THE TURTLE-DOVE PATTERN IN THE PHYLOGENY OF PIGEONS. 115 



color-marks are founded upon the blue color," i.e., upon the color and pattern of 

 the rock-pigeon. The whole series of changes and varieties are regarded as albinism 

 progressing within the limits and in harmony with the areas that preexist in the 

 original type (309, 310). "We can start with white on the head, or breast, or tail, 

 or wing, and it tends to extend to correlated parts. The law of the distribution of 

 white is based on correlation. " 3a 



The theory that black bars tend to spread over the whole wing (314 and previous 

 pages) is discussed at length. This theory is that of Darwin, and, as I have shown, 

 is decidedly false. 



What I have said above from my own experience I find agrees in many impor- 

 tant points with the "laws" laid down (page 300 onward) by Mr. Priitz in the Mus- 

 tertauben Buch. 



Black Crescentic Tips in Toy Pigeons. 



It is of interest to note that black crescentic tips can be obtained artificially 

 from domestic pigeons which start primarily with two black bars, these arising in 

 the first instance from longitudinal spots or streaks. 



These crescentic tips are found in so many different kinds of birds that we can 

 not assume that they have always arisen in precisely the same way. They have 

 been preceded by longitudinal streaks in geopelias and in crested pigeons (Ocy- 

 phaps). In crested pigeons we have subterminal transverse bars coming in by the 

 direct transformation of the original long spots. 



In Geopelia the long spot is, at least in some cases, continuous with the lower 

 end of the transverse bar, and the latter in the first feathers is subterminal — i.e., 

 just within a pale edge. But here we do not see that the crescent comes directly 

 by a transformation of the long spot, as we do in the crested pigeon. 



These black crescentic tips may arise in the following ways : 



(1) They may arise by breaking up the central spot (turtle-dove type of spot) 

 as shown in the francolin (see Chapter VII, page 136). 



(2) They may arise by transformation of the ancestral long spots, as in crested 

 pigeons. 



(3) They may arise as in geopelias, simply by a new distribution of the black 

 originally deposited in the long spot. This is a rebuilding during development, the 

 long spots ceasing to develop and the crescents succeeding them. 



(4) Finally, we may reach this end as in the case of some high-bred fancy or 

 toy pigeons. 



How are these transverse bars reached in toy pigeons? They are presented in 

 the ice-pigeon {Columba farinosa) as reduced remnants of the two original black 

 bars of the C. livia type. A good picture of this bird is given in the Mustertauben 



39 Among color peculiarities I note the following: 



(1) The "lace" pattern in common pigeons is a stage towards the end of chequers. Examples are common 

 pigeons and Briinn pouters — a dark border on red-and-white bars. 



(2) I have 6 or 7 common red pigeons from a dealer (January 1909) and every one has white tail and primaries. 

 The same is true of red jacobins. The red is thus associated with white, and is probably a weakened stage of black. 



(3) The "obsolete spot" sometimes leaves "structural imprints." Besides the ease (already noted) of the white- 

 winged pigeon (Melopclia leueoptera), I find in red tumblers and red barbs thai when the color is thin, the feathers 

 often have spot-areas — of stronger red — in the same place where black spot-areas are found in darker birds. 



(4) Black doves have young which, in their first plumage, often show distinctly the two posterior wing-bars, 

 and I have questioned whether the structural imprints are not always present and more deeply pigmented even in 

 what seems to be an even black. 



