R. C. PUNNETT 



39 



Fig. 1. 



As indicated in the scheme, the 7 blacks should be zygoticaliy of five 

 different sorts, viz. : 



1 DDEEAA. 



2 DDEEAa. 



1 DDEEaa. 



2 DdEEaa. 

 1 ddEEaa. 



Crossed with an animal of the constitution ddEEaa, the last three 

 classes should give only blacks; those of the constitution DDEEAa 

 should give equal numbers of blacks and agouti-blacks; while those of 

 the constitution DDEEAA should give agouti-blacks only. The three 

 different classes as revealed by this test should be in the proportion 

 4:2:1. Moreover no agouti should make its appearance in any of 

 these crosses. 



Blacks resulting from the matings between agouti-blacks of the 

 constitution DdEEAa were accordingly saved and tested by crossing 

 with the chocohite buck whose history was given in the earlier 

 account {Journ. Gen. 1912, p. 233). With respect to the factors in 

 question he was of the constitution ddEEaa. 



In all, 14 does were tested in this way and'gave the results shewn 

 in Table I. 



The results tally closely with expectation which demands that the 

 three classes should be found in the ratio 4:2:1. The actual numbers, 

 8:5:1, are not far removed from the expected 8:4:2. Moreover the 

 case of F 238 shews that the animal of the constitution DDEEAA is 



