152 On the Inker itance of Colon r in Pigeons 



result of 12 chequered to 7 oon-che(juered obtained from the mating 

 is not sufficiently definite to state the composition of the white. As 

 regards white the silver chequer ^ is homozygous for colour, as no 

 white birds are produced from this mating. It is worth noting, however, 

 that, although all the young are heterozygous as regards white, still 

 one of them shows apparently no white feathers, and seven have only a 

 very few, 



Exp. 64. Blue chequer, no white ? 1 x White J" 22. 



The $ was raised in Exp. 59, the </ in Exp. 60. The mating was 

 continued for three years, 25 young being raised. Of these two were 

 blue without chequering and having no white feathers, one was blue 

 showing a few ticks of darker shade which has been described as 

 intermediate in chequering, but classed here as non-chequei'ed, and also 

 having several white feathers, 17 were blue chequers with some white 

 feathers, and five were silver chequers with some white feathers. Of the 

 blue chequers nine had very few white feathers, and eight had several 

 white feathers. All the silver chequers had several white feathers. As 

 regards the factor for blue and the factor for chequering both parents 

 are obviously heterozygous, and wc should therefore expect a 3 : 1 ratio 

 for both characters. The homozygous non-chequered forms fall rather 

 short, and it is curious that no unchcquered silvers appeared, although 

 only one or two at most could be expected in 25. The Mendelian 

 expectation for the four forms would be 9 : 3 : 3 : 1, or with our figures 

 14-04 : 4'68 : 468 : 1'56 ; our actual results being 17 : 5 : 3 : 0. 



Exp. 65. Blue chequer, very few w. f. $ 35 x Blue chequer, very 

 few w. f. (/ 6. 



Exp. 66. Blue chequer, very few w. f. ^ 32 x Blue chequer, very 

 few w. f c/" 46. 



These four birds, raised in Exp. 64, were all reckoned as having very 

 few white feathers. From the two pairs eight young were raised, of which 

 four were blue chequers and four whites. Here we have a very high figure 

 for extracted recessives, as the proportion should have been six chequered 

 to two whites. The totals here are, however, too small. As regards 

 white feathers the chequer raised in Exp. 65 was reckoned as having 

 several white feathers, the three raised in Exp. 66 had none. The occur- 

 rence of a white bird with a small red patch or tick under the right 

 eye in Exp. 66 is remarkable. When the bird was first described three 

 months after hatching this abnormality was not noticed. It was, 

 however, seen after the moult when the bird was a year old. It will 



