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THE AMERICAN NATURALIST [Vol. XLVII 



The F 2 selections gave the results expected in Fj. 

 Counting the total progeny (248) from F x and F 2 hetero- 

 zygotes, the figures are: 



The F 2 heterozygotes were in appearance duplicates 

 of the F 1 individuals and after a little experience could 

 be easily distinguished from the abnormal homozygotes. 



Clean segregates were obtained from the heterozygous 



