IA.8 Allen, Origin and Distribution of N. A. Birds. \ April 



The term Sonoran, used in this extended sense, seems at least in- 

 appropriate if not misleading, as there are few if any strictly 

 'Sonoran' types represented in that portion of the United States 

 situated to the eastward of the Mississippi River. The more 

 descriptive and appropriate designation of 'Warm Temperate' is 

 therefore preferred for the region in question, since it not only 

 has priority, but is in harmony with the terms Arctic, Cold 

 Temperate, and Tropical, used currently for other coodinate 

 areas of the continent. 



Another, and perhaps the only other, important discrepancy 

 between Dr. Merriam and myself is in respect to the primary ' 

 subdivisions of the Warm Temperate or 'Sonoran' Subregion. 

 Here the difference is in respect to classification, Dr. Merriam 

 dividing the Warm Temperate into two transcontinental divi- 

 sions which he terms respectively 'Upper' and 'Lower Sonoran' ; 

 while according to my best judgment the primary division is in 

 a meridional line into an eastern and a western division, which 

 I have termed respectively Humid and Arid Provinces, borrow- 

 ing the terms from Dr. Merriam, who has used them in the same 

 geographical sense but not in the same nomenclatural relation, as 

 already shown in preceding pages. As the evidence, pro and 

 con, has already been submitted (see antca, pp. 128-131, and 

 Bull. Am. Mus. Nat. Hist., IV, pp. 230-232), it is unneces- 

 sary to rediscuss the matter here. 



In respect to the subdivisions respectively of the Humid and 

 Arid Provinces, my subprovinces correspond to his secondary 

 divisions of the ' Sonoran ' (with slight modifications, as already 

 explained), my Appalachian Subprovince being essentially his 

 ' Humid Upper Sonoran,' my Austroriparian Subprovince his 

 'Humid Lower Sonoran,' my Campestrian Subprovince his 

 'Arid Upper Sonoran,' and my Sonoran Subprovince his ' Arid 

 Lower Sonoran.' My division of the Campestrian Subprovince 

 into Districts conforms nearly with Dr Merriam's division of the 

 same geographical area, 1 and I have adopted for these areas the 

 same descriptive appellations. 



Taking Dr. Merriam's latest paper on the faunal areas of 

 North America and accompanying map, 2 one other point of 

 difference calls for notice, namely, his recognition of a 'Transition 



1 N. Am. Fauna, No. 3, p. 25. 



2 Proc. Biol. Soc. Wash., VII, pp. 1-64, April. 1892. 



