150 P. T. CLEVE, «YNOrSIS OF THE NAVICULOIl) DIATOMS. 



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

 Småland! Scotland (Greg.), Belgiiiiu (V. H.). 



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

 tliat species. If so Leguinen should be the specific name. 



23. S. (Pleurostauroii) Smitliii Gkun. (1860). — V. rliomboid-lanceolate, with slightlj- 

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

 mm. Stanros narrow, reacliing to the margins. Stria; 28 to 30 in O.oi ram., almost parallel. — 

 S. linearis W. Sm. B. U. p. fiO Pl. XIX f. 193 (1853). S. Smithii Grun. Verh. 1860 p. 464 Pl. VI 

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



Fresh or sliglitly brackish water: Sweden, Gnlf of Bothnia! Ujjsala! Saxony! Belgium (V. H.), 

 England! Illinois! Surinam! 



Tliis is a small, very characteristic form, which occiirs isolated among other diatoms. 



24. S. (Pleurostiiuron) Fraiienfeldiana Grun. (1867). — V. fusiform, subacute. L. 0,07 

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

 parallel, miuntely pnnctate. — Pleuros. Frauenf. Grun. Nov. p. 21 Pl. I f. 13. 



Fresh water: Java (fossil)! Xew Zealand! 



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

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

 0,01 mm. slightly radiate, pnnctate; pnncta abont 13 in 0, 01 mm. — Fleurost. javanic. Grcx. Xovara 

 p. 21 Pl. I f. 14. S. Ssontaglm Pant. III Pl. VHI f. 143 (1893). 



Fresh water: Europé, Hnngary, Bory (fossil)! Java! Australia (Blne ]\Ionntains)! Xova Scotia! 

 Canada! Chicago, interglacial peat! 



This form is scarcely specifically distinct from S. acnfa, althongh its form is nearly the 

 same as that of S. phoeniceuteron. 



2G. S. (Pleurostauron) acnta W. Sm. (1853). — V. rhonibic-lanceolate, gradnally tapering 

 from the niiddle to the narrow, obtuse ends. L. O, o 8 to 0,i5; B. 0,oi,=j to 0, 04 mm. Stauros broad, 

 dilated outwards, reaching the margin. Sti"i;e 12 to 16 in 0, 01 mm. composed of distinct puucta, 

 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. Koclui Pant. III Pl. VI f. 92 (1893). 



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

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



Var. Terryana Temp. — V. i)i L. 0,35; B. 0, 05.5 mm. Striaä and pnncta 13 in 0, 01 mm. 



Brackish water: Connecticut! 



Var. undulata Cl. — V. with txiundulate margins. L. O.ie; B. 0, 03 mm. Diaphragms 

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



Fresh water: Murray River, Australia! 



27. S. (Pleuros(aurou) Fulnien Btw (1859). — \. elongated, biconstricted. Median inflation 

 of about the same size as the others. Ends capitate. L. 0,2 to 0,22; B. 0,oo2s to U,03 mm. 

 Stauros reaching to the margins and soniewhat dilated outwards. Stripe 15 in 0, 01 mm., slightly 

 radiate, pnnctate; pnncta 13 in 0, 01 mm. forming nndulating, longitudinal rows. — Btw M. J. VII 

 p. 180 Pl. IX f. 6. 



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



St. Fidnicn is very nearly akin to S. acuta and niight be regarded as a varietv\ There is 

 the same relation between S. Fulnicn and S. acuta as betweeu S. Lcguiuvu and S. parvula. 



