66 MEXDELISM chap. 



following the results flowing from crosses between blacks 

 and whites. Experiments recently made by Staples- 

 Browne have shown that this case of reversion also can be 

 readily interpreted in Mendelian terms. In these ex- 

 Black Barb x White Fantail Black Barb x Spot 1 



I I 



Dark x Dark 



Among the offspring one very similar 

 to the wild blue rock. 



periments the cross was made between black barbs and 

 white f ant ails. The Fi birds were all black with some 

 white splashes, evidently due to a separate factor intro- 

 duced by the fantail. On breeding these blacks to- 

 gether they gave an F 2 generation, consisting of blacks 



Black Y White 

 Barb j Fantail 



Black j 



(White Splashed) 



c Black 



(White Splashed) 



Black Black Bl 



White Splashed) (White ! 



i i 

 ue Blue White 



Splashed) 



(9) 



(3) (4) 



(with or without white splashes), blues (with or without 

 white splashes), and whites in the ratio 9:3:4. The 

 factors concerned are colour (C), in the absence of 



1 This is an almost white bird, the colour being confined to the tail 

 and the characteristic spot on the head. 



