BIRDS. 
19 
tipped with white, their bases irregularly barred with transverse marks of 
brown and white. Under surface. — Chin, throat, breast, belly, thighs, under 
tail-coverts, under lining of wings, and edge of shoulders perfectly white. 
On the flanks, however, there are some brown feathers irregularly inter- 
spersed ; and on the lower part of the breast, most of the feathers show 
a most obscure margin of pale brown. Bill horn-colour. Cere and tarsi 
yellow. 
Form. — Cere and nostril as in the M. Leucurus, but the bill not quite so 
strong. Feathers on the sides and back of head narrow and rather stiff ; 
those on the shoulders obtusely pointed, — which character of plumage is very 
general in this sub-family. Wing : fourth primary very little longer than 
the third or the fifth, which are equal to each other. First primary three 
inches shorter than the fourth or longest, and more nearly equal to the 
sixth than to the seventh. Extremity of wing reaching to within about an 
inch and a half of the tail. Tarsi reticulated, with four large scales at the 
base : upper part covered with plumose feathers for about three quarters of an 
inch below the knee ; but these feathers hang down and cover nearly half of 
the leg. Middle toe with fifteen scales, outer ones with about nine. Claws 
of nearly the same degree of strength, curvature and breadth as in Polyborus 
Prasiliensis, or in M. leucurus , but sharper than those of the latter. 
Inch. 
Total length 
. 20^ 
Tail 
. 9 
Wings when folded .... 
. 15f 
From tip of beak to anterior edge of eye 
• 15 
Tarsus from soles of feet to knee joint 
■ 3 i 
Hind claw measured in straight line from 
tip to root ...... 
Claw of middle toe, a twentieth less than that 
of the hind one. 
Habitat, Santa Cruz, 50° S. Patagonia. {April.) 
Mr. Gould, at the time of describing this species, entertained some doubts 
whether it might not eventually prove to be the Phalcobcenus montanus of D'Orbigny, 
in a state of change. I have carefully compared it with the description of the 
P. montanus, and certainly, with the exception of the one great difference of 
M. albogularis having a white breast, whilst that part in the P. montanus is 
black, the points of resemblance are numerous and exceedingly close. The 
M. albogularis, appears to be rather larger, and the proportional length of the wing 
feathers are slightly different ; the cere and tarsi are not of so bright a colour ; 
the middle toe has fifteen scales on it instead of having sixteen or seven- 
teen. The black shades of the upper surface are pitchy, instead of having 
an obscure metallic gloss, and the feathers of the shoulders are terminated 
with brown, so as to form a collar, which is not represented in the figure of 
d 2 
