Bacferia and Viruses 85 



Rules 20, 21. Sect. 5. Changes in Names of Taxa 



RULE 20. When several genera are united as subgenera under one generic 

 name, the subgenus including the type of the generic name used must bear 

 that name unaltered. 



ANNOTATIONS 



Rule 20. Pederson 1945 included the genera Thermobacterium Orla- 

 Jensen 1919, Streptobacterium. Orla-Jensen 1919, and Betabacterium 

 Orla-Jensen 1919, in the genus Lactobacillus Beijerinck 1901. The 

 type species of Lactobacillus is L. caucasicus (Beijerinck 1889) Bei- 

 jerinck 1901. Pederson defined the subgenus Thermobacterium to 

 include L. caucasicus {Lactobacillus [Thermobacterium] caucasicus) . 

 This recognition of Thermobacterium as a subgenus does not con- 

 form to Rule 20. The subgenus which includes the type species of 

 the genus should bear the name Lactobacillus, of which the sub- 

 generic name Therjuobacterium (Orla-Jensen) Pederson becomes a 

 svnonvm. 



RULE 21. When several species are united as subspecies (varieties) under 

 one specific name, the subspecies v/hich includes the type of the species used 

 must be designated by the same epithet as that of the species. 



ANNOTATIONS 



Rule 2L Smith 1948, in his revision of the species Bacillus subtilis 

 Cohn 1872, included as subspecies Bacillus aterrimus Lehmann and 

 Neumann 1896 and Bacillus niger Migula 1900. He correctly re- 

 named them Bacillus subtilis var. aterriynus and B. subtilis var. niger. 

 Under the Bacteriological Rule Smith's revision automatically cre- 

 ated a third variety (subspecies) Bacillus subtilis var. subtilis of 

 which the type cultuie is that of the species. 



