Genus— MACE ORTH ONYX. 
Macrorthonyx Mathews, Austral Av. Rec., 
Vol. I., pt. 5, p. Ill, December 24th, 1912. 
Type (by original designation) ... ... Orthonyx spaldingi Ramsay. 
I differentiated this genus with the diagnosis : “ Differs from Orthonyx 
in its more powerful bill and stronger legs and feet, with longer wings and 
tail ; in the wing the first primary is proportionately longer and the second 
shorter than in Orthonyx ; the fourth, fifth and sixth primaries longest and 
subequal.” 
The birds are much larger, and constitute a well-marked genus showing 
the development in size and form without alteration in the coloration to any 
appreciable degree. 
Large Orthonycine birds with long stout bills, large stiff rounded wings, 
long broad tail and comparatively huge legs and feet. 
The bill is more than half the length of the head, the nostrils longer and 
more horizontal slits ; the tooth succeeding the tip is more pronounced and 
is followed by a secondary sinuation. The wing is larger, the feathers stronger, 
the wing formula differing slightly ; the first primary is longer, more than 
half the length of the third, the second is only a little shorter than the third, 
which is nearly as long as the fourth to eighth which are longest and subequal ; 
the ninth primary is equal to the second primary, which is exceeded by the 
secondaries. 
The tail-feathers are very broad, the spiny tips short, the shafts of the 
outer feathers not very stiff, but the barbs are not disintegrated ; the shape 
is a broad rounded wedge, the centre feathers stiffest. The legs are very stout 
and powerful; the tarsus booted in front and bilaminate behind; the toes 
are strong and stout, the outer longer than the middle ; the middle claw is a 
little longer than the outer claw but still the middle toe and claw are exceeded 
by the outer toe and claw ; the inner shorter ; all the claws very long and little 
curved ; the hind-toe about equal to the inner toe but the hind claw longer 
than the inner claw ; all the toes bearing pronounced long scutes. 
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