KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 26. N:0 2. 119 



Var. similis Grun. (1880). — V. linear, witli obtuse ends. L. 0,io to 0,2; B. 0,02 to 0,o24 

 mm. Median line central, sHghtly sigmoid, ending below tlie apices of the valve. Central area 

 small. StriiK equidistant, l(i to 17 in 0,o2 mm. — Plew. svmUe Grun. A. I), p. .^6. Per. VII f. 27. 



Fresh or brackisli water: Lagos (Grun.), Java! Samoa (Grun.), Tasmania! Cliina! Barbados! 



Var. sinensis Ehb. (1847). — V. gibbons in the middle and with incrassate ends. L. 0,i to 

 0,2; B. 0,01.3 to 0,022 mm. Median line strongly flexuose. T.S. : L.S. '-V,, in 0, 01 ram. — New. 

 sill. Ehb. Ber. 1847 p. 485 (accord. to Cliase). M. G. XXXIV, 7. f. 11. Per. VII f. 11. Pl sin. 

 rar. calmttensis Grun. A. D. p. 57. Per. VII f. 12. • "'■'i-l'- 



Var. californica Grun. (1879). — V. linear, sliglitly .sigmoid, with gradnally attenuated ends. 

 L. 0,2.') to 0,28; B. 0,028 mm. Transv. and longit. strise equidistant, 14 to 15 in 0,oi mm. — 

 Tleur. halt. rar. calif. Grun. in Cl. M. B. N:o 24(5. Per. VII f. 22. 



Brackish water: California! 



23. G, dimlnutum Grun. (1880). — V. linear, vriih. obliquely truncate and ronnded ends. 

 L. 0,1 to 0,11; B. 0,016 mm. Median line strongly flexno.se, excentric towards the ends. T.S. : L.S. 

 18/,,, 19/2^, «/^g in 0,01 mm. — Pleur. {halt. rar.?) dim. Grun. A. D. p. 56. Per. VII f. 31, 32. 



Marine: Balearic Islands! Adriatic (Grun.)! 



Var. constrida Grun. (1880). — V. gibbons in the middle and at the ends. L. 0,i; B. 0,oi3 

 mm. T.S. : L.S. -1,3 in 0,oi mm. ~- Pleur. (balt. rar.?) constr. Grun. A. D. p. 57. Per. VII 

 f. 13. Pleur. reversiim Greg. D. of Clyde p. 530 Pl. XIV f. 105. Per. VII f. 10? 



Marine: Adriatic (Grun.). 



Pl. hiharense Pant. III Pl. XLII f. 581 seems to be an akin form. 



24. G. Wansbecliii Donk. (185S). — V. linear, taperiug towards the slightly curved and 

 obliquely ronnded ends. L. 0, 11 to 0,17; B. 0,oi.^) mm. Median line excentric, sigmoid. T.S. : L.S. 

 •V20. '7i8 in 0,01 mm. — Pleur. halt. /? W. Sm. B. D. Pl. XXII f. 207 [j. Pl. Wansh. Donk. 

 T. M. S. VI p. 24 Pl. III f. 7. Per. VII f. 23. 24. 



Brackish and marine: Sea of Kära! North Sea! 



Var. Peisonis Grun. (18G0). — L. 0,09; B. 0,oi mm. T.S. : L.S. ^i/,^., 21..^,^ in 0,01 mm. — 

 Pleur. Peis. Grun. Verh. ISfiO p. 5fi2 Pl. VI f. 8. P. Spencerii var. Peis. Grun. A. D. p. 60. 

 Per. VIII f. 27. 



Brackish water: Sonderburg (Grun.), Neu.siedler See, Hungary (Grun.)! 



Var. suhsalina Per. (1891). — L. 0,i2 to 0,17; B. 0,oi2 mm. T.S. : L.S. 'Vjo- — -P?e«"'- 

 Spencerii var. suhs. Per. p. 24 Pl. VIII f. 16, 17. 



Brackish water: Médoc, France (Per.). 



25. G. (Rhoicosigina) arcticinn Ciu. (1873). — V. slightly sigmoid, tapering from the middle 

 to the subacute or obliquely ronnded ends. L. O.07 to 0,2; B. 0, 014 to 0,02 mm. Median line more 

 sigmoid than the valve, sometimes slightly sinuose. T.S. : L.S. -'/asi ^'/so' '"'V30 "^ *^'0i ^im. 

 Frustule more or less arcuate to almost straight. — Rhoicosigma arctieunt Cl. D. Are. Sea p. 18 

 Pl. III f. 16. Per. X f. 16, 17. 



Marine: Greenland! Spitsbergen! Sea of Kära! Finmark! Grip in Norway! Fii'th of Tay! 

 Barbados! Kerguelens Land! 



This. species varies in amount of tlexure. Specimens from Kerguelens Land, named by 

 Grunow Donkinia suhflexuosa (Icon. n. Part II Pl. I f. 3, 4), are straight, so also are specimens from 

 Barbados, but othervvise they differ in nothing of importance. The ends are subacute or obliquely 

 ronnded according to the position of the valve. 



As a Var. irregularis Peragallo has (p. 33 Pl. X f. 18) iigured an asymmetrical form from 

 the North Sea, which requires a more accurate study. 



26. (Donkinia) rectnm Donk. (1858). — V. convex, linear, straight, with obliquely ronnded 

 ends. L. 0, 11 to 0,23; B. 0,oi3to 0,o2 mm. Median line strongly excentric and sigmoid. Transverse 



