THE TURTLE-DOVE PATTERN IN THE PHYLOGENY OF PIGEONS. 99 



"bars"; but in that case we have to remember that they are yet a long way from 

 the finished bars of such birds as C. livid, the bleeding-heart (Phlogoenas) , many 

 Peristera?, and nearly all pigeons with bars in the adult plumage. So long as the 

 whole wing remains more or less uniformly marked with distinct lateral spots, con- 

 fusion may be avoided by describing it as spotted or chequered. C. affinis has been 

 so described, and Ectopistes, which has rows of spots both in young and adult stages, 

 is never described as a barred pigeon. American and European ornithologists have 

 generally, I believe, adhered to this mode of description. Salvadori, for example, 

 in his Catalogue of Pigeons, speaks of Ectopistes as having "scapulars, tertials, and 

 median wing-coverts with velvety-black spots," and of Chamcepelia as "marked 

 with blotches of a steel-blue with violet reflections." In all typical turtle-doves 

 we have rows of spots, but we never think of describing them as bars. The distinc- 

 tion between spots and bars has become so fixed in the breeder's terminology that 

 I did not realize the danger of any confusion or misunderstanding on this point 

 before reading Dr. Butler's very courteous review. Had it been possible to illus- 

 trate my paper with plates my meaning would probably have been clear in regard 

 to the evolution of wing-bars from chequers, at least in so far as concerns the rock- 

 pigeons and their descendants. 



The typical wing-bar of the adult bird, as I conceived it, represents a specific 

 regional mark — a continuous band of color on a uniform ground of contrasting color. 

 In such a bar the individualities of the elements are submerged in the individuality 

 of the bar. When, therefore, as in Columba affinis, we meet with rows of chequers, 

 and find that the posterior two rows are the homologues of the two black bars of 

 C. livia, and, further, that this two-barred condition is reached in domestic birds 

 through the obliteration of the anterior rows of chequers and by cutting down the 

 chequers in the remaining two rows to outlines that in each row flow together in a 

 single band, we are warranted in saying that bars are evolved from chequers. 



If we speak of the original rows of chequers as bars, then it becomes necessary 

 to distinguish between juvenal or primary bars and adult or secondary bars. The 

 direction of derivation remains the same. If we find cases in which the deletion of 

 spots has been carried still farther, until only a few of the larger spots in the poste- 

 rior rows remain, as in Zenaida and Zenaidura, we may then say that "spots" are 

 the true homologues of typical bar-elements in other species. 



I believe that the few spots in the wing of the adult Calopelia are such homo- 

 logues, and that they are preceded in the juvenal plumage by corresponding marks 

 which have been overlooked. I am aware that in the young of this species the 

 scapulars, wing-coverts, and tertials are said to be "barred with black." These 

 juvenal bars are probably of the same nature as those seen in the young tambourine, 

 the relation of which to chequers has already been indicated. 



These remarks will make it sufficiently clear that my view does not contradict 

 Dr. Butler's observations on African doves. 



In the above remarks 46 1 ventured some suggestions as to the phyletic sequence 

 of color-marks in the tambourine-dove and its nearest allies. These remarks on 

 this dove were based on the following description by Dr. A. G. Butler, 47 in which 



18 The following statements were written several months after the preceding account was published. In the mean- 

 time, the author had been able to see and study a few specimens of the tambourine-dove. — Ed. 

 47 Agricultural Magazine. Aug. 1900, p. 309. 



