SELECTED PAPERS 



been observed. No endospores formed. Photo-autotrophic, containing a green 

 pigment complex. Reduce carbon dioxide with the simultaneous oxidation 

 of H 2 S to sulfur. 

 The type species is Chlorobium limicola Nadson. 



2. Thiopolycoccus Winogradsky, 1888. 



Spherical cells, usually occurring in irregular masses, motility has not been 

 observed. No endospores formed. Photo-autotrophic, containing a red to purple 

 pigment complex. Normally reducing carbon dioxide with the simultaneous 

 oxidation of H 2 S or other inorganic sulfur compounds. 

 The type species is Thiopolycoccus ruber Winogradsky. 



3. Rhodococcus Molisch, 1907 (non Zopf). 



Spherical cells, motility has not been observed. No endospores formed. Photo- 

 heterotrophic, containing a red to purple pigment complex. 

 The type species is Rhodococcus capsulatus Molisch. 



4. Achromatium Schewiakoff, 1893*. 



Large spherical cells, motile (no flagella?). No endospores formed. Chemo- 

 autotrophic, oxidizing H,S or other inorganic sulfur compounds. 

 The type species is Achromatium oxaliferum Schewiakoff. 



5. Siderocapsa Molisch, 1909. 



Spherical cells, motility has not been observed. No endospores formed. 

 Chemo-autotrophic, oxidizing ferrous iron. 

 The type species is Siderocapsa treubii Molisch. 



6. Nitrosococcus Winogradsky, 1892. 



Spherical cells, motile by means of a single flagellum. No endospores formed. 



Chemo-autotrophic, oxidizing ammonia to nitrite. 



The type species is Nitrosococcus nitrosus (Migula) Buchanan. 



7. Neisseria Trevisan, 1885. 



Spherical cells, normally occurring in flattened pairs, immotile. No endospores 

 formed. Chemo-heterotrophic, oxidizing various organic compounds. Gram- 

 negative. 

 The type species is Neisseria gonorrhoeae Trevisan. 



8. Micrococcus Cohn, 1872.** 



Spherical cells, occurring singly, in pairs, or in irregular masses. Either motile 

 or immotile. No endospores formed. Chemo-heterotrophic, oxidizing various 

 organic compounds. Gram-positive. 

 The type species is Micrococcus luteus (Schroeter) Cohn. 



* It seems probable that the organisms described as Hillliousia, Modderula, Thio- 

 physa, and Thiovidum species belong to this genus. 



** There should, perhaps, be a genus containing Gram-negative oxidative cocci in 

 addition to the genus Neisseria, the more so since the katabolism of representatives 

 of this genus is insufficiently known. Although Prevot (I.e.) is inclined to include 

 also aerobic Gram-negative species in his genus Veillonella, this generic name will 

 be used by us to designate the corresponding anaerobic species only. 



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