STUDIES IN THE CLASSIFICATION AND NOMEN- 

 CLATURE OF THE BACTERIA 



IX. THE SUBGROUPS AND GENERA OF THE THIO- 

 BACTERIALES 



R. E. BUCHANAN 



From the Bacteriological Laboratories of the Iowa State College, Ames, Iowa 



Received for publication October 22, 1916 



Order IV. Thiobacteriales Ordo nov. 



Cells various, typically containing either granules of free sulphur, 

 or bacteriopurpurin, or both, usually growing best in the presence 

 of hydrogen sulphide. The cells are plant-like, not protozoan-like, 

 not producing a pseudoplasmodium or a highly developed encysted 

 resting stage. Spores are rarely or never formed. 



Classification -within this group is in a very unsatisfactory and 

 very superficial state. Few investigators have studied these 

 forms, and most of the work is old, and in need of careful revision. 

 Undoubtedly many of the genera are to be regarded as growth 

 forms, merely. 



The following names have been applied to families, subfamilies, 

 tribes and subtribes. 



Chromatiaceae Migula, 1900, p. 1047 

 Amoebobacterieae De Toni and Trevisan, 1889, p. 1043 

 Beggiatoaceae Migula, 1895, p. 41 

 Amoebobacteriaceae Migula, 1900, p. 1045 

 Thiocapsaceae Migula, 1900, p. 1042 

 Thiopediaceae Migula, 1900, p. 1044 

 Rhodobacteriaceae Migula, 1900, p. 1042 

 Lamprocystaceae Migula, 1900, p. 1043 

 Athiorhodaceae Molisch, 1907, p. 28 

 Thiobacteriaceae Jensen, 1909, p. 303 



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