Bacteria and Viruses 55 



Rule 9c. Designation of Nomenclatural Types 



(c) If none of the species named by an author in his original de- 

 scription and publication of a generic name can be recognized, 

 that is, if no identifiable type species can be selected in accord- 

 ance with the rules, the Judicial Commission may issue an Opinion 

 declaring such generic name to be a nomen rejiciendum and 

 without standing in nomenclature. However, if such generic 

 name has come into use for identifiable species named subse- 

 quently, one of these later species may be selected by inter- 

 national agreement as the type species with the generic name 

 ascribed to the author of the binomial designated as the type 

 species. Such selection of a type species and recognition of the 

 author of the generic name must be based upon an Opinion by 

 the Judicial Commission, and if such Opinion is questioned, its 

 validity shall be determined by action of the International Com- 

 mittee on Bacteriological Nomenclature. 



(d) The publication of a new generic name as an avowed substitute 

 for an earlier one does not change the type of the genus. 



ANNOTATIONS 



Rule 9c. The use of the type method as a guide in taxonomy and 

 nomenclature was first adopted by the zoologists, then by the botan- 

 ists. Recognition of the principle by the bacteriologists came later, in 

 part because of the difficulty in determining what should constitute 

 the type of a species. Obviously no nomenclatural types were desig- 

 nated for the genera described by the early ^vorkers in bacteriolog) . 



Botanical rules relating to the designation of type species. The 

 Botanical Code and the Bacteriological Code are substantially the 

 same in essentials. The Botanical Code provides that if the author of 

 the generic name did not designate a type species, but gave to a spe- 

 cies a specific epithet typicns or typus, that species shall be regarded as 

 the type species. 



Zoological rules relating to designation of type species. While 

 quite differently phrased and much more complex and detailed, the 

 Zoological Rules do not differ markedly in essentials from those of 

 the Bacteriological Code. 



The Zoological Rules permit tautonomy, that is, the use of the 

 same word for the generic name and for the specific name (specific 

 epithet) of the name of a species, as in the name Trutta trutta. 

 Tautonomy is forbidden in Botany and Bacteriology (Ride 25) . 



The Zoological Rules state: 



If a nominal genus, witliout originally designated or indicated type, 

 contains among its original nominal species one possessing the 

 generic name as its specific or subspecific name, either as its oldest 

 available name or as a synonym, that normal species or subspecies 

 becomes ipso facto type of the nominal genus. 



The Zoological Rules also include a Recommendation with a 

 list of precepts that should be followed in order of precedence in 



