CHAPTER VII. 



CROSSES OF JAPANESE TURTLE DOVES WITH BLOND AND WHITE 

 RING DOVES.' 



The considerable number of tables presented here will serve in general for refer- 

 ence in connection with the condensed account of fertility and sex as given in 

 Chapter II. More particularly, they offer: (1) an opportunity to compare crosses 

 which are intermediate to the "distantly related and the closelj^ related" forms 

 of Chapter IV; (2) they show again the effects of season and overwork on fertility, 

 longevity and sex; and (3) they present the following additional features not 

 hitherto considered : 



(A) The good effects of crossing related genera as seen in (a) the long term of life of 

 the offspring; (6) the development of all, or nearly all, of the eggs; (c) the predominance 

 of males from the eggs of the spring and early summer and from "imcrowded clutches" 

 generally. 



(B) It will be seen (a) that the two eggs of the clutch of the jjure females have different 

 sex tendencies, and (6) that there is some evidence that unpaired eggs (?'. e., eggs from 

 clutches of one egg only) apparently have stronger sex tendency than have the paired eggs, 

 in that they are more independent of season and overwork, in their prochiction of sex, 

 than are the paired eggs. 



(C) The fertility of hybrids from these related genera present the following situation: 

 (a) The hybrids crossed inter se or with their parent species are usually less fertile than 

 was the original cross, their young live less long, and the sex of the offspring is probably 

 less dependent upon season and overwork, and certainly bears little or no relation to the 

 order of the eggs in the clutch; {b) eggs from matings of complex hybrids are probably 

 more fertile than from matings of Fi inter se, or from Fi with the parent species; the term 

 of life is probably also longer than from that cross, though this term is shorter than that 

 for the Fi mdividuals themselves. 



(D) The further breeding of the Fi hybrids and also of complex hybrids, ]iroduced a 

 high percentage of (a) abnormal young, and (b) of hermaphrodites. 



(E) The crosses of St. alba and of St. risoria with T. orientalis show that color is here 

 a sex-limited character. 



' The text of this chapter was written by the editor; nearly all of the tabulated data are those of the author. 



Explanation of Platf 8. 



.A.. Adult female white ring-dove, Streptopelia alba, x 0.5. Houland dc\., Sept. 1911. 

 The ring has been over-emphasized in its depth of color. — Ed. 



15. Adult female blond ring-dove, Streptopelia risoria. x O.f). Hayiisiii del. 



View of entire bird. The three separate feathers nro (from left tn riRht) the (<\ln'mr tippir, niiddli', and Inwrr 

 parts of the ring or neck-mark. The general color c.iuld !«■ drsciilicd a^ a p.ilc (:\\\ n. m i>aliillinc, w liiili lirniiucs 

 lighter on the throat, and fades out towards and an mi id ilir \. ni , pa-Hii- iiii|n rr.pi ili|\ mi., i li.> « Im.' ..i' i h.' iin.lia- 

 tail-coverts. The black ring is sometimes narrowci- a i ii < inaMI.- ..n i li.' Lack ..i i !..■ iH.k i liaii ai ili.iiiil> Tins 

 fact, together with the complete interruption of the nuA on llu- hack ..I ili.- la .1, m i li. hi>i pliiinaL:.' :l.\ w lii.li it is 

 broken into two portions, one on each side of the neck, beginning a htl Ic l.rl..« ami I.. Inn.l i k. .ai -. ..\ . 1 1 - m.l uruwing 



narrowerbackward),suggests that the half-ring has arisen by thcextpiix I iw.. -|...is hk. ik..-. -.■.■,i m i Im' innurning- 



dove. This ring is creamy-white in the "Vienna white dove" {Si. (ilhai. It is ollcn riiliucd l.i a mcir sluidow, or 

 wholly absent, in the first plumage. 

 OS 



