KOXGL. SV. VRT. AKADKMIRNS IlANDLINGAH. HANI) 26. N':() 2. 119 



Var. similis Grun. (18^0). — V. linear, with ol)tuse ends. L. 0, lo to 0,2; B. 0,02 to 0,024 

 mm. Median line central, slightly sigmoid, ending below the apices of the valve. (Central area 

 small. StriiC equidistant, Ki to 17 in 0,02 mm. — Fkur. simile Grun. A. I). ]>. ')(;. Per. VII f. 27. 



Fresh or brackish water: Lagos (Grun.), Java! Samoa (Grun.), Tasmania! China! ]iarl)ados! 



Var. sivensis Eiib. (1S47). — V. gibbous in the middle and with incrassate ends. L. 0,i to 

 0,2; B. 0,01.'? to 0,022 mm. Median line strongly flexuose. T.S. : L.S. '^,7 in 0,oi mm. — Nav. 

 sin. EiiH. Ber. 1847 p. 485 (accord, to Chase). M. G. XXXIV, 7. f. 11. Per. VII f. 11. PI sin. 

 rar. calcuttensis (jRUN. A. D. p. 57. Per. VII f. 12. 



Var. calif orniea Grun. (1879). — V. linear, slightly sigmoid, with gradually attenuated ends. 

 L. 0,2.5 to 0,28; B. 0,028 mm. Transv. and longit. strife equidistant, 14 to 15 in 0,01 mm. — 

 Fleur. holt. rar. calif. Grun. in CI. U. I). N:o 246. Per. VII f. 22. 



Brackish water: California! 



28. G. diminutum Grun. (1880). — V. linear, with obliquely truncate and rounded ends. 

 L. 0,1 to 0,11; B. 0,0 16 mm. Median line strongly flexuose, excentric towards the ends. T.S. : L.S. 

 'V,.,, '"/si, ^V',6 in <^"i mm. — Plcur. (half, rar.?) dim. Grun. A. D. p. 50. Per. VII f. 31, 32. 



Marine: Balearic Islands! Adriatic (Grun.)! 



Var. ronstrida (tRUN. (1880). — V. gibbous in the middle and at the ends. L. 0, 1; B. 0,oi3 

 mm. T.S. : L.S. ""/^s in 0,oi mm. — Pleur. (bait, var.?) constr. Grun. A. I), p. 57. Per. VII 

 f. 13. Plenr. reversum Greg. D. of Clyde p. 530 PI. XIV f. 105. Per. VII f. 10? 



Marine: Adriatic (Grun.). 



PI. hiharcnsr Pant. Ill PI. XLII f 581 seems to be an akin form. 



24. G. Wausbecliii Donk. (1858). — V. linear, tapering towards the .■^lightly curved and 

 obli([uely rounded ends. L. 0,ii to 0,i7; B. 0,oi5 mm. Median line excentric, sigmoid. T.S. : L.S. 

 'V-u. '7i8 in <*.<»! mni. — Pleur. bait. /? W. Sm. B. D. PI. XXII f. 207 [i. PI. Wan.^^h. DoxK. 

 T."m. S. VI p. 24 PI. Ill f. 7. Per. VII f. 23. 24. 



Brackish and marine: Sea of Kara! North Sea! 



Var. Peisnnis Grun. (18()0). — L. 0,o9; B. 0,oi mm. T.S. : L.S. ^i/.,., -^^'-i^^ in 0,oi mm. — 

 PUur. Peis. Grun. Verb. 1«()0 p. 5fi2 PI. VI f. S. P. Sponcerii var. Peis. Grun. A. D. p. 60. 

 Per. VIII f. 27. 



Brackish water: Sonderburg (Grun.), Neusiedler See, Hungary (Grun.J! 



Var. subsalina Per. (1891). — L. 0,i2 to O.ir; B. 0,oi2 mm. T.S. : L.S. 18/22- — P^eur. 

 Spcncerii var. subs. Per. p. 24 PI. VIII f. 16, 17. 



Brackish water: Medoc, France (Per.). 



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

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

 sigmoid than the valve, sometimes slightly sinuose. T.S. : L.S. -V28' ^'''sc "'V30 in ^^01 mm. 

 Frustule more or less arcuate to almost straight. — Rhoicosigma arcticum Ch. D. Arc. Sea p. 18 

 PI. Ill f. 16. Per. X f. 16, 17. 



Marine: Greenland! Spitsbergen! Sea of Kara! Finmark! Grip in Norway! Firth of Tay! 

 Barbados! Kerguelens Land! 



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

 Grunow Donhinia, subflexiiosa (Icon. n. Part II PI. I f. 3, 4), are straight, so also are specimens from 

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

 rounded according to the position of the valve. 



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

 the North Sea, which requires a more accurate study. 



26. (Donkinia) rectum Donk. (1858). — V. convex, linear, straight, with obliquely rounded 

 ends. L. 0,i 1 to 0,2.t; B. 0,013 to 0,02 mm. Median line strongly excentric and sigmoid. Transverse 



