6 Allen on the Recognition of Geographical Forms. [January 



things in a new light, but from, I trust, a more advanced posi- 

 tion. My former tendencies, in common with those of others at 

 that time were in the direction of reducing doubtful forms to 

 synonyms, and closely related species to geographical forms. 

 Now, with much additional experience, some increase of knowl- 

 edge in respect to particular points at issue, and much more 

 abundant material, some of my former conclusions seem open to 

 revision, as I now realize that the resources then at command 

 were far less adequate for the settlement of questions at issue than 

 I then supposed them to he. 



The discoveries made during the last five years show that the 

 subject of North American ornithology is far from exhausted, 

 even in respect to the cataloguing of its numerous forms of bird 

 life, and especially as regards their distribution. To show how 

 much we did not know five years ago of the birds of even our 

 long-settled southeastern States, I have but to instance five or six 

 species — namely, Swainson's Warbler, Bachman's Warbler, Le- 

 conte's Sparrow, the Raven, and the Seaside Finches. Add to 

 this the new forms recently brought to light in this supposed 

 well-known area, and we must conclude that we are still only on 

 the threshold of a thorough knowledge of the birds of our South 

 Atlantic and Gulf States. What do we as yet know of the distri- 

 bution of many of the southern subspecies of this area, and of 

 their lines of inosculation with the northern forms? Nothing, 

 with exactness. What do we yet know of the breeding ranges of 

 the summer birds south of the Ohio Valley? Practically nothing. 

 To how slight an extent are we able to unravel the many per- 

 plexing problems of the bird fauna of the great State of Texas, 

 so peculiarly situated in relation to the East and the West, the 

 North and the South, as regards North America at large. The 

 o-reat Southwest and the great Northwest, with their opposite ex- 

 tremes of climatic conditions and peculiarities of environment, as 

 compared with the region to the eastward, still present to us 

 many perplexing problems. 



Under such a condition it is no wonder that the pendulum 

 again tends in the direction of refined subdivision. We are alert 

 for differences, with our wits sharpened to recognize slight varia- 

 tions in size, in form, and in tones of color. Our material is con- 

 stantly becoming more ample, and the meaning of slight variations 

 is thus more apparent than it otherwise would be. When large 



