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Show 506 DR. H. VON IHERING ON THE ' [Apr. 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 m e 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 published 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 have ever collected in South America, and the generalizations on geographical provinces based by Pelzeln on Natterer's collections, which seem to m e 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 Pelzeln's valuable memoir, but Science progresses and often modifies previous results. The work of Pelzeln was based essentially upon the collections of Natterer ; and iNatterer travelled neither in the States of Sta. Catharina and Bio Grande do Sul, nor in the littoral zone between Bio and Para. The lists given by Pelzeln have been greatly modified and augmented by m y 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 work. 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 discovering its zoo-geographical boundary-lines. This course I have taken in studying the fauna of Bio Grande do Sul, thus verifying the different zoo-geographical boundaries ; and a similar result has been obtainedfrom m y 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. |