154 s. CK)ïo : 



" Without calling iu question the accuracy of M. Peeeiek's determina- 

 tion, the occuiTenee of such instances as this of a form presenting strongly 

 marked variations at different stations within the area of its distribution, 

 m*ges upon natm-alists the necessitr^' of exercising extreme caution against 

 being led away by a tendency to group too comprehensively the forms which 

 may be included within a large and widely distributed genus ; for however 

 seriously the multiphcation of frivolous ' species ' may embarrass a classifica- 

 tion, the wholesale gi-ouping, or, in other words, the unlDounded extension of 

 the limits of specific character, is productive of much more injurious results, 

 in that it curtails the precision of definition, and, whilst ignoring environ- 

 ment as a factor, divests nomenclature of one of its liighest and most 

 important quaHties. 



" From the fact that forms are separated by much smaller and less 

 striking differences in an extensive genus than in one of more Hmited scope, 

 * species ' in the larger group have often not such clearly marked or con- 

 spicuous characters as those wliich are presented by ' varieties ' in a less 

 comprehensive genus. It follows that the judgment should be very cautiously 

 excercised when tempted to embrace witliiu a single species all the strongly 

 marked distributional extremes of any widely-spread type, however closelj* 

 their connexion may seem to be preserv^ed tlu"ough intermediate forms ; for 

 in many cases these gradations are nothing more or less than the links 

 which indicate to us the development of ' species,' and are, iu shoi-t, the 

 stages with which generally we are unacquainted, owing either to the im- 

 perfection of knowledge, or more frequently by reason of their destruction 

 tlu'ough the hostility of imfavom-able conditions. 



" Taking into consideration the advance which knowledge is continuallj' 

 making by means of the addition of new material from liitherto unexplored 

 fields, the process of too comprehensive grouping would ultimately result in 

 the fomation of series which, from their unwieldiness, would require arbitrary 

 division for the mere purposes of classification and comprehension, if the 

 ordinaiy natural distinctions be ignored. Of course it will be acknowledged 

 that • species ' are but arbitraiy divisions after all, and that a nomen triviale 

 serves but to register the state of information and our opinions upon ceiiain 



