R. Staples-Browne 139 



Exp. 48. Silver ? 43 x Typical G. livia </* 44. 



Both birds were raised in Exp. 47. Ten young were produced, all 

 being blue, of which six had white rumps and four blue rumps. The 

 experiment shows the dominance of blue to silver. 



£ay. 49. Blue, no wh. $ 27 x Blue, no wh. </• 39. 



These birds, both raised in Exp. 48, produced a family of ten, of 

 which eight were blue and two silver. The rumps of the oflfspring were 

 of a lighter shade of blue and silver respectively, but no white feathers 

 were seen. 



On the crossing of Rock Doves with White Domestic Pigeons. 



From the foregoing description of the Rock Doves obtained, and 

 the varieties produced from them, it will be seen that four types were 

 available for crossing with whites, viz.: 



Typical G. lima (Irish). 

 Typical G. livia (Lincolnshire). 

 Blue-rumped Rock Dove. 

 Silver Rock Dove. 



The Blue-rumped variety was not used as a starting point for 

 crossing experiments, owing to the limited space at my disposal, but 

 the other three types were mated to whites *. The results are given in 

 detail. The crossing of the Irish typical Rock Dove (Exps. 50 and 5] ) 

 and of the Lincolnshire Rock Dove (Exps. 52 — 55) with whites are 

 given in Series B {v. Table II). The experiments with the Silver are 

 given in Series C {v. Table III). The remaining matings here 

 described (Series D and E) were suggested by the preceding series of 

 experiments. 



No fresh colours appeared in these matings, the birds bred in the 

 whole series of experiments consisting entirely of varieties of blue or 

 silver, to be described in detail later, and, of course, extracted whites. 



From the matings of the typical Rock Doves with whites no silvers 

 resulted. From the result of Exp. 48, already described, this was to be 

 expected, and we had no evidence that the Irish Rock Dove was hetero- 

 zygous in this or any other character. 



From the matings of silver with white, however, I obtained some 

 Hues in every case. It appears, therefore, that the factor Bl., which is 

 present in the blue and absent in the silver, may be carried by the 



^ For an acconnt of the whites need see below, p. 141. 



