CROSSES OF JAPANESE TURTLE-DOVES WITH BLOND AND WHITE RING-DOVES. 69 



The tabulations presenting these breeding data fall more or less naturally into 

 four groups. Those four groups will be considered after a survey of the se.x-limited 

 phenomena involved in these crosses. This order of treatment will jiermit the reader 

 to become more quickly familiar with the appearance and general characteristics 

 of the forms crossed and of the resulting hybrids. 



The Japanese turtle-dove has already been seen in color in pi. 1; the white 

 ring-dove (St. alba) and the blond ring-dove (St. risoria) are here shown in pi. 8. 

 It will be observed that these three species are markedly different and distinct 

 in color and color-pattern. 



SEX LIMITED INHERITANCE OF COLOR IN BLOND AND WHITE RING-DOVES CROSSED WITH 

 JAPANESE TURTLE-DOVES. 



Reciprocal Crosses of St. alba and T. orientalis. — The offspring of a St. alba 

 male mated to a T. orientalis female are of two colors. One of these colors is quite 

 dark (males), though not as dark as that of the female i:)arent. It is nearly like 

 the male of the reciprocal cross which is shown in color in pi. 10. The other color 

 is "almost white." Indeed, unless the bird and its feathers are given more than a 

 glance, one may overlook the traces of brownish pigment present in most body 

 feathers, and the more than a trace of brown in the neck-mark and in the under 

 proximal parts of the rectrices. These birds, which will be spoken of as "white," 

 are, therefore, not pure white, as is their father.^ The bird figured in pi. 9 will 

 demonstrate, however, that this group is most sharply differentiated from the dark 

 members of this fraternity. Text-fig. 1 gives a photographic view of a brother 

 and sister. 



Matings of these two species, with the white ring as father, have yielded 59 

 dark and 43 white offspring. The sex of 45 of the dark birds is known; ' they were 

 males in every case. The sex of 40 of the 43 white birds is known; they were females 

 in every case. The records are available in tables 23, 24, 42, 43, and 44. It is 

 reasonablj' clear, therefore, that in this cross the white color of the father is exhibited 

 by all of his daughters and by none of his sons. 



When, however, the white ring is used as the female of the cross no white off- 

 spring are produced. Sons and daughters are both of dark color. But close 

 examination of these young shows there is a slight color difference between the 

 males and the females. In this case the males are perceptibly lighter in color; 

 the females a trace darker. The difference is made clear in pis. 10 and 11, which 

 reproduce the colors of the male and female respectively. From this cross 34 

 males and 39 females were obtained. Tables 37 to 41 (with 25, 31, 35) present 

 the whole of these data. 



Reciprocal Crosses of St. risoria and T. orientalis. — Blond ring-dove males mated 

 to Japanese turtle females produce young of two colors. These bear a relation to 

 the parental colors somewhat similar to that described above for the white ring x 

 Japanese cross. Darker and lighter forms appear; the dark birds are all, or 



- Neither of these two colors therefore represents a "pure" or complete segregation of a parental color. 



' About 10 other (lark hinls of this series are alive, but their sex is not yet fully tested. Where an interrogation 

 point precedes the sex-siiiii m I he tables referred to above, this point is intended to indicate that the sex of the bird 

 has not yet been positinhj Iraninl. Where a question mark is not followed by a sex-sign the mark usually indicates 

 that the sex-glands of tlie bird were abnormal, and invites attention to a further statement concerning it. (All of 

 the ten dark birds later proved to be males.) 



