94 NOMENCLATURE. 



"The generic name should always be retained for that portion of the original 

 genus which was considered typical by the author." 



" Example. The genus Picumnus was established by Temminck, and included two 

 groups, one with four toes, the other with three, the former of which was regarded by 

 the author as typical. Swainson, however, in raising these groups at a later period 

 to the rank of genera, gave a new name, Asthenurus, to the former group, and re- 

 tained Picumnus for the latter. In this case we have no choice but to restore the 

 name Picumnus Tern., to its correct sense, canceling the name Asthen,urus Sw., 

 and imposing a new name on the three-toed group which Swainson had called 

 Picumnus." 



" When no type is indicated, then the original name is to be kept for that 

 subsequent subdivision which first received it." 



"When the evidence as to the original type of a genus is not perfectly clear 

 and indisputable, then the person who first subdivides the genus may affix the orig- 

 inal name to any portion of it at his discretion, and no later author has a right to 

 transfer that name to any part of the original genus." 



" When an author infringes the law of priority by giving a new name to a 

 genus, which has already been properly defined and named, the only penalty which 

 can be attached to this act of negligence or injustice, is to expel the name so in- 

 troduced from the pale of science." 



" When two authors define and name the same genus, both making it exactly 

 of the same extent, the later name should be canceled in toto, and not retained in a 

 modified sense." 



" No special rule is required for the cases in which the later of two generic 

 names is so defined as to be less extensive in signification than the earlier ; for if the 

 later includes the type of the earlier genus, it would be canceled by the opera- 

 tion of the rule that the generic name should always be retained for that portion 

 of the original genus which was considered typical by the author." 



"If the later name be so defined as to be equal in extent to two or more 

 previously published genera, it must be canceled, in toto." 



"A genus compounded of two or more previously proposed genera, whose 

 characters are now deemed insufficient, should retain the name of one of them. If 

 these original generic names differ in date, the oldest one should be the one 

 adopted." 



The committee on zoological nomenclature, appointed by the American Asso- 

 ciation for the Advancement of Science, said : 



"A change in the diagnostic characters, or a revision which carries with it the 

 exclusion of certain elements of a group, or the inclusion of new elements, does 

 not authorize the change of the name or names of a group." 



" When a group or genus is divided into two or more groups, the original 

 name must be preserved and given to one of the principal divisions. The division 

 including the typical species of the primitive genus, if any type had been specified, 

 or the oldest, best known, or most characteristic of the species originally included 

 when the primitive genus was first described by its author, is the portion for which 

 the original name is to be preserved. If there is no section specially so dis- 

 tinguished, that which retains the larger number of species should retain the old 

 name, but the latter can not be applied to a restricted group containing none of the 



