1907] Beebe: Geographic Variation in Birds. 35 



of a permanent change of color, such as marks geographical races 

 or representative species for example, must obviously be due to 

 the long-continued action of the environing conditions upon the 

 whole organism." 



F — Correlation with Taxonomy. 



Up to the present time, considerations of ontogenetic, as 

 compared with phylogenetic characters or "species" have been 

 of little import to the taxonomist, considered strictly as the de- 

 lineator of living species. His business is to perfect, as nearly 

 as possible, the forging of the nomenclatural handle by means 

 of which we may grasp present conditions of life on the earth, 

 and which enables us intelligently to communicate to one another 

 the results of our studies. 



To speak in hyperbole — it has not directly concerned him 

 whether the color of Scardafella is as fleeting as the life cycle 

 of a single feather, or as permanent as the power of flight in 

 these doves. Through the processes of evolution both color and 

 flight were acquired in past time — whether at the preceding 

 moult or during the Jurassic Age; whether by a rapid chemico- 

 physical process or by gradual synthetic variation through geo- 

 logical ages — has made no difference in the delineation of species 

 living on the earth to-day. Nevertheless, in the words of Dr. 

 Merriam, "a knowledge of the degree of difference between re- 

 lated forms is infinitely more important than a knowledge of 

 whether or not the intermediate links connecting such forms 

 happen to be living or extinct." 



Regarding the characters of ontogenetic species Dr. Jordan 

 writes: "Perhaps our ornithologists will some day test their 

 species and subspecies by a test of the permanence of this class 

 of characters. No doubt we should drop from the systematic 

 lists all forms which may prove to be merely ontogenetic, all 

 whose traits are not fixed in heredity." In answer to this Dr. 

 Allen says, "any attempt to distinguish ontogenetic species from 

 other species or subspecies tends to confusion of ideas rather 

 than to any useful discriminations." 



Of course, at best, only a small proportion of living forms 

 could be so successfully subjected to transplanting or to experi- 

 mental conditions, that their exact status in an onto-phylogenetic 

 classification could be ascertained. Nomenclature is avowedly 

 artificial and imperfect: its permanence, dependent on the ex- 

 istence of the historical period of the human race; its advance, 

 on the increase of knowledge. When the new science of experi- 



