1908.] 



INHERITANCK OF COLOUR IN PIGEONS. 



Barb-Fantail Cross. 



101 



In connection with the above tables it may be noted that in 

 the matings of orange x black irides, the excess of blacks over 

 oranges in the offspring 'is in some measure associated with the 

 excess of white-plumaged birds over blues in Exps. 16-23 where 

 equality was expected. Further, in the White x Orange ex- 

 periments, all the ofispring from two matings, amounting to 

 12 birds, had white irides. 



The bird already mentioned as having one iris black and the 

 other orange was raised from $ with black irides x c5" with 

 orange. This bird when mated to a bird with black irides gave 

 5 young all with black irides. 



In the Barb-Nun experiment 21 birds were reared to an age 

 at which the adult colouring of the iris showed itself. In all 

 these foregoing birds the irides were white. In the two Nun- 

 Fantails described the irides were black. The Tumbler-Fantail 

 cross is exceedingly interesting in respect of the irides. As has 

 been stated, white irides cannot be kept in a strain of white 

 Tumblers without the occasional introduction of birds having 

 some coloured feathers. In the cross between the white-eyed 

 Tumbler and the black-eyed Fantail, 36 birds were raised. Of 

 these 35 had black irides, and one had a small part of the left iris 

 white, the remainder being black. This was a splashed bird in 

 the F. 2 generation (Exp. 44, No. 14). 



The foregoing facts as far as they go suggest the conclusion 

 that the black iris is correlated with the white plumage, and that 



