106 



Shull. 



The Fs families of the second group, as arranged in Table II, 

 include those which are referable to the expected ratio 15:1, the parents 

 of these families having had both the duplicate genes, C and D, 

 heterozygous. As this was the condition of all the F2 families from 

 which the Fs was derived, the F^ families produced by bursa-pastoris 

 individuals in this group should repeat the conditions found in the Fs, 

 being again distributed among the same three types. Table III includes 

 27 F4 families derived from this 15 : 1 group of the Fs, and 50 F 5 

 families produced from the corresponding group in F*. No confusion 

 results from tabulating the two generations together in this way, as the 

 expectation is the same in both. If for any reason it should be desired 

 to distinguish between the F 4 and Fs families, this may be easily 

 accomplished by reference to the pedigree-numbers. 



Table III. 



