THE BIRDS OF AUSTRALIA. 
Utakwa Rivers, South-west New Guinea, wrote : “ I am not fully satisfied that 
these three birds have been rightly referred to typical C. castaneiventris. 
Compared with the type specimen from Cape York and with birds from the 
Astrolabe Mountains, they seem rather darker, especially on the underparts, 
and sUghtly larger. Wing 115, 115, 116, as compared with type 112 and 
Astrolabe Mts. 112 and 112 mm.” 
I had in the Austral Avian Record, Vol. II., p. 92, 1914, described Cacomantis 
castaneiventris hihagi from Bihagi, head of the Mambare River, British New 
Guinea, writing : “ Differs from C. c. castaneiventris in being much darker on 
the under-surface.” 
Ogilvie-Grant also admitted from the Mimika, Wataikwa and Iwaka 
Rivers a series under the name G. c. arfahianus Salvadori, writing : “ These 
birds seem to be undoubtedly referable, and agree with the description in 
being smaller and paler both above and below.” 
I have examined the series Ogilvie-Grant was considering and find they 
are all referable to one form, the dark coloured specimen being adult, while the 
fighter ones are the first adult plumage, the shortness in wing measurement 
being due to the fact that the birds were in moult. That they should have 
been regarded, for a moment, as representing two forms, indicates the com- 
plexities in connection with the identification of birds of this family. 
Ogilvie-Grant also described a young bird, remarking : “ As in the young 
of C. castaneiventris Gould,” but only the New Guinea young had been 
previously described by Rothschild and Hartert {Nov, Zool., Vol. XIV., p. 436, 
1907), and the only immature of the Australian bird that I Imow is in my 
collection. 
I here describe the young and have had a figure prepared, which will appear 
later, and have based a generic distinction upon the difference between the 
immature and those of its supposed congeners. In this way we may arrive at 
the truth. Recently a noted worker suggested that the nomenclature of 
birds was more necessary as a “ left luggage ” ticket than as a means of 
displaying facts — an extraordinary conclusion with which I totally disagree. 
The whole end of ornithology in my view is the elucidation of the economics 
of bird-life and structure, internal and external, to the co-operation with 
other scientists in the advancement of knowledge. 
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