24(J THE AMERICAN NATURALIST [Vol. XLII 



Some of these are almost certainly hybrids, but it would 

 not be safe for us to conclude that they all are. Some 

 light has been thrown on this question by the growing 

 of the extreme forms side by side, and more informa- 

 tion can doubtless be thus obtained, the principal diffi- 

 culty being that the environment of the one is often fatal 

 to the other. A better method would be to grow the 

 two apparent extremes within the natural environment 

 of the apparent intermediates. 



3. The Taxonomic Treatment of Geoitps assumed to 

 BE OF Lower Rank than Species 



There is perhaps no taxonomic subject on which 

 greater diversity of opinion and practise exists than in 

 the arrangement and nomenclature of groups of individ- 

 uals not accorded full specific value. The relationships 

 of these groups to the group assmned to constitute the 

 species proper, and the nomenclature of these subsidiary 

 groups, vary all the way from regarding them all as 

 species, to regarding some of them as subspecies, some 

 as varieties, some as subvarieties, others as forms, while 

 even finer distinctions have been attempted, and elabo- 

 rate monographs of many genera have been written in the 

 attempt to express descriptively these interrelationships. 

 It has been very evident that these described groups 

 are of unequal value, some resembling the assumed typ- 

 ical group more, some less, and in a good many instances 

 very little. The general result of these attempts to dis- 

 sect nature has been embarrassing, because when a sub- 

 sequent student takes up the group he is wholly unable 

 to determine from any descriptions that can be written 

 where any given individual would have been grouped by 

 the previous author, unless he has access to the cxctual 

 specimens which the previous author studied, and the 

 subsequent student also finds that the examination of a 

 large number of different individual specimens from 

 those studied by his predecessor contains some which 



