R. Staples-Browne 151 



chequered and 5 non-chequered '. The Meudelian expectation on this 

 mating was chequered : non-chequered :: 12 : 4, with which ratio the 

 figures obtained comply. No white feathers were produced ; we may 

 therefore presume that white was not being carried by either parent. 

 In the nest a few of the birds were thought to have some white feathers, 

 but these were seen to be Hght silver when the birds gi-ew up. One 

 bird also which had some feather deformity was counted as non- 

 chequered in the nest ; on maturing, however, when the feathers attained 

 their normal development, it was seen to be a light chequer. 



Series D. (v. Table IV.) 

 Exp. 62. Silver chequer, no white ? 31 x White ^ 20. 

 This small experiment was made to further demonstrate that the 

 factor for blueness can be carried by a white bird. Here the silver 

 chequer % is the same bird that was used in the last mating (Exp. 61), 

 which there gave silver birds only when mated to a silver ^. The 

 white (/, raised in Exp. 55, carries the blue factor, but not the 

 chequering factor, which is introduced by the silver. Only two young 

 were raised from this mating, both being blue chequered with black, 

 having only a very few white feathers at the vent and thighs. 



Exp. 63. White $ 32 x Silver chequer, very few w.f. </ 14. 



The $ is an extracted Fn white raised in Exp. 60, the silver 

 chequer ^ is from a DR x R mating in Exp. 59. The mating was 

 continued for three years, and 19 young were produced, as follows : 



Blue, very few wh. feathers 3 1 . 



„ many wh. feathers 2j . 



Blue Chequer, very few wh. feathers ...3 

 „ „ many wh. feathers 5 



Silver, many wh. feathers 2 2 



Silver chequer, no wh. feathers 1 \ \ 6, 



„ „ very few wh. feathers ...1 I 4 

 „ „ many wh. feathers 2 I 



Here the white $ is obviously heterozygous in the blue character. 

 We should have therefore expected an equality of blues and silvers. 

 There is however an excess of blues. As regards chequering we know 

 the silver chequer % to be heterozygous in this character, but the 



^ One of these birds was an intermediate. 

 Journ. of Gen. ii 11 



