22 RUDOLF SÖDERBERG, STUDIES OF THE BIRDS IN NORTH WEST AUSTRALIA. 
bird it is possible for the central part of the band to have entirely white feathers 
as »pins». But often there is to be seen a faint dark watering in different parts of 
the band. (See fig. 5 and plate 2, fig. 9 a and 9 b.) 
If we examine the juvenal, we shall notice how narrow the collar is. It is 
mixed with black-margined and black-mottled feathers; no feather seems to be quite 
without a dark admixture. 
” 
a 6 
Fig. 5. Fig. 6. 
Fig. 5. A pectoral feather from Halcyon sanctus Fig. 6a, b, ce. Feathers from the plumage of Calyp- 
showing the development of the white colour by shedding torhynchus macrorhynchus, ?, showing phenomena in the 
the edge of the feather, moulting process. g” yellow spots or stripes, which have 
been shed. ga yellow spot in a new feather. 
Få 2 
7 TS 
Fig. 7. Fig. 8. 
Tailfeathers from: B Melopsittacus undulatus, A Ca- Fig. 8. Feathers from Podargus, an old and a new one. 
o 
lyptorhynchus macrorhynchus. g" yellow stripes, which 
have been shed. 
We might therefore be justified in supposing that the white band in the adults, 
where it is expanded to such a degree, is gradually developed out of feathers which 
all were in the beginning margined, but from which the edgings passed away by 
border-moulting. 
This is undeniable an interesting fact from a genetic point of view as well. 
The loss of the edges of the feathers is without doubt an old phenomenon in con- 
nection with the birds feathers, and it is impossible to avoid noticing that it looks 
