X INTRODUCTION. 



At the same time in a few cases where confusion may 

 arise the Committee have adhered to the better known name, 

 though it may not be the oldest. In these cases the name is 

 marked with J^.C., i. e. "nomen conservandum," and a list 

 of these will be found in Appendix II., together with the 

 " priority " name under the rules of nomenclature. 



GENERIC NAMES. 



Generic names can have no fixity unless the type species 

 of the genus has been determined, so that if a genus has 

 been subsequently split up, the old generic name must 

 contain the type species. 



Modern authors now almost invariably designate the type 

 species when describing a new genus, but the older 

 authors in the early part of the last century seldom 

 did so. It is therefore necessary to fix a type for these 

 older genera. 



George Robert Gray, of the British Museum, was the first 

 zoologist to recognise the great importance of the fixation of 

 the types of genera, and in 1841 he published a list of all 

 the genera of birds known to him with the type as deter- 

 mined by him. His work in this respect has been generally 

 accepted by later authors. 



The methods by which the type of a genus may be fixed 

 are as follows : 



(1) By monotypy. 



(2) By tautonymy. 



(3) By original designation. 



(4) By subsequent designation. 



(5) By (in the case of Linnaeus' genera) Linnean 



tautonymy. 



