92 ORTHOGENETIC EVOLUTION IN PIGEONS. 



alternating with three white bars on feathers of the front neck (pi. 39, figs. 1 to 3). 

 If the apical black be considered, then we have three black and three white bars. 



In the lower half of the front neck the rule is three black bars (the inner one 

 being weak) alternating with white ones. In the upper half of the front neck we 

 come to feathers with only two black bars, and below the ear-coverts the little 

 feathers have only one black bar (discarding the apical). 



On the back half of the neck, in the middle region (fig. 5) we find two black bars 

 (apical one not counted) ; and near the upper limit of the bars we find only a single 

 black bar (fig. 4). Besides, in this part of the neck the white bars are replaced more 

 and more with pale fulvous. 



The apical black bars are most nearly obliterated in the mid-front of the neck; 

 sometimes they are quite gone, at other times reduced to an extremely thin vestige. 

 These vestiges become stronger as we go from mid-front to mid-back (of neck), 

 and in the lower back part of the neck they finally attain full size (fig. 9), passing 

 into the well-developed black edges of the general surface of the body and wings. 



The throat and cheeks are pale gray. The breast below the barred region is 

 delicate vinous, becoming white on the abdomen. There are no bars on the lower 

 breast, abdomen, or sides. 



Although the bars run across the whole front of the neck, I notice in the mid- 

 front region just a trace of the vinous tinge, as if this species were in a very low 

 degree anticipating the condition seen in Geopelia striata. 



The question of the relative rank of Geopelia striata or G. tranquilla receives a 

 mixed or compounded answer. G. striata comes nearer the inca-dove in one respect— 



Explanation of Plate 39. 

 A. Adult Geopelia tranquilla. x 1.4. Hayashi del., Jan. 1903. 

 Shows the bars completely circling the neck. 



1 to 9. Neck-feathers of adult Geopelia tranquilla. x 3. Hayashi del., Jan. 1903. 



la and 3 from middle front of neck; 4 and 6 from middle side of neck; 7 and 9 from middle back of neck; la, 

 4, and 7 taken from corresponding upper height; 2, 5, and S taken from corresponding mid-height; 3, 6, and 9 taken 

 from corresponding lower height. 

 Middle front of neck: 



la. Apical bar quite faint, then a strong bar, then a dark gray bar near middle of feather. There are 3 light or 

 white bars, alternating. Basal portion pale gray. 



2. Apical bar weak, then a strong black bar, then another dark gray, broadly V-shaped. Three light bars, outer 



one with a slight tinge of fulvous. Basal portion pale gray. 



3. No apical bar. Under a microscope I can detect an intimation of it in a few barbs, but this part is so nearly 



bleached out that it appears as a part of the white bar. The barbs of the apical-bar region are usually 

 reduced in length to near the point of annihilation. 

 Middle side of neck: 



4. Just under ear-coverts (at same height as figs. 1 and 7). Apical bar fairly strong; next is the strong bar, and 



then a faintest touch of another bar. (Mr. Hayashi has separated this rudiment from the strong bar 

 too widely. It should stand as far from the latter as this stands from the apical.) 



5. Apical bar is stronger and wider than in figure 2; first light bar (tinged slightly fulvous) is narrower than in 



figure 2, but the artist has made it too narrow, relatively; it should be fully two-thirds as wide as in figure 2. 

 The middle black bar is wider than in figure 2, and the inner bar is much weaker than in figure 2; the 

 artist has made it much too strong. 



6. Apical bar about the same as in figure 5. The light bars are pale fulvous. Basal half is pale gray, darker at 



middle. 

 Middle back of neck: 



7. Weak apical bar, then a fulvous bar, then a very weak dark bar. 



8. Apical about same as in figure 5, perhaps a little stronger; then a fulvous, then a black or dark-gray bar, 



then fulvous, then just a faint dark bar, more obscure than in drawing. 



9. Apical bar a little stronger than in figure 6, then a fulvous bar; then even gray to middle of feather; thereafter 



much paler. 



