n6 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



turns iu the cell ; fertile cells much swollen, vesicular, not 

 shortened, extreme diam. 37-42 p. ; spores ellipsoid, yellow at 

 maturity, 2 diam. long, diam. about 30 p.. Mass., R. I. 



Europe, New Zealand. 



The smallest of our species and easily recognized. 



29. S. INFLATA (Vauch.) Kiitzing, 1843, p. 279; Petit, 1880, 

 p. 7, PI. I, figs. 4-6; Wolle, 1887, p. 207, PI. CXXXII, figs. 6 

 and 7; P. B.-A., No. 363. Filaments 15-18 /u, diam., cells 3-8 

 diam. long ; chromatophore single, quite broad, making 3-8 

 turns in the cell ; fertile cells much swollen, somewhat shortened, 

 42-48 p. diam.; spores ellipsoid, dark yellow at maturity, 2 diam. 

 long, diam. 30-36 /*. Mass., Conn., N. J. Europe. 



Resembles 6". temiissima, but larger, with broader and more 

 densely twisted spiral. 



30. S. SPREEIANA Rabenhorst, Algen, No. 988 ; Petit, 1880, 

 p. 7, PI. I, figs. 7-9 ; Wolle, 1887, p. 208, PI. CXXXII, figs. 4 

 and 5; P. B.-A., No. 1019. Filaments 18-21 p. diam., cells 

 10-25 diam. long; chromatophore single, slender, making 1^-4 

 turns in the cell ; fertile cells swollen, not shortened, 30-42 p, 

 diam.; spores ellipsoid, yellowish at maturity, 2-3 diam. long, 

 diam. up to 36 p.. Mass., Washington, Cal. Europe. 



The very long cells, with a loose, almost inconspicuous spiral, 

 the swelling in the fertile cells tapering to each end of the cell, 

 sufficiently distinguish this species. 



31. S. QUADRATA (Hass.) Petit, 1874, p. 41, PL I, fig. 2; 

 1880, p. 8, PI. I, fig. 13; Wolle, 1887, p. 208, PL CXXXII, 

 figs. 8-10 ; P. B.-A., No. 366. 5. bifaria (Bailey) Kiitzing, 

 i855a, p. 7, PL XXI, fig. 3. Filaments 24-27 p. diam., cells 3-9 

 diam. long; chromatophore single, broad, making 1^-5 turns 

 in the cell ; fertile cell much swollen, up to 54 p. diam., appear- 

 ing like a rectangle with rounded corners ; spores ellipsoid or 

 cylindric-ellipsoid, brown at maturity, 1^-2 diam. long, diam. 

 42-48/11. Mass., N. Y., Pa. Europe. 



Easily recognizable by the peculiar shape of the fertile cells. 

 According to Wolle, S. pulchella Wood, 1872, p. 164, PL XIV, 

 fig. 2, is a synonym of this species. The plate, though appar- 

 ently not very characteristic, does not contradict this conclu- 

 sion. Zygnema bifaria Bailey, from examination of authentic 

 specimens, agrees fully with 5. quadrata. 



32. S. WEBERI Kiitzing, 1843, p. 279 ; Petit, 1880, p. 9, PL I, 

 figs. 10-12; Wolle, 1887, p. 208, PL CXXXII, fig. u ; P. B.-A., 

 No. 368. Filaments 22-28 p. diam., cells 6-16 diam. long; 



