FRILLS AND FUNDAMENTAL BARS AS PLUMAGE CHARACTERS. 149 



dition here that favors this position of the feathers. They are certainly the same 

 feathers that are normally present, but here for some reason they are turned or 

 curled out of position (text-fig. 27, fig. C). I did not notice this frill in the bird until it 

 was about 4 weeks old, and I think I should have done so if it had been present; the 

 bird was often looked at in the nest, and I sometimes took it in my hands. This 

 fact makes the recurving or twisting of the breast-feathers seem, in some way, a result 

 of the later development. I find that the wing-bars are obsolete in this bird, and 

 that the black or dark colors are everywhere reduced below that of either parent. 



One of the offspring (C 2) of the above-described homer at the age of 9J/2 weeks 

 showed a similar condition of the breast. Here a feather in the pin-stage, lying 

 just below a frilled or upturned definitive feather, was found turned upward (text-fig. 

 27, fig. B). This homer has gray wings and black bars, but no chequers. 



A juvenile African owl-pigeon which showed a very wide median unfeathered 

 tract was figured at three different juvenile stages (text-fig. 28). This bird hatched, 

 from the second egg of the clutch, on May 21. At the age of 2 1/2 weeks the wide 

 median tract, which was unfeathered at first, has several pin-feathers appearing, and 

 a few of these are turned mediad and a little upward; about 5 pins point upward. 



At the age of 3 weeks and 5 days (fig. 2) the mid-tract is still bare in the upper 

 part of the earlier-unfeathered area; this quite bare region is nearly 13 mm. broad 

 at a point just below the base of the beak; the sides of the former naked area are 

 now covered with pin-feathers. A few pins on each side are turned upward; some 

 turn up and inward. Directly in the middle of this mid-area may be seen 2 pins 

 parallel, but turned in opposite directions. Lower down, in what was formerly 

 unfeathered area, the side-feathers now meet in the middle line; and just above the 

 place of meeting are about 9 feathers of the mid-area turned in different directions. 



When 5 weeks old (fig. C) the last pin-feathers necessary to cover the naked 

 space under the chin are in place. On the lower throat and upper breast, however, 

 a part of the crease persists; and some of the upturned and variously turned feathers, 

 which should smooth and fill the crease, are expanded into a frill. 



In an adult male owl-pigeon of light silver color the frill is more highly developed 

 than in the homers described above. The feathers of the left side of the upper 

 breast here turn strongly towards the right side. Above this shell-shaped mass of 

 feathers are two imperfect rows of feathers which curve outward, or away from the 

 median line (text-fig. 29, A). These curving feathers are evidently feathers of the 

 median tract, and it has already been noted that the feathers of this area develop 

 later than the lateral feathers. 



ON FRILLED OR FRIZZLED RACES OF BIRDS. 



THE PIGEON. 



The frill-back race or variety (Columba hispida) of domestic pigeon is described 

 as follows by Fulton and Lumley : 9 



This pigeon belongs to the German toy class, but on account of the conspicuous 

 reverse growth of the feathers, it frequently has a separated class allotted to it in exhibi- 

 tions. . . . The legs are rather short and closely grouse-muffed. The flights are quite long, 

 and fluted on both webs, but more strongly above than below. 



Book of Pigeons, Cassell & Co., London, 1895, page 481. 



