154 ORTHOGENETIC EVOLUTION IN PIGEONS. 



In a 6-weeks-old homer I find the tertials and a few secondaries are transversely 

 barred. And, as a second surprise, the second (anterior) wing-bar is reduced on the 

 lower web of the long coverts to a "marginal remnant," looking like a long edge- 

 streak that we find on these feathers in the young of Geopelia hwneralis. 



This bird is the first pigeon in which I have noted these peculiar barred feathers. 84 

 For the first 10 days or more this bird fell far behind its mate in size and weight, 

 but kept healthy. I then began giving the old birds extra food and they fed it 

 better; it then grew rapidly, and is now an average-sized bird very pale gray 

 and with the weakest second wing-bar that I have yet seen. The long coverts show 

 at their tips parallel fine lines dark and light alternating due probably to defec- 

 tive nourishment during the first two weeks of life. This suggests that the bars 

 (marginal remnants) on the tertials may be due to the same cause. 



" The author made no further note on this matter, but to the editor it seems most interesting that a reduction of 

 pigment in the ontogeny (of this homer) should so closely parallel the state and appearance of the character in a form 

 (G. humeralis) which has made the reduction in its phytogeny. 



14 In October 1903 I find the same in a bronze-winged pigeon; a little later in two old pale-gray owl-pigeons, and 

 still later in a green-winged pigeon, where the bars are plainest in the gray part of the feather. 



EXPLANATION OF PLATE 72. 



Transverse barring in an adult male owl-pigeon. Toda del., Feb. 1905. 



This bird was 4 to 5 years old when these feathers were plucked (July 23, 1903). The feathers are somewhat 

 worn and faded, the bird having already begun to molt the primaries. The color of the bird is a pale silver, with 

 brown-black bars. 



Notice in the lower two-thirds of the row of long coverts (smaller feathers of the figure) that the transverse bars 

 can be clearly seen all the way from the dark chequers to the tip of the feather. The same can be seen in the lower 

 web of the secondaries and the tertials. These bars are strongest in the tertials and inner (upper) long coverts. 



Measurements of feathers and width of their bars: 



In upper tertial (57 mm. long), 10 bars, 19 mm. In fifth tertial (61 mm. long), 10 bars, 31 mm. 



In second tertial (67 mm. long), 10 bars, 21.5 mm. In lower secondary (108 mm. long), 10 bars, 32 mm. 



In third tertial (75 mm. long), 10 bars, 23 mm. In third long covert (50 mm. long), 10 bars, 20 mm 



In fourth tertial (84.5 mm. long), 10 bars, 28 mm. In eleventh long covert (64 mm. long), 10 bars, 25 mm. 



The bars (light and dark) are wider in the longer feathers. Allowing that the feathers get their whole length in 

 4 weeks, and that the terminal half is formed in 14 days, it is found that the number of bars corresponds nearly to 

 the number of days of growth. If this be so, then the bars would be zones of daily growth (light - day, dark - night, 

 or vice versa). 



EXPLANATION OF PLATE 73. 



Fundamental bars and extended wing-bars in adult male owl-pigeon, same as pi. 72. x 0.8. Toda 

 del., Mar. 1905. 



These feathers plucked from above bird when nearly 2 years older than when feathers were taken for plate 72. 



The two rows of feathers bearing the two wing-bars of the right wing. The chequers are much darker than in 

 plate 84, and the barring would not be noticed at first sight. On closer examination I can make out very obscure 

 cross-bars (to compare with pi. 72). 



The artist has strengthened the bars considerably. The chequers are much darker and larger than in plate 72; 

 so much so that one would hardly suspect that one bird had furnished both sets of feathers. The cross-bars are 

 correspondingly obscured, but they can be detected in favorable light. 



Notice that the feathers (especially the long coverts) are decidedly larger than in plate 72. 



The important point to be here noted is that the first wing-bar extends clear down through the primaries, only 

 the two outer primaries being without any mark. 



In the first (inner) primary, the spot is 25 mm. long, on the lower edge of the feather, extending in width to about 

 midway to shaft. It is more or less flecky. It is 37 mm. from the tip of the feather. 



The remaining 7 chequers are more and more thin-flecked, the eighth being only a trace. The chequers form a 

 bar on the primaries, which does not run vertically, but downward and backward at about 45 inclination. 



A similar flecky series of chequers is found on six of the inner primary coverts; this series has same slanted direc- 

 tion, and lies just in front of the series on the primaries. 



I have seen such extensions of the wing-bars in some other domestic pigeons. 



