170 ORTHOGENETIC EVOLUTION IN PIGEONS. 



streak (homologue of the guinea-mark. ED.) of the feather is less conspicuous, and 

 often fails to reach fully to the tip of the feather. 30 It thus ends somewhat more nearly 

 as in the young of Leptoptila. 



In the breast feathers of both 10 and 11 the Leptoptila condition is feebly 

 indicated. In 10 the lower black mark on the side of the head has each black feather 

 narrowly edged with whitish. This is less plain in the upper streak. Both of the 

 black head-sTreaks are present in the young Zenaida. 



Two other young (IS and 14} of about 5 weeks, are of a lighter shade than 12; 

 14 is of lighter color than 13. No. 18 is in turn a shade lighter than 12. In 14 the 

 mid light line dividing the feathers is white or nearly so, and very strongly marked, 

 especially on the breast. Note should be made of the fact that there is a narrow 

 streak of feathers running longitudinally through the middle of the breast where 

 this mid-line (part of guinea-mark) of the feather is not seen ; i. e., these feathers are the 

 later ones to appear, 31 and they have a stronger tinge of brown than the more lateral 

 (ashy-brown) feathers. In some of the feathers of this breast-streak, especially in 

 its lateral boundaries, the dividing-line of the feather is present as a triangular 

 mark, but it is weaker and more nearly like the general color of the feather, so that 

 it ceases to be conspicuous. This median streak in the breast and neck feathers is 

 a pale brown perhaps to be regarded as a grade towards the adult color (this color 

 is a little stronger brown on IS). 



The mid light line (part of guinea-mark) is seen not only on the breast, neck, and 

 head (it vanishes in the lower half of the posterior neck-feathers and the interscapu- 

 lar region), but is also well-marked in the lesser wing-coverts, and is present in all 

 of the coverts, but becomes less sharp in outline in the two longer rows of coverts; 

 it is obsolete in the tertials. 



The primaries are not very dark brown, and they lighten up at the edges and 

 tips; the shaft-line is pale reddish. The flanks above the legs are gray. The spots 

 (chequers) are weak. On the tertials 2 are visible, on the long coverts 3, and on 

 the second coverts there are 3. On the scapulars the spots are very feeble. The 

 under tail-coverts are pale rufous-vinous, and are nicely marked at the tip with 



" The mutational mark that appeared in the mutant No. 21 was thus observed to be slightly accentuated in 

 the mother of the mutant. ED. 



" This fact was noted in the preceding chapter to hold for "young" birds in general, and the "breast-crease" 

 of these birds was thus explained. ED. 



EXPLANATION OF PLATE 83. 



M. Adult male Zenaida vinaceo-rufa. x 0.9. Toda del., Jan. 1907. 



Imported direct from Venezuela, May 1906; died of tuberculosis March 1907. This bird was slightly larger than 

 other birds obtained from the same region. The number of spots (chequers) is notably small. The tail is short, as 

 in other zenaidas, and has 14 feathers. No trace of modified edges or median (normal buff) streaks of the juvenile. 

 Also, none of secondaries or coverts with any white as in Z. amabilis (pi. 87). The color is strong with red. 



B. Juvenal female Z. vinaceo-rufa (12), age 7 weeks and 5 days. Natural size. Hayashi del., July 

 1905. 



(For origin, see table 6. ED.) 



This is a rather dark specimen, some being a few shades lighter (first plumage). The feathers of the lower neck, 

 in front and on the sides, have very narrow mesial streaks (pale-rufous) widening a little at the apex, where they 

 become continuous with the pule apical margin. This same streak appears in some of the upper tail-coverts. This 

 dam, then, exhibits in a very weak way the marks presented in the daughter (No. 21). Ordinarily such marks are 

 not to be seen in this species. 



