WALKER : ON THE USE OF CERTAIN I'REOCCUI'lED NAMES. 239 



That this rule is necessary so far as specific names are concerned is 

 obvious. But its application to sub-specific and varietal names is of 

 comparatively recent date and would seem to be neither necessary nor 

 expedient. The only reason for its adoption that can be urged is that 

 the line between species and varieties is a fluctuating one, and in many 

 cases, a matter of individual opinion ; and that in case a variety, 

 which bears the name already in use for a species, is raised to specific 

 rank, its varietal name would (if subsequent) become a homonym and 

 have to be changed. While this is undoubtedly true, the real question 

 is whether it is not better to deal with such comparatively rare cases 

 in that way rather than to precipitate the tremendous confusion that 

 will necessarily result if the rule of tlie International Code is to be 

 enforced in the nomenclature of the Palsearctic Fauna. 



That the rule has never been recognized by the European con- 

 chologists is evident upon a most cursory glance at the Conchological 

 Society's " List of Brit. L. & F. W. Shells " or Westerlund's 

 Palaearktischen Fauna, where, in species after species, varietal names 

 such as major, minor, alba, or?iata, etc., etc., are recognized as 

 perfectly valid. Indeed, there is no good reason why there should 

 not be a var. major and a var, minor (if the facts justify the descrip- 

 tion at all) of every species in the list. There would be no practical 

 confusion as the varietal name is always used in connection with 

 the specific one. 



Moreover, cases where forms described as varieties are subsequently 

 given specific rank have always been comparatively rare, and in these 

 days of nice distinction are even less hkely to occur. 



On the other hand, the enforcement of the rule (and it should not 

 have been promulgated, if it was not to be enforced) will result in the 

 renaming of hundreds of well recognized varieties and the creation of 

 an equal number of unnecessary synonyms. And all for no practical 

 purpose, except perhaps the enhancement of the fame of the closet 

 naturalists at the expense of those, who in good faith and in 

 accordance with the recognized usage of their day have done original 

 investigation. 



Ex post facto laws are usually unjust, are abhorrent to the judicial 

 mind and in many countries are void in their inception. It would 

 certainly seem that in so far as Article XI makes specific and varietal 

 names in force before its adoption of co-ordinate rank, it is an ex post 

 facto law of the rankest kind and should never have been adopted. 



As a practical example of the evils that will result from the 

 application of this rule, take the case of the use of the var. major. 



It appears from the Society's List that four British Helices have 

 recognized varieties under this name. Moquin-Tandon describes 



