204 



Bulletin No. 155. — 1913. 



These expected results may be summarized, and compared wdth 

 the actual results, as shown below: 



When the actual results (Table 17, p. 181) are compared with the 

 expected it is clear that there is a close agreement. At the time this 

 paper goes to press, it is impossible because of the immaturity of the 

 stock to ascertain the sex-ratios and their relation to barring. It 

 may be stated, however, that the 1913 progeny undoubtedly contains 

 the expected proportion of cf cf homozygous for barring. It already 

 appears possible to predict which these birds are by means of their 

 lighter color. In this young stock there have alread\' appeared birds 

 which possess a much better grade of barring than any observed in 

 the earlier stages of the investigation. To what extent selection for 

 two or three years may be effective in further improving the character 

 of the barred pattern remains of course to be ascertained. Suffice it 

 to say at present that the mating described in Case 5 has finally 

 yielded the expected c^ d^ homozygous, and 99 heteroz^-gous, for 

 the barring factor; and these birds will now be used as selection = 

 material for further improvement of the character under discussion. 



B. Discussion of Additional Data not Included in the 



Foregoing Cases. 



During the course of these investigations a few other matings 

 bearing upon the constitution of the White Leghorn have been made. 

 These may be discussed briefly at this time, although the detailed 

 results must await further breeding. These data relate to (1) the 



