OF THE KAGU, SUN-BITTERN, AND BOATBILL. 483 
the Kagu and Cockatoo ; and in their insulation closely resemble the ardeine patches. 
Although Nitzsch' affirms of the Variegated Tinamou (Crypturus variegatus) that its 
powder-down feathers of themselves form no true tract, but are inserted into the gaps 
of the contour-feathers of the dorsal tract, in fact enclose as a fringe the hinder 
dilatation of the latter; yet a comparison of his description and figure with what 
obtains in Eurypyga and Rhinochetus persuades me that these powder-downs are a stage 
or relic of their mid-elongate dorsal patch—in short, are developed consistently with the 
nature and disposition of the dorsal contour-feather tract in the Tinamou. Again, we 
Fig. 6. 
Hinder segment of the body of Podargus cuvierii, nat. size, stripped of feathers, 
excepting the pair of lateral sacral powder-down plumose patches.—From P. Z. 5. 
1866, p. 582. 
find, in the same author’s description? of the peculiar powder-down strips in Ocypterus 
leucorhynchus, that these, three or four on each side, are fringes to the rhombic 
saddle of the spinal, femoral, and lateral branches of his inferior contour-tracts—as I 
would interpret, costo-thoracic, femoral, and dorsal powder-patches, the latter only 
developed as an ilio-lumbar segment compared with the Kagu. Of the Rapacious 
birds Gypaétus barbatus, at least in my reading of Nitzsch’s observations, possesses, as do 
the Cockatoos, a sparse distribution, on the head and neck, of what I term cranio-nuchal 
1 Ray Society’s ed. pp. 38, 117, tab. viii. fig. 12. 2 Op. cit. pp. 38, 80, tab. iii. fig. 4: 
y's ed. pp . 
3 Y 2 
