t curved like a split quill, and
resembling thin half cylinders of horn or whalebone. When a dead bird
is laid on its back, it is seen that these ribands take a curve or set,
which brings them round so as to meet in a double circle on the neck
of the bird; but when they hang downwards, during life, they assume a
spiral twist, and form an exceedingly graceful double curve. They are
about twenty-two inches long, and always attract attention as the most
conspicuous and extraordinary feature of the species. The rich metallic
green colour of the throat extends over the front half of the head to
behind the eyes, and on the forehead forms a little double crest of
scaly feathers, which adds much to the vivacity of the bird's aspect.
The bill is gamboge yellow, and the iris blackish olive. (Figure at p.
353.)

The female of this species is of a tolerably uniform coffee-brown
colour, but has a blackish head, and the nape neck, and shoulders
yellow, indicating the position of the brighter colours of the male. The
changes of plumage follow the same order of succession as in the other
species, the bright colours of the head and neck being first developed,
then the lengthened filaments of the tail, and last of all, the red side
plumes. I obtained a series of specimens, illustrating the manner in
which the extraordinary black tail ribands are developed, which is very
remarkable. They first appear as two ordinary feathers, rather shorter
than the rest of the tail; the second stage would no doubt be that shown
in a specimen of Paradisea apoda, in which the feathers are moderately
lengthened, and with the web narrowed in the middle; the third stage is
shown by a specimen which has part of the midrib bare, and terminated
by a spatulate web; in another the bare midrib is a little dilated
and semi-cylindrical, and the terminal web very small; in a fifth, the
perfect black horny riband is formed, but it bears at its extremity
a brown spatulate web, while in another a portion of the black riband
itself bears, for a portion of its length, a narrow brown web. It is
only after these changes are fully completed that the red side plumes
begin to appear.

The successive stages of development of the colours and plumage of the
Birds of Paradise are very interesting, from the striking manner in
which they accord with the theory of their having been produced by the
simple action of variation, and the cumulative power of selection by the
females, of t