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THE AMERICAN NATURALIST [VOL. XLV 



permanent and do not, at least in some cases, gradually 

 change into something new, the large accumulation of 



FIG. 1. Each ear in this exhibit represents a different pedigreed family. 

 In each family the variation was slight, and the ear chosen for the exhibit was 

 fairly representative of the entire family. The two self-fertilized ears under 

 selection number " 12 " belong to two distinct strains, the left-hand one being 

 my " Strain A " of other publications. During the last two years this has been 

 selected to its own modal number, while the right-hand ear has been selected to 

 twelve rows throughout the course of the experiments. 



