R K. Nabours 45 



to colours of Paratettix, combs of fowls, and colours of the albumen of 

 peas, it as readily applies to all the inheritance behaviour exhibiting 

 the 1 : 3 (actually 1 : 2 : 1) ratios, and the 9:3:3:1 (actually 

 1:1:1:1:2:2:2:2:4) ratios described in the literature which I 

 have had time so far to examine. I suggest also that those matings 

 which result in the apparent 27:9:9:9:3:3:3:1 ratios actually 

 consist of one pair of allelomorphic characters, each allelomorphic to the 

 other and two non-allelomorphic or unpaired characters, of the nature 

 of ©, each allelomorphic only to its absence, and neither one allelo- 

 morphic to the other, nor to any other, character. 



One multiple allelomorphic factor of the nature oi A, B, C, or others 

 of this series, and two non-allelomorphic factors of the nature of @, or 

 three factors of the nature of and the factor, or factors, of the nature 

 of A, B, C, etc., unnoticed, or ignored, though necessarily present, proT- 

 duce the 1 : 1 : 1 : 1 : 2 : 2 : 2 : 2 : 4 (9 : 3 : 3 : 1) ratios. One multiple 

 allelomorphic factor and three non-allelomorphic factors like 0, or four 

 factors of the nature of and the factor, or factors, like A, B, C, D, etc., 

 unnoticed or ignored, will give the 27 : 9 : 9 : 9 : 3 : 3 : 3 : 1 ratios. In 

 no instance can more than one multiple allelomorphic factor (^, B, C, D, 

 etc.) be found in one gamete, or two in a zygote ; but any number of 

 factoi's like © can be accommodated in a gamete or zygote. The 

 behaviour of these factors as illustrated in the tables lends emphasis to 

 these distinctions which are of fundamental importance in studies of 

 inheritance. 



During the last three years of the breeding work, and in the pre- 

 paration of the data and illustrations, Mr A. W. Bellamy has given me 

 the most valuable help. The initiation of the work at the Kansas 

 Experiment Station was made possible by the open-minded and helpful 

 consideration of Dr T. J. Headlee, now of the New Jersey Station. The 

 Adams fund has cared for part of the expenses, and State funds for the 

 balance. Director W. M. Jardine has given the most complete encourage- 

 ment throughout. 



