134 On the Inheritance of Colour in Pigeons 



The following experiments confirm the statement in my previous 

 paper that colour is dominant to white ; they also show the dominance 

 of blue to silver, and suggest that of black to dun, with the sex-limited 

 provision. 



Two pattern characters have also been studied in the Rock 

 Dove X white matings, viz. Chequering and the colour of the rump, 

 and it is shown that the chequered form is dominant to the non- 

 chequered form in both blues and silvers. The matings of chequered 

 birds to blacks and duns have not yet been undertaken other than the 

 matings of the " reversionary blues " described in my previous paper. 



Further it has been found that the white rump of the Rock Dove is 

 dominant to the blue-rumped form. These two results have already 

 been mentioned by Mr Bateson (Mendel's Principles of Heredity, p. 43, 

 1909). 



A valuable paper has recently been published by Messrs Bonhote 

 and Smalley (P.Z.S. 1911, p. 601), dealing with the relation of blue and 

 silver, and also with chequering, I am able to confirm their results of 

 the dominance of blue to silver, and chequered to non-chequered forms. 

 They have, however, not made many matings between blue $ and 

 silver (/*. Only four are recorded. In two of which (Nos. 154 and 158) 

 the ? may have been heterozygous, and in the other two (Nos. 159 and 

 162) it was known to be so. The sex-limitation of the inheritance has 

 consequently not been found. The remainder of the paper deals with 

 Grizzles and Mealies, birds of which I have had but little experience 

 as yet. 



The numerical results of the Rock Dove matings, and also of the 

 Rock Dove x white matings follow fairly closely the Mendelian ratios 

 as the table on p. 135 shows. In all experiments where more than one 

 type of offspring is to be expected allowances must be made for the 

 small totals produced. 



As regards the relations of the four colours black, blue, dun and 

 silver, there is little doubt that all can be correctly represented as 

 a series made by the combinations of the presences and absences of 

 two pairs of factors. Silvers breed true and are therefore the double 

 recessive. Blues can throw silvers or breed true. Duns have not yet 

 been tried, but presumably can throw silvers. Blacks have thrown duns 

 and blues, but I have not hitherto had a certain silver; this however would 

 come only once in 16 birds. Moreover dun x blue gives black. Taking B 

 as black, and D as a factor for density of colour, BD is black and bd silver. 

 I had been disposed to regard bD as dun, and Bd as blue, thinking, that 



