OCELLI. 421 



in the Golden and Silver-spangled Polish, the Houdans, and 

 CrSve-coeur breeds. In some natural species we may observe 

 exactly the same correlation in the colors of these same feathers, 

 as in the males of the splendid Gold and Amherst pheasants. 



The structure of each individual feather generally causes any 

 change in its coloring to be symmetrical; we see this in the 

 various laced, spangled, and penciled breeds of the fowl; and 

 on the principle of correlation the feathers over the whole body 

 are often colored in the same manner. We are thus enabled 

 without much trouble to rear breeds with their plumage marked 

 almost as symmetrically as in natural species. In laced and 

 spangled fowls the colored 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 colored 

 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 colored 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 col- 

 ored 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 tall feathers white; now there 

 is a sub-variety having a white instead of a blue tail, with precise- 

 ly that part black which is white in the parent species." 



Formation and Variability of the Ocelli or eye-like Spots on the 

 Plumage of Birds. — As no ornaments are more beautiful than the 



" Bechsteln, 'Naturg-eschichte Deutschlands,' B. iv. 1795, s. 31, on a 

 sub-variety of the Monck pigeon. 

 23 



