THE MUTATION THEORY AND MUTATIONS. 169 



and body) in a more or less extended or intensified condition. The extension is less 

 in Zenaida, where the type-marking is preserved; the typical light edge is here 

 merely emphasized. In Zenaidura this typical light edge is still apparent in the 

 superciliary streak, but in the auricular streak it is extended until it represents the 

 dominant color. The color-marks are not carried quite so far — i.e., are not so highly 

 developed in Zenaida as in Zenaidura. 



The feathers of the breast in Zenaidura are ashy-brown, with a pale, almost 

 whitish edge; in Zenaida the color is stronger and richer. The pale edges are more 

 conspicuous, and the feather is neatly divided by a median streak, which widens at 

 the tip, just where the tuft of down is attached, and which is a strong shade lighter 

 than the rest of the distal edge (pi. 83, fig. B). This median streak I frequently 

 find in young Japanese turtle-doves, and occasionally in the European turtle-dove. 

 I have seen it also in the young of Florida ground-doves and of Leptoptila. 



The general color of Zenaidura is more grayish; Zenaida has a little more 

 reddish-brown. This indicates a higher development in Zenaidura. Thus, in head, 

 neck, and breast, Zenaida comes nearer the turtle-dove pattern in general color 

 and in the color of the feather's edge. 26 



Most of the scapulars bear two dark spots in both of these birds. The spots 

 on the tertials, long coverts, and the second row of coverts are larger and more 

 numerous in Zenaidura than in Zenaida. In this respect Zenaidura seems nearest 

 to the original turtle-dove condition. 27 



Other young Zenaida™ compare as follows with the zenaida (12) just described: 

 In zenaida 10 the breast is duller in color in every way than in 12, and the median 



Table 6. — Reconstructed - 3 breeding-record of Zenaida, 1905-06. 



_ . , cf Zenaida vinaceo-rufa (2) (imported, probably from Venezuela. 1904). 



Fair 1. 



9 Zenaida vinaceo-rufa (2) (imported, probably from Venezuela, 1904). 



?1. May 26, 1905*; 11; normal; dead Mar. 1907. 



?2. May 27, 1905*; 12; 9; normal; shade darker than 13 (see pi. 83). 



?1. June 24*; 13; normal; shade lighter than 12. 



?2. June 25*; 14; normal? or weak mutant?; shade lighter than 13. 



o" Z enaida vinaceo-rufa (0) , imported from Venezuela 1905. 



9 Zenaida vinaceo-rufa (12), May 27, 1912 (see above, and pi. 83). 



Aug. 18, 1906*; 20; normal; alive June 10, 1907 (see pi. 84). 



?1. Sept. 12 (?) ; not hatched. 



?2. Sept. 28, 1906*; 21; 9 MUTANT; dead Sept. 21, 1908 (see pi. 84). 



* Indicates date of hatching. 



26 The beak of Zenaida is "fleshy white," just beginning to show a tinge of duskiness, or horn-color. In Zenaidura 

 the beak is dark horn, except the operculum (nasal scale), which is still very light horn-color. The feet and legs are 

 only a shade lighter in Zenaida than in Zenaidura: The color is "reddish flesh-color." 



27 A pair of young mourning-doves, about 10 days old, were found and kindly brought to me by Dr. R. M. Strong 

 in June 1905. In these birds every scapular seems to be double-spotted; the spots are, however, not as dark as in the 

 adult. Elsewhere also the spots are fairly numerous. As the bird sits at rest, there are to be seen about 5 spots on 

 the tertials; 3 on the long coverts; 5 on the next row of coverts; 3 to 4 on the third row of coverts; and 3 to 4 on the 

 fourth row of coverts. In the coverts anterior to these rows, the spots are seen in most of the feathers in the upper 

 half of the wing, but they are dull and not at all conspicuous. At the fore end of the wing the coverts are each marked 

 with 2 dull spots. In these birds also it is the operculum that has a whitish horn-color— not quite so light a flesh- 

 color as in Zenaida. 



2« No. / 7 is a nest-mate of 12; 13 and 14 are sisters of 12 (see table 6) ; the relationship and age of 10 can not be 

 learned from the available data. — Ed. 



29 Complete records were of course made by the author, and I find specific references to them; bul unfortunately 

 they are not available to the editor. The tabulation represents that part of the record which is repeated, either in 

 summary comment on breeding records (where these offspring were used as parents), or in legends lor illustrations, 

 etc. The interrogation points in the first column indicate that the "number of eggs," which had been laid during 

 the season prior to the egg described, is unknown. 



