484 DR. J. MURIE ON THE DERMAL AND VISCERAL STRUCTURES 
powder-down patch. Others (the noble Falcons and the Kites, to wit) have short, or 
more elongate, dorsal powder-down patches. 
The above distinguished ornithologist, while in general disallowing or, more strictly 
speaking, not accepting the dust-bearing feathers as being distributed in special tracts, 
subsidiary or equivalent to his contour-feather lines and featherless interspaces, never- 
theless was shrewd enough partially to employ them for characterizing a few of the 
species of Falconide. He shows that in Elanus furcatus there is a large powder-down 
strip on the hinder surface of the back, but that in EZ. melanopterus and Cymindis 
uncinata they form two symmetrical tracts on the sides of the pelvis. 
Furthermore, even laying more weight on the shortening and lengthening of this 
obvious dorsal powder-patch, he says’, “but the Harriers may be with more certainty 
distinguished as a form differing at least from all other European Falcons by the 
powder-down tracts which ascend on each side of the dorsal portion of the spinal tract 
as far as the shoulders.” 
It follows, from what precedes, that mere possession of powder-down feathers does not 
prove alliance of ornithic orders—but species, genera, and subfamilies in some instances 
indicate their connexion or distinctness by the restricted or profuse character of their 
powder-down patches,—also that this continuously growing plumage casting off dust- 
particles is not indiscriminately strewn among the feathering, but occupies in all birds, 
where present, different areas referable to a type whereof the Kagu affords a well- 
developed example. The powder-downs, besides, may be closely aggregated in a brush, 
set in serried ranks, or even only discernible as short sproutlets intermingled with the 
ordinary down-, contour-, and other feathers. 
2. Tegument of the Lower Limb. 
The superficial dermal vestment of the lower extremities of the Kagu presents the 
subjoined characteristics, which are more or less displayed, on a reduced scale, in the 
accompanying figs. 4 & 5, Pl. LVI. ‘The legs and feet are clothed with bright orange- 
coloured cutaneous scales, having the following shapes and dispositions:—At the 
tibio-tarsal joint in front are numerous (17 or 18) rows of very small roundish or 
polygonal scales, which diminish in numbers (12) laterally. Behind the same joint, 
and slightly on a lower level, are a score or more somewhat larger transverse scale- 
plates, some of which at the sides have tiny marginal attached scales, these inter- 
digitating with the common intervening lateral ones. In front of the tarso-metatarsal 
bone are some twenty large scutes or scales stretching from side to side of this part of 
the leg, but leaving clear longitudinal side interspaces between them and the posterior 
scutes. The middle dozen or thereabouts of these anterior scales assume very convex 
upper and concave lower margins; but those placed at the proximal and distal 
extremities of the long bone become less arched in form, while decreasing likewise in 
' Pterylography, p. 66, Engl. ed. 
