OF THE KAGU, SUN-BITTERN, AND BOATBILL. 48] 
formed or supplanted by the dust-bearing kind, have not been so arrested in Psophia, 
but are long, powderless, and with remarkably downy barbs and barbules on the 
contour-feathers. 
In the Ardeide the powder-downs are not diffused, but restricted to patches, which 
Nitzsch shows number three or two pairs. I have myself, however, detected a very 
few solitary rootlets, here and there, in the body of the Great White Egret. 
It seems, according to the above authority, that pectoral and rump-patches obtain in 
all the group, and, with the exception of the Common and Little Bittern, also inguinal 
patches. ‘Those on the hip doubtless constitute my so-called caudal clump of the 
dorsal patch; while the inferior segregate areas may be either homologous with 
separated extremities of a long lateral ventral strip, or simply furcular and crural 
patches. 
In the Common Heron, several of which came under my inspection, I have been 
impressed with the resemblance between its powder-down patches and those of the 
Boatbill. They are of a darker straw-colour, however, at the roots, and each feather- 
thread stronger. The rump-patches I have noticed incline towards the femoral region, 
therefore carried but a stage further in Cancroma, and the abdominal patches similarly 
bridge outwards to the groins. 
Whatever may be the affinity of the three Gralline forms (the gist of this Memoir) 
to the Cranes, Grus and its generic modifications resemble neither in their absence of 
powder-down plumage. The Storks and Ibises are equally unprovided. 
Among the family Psittacide some of the Cockatoos are notorious for free sprinkling 
of chalky dust, as those who may have handled a Cacatua cristata can well substantiate. 
Others are destitute of apparent pulverulent secretion. These facts had long been 
known; but the nature of the powder-bearing feathers was not collated and associated 
with those plumose powder-clumps in the Wading Birds until the issue of Nitzsch’s 
thesis ‘ Pterylographie.’ 
Species of the following genera of Parrots are said to have scattered powder-downs! :— 
Cacatua, Chrysotis, Psittacus, and Calyptorhynchus. 1 think Licmetis possibly might 
be added. The genera individually examined by Nitzsch and found to be perfectly 
deficient in the modification of plumage in question are:—Ara, Conurus, Pionus, 
Psittacula, Paleornis, Platycercus, and Trichoglossus. ‘To my own knowledge, besides 
the foregoing, species of the genera Brotogerys, Electus, Loriculus, Lathamus, Geopsit- 
tacus, Melopsittacus, Calopsitta, Euphema, and others show no sign, even in rootlets, 
of the development of powder-down. 
I have less desire in this place to lay special stress on the Psittacine subfamilies, or 
otherwise, which have powder-downs, than to establish the primdé facie inference that 
their supposed irregular disposition of the latter harmonizes with the leading lines or 
patches demonstrated in the Kagu and other Gralle. Two species of different groups 
* See Ray Soviety’s translation of Nitasch’s Pterylography, p. 98 et seq. 
VOL. VII.—PART VI. June, 1871. 3Y 
