850 MANUAL OF DETERMINATIVE BACTERIOLOGY 



3. Amoebobactergranula Winogradsky. usually fills most of the cell. Because 



(Schwefelbacterien, Leipzig, 1888, 78.) of the high refractive index of this glob- 



From Latin gramdus, a granule. ule, it becomes difficult if not impossible 



Cells: Spherical, small, about 0.5 to 1 to make accurate observations of the 



micron in diameter. Faint pigmenta- cell shape. 



tion; the sulfur inclusions give the cell Habitat: Mud and stagnant water con- 

 masses a black appearance. Aggregates taining hydrogen sulfide and exposed to 

 are apt to consist of closelj^-knit masses light; sulfur springs, 

 which are difficult to separate. Illustration: Winogradsky, loc. cit.. 



When sulfur is stored, a single droplet PI. Ill, fig. 8. 



Genus IX. Thiopolycoccus Winogradsky. 



(Winogradsky, Schwefelbacterien, Leipzig, 1888, 79; Rhodopolycoccus Orla- 

 Jensen, Cent. f. Bakt., II Abt., 22, 1909, 334.) From Greek theion, sulfur; polys, 

 many; and kokkos, granule or small cell. 



Purple sulfur bacteria which form dense aggregates of rather solid construction 

 and irregular shape. The colonies appear, in contrast with Amoebobacier, non-mo- 

 tile and do not tend to form hollow zoogloeal structures by which they are differen- 

 tiated from Lamprocystis. Cell masses held together by mucus which does not, 

 however, appear as a regular capsule. Large clumps may fissure with the formation 

 of irregular shreds and lobes which continue to break up into smaller groups of cells. 

 Individual bacteria spherical, motility not observed. Contain bacteriochlorophyll 

 and carotenoid pigments, so that the aggregates, in accord with the dense packing 

 with individual cells, appear distinctly red. Capable of photosynthesis in the pres- 

 ence of hydrogen sulfide, when the cells store elementary sulfur as droplets inside 

 the cells. 



The type species is Thiopolycuccus ruber Winogradsky. 



1. Thiopolycoccus ruber Winogradsky. Habitat: Mud and stagnant water con- 



(Winogradsky, Schwefelbacterien, Leip- taining hydrogen sulfide and exposed to 



zig, 1888, 79; Micrococcus ruber Migula, light; sulfur springs. 



in Engler and Prantl, Die natiirlichen Illustrations: Winogradsky, loc. cit., 

 Pflanzenfamilien, i, la, 1895, IS.) From PI. IV, fig. 16-18; Issatchenko, Re- 

 Latin ruber, red. cherches sur les microbes de I'ocdan 



Cells: Spherical, about 1.2 microns in glacial arctique, Petrograd, 1914, PI. II, 



diameter. No motility observed. fig. 7. 



Genus X. Thiospirillum Winogradsky. 



{Ophidonwnas Ehrenberg, Die Infusionstierchen, Leipzig, 1838, 43; Winogradsky, 

 Schwefelbacterien, Leipzig, 1888, 104; Thiorhodospirillum Fuhrmann, Vorlesungen 

 ii. techn. Mykologie, Jena, 1913, 325; Rhodothiospirillum Bavendamm, Schwefel- 

 bakterien, Jena, 1924, 115.) From Greek theion, sulfur, and diminutive of spira, 

 screw. 



Purple sulfur bacteria, occurring singly, as spirally wound cells, motile by means 

 of polar flagella. Contain bacteriochlorophyll and carotenoid pigments, coloring 

 the cells brownish- to purplish-red. Capable of photosynthesis in the presence of 

 hydrogen sulfide, during which they produce and store, as an intermediate oxidation 

 product, elementary sulfur in the form -of droplets inside the cells. 



The differentiation of species in this group has been based exclusively on observa- 



