2 Proceedings of the Royal Society of Victoria. 



bill. In reality, as I see it, the specimens of G. tibicen show an 

 advance in plumage development by losing nearly all of the 

 black saddle in favour of a " white-back," while certain of those 

 of G. leuconota have undergone reversion, in part, to the 

 present day " black-back." Specimens by measurement connect 

 the two. It is particularly interesting to see in specimens of 

 the fledglings of G. dorsalis, the nearest approach to what 

 appears to me as the original uniform black type. 



The principal plumage-phases of all the Gyuinorhinae appear 

 in G. dorsalis. 



(1). We have the fledgling shewing two phases — one, appar- 

 ently a relic of an early ancestor of the various existing magpies, 

 with the back almost black, or more or less slightly pied, from 

 the nape to the upper tail coverts, both of these narrow regions 

 being pure white ; and the second with a very small amount of 

 black upon a nearly pux'e white back. 



(2). The saddle-back of G. tibicen, slightly greyer in colour, is 

 shewn in an immature male bird found to be breeding. 

 (3). A pur-e white-back in the adult of each sex. 

 At Bacchus Marsh, Victoria, the hybrid-like birds of G. leuco- 

 nota are plentiful, as Messrs. C. C. and T. A. Brittlebank have 

 observed ; while at Western Port, Victoria, they are less so. 

 At Horsham, Victoria, the hybrid-like phase of G. tibicen is 

 plentiful, while whole white-backs are found breeding in the 

 same district and have been shot from the same flocks. Just as 

 a black -backed phase of G. dorsalis has been observed in Western 

 Australia, by the writer, to be mated with a whole white-back, 

 so has the .same been noted with G. tibicen and G. leuconota 

 (judging by the backs alone) in the Wimmera. One female bird 

 procured at Essendon, Victoria, referred to later, I can only 

 place as a probable specimen of G. leuconota. In Central 

 Australia specimens were collected by Mr. Keartland on the 

 Horn Expedition, and marked by Mr. North as belonging to G. 

 tibicen. The " saddles " are feebly represented (narrow and 

 disjointed) and belong to birds shewing reversion if G leuconota, 

 "development" if G. tibicen, or hybridisation. 



It is generally thought that G. tibicen and G. leuconota 

 occupy different sides of the Great Dividing Range of Victoria. 

 To an extent only that is so. Each of their young ha.s been found 



