PKINCirLES, CANONS, AND RECOMMENDATIONS. 



43 



as the type, or were it permitted to take species subsequently added to the 

 croup, and whicii the original author did not know wiicn he cstablialied 

 his "-cnus. No arbitrary rule will sufiice to determi-.p, off-iuind, questions 

 of so much complic.itiun as is often thu decision i.i rcijard to the type of 

 an ancient ;;enus which has been studied by a nujnbcr of authors." (A'ty>., 



pp. 39' 43-) 



CaNon XXII. In no case should tlie name be transferred 

 to a group containing none of tlie species originally included in 

 the genus. 



Remark. — This rule is in strict accordance with the B. A. Code and 

 with current usage. 



Caxon XXIII. If, however, the genus contains both exotic 

 and non-exotic species, — from the standpoint of the original 

 author, — and the generic term is one originally applied by the 

 ancient Greeks or Romans, the process of elimination is to be 

 restricted to the non-e.xotic species. 



Remarks. — The purpose of this restriction in the application of the ' prin- 

 ciple of elimination ' is to prevent the palpable impropriety of the transference 

 of an ancient Greek or Latin name to species unknown to the ancients. By 

 the unrestricted action of the principle of elimination the genus Teirao, for 

 example, becomes transferred to an .American species, viz., Tetrao p/iasia- 

 ncllus of Linnceus, the transference being in itself not only undesirable, but, 

 as it happens, subversive of currently accepted names. The working of the 

 proposed modification of the principle of elimination may be thus illustrated. 



The genus Tetrao Linn., 1758, contains the following 



EXOTIC SPECIES. 



3, canadensis. 



5. phasianelhis. 



6. ciipido. 



NON-EXOTIC SPECIES. 



1. nrogallus (^UrogallusY\^\Xi.^ 1822). 



2. tctrix. 



4. lagopus {Lagopus Briss , 1760). 



7. bonasia {Bonasia Steph., 1S19, -)- Bon., 1828). 



This leaves tetrix as the type of the genus Tetrao, since Lyrurus Sw. 

 was not established for it till 1831. 



On the other hand, the process of unrestricted elimination would result as 

 follows : — 



1. urogallus {UrogallHsY\tm.y\Zzz)\ 



2. tetrix {Lyrurus Sw., 1831) ; 



3. canadensis {Canace Reich., 1852) ; 



4. lagcpus {Lagopus Briss., 1760) ; 



5. phasiancllus {Pediocates Bd., 1858) ; 



