PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM 79 



wliicli it is equally evident demand, in the interests of science, proper 

 recognition. Without triuominals it would be necessary to either name 

 such forms as species, and thus convey an idea of their rank which the 

 person bestowing the name knows to be false, or else ignore them alto- 

 gether, which wonld be plainly a dereliction of duty and a positive im- 

 pediment to the progress of the science. Every local or geographical 

 variation of size, form, or color, no matter how slight, if reasonably con- 

 stant, is just so much evidence affecting the question of the derivation 

 of species, and no excuse for the exclusion of such evidence can be 

 allowed. The inability of a i)erson who has not access to specimens for 

 comparison to discriminate between slightly differentiated forms — or 

 the professed inability of the professional, whose ideas are "inspired," 

 and who therefore finds it unnecessary to descend to the drudgery of 

 handling specimens — is not a matter to be considered. As well might 

 one become a ])hysician, and be able to diagnose correctly any disease, 

 by simply having a taste for the medical profession and no opportunity 

 to devote his time ajid thought to the subject — or, on the other hand, 

 having the opportunity and means, yet discarding all the essential aids 

 to his knowledge." 



The importance of distinguishing between even slightly differentiated 

 local forms may be illustrated by an example. 



vSuppose we knew a species the breeding range of which included the 

 Eastern and Middle States of North America and the West India Isl- 

 andis. Suppose, also, that we knew that it occurs during the winter in 

 the West Indian Islands (the species consequently being resident there), 

 in Eastern Mexico, and Central America. Considering the migration of 

 such a species, we would face several important questions : Do the birds 

 living in the Eastern States during the summer pass the winter on the 

 West India Islands, and on which ? Or do they travel round the Giilfj 

 uniting with those froni the Mississippi Valley in going- down to Mexie(> 

 and Central America ! It will be seen that the solution of the questions 

 is rather difficult. How are we going to tell the birds coming down in 

 winter from the States from those remaining the whole ye'ar in the 

 Antilles? We might establish observers all along the coast to be on 

 the lookout where the migrants were wending their way, but I am afraid 

 the evidence wonld be hard to obtain, as even the whole A. O. U. "com- 

 mittee on migration," with all its observers, might look in vain for the 

 passing birds. Or we might catch lots of the latter, nml- Lave them 

 marked by differently colored ribbons, or the like. Trne,.if we could 

 X)Ossibly do it, the question might be solved in that way. I think, how- 

 ever, we will agree that the project is not practicable. Bi« if nature 

 herself had marked the birds, then we could tell just j?s well! If we 

 could possibly dislinguish those living the whole year in the Antillean 

 Islands from those breeding in the East, and the latter ap^ain from the 

 inhabitant of the Mississippi Valley, no matter how slight the distinc- 

 tion, no matter how expert the identifyer needs be, only let ii> be yo«s) 



