Zoological Society. 403 



ranging between Haliaetus and Pandion, of which latter genus the 

 Osprey of Europe may be regarded as the type, and of which a single 

 species inhabits Australia. This bird appears to accord most accu- 

 rately with European specimens excepting in its smaller size ; and if 

 this should ultimately prove to be identical with our bird, it may 

 then be said to be universally distributed over the Old World. The 

 Osprey of America, on the contrary, presents us with some slight 

 differences, which being constant, may I think be safely regarded as 

 specific. 



" Of the genus Falco, the Peregrinus is replaced by a species most 

 nearly allied to, and hitherto considered identical with that bird : the 

 experienced eye of the ornithologist will, however, readily distinguish 

 an Australian specimen when placed among others from various parts 

 of the globe, so that there will be but little impropriety in assigning 

 to it a separate specific name. As, however, my engagements have not 

 allowed me to make that minute examination which is necessary to 

 determine the point, I defer for the present affixing a new specific 

 name for this species. The Hobby, so familiar as a European 

 bird, is represented by the Falcon, for which I now propose the 

 specific name of rufiventer, as I believe it to be undescribed. The 

 third species, which I have provisionally followed Messrs. Vigors and 

 Horsfield in placing among the true Falcons, is the Falco Berigoru, 

 whose lengthened and slightly-formed tarsi indicate a difference in 

 structure, which may ultimately prove to be generic. The Cerchnis 

 cenchroides {Falco cenchro'ides of Messrs. Vigors and Horsfield,) ex- 

 hibits a beautiful analogy with the Common Kestril of our island, 

 but although nearly allied possesses several important and permanent 

 differences. 



" The great variety of changes to which the members of the genus 

 Astur are subjected, has led to vast confusion, and it is only by a 

 minute examination of the numerous examples in my collection in 

 various stages of plumage, that I have been able to determine the 

 species with satisfaction to myself ; and if I have found it necessary 

 to consider as identical two or three species of this genus charac- 

 terised by Messrs. Vigors and Horsfield, I feel confident that it was 

 owing to the absence of sufficient materials at the time the Linnaean 

 collection was so ably named by those gentlemen, that they were 

 described as distinct. 



" My attention has of course been directed to the great difference 

 in size which exists between the males and females, and the various 

 changes from youth to maturity which occur in the members of the 

 genera Astur and Accipiter ; and I must now call the attention of 



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