FAMILY I. THIORHODACEAE 



47 



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 rec- 

 ognizable difference from Thiospirilhan san- 

 (juineiim. 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 Thiospiril- 

 lumjenense; the 80-microns-long Thiospiril- 

 lum jenense forma maxima Szafer (Bull. 

 Acad. Sci. Cracovie, S6r. 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 con- 

 stitutes a valid criterion for their mainte- 

 nance 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 con- 

 taining hydrogen sulfide and exposed to 

 light; more rarelj' in sulfur springs. 



Illustrations: Zettnow, Ztschr. f. Hyg., 

 24, 1897, PI. II, fig. 49-52; Buder, op. cit., 

 1915, 534, fig. 1; Szafer, op. cit., 1910, PI. IV, 

 fig. 4; Hama, op. cit., 1933, PI. 18, fig. 1, 8a; 

 PI. 19, fig. 1. 



2. Thiospirillum sanguineum (Ehren- 

 berg, 1840) Winogradsky, 1888. (Ophido- 

 monas sanguinea Ehrenberg, Verhandl. 

 Akad. Wiss. Berlin, 1840, 201 ; Spirillum san- 

 guineum 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 }4 to }{o 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 con- 

 ditions. 



Habitat: Mud and stagnant water con- 

 taining hydrogen sulfide and exposed to 

 light; rarely in sulfur springs. 



Illustrations: Cohn, op. cit., 1875, PI. VI, 

 fig. 15; Warming, Vidensk. Meddel. natur- 

 hist. Foren., Kjobenhavn, 1876, PI. VII, fig. 

 8; Buder, Jahrb. wiss. Bot., 56, 1915, 534, 

 fig. 2. 



3. Thiospirillum violaceum (Warming, 

 1876) Winogradsky, 1888. {Spirillum vio- 

 laceum Warming, Vidensk. Meddel. natur- 

 hist. Foren., Kjobenhavn, 1876, 395; Wino- 

 gradsky, 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. Onl}^ 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 re- 

 lated to a scarcity of sulfur droplets in the 

 cells. 



Habitat: Mud and stagnant water. 



Illustration: Warming, op. cit., 1876, PI. 

 VII, fig. 3. 



4. Thiospirillum rosenbergii (Warm- 

 ing, 1875) Winogradsky, 1888. (Spirillum 

 rosenbergii Warming, Vidensk. Meddel. na- 

 turhist. Foren., Kjobenhavn, 7, 1875, 346; 

 Winogradsky, Schwefelbacterien, Leipzig, 

 1888, 104.) 



ro.sen.ber'gi.i. M.L. gen. noun rosen&er^n 

 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 mi- 

 crons. Color very dark, due to numerous 



