508 DK. H. TON IHERING ON THE [-^-pr. 18 



2. On the Ornis of the State of Sao Paulo, Brazil. 

 By H. VON Ihering, C.M.Z.S. 



[Eeceived March 3, 1899.] 



(Plate XXVII.) 



Since my paper " As aves do Estado do Sao Paulo " (Eevista 

 do Museu Paulista, vol. iii. Sao Paulo, 1898, pp. 113-476) is 

 written in Portuguese, I believe it may be useful to offer to the 

 Zoological Society of London an account of the general results 

 at which I have arrived on this subject. 



The studies made by me during the past six years on the Ornis 

 of this State have led to conclusions concerning the geographical 

 ■ distribution of its Birds which differ essentially from those pub- 

 lished by Pelzeln in his work on the Birds collected by Natterer, 

 It is necessary to distinguish between the material results due to 

 the efforts of Natterer, the most successful of all those who h^-ve 

 ever collected in South America, and the generalizations on geo- 

 graphical provinces based by Pelzeln on batterer's collections, 

 which seem to me to be unsatisfactory. It is true that with 

 reference to Sao Paulo, Pelzeln has noted the extension of the 

 ' Minas and Matto-Grosso faunistic element into this State, but 

 he has established artificial zoo-geographical boundaries, and has 

 not noticed those really existing. 



I do not wish to be understood as in any way underestimating 

 Pelzehi's valuable memoir, but Science progresses and often modifies 

 previous results. The work of Pelzeln was based essentially upon 

 the collections of Natterer ; and Natterer travelled neither in the 

 States of Sta. Catharina and Eio Grande do Sul, nor in the littoral 

 zone between Eio and Para. The lists given by Pelzeln have been 

 greatly modified and augmented by my paper above referred to and 

 by other recent publications ; and the marked differences between 

 the highland and the coastal lowland of Sao Paulo were not 

 noticed by Natterer and Pelzeln. 



There is another reason for the differences between Pelzeln and 

 myself. Pelzeln used a statistical method to define the different 

 regions which he created, by compiling lists of the birds found in 

 one, two, or more of his regions. I believe that accurate material 

 is not yet available for this kind of Avork. This method is that of 

 abstractions and generalizations, as used by Wallace, Sclater, and 

 other great masters of Zoo-geography. But besides this method 

 we can use another, that of studying analytically the different 

 elements of the fauna of a restricted area and discoA^ering its zoo- 

 geographical boundary-lines. This course I haA^e taken in studying 

 the fauna of Eio Grande do Sul, thus verifying the different zoo- 

 geographical boundaries; and a similar result has been obtainedfrom 

 my studies on the fauna of Sao Paulo. These boundaries are of 

 secondary importance, marking natural divisions in the greater 

 Zoo-geographical Provinces : as, however, they are not artificial 

 but natural boundaries, it is important to discover them. 



