INTERNATIONAL RULES FOR ZOOLOGICAL NOMENCLATURE. 207 



a type was originally established for said genus, the generic name is 

 retained for the restricted genus containing said type. 



Art. 30. — If the original type of a genus was not indicated, the 

 author who first subdivides the genus may apply the name of the 

 original genus to such restricted genus or subgenus as may be 

 judged advisable, and such assignment is not subject to subsequent 

 change. 



In no case, however, can the name of the original genus be trans- 

 ferred to a group containing none of the species originally included 

 in the genus ; nor can a species be selected as type which was not 

 originally included in the genus, or which the author of the generic 

 name doubtfully referred to it. 



Recommendation— In selecting a type, authors should govern themselves by 

 the following : — 



a. A genus which contains a species bearing the same name, either as a valid 

 name or as a synonym, takes that species as type. 



I). Select as type some species which the original author studied personally, 

 unless it can be definitely shewn that he had some other species more particularly 

 in mind. 



c. If the original genus has already Ijeen divided without designation of type, 

 the type should be restricted by elimination, namely, by successively rejecting all 

 the species which have already been transferred to other genera ; the type is then 

 selected from the species which remain. 



If the genus contains both exotic and non-exotic species, from the standpoint of 

 the original author, the type is to be selected from the non-exotic species. 



d. Select as type the species which is best described, or best figured, or best 

 known. 



Art. 31. — The division of a .species into two or more restricted 

 species is subject to the same rules as the division of a genus. But 

 a specific name which undoubtedly rests upon an error of identifi- 

 cation cannot be retained for the misdetermined species, even if 

 the species in question are afterwards placed in different genera. 

 Example : Tcenia pecthiata Goze, 1782 = Cittotcenia pectinata (Goze), 

 but the species erroneously determined by Zeder, 1800, as ''•Tcenia 

 pectinata Goze " =: Andrya rhopalocephala (Riehm) ; the latter 

 species does not take the name Audrya pectinata Zeder. 



Rejection of Names. 



Art. 32. — A generic or a specific name, once published, can not 

 be rejected, even by its author, because of inappropriateness. 

 Examples : Names like Polyodon, Apus, albus, etc., when once pub- 

 lished, are not to be rejected because of a claim that they indicate 

 characters contradictory to those possessed by the animals in question. 



Art. 33. — A name is not to be rejected because of tautonymy, 

 th,at is, because the specific or the specific and subspecific names 



