198 



Bulletin No. 155.— 1913. 



and of the barred birds one c/" should be homozygous, one hetero- 

 zygous, and one 9 heterozygous for this character. 



The experimental data presented in Case 3c may now be compared 

 with these theoretical results. In Table 12, it was demonstrated 

 that of 34 birds raised 17 were white and 4 were black, while 13 were 

 barred as shown in the following diagram: 



It will thus be seen that the correspondence between the actual 

 and the theoretical results is very close. 



Case 3e. — d^ 



{ (White Leghorn cf X Black Minorca 9) d^ 



( Black Minorca 9 



(White Leghorn cf X Black Minorca 9) d^ ] 



1 



X 



, —(Table 13, p. 177). 

 Black Minorca 9 



The experimental data presented under the head of Cases 3c and 3d 

 made it apparent that cf 325B was actually heterozygous for the 

 barring factor, and had the zygotic constitution, C2Bhf2i2- The next 

 step in the process of obtaining (from the 325 group) the barring 

 factor in a pure, homozygous condition was to obtain a 9 cross- 

 bred heterozygous for this character. 



Under the heading of Case 3b it has been shown that from the 

 mating (White Leghorn X Black Minorca ) d X Black INIinorca 9 

 there were produced, along with the barred d 325B, black 99 and 



