with their plumage marked almost as symmetrically as in natural
species. In laced and spangled fowls the coloured margins of the
feathers are abruptly defined; but in a mongrel raised by me from a
black Spanish cock glossed with green, and a white game-hen, all the
feathers were greenish-black, excepting towards their extremities,
which were yellowish-white; but between the white extremities and the
black bases, there was on each feather a symmetrical, curved zone of
dark-brown. In some instances the shaft of the feather determines the
distribution of the tints; thus with the body-feathers of a mongrel
from the same black Spanish cock and a silver-spangled Polish hen, the
shaft, together with a narrow space on each side, was greenish-black,
and this was surrounded by a regular zone of dark-brown, edged with
brownish-white. In these cases we have feathers symmetrically shaded,
like those which give so much elegance to the plumage of many natural
species. I have also noticed a variety of the common pigeon with the
wing-bars symmetrically zoned with three bright shades, instead of
being simply black on a slaty-blue ground, as in the parent-species.
In many groups of birds the plumage is differently coloured in the
several species, yet certain spots, marks, or stripes are retained by
all. Analogous cases occur with the breeds of the pigeon, which usually
retain the two wing-bars, though they may be coloured red, yellow,
white, black, or blue, the rest of the plumage being of some wholly
different tint. Here is a more curious case, in which certain marks are
retained, though coloured in a manner almost exactly the opposite of
what is natural; the aboriginal pigeon has a blue tail, with the
terminal halves of the outer webs of the two outer tail feathers white;
now there is a sub-variety having a white instead of a blue tail, with
precisely that part black which is white in the parent-species. (47.
Bechstein, Naturgeschichte Deutschlands, B. iv. 1795, s. 31, on a
sub-variety of the Monck pigeon.)
FORMATION AND VARIABILITY OF THE OCELLI OR EYE-LIKE SPOTS ON THE
PLUMAGE OF BIRDS.
[Fig. 53. Cyllo leda, Linn., from a drawing by Mr. Trimen, shewing the
extreme range of variation in the ocelli. A. Specimen, from Mauritius,
upper surface of fore-wing. A1. Specimen, from Natal, ditto. B.
Specimen, from Java, upper surface of hind-wing. B1. Specimen, from
Mauritius, ditto.]
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