150 On the Inheritance of Colour in Pigeons 



white tinged with blue, and four white tertiaries. Twelve young were 

 produced as follows : 



Blue, chequered 1, non-chequered 2. 

 Silver, chequered 7, non-chequered 2. 



White feathers were noticed on two birds only, viz. one blue and 

 one silver chequer. In both instances they consisted only of a very few 

 white feathers at the vent. We should naturally, however, presume 

 that about six birds were carrying white although they were not 

 distinguishable by plumage. In this experiment equality was expected 

 between both blue and silver, and also chequered and non-chequered 

 forms. Although the numbers obtained deviate from the Mendelian 

 figures, the totals for the whole series of matings, as has been already 

 explained, approximate closely with the expected ratio. 



Exp. 60. Blue chequer, several w.f. $ 115 x Blue chequer, several 

 w.f. c/* 114. 



These two F^ birds were raised in Exp. 56. Both had several white 

 feathers, the distribution of which has already been indicated. A family 

 of 10 F.2 birds was produced, as follows : 



Blue, non-chequered, much white, 1. 



Blue, chequered, much white, 3 \ 



„ „ very few w.f. on rump, vent and thighs, 1 > 5. 



„ „ no white feathers, 1 J 



Silver, non-chequered, much white, 1\ 

 Silver, chequered, very few w.f. on rump and thighs, 1. 

 White 2. 

 The numerical results of this F^ mating follow fairly closely the 

 Mendelian ratios, the observed figures being : 

 Coloured : White : : 8 : 2. 

 Of the coloured birds : 



Blue : Silver : : 6 : 2. 



Chequered : non-chequered : : 6 : 2. 



White feathers in plumage. 



No w.f. : very few w.f. : several w.f : : 1 : 2 : 5. 

 Eocp. 61. Silver chequer, no wh. $ 31 x Silver chequer, no wh. j/* 2. 

 Both these birds were raised in Exp. 59. The mating was continued 

 for two years, and 16 young were produced, all silver, of which 11 were 



1 This bird was an intermediate and is counted as non-chequered. 



