Page:Bergey's manual of determinative bacteriology.djvu/69

 Jena; named for the city of Jena, Germany, where Ehrenberg discovered this organism.

Cells 2.5 to 4.0 microns thick, cylindrical, sometimes pointed at the ends; coiled as spirals, generally 30 to 40 microns in length, but may be as long as 100 microns. Complete turns may measure from 15 to 40 microns with a wave depth of 3 to 7 microns. Polar flagellate. Tufted at both ends. Olive-brown, sepia-brown and reddish brown.

This coloring appears to be the only recognizable difference from Thiospirillum sanguineum. Thiospirillum crassum Hama (loc. cit.), reported to be 3.7 to 4 by 12 to 40 microns and yellowish brown in color, thus becomes indistinguishable from Thiospirillum jenense; the 80-microns-long Thiospirillum jenense forma maxima Szafer (Bull. Acad. Sci. Cracovie, Sér. B, 1910, 162) does not, at present, justify recognition as a special taxonomic entity.

It is even doubtful whether the observed color difference between Thiospirillum jenense and Thiospirillum sanguineum constitutes a valid criterion for their maintenance as two distinct species (Buder, Jahrb. wiss. Bot., 56, 1915, 534; Bavendamm, Die farblosen und roten Schwefelbakterien, Pflanzenforschung, Heft 2, 1924, 131).

Habitat: Mud and stagnant water containing hydrogen sulfide and exposed to light; more rarely in sulfur springs.

Illustrations: Zettnow, Ztschr. f. Hyg., 24, 1897, Pl. II, fig. 49-52; Buder, op. cit., 1915, 534, fig. 1; Szafer, op. cit., 1910, Pl. IV, fig. 4; Hama, op. cit., 1933, Pl. 18, fig. 1, 8a; Pl. 19, fig. 1.

2. Thiospirillum sanguineum (Ehrenberg, 1840) Winogradsky, 1888. (Ophidomonas sanguinea Ehrenberg, Verhandl. Akad. Wiss. Berlin, 1840, 201; Spirillum sanguineum Cohn, Beitr. Biol. Pfl., 1, Heft 3, 1875, 169; Winogradsky, Schwefelbacterien, Leipzig, 1888, 104.)

san.gui′ne.um. L. adj. sanguineus blood-colored, blood-red.

Cells cylindrical, sometimes attenuated at ends, spirally coiled; 2.5 to 4.0 microns in width, commonly about 40 microns long with a range of from 10 to 100 microns. Size and shape of coils variable, complete turns measuring from 15 to 40 microns in length and from $1/2$ to $1/10$ of the length in width. Polar flagellate, usually tufted at both ends. Individual cells rose-red with a grayish hue, groups of cells deep red. Sulfur droplets numerous under appropriate conditions.

Habitat: Mud and stagnant water containing hydrogen sulfide and exposed to light; rarely in sulfur springs.

Illustrations: Cohn, op. cit., 1875, Pl. VI, fig. 15; Warming, Vidensk. Meddel. naturhist. Foren., Kjöbenhavn, 1876, Pl. VII, fig. 8; Buder, Jahrb. wiss. Bot., 56, 1915, 534, fig. 2.

3. Thiospirillum violaceum (Warming, 1876) Winogradsky, 1888. (Spirillum violaceum Warming, Vidensk. Meddel. naturhist. Foren., Kjöbenhavn, 1876, 395; Winogradsky, Schwefelbacterien, Leipzig, 1888, 104.)

vi.o.la′ce.um. L. adj. violaceus violet-colored.

Cells short and fat, 3 to 4 by 8 to 10 microns, ends smoothly rounded. Slightly curved, bean- or vibrio-shaped. Only rarely are they twisted suggesting a spirillum. Polar flagellate.

The shape of cell seems to fit the genus Chromatium rather than Thiospirillum, and Warming (op. cit., 1876, 395) emphasizes the resemblance to Chromatium okenii.

Color: Bluish violet; this color may be related to a scarcity of sulfur droplets in the cells.

Habitat: Mud and stagnant water. Illustration: Warming, op. cit., 1876, Pl. VII, fig. 3.

4. Thiospirillum rosenbergii (Warming, 1875) Winogradsky, 1888. (Spirillum rosenbergii Warming, Vidensk. Meddel. naturhist. Foren., Kjöbenhavn, 7, 1875, 346; Winogradsky, Schwefelbacterien, Leipzig, 1888, 104.)

ro.sen.ber′gi.i. M.L. gen. noun rosenbergii of Rosenberg; named for Rosenberg, a Danish algologist.

Cells 1.5 to 2.5 by 4 to 12 microns; coiled, with turns of about 6 to 7.5 microns in length and variable width up to 3 or 4 microns. Color very dark, due to numerous