282 



Fl 



Toyama. 



Actual figures 

 Expectation . 



all \V. 



all white 



Fj all W. (W : Y) 



Actual figures 59 o 



Expectation . all white (3 W : i Y) 



(^V 



40 

 45^/4 



Y) 



F3 all W. 



Actual . . 2 matings all W. 

 Expectation all white 



(\V 



one mating all W. 

 all white 



Y) all yellow 

 o all yellow 



(3 W : I Y) all yellow 



2. Bagdad white females doubly mated with Bagdad white and 

 French yellow males. 

 Fl all w. 



Actual figures 



Expectation . 



all w. 

 all w. 



Fo all W. (W : 



Actual figures all white (-> matings) i 



Expectation . all white (3 w 



I y) 



F3 \\-. (W 



Actual figures all white 32 

 Expectation . all white 2S.5 



Y) 



6 



9-5 



all white 



all white {3 w 



In spite of a few cases not producing the expected results the 

 first mating may be considered as a case of our B mating and the 

 second as C mating. 



B. Posterity of F^ mixed broods produced by recessive white 

 females. 



In this series of matings we have three sorts of iW:iY broods. 

 All the whites derived from these broods breed true in the succeeding 

 generations and all the yellow whose zygotic composition is wy 

 segregate into white and yellow after the normal monohybrid principle. 



Matings between Fi white and yellow give, on the contrary, 

 two kinds of mixed F2 broods as shown below: 



1. Fj white >' F] yellow = ww x wY = w\v -)- wY' = i w : I Y'. 



2. ,, :■: ,, = Ww ;< wY' = Ww 4- WY -|- ww -|- wY' = 3 w : : y. 



The former is a case of back-crosses of monohybrid, and the 

 latter 3 w : i Y brood has a different zygotic composition from normal 

 3 w : I Y broods before mentioned. 



As the formula shows, the white is a mixture of three sorts of 

 whites, Ww, WY and ww and the yellow, wY, both F2 forms when 

 paired inter se will segregate according to the following formulae: 



