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



Var. hengalensis Grdn. (1875). — V. less asymmetrical, almost boat-shaped, with straight 

 or slightly centrally gibbous ventral margins. Ends obtuse. L. 0,08 to 0,ii; B. 0,o24 to 0,o27 

 mm. Median line slightly arcuate. Axial area linear, scarcely dilated around the central nodule. 

 Strife 7,5 (middle) to 9 (ends) in 0,oi mm., coarsely punctate; puncta 12 to 13 in 0,oi mm. — 

 C. beng. Grun. in A. S. Atl. IX f. 12, 13; LXXI f. 79. Kitton Linn. Soc. Bot. XX PL XLVIII 

 f. 6 (1884). Cl. M. D. N:o 194. 



Fresh water: Bengal! Socotra (Kitton). 



C. aspera is a very common species, easily recognized by its boat-shaped outline, its coarsely 

 punctate strise and always distinct area. It appears to be more closely akin to C. Ehrenhergii 

 than to the boat-shaped C. lanceolata, C. Cistula etc. It seems questionable whether the var. crassa, 

 which I have not seen, really belongs to C. aspera. It may possibly be more akin to G. Cistula. 



* C. salina Pant. (1889). — V. boat-shaped, with arcuate dorsal margin, straight ventral 

 margin and obtuse ends. L. 0,o585; B. 0,oi3 mm. Median line arcuate. Axial area distinct linear, 

 slightly dilated around the central nodule. Striee 12,5 to 13 in 0,oi mm. punctate. — Pant. II 

 p. 40 PI. I f. 9. 



Brackish water: Hungary, fossil (Pant.). 



This species is not known to me, but seems, to judge from the fig. in Pantocsek's work to 

 be allied to C. aspera, from which it differs by smaller size and closer striee. 



60. C. tumida BriSb. (1849). — V. boat-shaped with slightly centrally gibbous ventral 

 margin. Ends rostrate-truncate. L. 0,05 to 0,i; B. 0,oi8 to 0,022 mm. Median line arcuate. 

 Axial area narrow, linear, suddenly dilated around the central nodule to an orbicular or sub- 

 quadrate central area. A stigma with a fine fissure below the central] nodule. Striee 8 or 9 

 (middle) to 10 or 12 (ends) in 0,oi mm., radiate, towards the ends almost parallel, distinctly 

 punctate; puncta about 20 in 0,oi mm. — Coccon. tumidum Br^b. in Kiltz Sp. Alg. p. 60. Cy. 

 turn. V. H. Syn. p. 64 PL II f. 10. Cocc. gibbum A. S. Probst, f. 17. Cy. stomatophora Grun. in 

 A. S. Atl. X f. 28 to 30. Coccon. stomat. G-run. A. D. p. 26. 



Fresh water: Sweden (Westergotland, Goteborg)! Holstein (V. H. T.), Belgium (V. H.), 

 Germany! France! Mouth of Jenissey! Japan! Bengal! New Zealand! Australia, Victoria! Ame- 

 rica (Illinois, California)! 



Var. borealis Grun. (1880). — Ends obliquely truncate, not rostrate. Striae 8 in 0,oi mm. 

 — Cocc. stomat. var. borealis Grun. A. D. p. 26. 



Fresh water: Sweden (Grun.), Niagara Falls! 



Var. gibba Grun. (1880). — Dorsal margin with 3 to 4 undulations. Striae 8 to 9 in 0,oi 

 mm. — Coccon. stomat. var. gibba Grun. A. D. p. 26. 



Var. fossilis Grun. (1880). — V. with less rostrate and more rounded ends. Stigma with 

 shorter fissure than in the type. — Coccon. stomat. var. fossilis Grun. A. D. p. 26. 



Fresh water: Habichtswald, fossil (Grun.). 



61. C. australica A. S. (1875). — V. boat-shaped with centrally gibbous ventral margin 

 and truncate or rounded obtuse ends. L. 0,i to 0,i4; B. 0,026 to 0,03 mm. Median line arcuate. 

 Axial area linear, suddenly dilated around the central nodule to an orbicular space. A stigma 

 with a distinct fissure below the central nodule. Striae 7 (middle) to 9 (ends) in 0,oi mm. slightly 

 radiate in the middle, parallel at the ends, coarsely punctate; puncta about 13 in 0,o] mm. — 

 Cocc. austr. A. S. Atl. X f. 34, 35. Cl. M. D. N:o 295. 



Fresh water: Australia! New Zealand! 



62. C. punctifera Cl. N. Sp. — V. boat-shaped, with truncate ends. L. 0,i3; B. 0,02 mm 

 Median line arcuate; terminal fissures reflexed. Axial area linear, suddenly dilated to an orbicular 

 central area. Stigma in the middle of the central nodule, without distinct fissure. Striae 8 in 0,oi 



