Art. I, — A Revision of tie genus Gymnorhina. 



By ROBERT HALL. 



[Eead 16th May, 1901.] 



The warrant for the acceptance of the species of this genus 

 appears to be as follows : — The white-backed species is difierent 

 from the black-backed species in the region of the back. The 

 Lesser white-backed species is said to be smaller than the white- 

 backed. The long-billed species is said to have a longer and 

 slenderer bill than any other of this genus. Thus, briefly, we have 

 the leading characters of the four species of this Australian 

 genus. 



Just as Gr. tibicen, Lath., of the interior of New South Wales, 

 is found to be smaller than the representatives of the same 

 species along the coast of that colony, so does G. hyperleuca, 

 Gld., of Tasmania, compare with G. leuconota, GId., which is 

 defined by Dr. Gadow^ as a smaller race of the mainland species. 

 G. tibicen I make a variety of G. leuconota, as intermediate links 

 exhibited will show, or to place it in the way suggested above, 

 G. leuconota is the larger and more developed race of G. tibicen. 

 This latter species appears to me to be the intermediate phase 

 between an extinct piping-crow, and the present whole-white- 

 backed piping-crow or magpie. 



In dimensions, certain specimens of G. leuconota show the bill 

 and body to have the same measurements as those of G. hyper- 

 leuca on the one side, and of G. dorsalis, Campbell, on the other. 

 Although the slender bill of G. dorsalis,, and the shorter one of 

 G. hyperleuca may stand as leading characters in a large number 

 of specimens, they fail to do so in a small number. There are 

 numerous specimens of G. tibicen and G. leuconota that will not 

 answer to any key to the species of Gymnorhina yet given. 

 Each appears to show reversion or hybridism upon the back for 

 the one part and want of agreement with recognised measure- 

 ments on the other, and this is especially so in the case of the 



1 Brit. Mus. Cat. Bds., vol. viii., p. 93 (1883). 



