OF THE KAGU, SUN-BITTERN, AND BOATBILL. 475 
(c) Distribution and Nomenclature of the Powder-downs in Rhinochetus—I may 
premise that the above-termed feathering, as far as is known to me, is more fully and 
generally developed in the Kagu than in any other bird. In this respect it may be 
considered typical, not alone from the great masses or areas that are present, but from 
the very regular way in which they are distributed. I shall proceed, therefore, to 
describe at length their distribution in Rhinochetus, afterwards comparing with it those 
of the Sun-bittern, Boatbill, and forms allied and otherwise. 
(1) In the Kagu (Pl. LVI. fig. 1), then, this remarkable dermal structure commences 
on the top of the head, above the eyes, and running backwards and downwards, on both 
sides of the crest, forms a broad but rather scanty collar round the neck. ‘his latter, 
however, is thickest where it covers the angle of the mandible. 
The whole of the powder-down feathers composing the above-mentioned patch are 
short, in some spots sparse, and throughout intermingled with the contour and true 
down-feathers of the spinal and ventral tracts. 
Agreeably to, or in accordance with, Nitzsch’s names of the feather-tracts and spaces, 
the position of the powder-down patch above described in the Kagu might either be 
the head-patch, the anterior portion of the spinal patch, or the gular portion of the 
ventral patch. 
For the sake of precision, and withal not to confound it with the conjoined feather- 
tracts, it may, as a whole, be termed the cranio-nuchal patch. Its several subdivisions 
then, though not rigidly defined, nevertheless would bear respectively the additional 
affix of head, nape, and throat portions, according to their regional area. In Pl. LVI. 
figs. 1, 2, & 3, therefore, the patches mentioned are lettered in sequence Cn*, Cn’, 
and Cn‘. 
The cranial portion of this upper neck-patch, as it divaricates, would lie on the outer 
margin, or enclose the head-space of Cockatoos &e. 
If, however, it can afterwards be shown in other birds that this upper neck-patch is 
but an interrupted continuation of the dorsal or spinal patches yet to be spoken of, the 
above term, cranio-nuchal patch, might be so altered as to correspond with the divisions 
( pteryla spinalis of contour-feathers) anterior and posterior of the dorsal or spinal tract. 
These are so separated from the head and upper patches in Rhinochetus, however, 
that I prefer to designate them as above. 
(2) Two elongate, but diamond-shaped, thick-set patches lie below the middle of each 
side of the neck; and their inferior extremities reach to about an inch above the 
shoulder-joint. These powder-down patches are situate in the hollows between the 
trachea and the cervical vertebre. ach is an inch in long diameter and a quarter of 
an inch across at the centre or point of greatest breadth. 
They are completely isolated, and remarkably well defined from the other nuchal 
powder-down feathering and strips. They occupy what Nitzsch has denominated the 
lateral neck-space and tract. 
3x2 
