86 THE ZOOLOGIST. 
moult, and particularly young birds, belonging to this group, 
after their first winter. 
2. Point with radii casting takes place with such species as 
have the colouring matter in the rami of their feathers. Here 
not only the points are cast, but also the colourless radii, with 
whose points the rami are to some extent covered, and thus their 
colour appears faint. Naturally the points disappear first, and if 
we examine such a feather towards the spring we observe at first 
the plain point casting, and although the colours by that time 
have become much clearer, we see upon them nevertheless a sort 
of hoar (pruina), which disappears, however, in proportion as the 
radii-casting extends downwards. The colour does not show 
itself in its full lustre until the coloured portion of the rami is 
entirely free from radii. 
The feather is now not only much shorter, but also nar- 
rower, inasmuch as the radii do not now hinder the rami from 
approaching each other. Fig. 3 shows a breast-feather in the 
autumn of the Common Redpoll, Linota linaria, male; fig. 4 
a centre-piece of a branch from the same feather, much magnified 
in order to show that the points of the radii overlap the nearest 
rami; and fig. 5 a breast-feather of the same species in July, 
when the bird is in full summer plumage. 
In some feathers the radii are of very short duration—e. g. 
the.red under tail-feathers of the Greater Spotted Woodpecker, 
Picus major. While growing these are covered closely with fine 
thin radii, so that they look as if strewn] with powder; but the 
feather has scarcely attained its full length when the radii- 
casting commences. Fig. 6 represents a portion of such a feather 
in October. The outer points, which were already free from 
radii, are not drawn. Similarly the red or yellow feathers on the 
heads of the Woodpeckers are ab initio without these covering 
radii, and therefore directly on appearing they have their intense 
colour. Fig. 7 shows such a new feather of the Great Dit 
Woodpecker, Picus martius. 
To this group belong, further, F'ringilla cannabina, erythrina 
and flavirostris ; Loxia pityopsittacus, curvirostra and bifasciata ; 
Corythus enucleator; Sylvia suecica (the blue feathers); all 
Woodpeckers with the above-mentioned feathers; Anas boschas, 
clypeata and tadorna ; Podiceps auritus (the brown and reddish- 
brown feathers of the under parts), and some others, 
