^iHAP. XIV. Ocelli. 427 



change in its colouring to be symmetrical ; we seo this in the 

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

 on the principle of correlation the feathers over the whole body 

 arc often coloured 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 

 apangled fowls the coloured margins of the feathers are abruptly 

 detined ; 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 

 alver-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 diflerently 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.'" 



Formation and Varmbility of the Ocelli or tye-like Spots on the 

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

 ocelli on the feathers of various birds, on the hairy coats of some 

 mammals, on the scales of reptiles and fishes, on the skin of 

 amphibians, on the wings of many Lepidoptera and other insects, 

 they deserve to be especially noticed. An "ocellus consists of a 

 ^pot withia a ring of another colour, like the pupil within the 



" Bechsteia, ' Natuvgeschiehte Deutschlands,' B. iv. 1795, s. 31, on a 

 sub-variety of 'he Mmick pigeuu. 



