Genus— ACANTHIZA. 
Acanthiza Vigors and Horsfield, Trans. Linn. Soc. 
(Lond.) Vol. XV., p. 224, Feb. 17, 1827. Type 
( by original designation) ... ... ... ... Motacilla pusilla White. 
Very small birds with medium bills, long rounded wings, long rounded tail 
and long slender legs and weak feet. 
The bill is more than half the length of the head, very slender, laterally 
compressed but a little expanded basally ; the culmen ridge sharp, nearly 
straight, a little decurved at the tip which is rather long and sharp with a notice- 
able posterior notch ; the nostrils are linear, strongly operculate, the nasal 
groove less than one-third the length of the bill ; nasal bristles few, rictal 
bristles strong and about six in number ; under mandible fairly strong, inter- 
ramal space very small and feathered. 
The wing-feathers are strong, the fourth, fifth, sixth and seventh primaries 
equal and longest, the third a little less and subequal to the eighth, which is 
longer than the secondaries ; these, however, exceed the second primary in length 
which is about twice the length of the short first primary. 
The tail is long and a little rounded in shape. 
The legs are long and slender, the tarsus booted in front and bilaminate 
behind ; the feet are weak, the middle toe and claw equal to the hind-toe and 
claw, the latter claw strong and rounded, those of the anterior toes delicate ; 
the inner and outer toes are subequal, and inner toe and claw just exceeds 
middle toe without claw. 
These little Australian birds, known in Australia as Tits, are classed by 
extra-limital systematists in the Sylviidse, but there is so little known about 
the anatomy of small passerine birds that such an association cannot be success- 
fully tested at present. I certainly question any near Sylviine relationship 
judging from European typical Warblers. 
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