PROSPECTS FOR A NATURAL SYSTEM OF CLASSIFICATION OF BACTERIA 



II. Tribe Vibrioneae 



i. Chromatium Perty, 1852. 



Slightly curved rods, motile by means of cephalotrichous flagella. No endo- 

 spores formed. Photo-autotrophic, containing a red to purple pigment com- 

 plex. Normally reducing carbon dioxide with the simultaneous oxidation of 

 H 2 S or other inorganic sulfur compounds. 

 The type species is Chromatium okenii Perty. 



2. Rhodovibrio Molisch, 1907. 



Slightly curved rods, motile by means of cephalotrichous flagella. No endo- 



spores formed. Photo-heterotrophic, containing a red to purple pigment 



complex. 



The type species is Rhodovibrio parvus Molisch. 



3. Didymohelix Griffith, 1853. Syn. : Gallionella Ehrenberg, 1838. 



Curved rods, motile (?). No endospores formed. Chemo-autotrophic, oxidizing 

 ferrous iron. The ferric hydroxide is deposited in the form of a twisted band 

 which carries the organism at the top. 

 The type species is Didymohelix ferruginea (Ehrenberg) Griffith. 



4. Vibrio Miiller, 1773. 



Curved rods, motile by means of cephalotrichous flagella. Occasionally spiral 

 forms are present. No endospores formed. Chemo-heterotrophic, oxidizing 

 various organic compounds. Gram-negative. 

 The type species is Vibrio comma (Schroeter) Bergey et al. 



5. Desulfovibrio nov. gen. 



Curved rods, motile by means of cephalotrichous flagella. Occasionally spiral 

 forms are present. No endospores formed. Chemo-heterotrophic, anaerobic, 

 oxidize organic substances with the simultaneous reduction of sulfate to sulfide. 

 The type species is Desulfovibrio desidfuricans (Beijerinck), Syn.: Spirillum desul- 

 furicans Beijerinck. 



III. Tribe Pseudomonadeae 



I. Thiothece Winogradsky, 1888*. 



Ellipsoidal to rod-shaped bacteria, motile by means of cephalotrichous flagella. 

 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 Thiothece gelatinosa Winogradsky. 



* It seems highly doubtful whether the other genera created by Winogradsky for 

 similarly shaped organisms (Thiocystis, Lamprocystis, Amoebobacter, Thiodictyon) are 

 sufficiently different to be maintained. Also various of the purple sulfur bacte- 

 ria which have been described as Chromatium species should be reckoned to 



Thiottiece. 



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