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THE AMERICAN NATURALIST [Vol. XLV 



He finds on using a white bull of roan parentage that the offspring 

 are liable to come dark, some almost black, in color and others very 

 dark blue-gray." 



No better material for Mendelian interpretation than 

 this could be offered. It simply means that the white 

 bull of "white parentage" is more likely to be of type 

 "9" (a roan bull of type 7 or 8 would do as well) ; the 

 whole becomes a mating of type No. 20, which expects 

 100 per cent, roans— black taking the place of red the 



roan becomes blue-roan or "blue-gray." A white bull of 

 "roan parentage" is more likely to be of type "6" (a 

 roan of type 4 or 5 would do as well — see matings Nos. 

 5 and 14), which mated to a pure black would produce 

 50 per cent, blue-roans and 50 per cent, blacks, in 

 accordance with a mating of type No. 23. Wild 

 white cattle which occasionally drop red or black calves, 

 when crossed with a white Shorthorn produce white off- 

 spring. Such a female offspring when bred to a white 

 Shorthorn bull "may produce a considerable percentage 

 of both roan and red as well as of white calves." 10 



'Ibid., p. 432. 

 10 Ibid., p. 442. 



