28 to 30 in 0,oi mm., almost parallel. — 

 S. linearis W. Sm. B. D. p. 60 PI. XIX t 193 (1853). S. Smithii Grun. Verh. 1860 p. 464 PL VI 

 f. 16. V. H. Syn. p. 69 PI. IV f. 10. Pleurostauron linearis Hilse Rab. A. E. N:o 1161 (1861). 



Fresh or slightly brackish water: Sweden, Gulf of Bothnia! Upsala! Saxony! Belgium (V. H.), 

 England! Illinois! Surinam! 



This is a small, very characteristic form, which occurs isolated among other diatoms. 



24. S. (Pleurostauron) Frauenfeldiana Grun. (1867). — V. fusiform, subacute. L. 0,o7 

 to 0,11 ; B. 0,008 to 0,009 mm. Stauros strong and dilated at the margins. Strise 21 in 0,oi mm. 

 parallel, minutely punctate. — Pleuros. Frauenf. Grun. Nov. p. 21 PL I f. 13. 



Fresh water: Java (fossil)! New Zealand! 



25. S. (Pleurostauron) javanica Grun. (1867). — V. lanceolate with rounded obtuse ends. 

 L. 0,12 to 0,21 ; B. 0,027 to 0,04 mm. Stauros linear, reaching the margin. Striae 12 to 14 in 

 0,01 mm. slightly radiate, punctate; puncta about 13 in 0,oi mm. — Pleurost. javanic. Grun. Novara 

 p. 21 PL I f. 14. S. SzontagUi Pant. Ill PL VHl f. 143 (1893). 



Fresh water: Europe, Hungary, Bory (fossil)! Java! Australia (Blue Mountains)! Nova Scotia! 

 Canada! Chicago, interglacial peat! 



This form is scarcely specifically distinct from S. acuta, although its form is nearly the 

 same as that of 8. phoenicenteron. 



26. S. (Pleurostauron) acuta "W. Sm. (1853). — V. rhombic-lanceolate, gradually tapering 

 from the middle to the narrow, obtuse ends. L. 0,08 to 0,i5; B. 0,oi5 to 0,04 mm. Stauros broad, 

 dilated outwards, reaching the margin. Strite 12 to 16 in 0,oi mm. composed of distinct puncta, 

 12 to 16 in 0,01 mm. Frustules coherent in short bands. — W. Sm. B. D. I p. 59 PL XIX f. 187. 

 V. H. Syn. p. 68 PL IV f. 3. S. Eochii Pant. Ill PL VI f. 92 (1893). 



Fresh water: Franz Josephs Land (Grun.), Sweden! Finland! England! Belgium (V. H.), 

 Germany! Greenland! Nova Scotia! Canada! Massachusetts! Argentina! Australia! New Zealand! 



Var. Terryana Temp. — V. in L. 0,35; B. 0,055 mm. Strise and puncta 13 in 0,oi mm. 



Brackish water: Connecticut! 



Var. undulata Cl. — V. with triundulate margins. L. 0,i6; B. 0,03 mm. Diaphragms 

 broad. Striae 15 to 16, puncta 15 in 0,oi mm 



Fresh water: Murray Eiver, Australia! 



27. S. (Pleurostauron) Fulnien Btw (1859). — V. elongated, biconstricted. Median inflation 

 of about the same size as the others. Ends capitate. L. 0,2 to 0,22; B. 0,oo28 to 0,03 mm. 

 Stauros reaching to the margins and somewhat dilated outwards. Striae 15 in 0,oi mm., slightly 

 radiate, pimctate; puncta 13 in 0,oi mm. forming undulating, longitudinal rows. — Btw M. J. VII 

 p. 180 PL IX f. 6. 



Fresh water: Java (foss.)! N. Zealand! Australia (Carpentaria Bay, Murrey River)! 

 St. Fulmen is very nearly akin to S. acuta and might be regarded as a variety. There is 

 the same relation between S. Fulmen and S. acuta as between S. Legumen and S. parvula. 



