138 ORTHOGENETIC EVOLUTION IN PIGEONS. 



that the "immature plumage" is generally more or less barred, and that in adults 

 (3 or more years old) the bars are lost. This is another case of the disappearance 

 of color-marks. In geopelias we have, similarly, bars in all of the young, but these, 

 after one molt, are lost in different degrees in the different species. 



In the emu it seems that the barring varies greatly. Some young may have 

 "no bars," and others may have nearly every feather barred. At the end of the 

 first year, when the barred feathers are shed, they axe, as a rule, replaced with 

 feathers "without bars." Occasionally, barred feathers again appear after the first 

 molt, and sometimes they appear again in the third year, "especially on the upper 

 part of the back and the base of the neck." The male seems to lose his bars sooner 

 than the female. Of two young from the same nest, the male lost his bars at the 

 end of the first year, but the female had many barred feathers the second year, 

 and in the third year she had "a few only faintly barred." All of her bars disap- 

 peared in the fourth year. 51 



Concentric Crescentic Bars. 



These are found in some birds, but they are perhaps plainest in certain species 

 of A7ias. In some of these species it is clear that the crescentic bar is closely 

 akin to the transverse bar. 



(1) Buff on 52 calls attention to the feathers of the neck, breast, and whole under 

 surface of Anas javana which are "richly adorned with festoons of black and white." 

 The dark and light crescents alternate and are parallel to the edge of the feather. 

 Near the vent they become less curved and are more like the usual transverse 

 lineation. These concentric semicircles are seen in a less-marked condition in other 

 ducks and in other birds. 



(2) In the common sarcelle (Anas clypeata Linnaeus) the female has dark centers 

 in the feathers of nearly the whole surface, while the male has them only in the 

 mantle. His breast has each feather marked along its tip and lateral edges with a 

 single crescent of black; this is followed by a fairly broad light crescent, and this 

 by a (black?) spot which is variously shaped, but which is plainly in its place as 

 the rudiment of a dark center. From the legs backward to the tail we find narrow 

 transverse bars. In the smaller teal, or common teal of Europe, the transverse 

 barring of the male is carried out on the back and under sides, while the front 

 breast and the lower neck have dark centers in all or most of the feathers. 



Transverse Bars in Common Fowls. 



Tegetmeier 53 remarks (page 278) as follows on these bars: 



The singular character of plumage known as the cuckoo feather, consisting of trans- 

 verse pencillings of bluish-gray 011 a lighter ground, is found in many varieties. In England 

 we have Cuckoo Dorkings, Cuckoo Cochins, Cuckoo Polish, Cuckoo Bantams, etc.; in 

 France there are several races with "Plumage Coucou," although the characters are not 

 very distinct; and in America a breed of Cuckoo or, as they are called, Dominique Game, 

 are frequently exhibited. In addition to these breeds there are others which are constantly 

 characterized by the cuckoo plumage, such as the Scotch Grays of North Britain and the 

 Dominiques of America. 



61 The color of the adult is nearly black, or it may be light grayish brown, or any variation between. One albino 

 is reported, besides several individuals with a few stray white feathers. 



62 Ois., vol. ix, page 275, pi. enl. No. 930. 

 65 The Poultry Book, 1873. 



