THE BIRDS OF AUSTRALIA. 
longer and subequal, the second being noticeably shorter and equal to the 
seventh, the first narrow and very small, less than one-fifth the length of the 
second ; secondaries medium. 
The tail is long and square, tail-coverts short. 
The legs are small, the tarsus little longer than the exposed culmen, the 
anterior portions covered with five scutes with a tendency to coalescence, 
the posterior portion bilaminate. The toes are short, the hinder-toe and 
claw stoutest and longest, all claws comparatively small; anterior toes delicate, 
inner a little less than the outer. 
This small, well-defined group with no near relations provides a pleasant 
little study in the evolution of Australian birds. The series has developed 
from a rather plain little bird hi various manners, probably at varied times, 
the species retaining the coloration nearest the ancestral one being M. atri¬ 
capillus. This was mistaken for an immature by Gould, and quite recently 
De Vis described the immature of the most highly'- developed species as a new 
species allied to atricapillus. Its distribution is southern, but more restricted 
to the dry, poor Mallee lands; it also occurs on Kangaroo Island. This is quite 
an important item in the philosophical criticism of Australian bird-life. Then 
two black-headed variations evolved, one with a blackish throat, one without. 
The former exists in Tasmania as a larger bird altogether, the latter is missing, 
but a bird with an entirely black head and neck and throat appears in its place. 
In the north the former has grown a little large but appears in a more gaudy 
plumage as regards the back, otherwise with little change, while the latter 
shows scarcely any variation whatever. 
Key to the Species. 
Melithreptus. 
Head and throat black. M. affinis 
Head brown (under-surface not white) . M. atricapillus 
Head black ; white crescent-shaped mark on nape, under¬ 
surface white (smaller) . M. lunatus 
Small black patch on throat, under-surface dull (larger) 
No yellow collar on neck .. .. .. .. M. validirostris 
Small yellow collar on neck .. . M. gularis 
Pronounced yellow collar on neck (rump yellow) .. M. Icetior 
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