102 MR. R. STAPLES-BROWNE ON [Feb. 18, 



possibly there may also be, although in a much lesser degree, some 

 correlation between the white iris and the black plumage. The 

 figures respecting blue birds are not so conclusive, but seeing that 

 the orange iris is the only one found in C. livia, the suggestion 

 may be hazarded that there is possibly some correlation between 

 the orange iris and blue plumage. The matter becomes more 

 complex when we study the blue and black birds in the plumage 

 of which white feathers occur. It is, however, suggested that the 

 amount of white pi'esent in the plumage may have some influence 

 on the determination of the colour of the iris. Whether the 

 association of certain eye-colours with certain types of plumage- 

 colour arises through gametic coupling or not cannot yet be 

 positively asserted. 



With regard to the question of dominance, it has already been 

 shown that white is a simple dominant to black in the case where 

 the record of the irides of the original parents was kept, and a 

 Mendelian ratio of 3:1 was obtained in F. 2. In the table of 

 the Barb -Fan tail- Nun cross also, a 3 : 1 ratio was given when 

 birds having white irides were mated together. It is further 

 shoAvn that extracted black irides breed true without exception. 



Further experiments are necessary before the relation of 

 orange to black, and white to orange can be definitely asserted. 

 It appears probable, how^ever, that black will be eventually found 

 to be recessive to orange, and that orange may be recessive to 

 white. 



Beaks and Claws. 



In the Barbs used the beaks were either white tipped or tinged 

 with black, or were horn-colour. The claws also were horn-colour. 

 In the white Fantails the beaks and claws were white ; they were 

 also white in the white Tumbler, and in the Nun they were 

 black. In the Barb-Fantail and Barb-Nun- Fantail crosses the 

 following types of beaks and claws were met with: — (1) Birds 

 having quite black beaks ; in these the claM-s were usually black, 

 sometimes white, and sometimes mixed, some of the claws of an 

 individual being black and others white. (2) Birds having white 

 beaks with some dark pigment. This might be a white beak 

 tipped with black, or one mandible might be black and the other 

 white, or the beak might be' of a general horn-colour. In these 

 birds the claws were usually mixed, but some individuals were 

 produced having all the claws black, white, or horn. (3) Birds 

 having white beaks ; these invariably had white claws. [One 

 bird only is recorded as having a white beak and black claws, it 

 was black in plumage, and was killed when only just over a fortnight 

 old. The record is probably erroneous, and had the bird reached 

 matuinty it would have been found to have a white beak tipped 

 with black.] There is a very marked correlation between the 

 colour of the beak and claws and that of the plumage. White 

 beaks and claws have been found on every white- plumaged bird 

 bred, also on whites with some coloured feathers, and reds. Black 



