THE BIRDS OF AUSTRALIA. 
I have critically examined the accumulation of these birds at the British 
Museum and at the Rothschild Museum, Tring, and I do not consider the 
facts to be clearly expressed by the acceptance of one specific entity. 
I would consider the recognition of two species to more nearly suggest the 
truth. I was impressed bj^^ the fact that the interbreeding of the dark and 
white forms has been so much discussed, that every collector has obtained, 
if possible, a specimen showing such interbreeding in its plumage ; yet these 
are comparatively few, and some noticeable points can now be formulated. 
As first suggested, the white is neither the adult nor juvenile of the 
dark form, but is quite a fixed albinism, breeding true ; when it does inter- 
breed we find recorded pure white and dark young in the nest, all dark 
young, or all pure white in the nest. The collected birds which, it is 
suggested, prove the dimorphism of the species, are nearly all white with 
odd dark feathers. Very rarely are dark birds with a few white feathers 
recorded or collected. This is suggestive. From many localities no inter- 
breeding, or very little, is known ; while in some few localities quite a 
considerable amount of interbreeding takes place, but even then it is to 
quite a limited extent. 
Now, if these were simply dimorphisms, interbreeding would be the rule, 
not the exception ; we should find every variation of plumage in a colony, 
and have a large number of birds with the dark colour predominating. This 
is not the case, and in New Zealand the white bird does not occur at all, while 
to the North of this place the most pronounced cases of interbreeding occur. 
The interbreeding of the Carrion-Crow and the Hooded Crow has attracted 
the attention of many European ornithologists, yet these are admitted to be 
distinct species. 
I conclude that these dark and white Herons constitute a parallel case, 
and am recognising two species, and consider the birds showing mixed 
plumage should be ranked as hybrids. This conclusion forces the rejection 
of Ardea sacra Gmelin, as being based upon a hybrid. 
The next name to be considered is Ardea novce-guineoe Gmelin {Syst. Nat., 
p. 644, 1789 ; New Guinea), which must also be considered too doubtful to 
use. The figure is too bad for accurate determination, and the length is 
given as “10 pollices longa.” 
We must next investigate the name Ardea matooTc VieiUot {Nouv, Diet. 
d'Hist. Nat, Vol. XIV., p. 416, 1817), which is thus introduced : “ Ardea 
matook, Vieill., se trouve a la Nouvelle HoUande, sur les rivages du Canal 
de la Reine Charlotte, ou il porte le nom que nous lui avons conserve. II 
est de la taille du crabier bleu a cou brun, auquel Latham le rapporte. Le 
matook a le bee, I’iris, le lorum et les pieds jaunes ; la gorge blanche ; les 
