92 International Code of Nomenclature 



Rule 24. Rejection and Replacement of Names 



Rule 24d. Pfeifferelln Buchanan 1918, proposed as a generic name 

 in bacteriology, is illegitimate because it is a later homonym of 

 Pjeifferella Labbe 1899, proposed as a name for a genus of protozoa. 



Rule 24e. Bncterium Ehrenberg 1828 has as its type species Bacterium 

 triloculare Ehrenberg 1828. The type species has never been identified 

 or observed with certainty since Ehrenberg's first observation. The 

 generic name has been applied by later writers in so many ways as 

 to lead to major confusion and misunderstanding. The Judicial 

 Commission issued an Opinion placing the generic name Bacterium 

 Ehrenberg 1828 in the list of rejected names {nomina rejicienda) , 

 as an ambiguous name (nomen ambiguum) . 



Rule 24 j. Names have been given to many taxa of bacteria, particu- 

 larly to species, for which there are no descriptions adequate for 

 identification, and of which there are no known cultures. Such names 

 are placed in the list of noynina rejicienda as nojnina ditbia. Oc- 

 casionally a later student may be able to reisolate and identify ade- 

 quately an organism named in the list of nomiua duhia, from which 

 list it will then be removed. 



Rtile 24g. There are numerous instances in the literature of bac- 

 teriology in which the description of a purported new species was 

 based upon a mixed or impure culture. Weinberg and Seguin (1918) 

 described a new species under the name of Bacillus aerofoetidus. This 

 was later shown to be a mixed culture containing three species, two 

 of them being Clostridium welchii (C. perjringens) and C. oede- 

 matis. The characters of the genus Malleomyces Hallier 1870 were 

 derived from various fungi and bacteria erroneously supposed to be 

 growth forms of a single organism. The name is illegitimate. 



Rule 24h. A bacterial culture which became infected with a bac- 

 teriophage might produce colonies not characteristic of the species, 

 and the supposedly different organism might be given a new name. 

 Such a variant culture would be classed as an abnormality, and a 

 new species name gi\en to distinguish it would be illegitimate. 



