September 5, 1902.] 



SCIENCE. 



385 



extent animals are modified by their environ- 

 ment, is not tlie proper arbiter to determine 

 the value and bearing of expert knowledge. If 

 in other fields of scientific research it is not 

 demanded that the investigator stop his work 

 at the point where his results are within the 

 comprehension of the lay mind, why should the 

 student of birds and mammals be expected to 

 refrain from extending his researches be- 

 yond the point of convenience for the layman? 



Mammals, being sedentary, are very suscep- 

 tive to climate or other physical influences; 

 birds being to a greater or less extent migra- 

 tory, are perhaps, generally speaking, less so 

 although when non-migratory they respond, 

 often with great readiness, to environmental 

 influences; but in the case of non-sedentary 

 species, the fact of migration, combined with 

 the ever-varying seasonal conditions of plum- 

 age, increase the difiiculty of discriminating 

 and geographically limiting localized forms. 

 The factor of intergradation between neigh- 

 boring forms over areas connecting the main 

 differentiation regions also complicates the 

 problem of identification and leaves a consid- 

 erable proportion of connectant specimens that 

 cannot be satisfactorily referred to one rather 

 than to another of two or more geographically 

 adjacent forms. But this is as it should be, 

 if environment has any influence in modify- 

 ing animals. The real trouble is the tempta- 

 tion to indiscreet or over-ambitious special- 

 ists to give names to too many connectant 

 forms that would be better left unnamed. 



Experience shows that the ' characters ' 

 claimed by describers for their new forms are 

 rarely without basis; when the same material 

 is independently examined by several different 

 experts they generally agree as to whether or 

 not certain alleged differences exist, but they 

 may, and often do, differ in their estimates of 

 the nomenclatorial value of the differences. 

 This, as before intimated, is a condition of 

 things beyond present remedy. As regards 

 North American birds, the aspiring young 

 ornithologist has now a comparatively barren 

 field so far as the discovery of well-marked new 

 forms is concerned and the tendency is to 

 name forms not fairly entitled ' to bear the 

 weight of a name.' His ' discoveries ' are 



often not new zoological facts, but a reestimate 

 of the nomenclatorial value of facts long 

 known to the older," more experienced, and 

 more conservative workers, who have simply 

 not deemed them entitled to serve as the basis 

 of a name. But there are many exceptions; 

 as material collected in the breeding season 

 from many and widely separated regions be- 

 comes available for comparison, it not infre- 

 quently happens that differences previously 

 unnoticed, or if noticed incorrectly attributed 

 to seasonal or individual variation, are found 

 to have a local habitation and to characterize 

 distinct geographic areas. Although such dif- 

 ferences are commonly slight, at least from 

 the layman's point of view, they are zoological 

 facts that may well be recognized by making 

 them the basis of a name. 



In this connection it may be well to recall 

 the fact that not all of the many new ' sub- 

 species ' of North American birds proposed in 

 recent years are admitted to recognition by the 

 American Ornithologists' Union Committee 

 on Nomenclature, whose duty it is to examine 

 the merits of each and rule upon their admis- 

 sibility to the A. O. U. ' Check-list of North 

 American Birds ' ; at least one third having 

 been ' turned down ' or disapproved by the A. 

 O. U. Committee, while many more are still 

 in abeyance awaiting further investigation 

 by the Committee. But the adverse ruling of 

 the Committee does not always result in their 

 effectual suppression, as their authors, with a 

 small personal following, sometimes continue 

 indefinitely to recognize in their ovsoi writings 

 some at least of the discredited names. 



As already said, Mr. Clark's article is timely 

 and voices a widespread feeling among lay- 

 men, but who, it is not too much to assume, 

 are necessarily poorly equipped to render a 

 proper verdict in a field where expert knowl- 

 edge is necessary. Yet it must be conceded 

 that the laymen are in part right ; ' splitting ' 

 is undoubtedly carried too far, and that the 

 fact is well recognized, and the practice es- 

 teemed a great evil by competent judges, is 

 evidenced by the decisions made each year by 

 the A. 0. U. Committee. On the other hand 

 Mr. Clark's presentation of the case, if allowed 

 to pass without comment, might lead to erron- 



