EXTERNAL ANATOMY. SCANSORIAL FEET. 143 
hatches, of equal length to the middle one ; yet it is 
even of greater power than in these latter birds, for 
towards the end of the claw there is a small notch, 
apparently intended to give an additional supporting 
power to the hallux, this notch being constructed for the 
purpose of resting upon the bark, in like manner as the 
point itself : there is a very shght tendency to this 
structure, almost imperceptible, in our common nut- 
hatch ; but it has never been noticed, and probably 
would not have been now observed, had not our atten- 
tion been drawn to it by finding it so conspicuous in 
the Brazilian bird. Having now described the foot of 
Sclerurus, the rasorial genus of the circle of Certhiarue, 
the ornithologist will be Iwtter prepare<l to understand 
the next modification, as seen in 
the Australian genus Orthonyx 
{fig. 77')- imagine, 
therefore, a bird rather larger 
than a sparrow, but with the 
general form and proportions 
of the Menura, except in the 
tail, which is that of Sde.ru- 
rus. Like ilf finMra,the bill (a ,«) 
is short, arched, and rasorial, 
the wings rounded, and the feet 
enormously large and strong. The relative length of the 
toes (b) is altogether peculiar ; the outer one is actually 
longer (in a slight degree) than the middle, while the 
two outer claws (unusually slight in their curvature) 
are one-third as long as the toes ; the hallux is as long 
as the middle toe, but one-half its length is occupied by 
the claw. Now we think it quite obvious that claws, 
so constructed, were never intended to he used for 
ascending trees, and yet the rigidity of the tail would 
imply that this most singular bird feeds in a semi- 
perpendicular attitude, for if otherwise, such a tail 
could be of no use. Our specimen confirms this sup- 
position, for the ends of the feathers, or rather the 
webs, are much worn away. We hazard the conjecture. 
