368 ZOOLOGICAL NOMENCLATURE. 



or when a name in derived from an accidental monstrosity, as 

 in Picus semirostris of Linnaeus, and Helix disjnncta of Turton, 

 we feel justified in cancelling these names, and adopting that 

 synonym which stands next in point of date. At the same 

 time we think it right to remark that this privilege is very 

 liable to abuse, and ought therefore to be applied only to ex- 

 treme cases and with great caution. With these limitations we 

 may concede that 



§ 11. A name may be changed when it implies a false 



proposition which, is likely to propagate important errors. 



\_Names not clearly defined may be changed."] 



Unless a species or group is intelligibly defined when the 

 name is given, it cannot be recognised by others, and the 

 signification of the name is consequently lost. Two things are 

 necessary before a zoological term can acquire any authority, 

 viz., definition and 'publication. Definition properly implies a 

 distinct exposition of essential characters, and in all cases we 

 conceive this to be indispensable, although some authors main- 

 tain that a mere enumeration of the component species, or 

 even of a single type, is sufficient to authenticate a genus. 

 To constitute publication, nothing short of the insertion of the 

 above particulars in a printed book can be held sufficient. Many 

 birds, for instance in the Paris and other continental muse- 

 ums, shells in the British Museum (in Dr. Leach's time), 

 and fossils in the Scarborough and other public collections, 

 have received MS. names which will be of no authority until 

 they are published.' 3 *' Nor can any unpublished descriptions, 

 however exact (such as those of Forster, which are still shut 

 up in a MS. at Berlin), claim any right of priority till publish- 

 ed, and then only from the date of their publication. The 

 same rule applies to cases where groups or species are pub- 

 lished, but not defined, as in some museum catalogues, and in 

 Lesson's " Traite d'Ornithologie," where mauy species are 

 enumerated by name, without any description or reference by 

 which they can be identified. Therefore, — 



§ 12. A name which has never been clearly defined in some 



published work should be changed for the earliest name by 



which the object shall have been so defined. 



[Specific names, when adopted as generic, must be c7ianged.~\ 



The necessity for the following rule will be best illustrated by 

 an example. The Corvus pyrrhocorax, Linn., was afterwards 



* These MS. names are in all cases liable to create confusion, and it is 

 therefore much to be desired that the practice of using them should be avoided in 

 future. 



