470 DR. J. MURIE ON THE DERMAL AND VISCERAL STRUCTURES 
where the barbs become filiform. The upper third of each feather has fewer barbules, 
the barbs appearing mainly hair-like (see fig. 2, p. 469). The tail- and wing-feathers 
have strong shafts, and the vane is more or less equally disposed on either side of the 
shaft. Further satisfactory examination was prevented in consequence of their imper- 
fect condition. 
The contour-feathers, for example the upper wing-coverts (see fig. 3, p. 469), retain, to 
a certain extent, the peculiarities mentioned in the crest-feathers. They have also 
accessory plumes, but of increased size. The proximal two-thirds of the vane has 
remarkably long and beautiful plumose barbs downy to its very extremity. The 
distal third of the feather has stronger barbs, more closely set together, and inter- 
woven by the overlapping barbules. Only at the tips is the capillary nature of the 
barbs witnessed. 
The down-feathers are very profuse; they likewise have elongated, very velvety 
accessory plumes. Their barbs are almost of equal length from base to tip of the vane ; 
and the barbules, very great in number, are extraordinarily light and delicate (see fig. 4, 
p. 472). Between these down-feathers of the Kagu and those of Psophia there is a 
strong resemblance. 
The feathers of the Sun-bittern come wonderfully close to those of the Kagu, with- 
out, however, assuming identity. Whilst fashioned in general as above described and 
figured, the following differentiation is noticeable:—The accessory plume is not so 
strongly developed, the barbules and barbs are less downy, and, of those that possess 
them, the filiform terminal points are harsher. The elegant, soft, fluffy barbs and 
barbules, so characteristic of the down-feathers in the Kagu, are much reduced in the 
Sun-bittern. 
With regard to colouring, although the outward hue of Rhinochetus is slaty, yet, as 
Mr. Bartlett has stated, the markings upon the wing- and tail-feathers, viz. the bars of 
brown, black, and grey, bear much resemblance to those of Hwrypyga. The same 
cannot be said of Cancroma, where a generally diffused brown tint is prevalent. 
In the Boatbill the feathers are of a stiffer nature than in the two species already 
compared. This is in the main caused by the strength of the shaft and the barbs. 
The component parts of the feathers otherwise are like those of the Kagu, but, from 
the peculiarity mentioned, appear far less plumose and downy. ‘They possess the 
accessory plume. 
So far as structure is concerned, the feathers of the Boatbill approach much nearer 
to those of the Night-Heron (Nycticorax) than to those of the Kagu or Sun-bittern, In 
the Night-Heron the feathering of the upper wing-coverts, if compared with those of 
the Kagu, shows far greater interlocking of the barbules. So much is this the case 
that only in the lower third of the feather, and that in the outer half of the vane, is 
plumose character as freely developed as obtains in the Kagu. This remark is more or 
less applicable to the thigh- and other feathers generally. 
