1908.] INHERITANCE OP COLOUR IN PIGEONS. 69 



By far the greatest number of matings here described belong to 

 the Barb-Fantail experiment. In all 33 such matings were made. 

 The descriptions of the pure bred birds and the several types of 

 cross-bred birds produced are first given. The details of the 

 various matings are then described. For the sake of clearness 

 these are not given in the order in which they were made but are 

 divided into three series. 



Series A, comprising Exps. 1-11, deals with matings in the 

 direct line, together with the testing of extracted whites. The 

 results are further tabulated in Table I. 



Series B (Exps. 12-26) shows the matings of ci-ossbreds, chiefly 

 blues, to whites, and the subsequent matings of birds derived 

 from such crosses. Tables II. and III. deal with results in this 

 series. 



Series C (Exps. 27-33) deals with the matings of blues and 

 blacks and the further crossings of offspring produced from such 

 matings. 



The minor characters — irides, beaks, claAvs, and eye-wattles — are 

 described at the end of the paper ; the details given under the 

 descriptions of the experiments refer to plumage only. 



The general results of the Barb-Fantail experiments may be 

 briefly summarised as follows : — 



The F. 1 generation shows a dominance of black to white, and 

 the further matings show that blue is also dominant to white. 

 This dominance of the coloured to the non-coloured type is, how- 

 ever, imperfect, as the majority of birds produced from the mating 

 of black or blue with white show some white feathers, chiefly on 

 the rump. 



In the F. 2 generation the following types appear : — 



Black. 



Black, with some white feathers. (Black w. f .) 



Blue. 



Blue, with some white feathers. (Blue w. f .) 



Bed. 



White, with some coloiu^ed feathers. 



White. 



The blue type may be homozj^gous or may be dominant to 

 white. Black was never obtained from the mating together 

 of two blues. The matings of blues and blacks in Series 

 show that blue is a simple recessive to black. The absence of 

 white feathers in blue birds of the F. 2 generation does not 

 necessarily indicate that they are homozygous, for Exp. 30 shows 

 such a blue to contain white. Conversely, an F. 2 blue with some 

 white feathers is shown in Exp. 13, when mated with a white, to pro- 

 duce blues with some white feathers only. The significance of the 

 presence or absence of white feathers has not been clearly made out. 

 It was at first thought their presence was indicative of the fact that 

 the bird was giving off white-bearing gametes. This, however, is not 



