SUBGROUPS AND GENERA OF THE THIOBACTERIALES 471 



Genus II. Rhabdomonas Cohn, 1875, p. 167 



Synonyms : 



Mantegazzaea Trevisan, 1879, p. 137 in part 

 Rhabdochromatium Winogradsky, 1888, p. 150 



Differentiated from Chromatium by the elongated rod-shaped 

 or spindle-shaped cells. Cells red, with sulphur granules, polar 

 flagella. 



The type species is Rhabdomonas rosea Cohn. 



Genus III. Thiospirillum Winogradsky, 1888, p. 104 



Synonym : 



Ophidomonasf Ehrenberg. 



Spiral motile bacteria containing sulphur granules and bacterio- 

 purpurin. 



The type species is Thiospirillum sanguineum (Ehrenberg) 

 Winogradsky. 



Genus IV. Rhodocapsa Mohsch, 1906, p. 223 



Cells spherical, free {not united into families) not capable of 

 swarming {non-motile). In mass the organisms are cherry red. 

 Contain sulphur granules. 



The type species is Rhodocapsa suspensa Mohsch. 



Genus V. Rhodothece Mohsch, 1906, p. 223 



Cells usually spherical and in pairs, each surrounded by a spheri- 

 cal or an ellipsoidal capsule. Non-motile. Cells not united into 

 families. Cells contain bacteriopurpurin and sulphur granules. 



The type species is Rhodothece pendens Mohsch. 



Subfamily II. Rhodobacterioideae Subfam. nov. 



Synonym : 



Athiorhodaceae Mohsch, 1907, p. 28 



Cells not filamentous, containing bacteriopurpurin but not granules 

 of sulphur. 



The genera of this subfamily have all been described by 

 Mohsch. They may be differentiated by the following key: 



