150 p. T. CLEVE, .SYNOPSIS OF. THE NAVICULOID DIATOMS. 



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

 Smaland! Scotland (Greg.). Belgium (V. H.). 



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

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



23. S. (Pleurostaiiroii) Sinithii Grun. (18G0). — V. rhomboid-lanceolate, with slightly 

 triundulate margins; the median intiation being larger. Ends apiculate. L. 0,o2 to 0,03; B. 0,007 

 mm. Stauros narrow, reaching to the margins. Strijii 28 to 30 in 0,01 mm., almost parallel. — 

 S. linearis W. Sm. B. i). p. 60 PI. XIX f. 193 (1853). S. Smithii Grun. Verb. 1860 p. 464 PI. VI 

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



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

 England! Illinois! Surinam! 



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



24. S. (Pleurostsiuron) Frauenfeldiana Grun. (1867). — V. fusiform, subacute. L. 0,07 

 to 0,11; B. 0,008 to 0,009 mm. Stauros strong and dilated at the margins. Strite 21 in 0,01 mm. 

 parallel, minutely punctate. — Fleuros. Francnf. Grun. Nov. p. 21 PI. 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. StrijE 12 to 14 in 

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

 p. 21 PL I f. 14. S. Szontaiihii Pant. Ill PL VIII 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. aeiita, although its form is nearly the 

 same as that of S. j'hoeniccnteron. 



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

 from the middle to the narrow, obtuse ends. L. 0,o8 to 0,15; B. 0,oi5 to 0,04 mm. Stauros broad, 

 dilated outwards, reaching the margin. Stri.p, 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. -5. Kochii 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. 0,3.-); B. 0,o5.'i mm. Strife and puncta 13 in 0,oi mm. 



Brackish water: Connecticut! 



Var. undulata Cl. — V. with triundulate margins. L. 0,i6; B. 0,o;5 mm. Diaphragms 

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



Fresh water: Murray River, Australia! 



27. S. (Pleurostauron) Fulnien Btw (1859). — V. elongated, bicoustricted. Median intiation 

 of about the same size as the others. Ends capitate. L. 0,2 to 0,22; B. 0,oo28 to 0,o3 mm. 

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

 radiate, punctate; 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. FulmeH. 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. 



