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THE AMERICAN NATURALIST [Vol.XLVI 



In three of the six ears the deviation from the cor- 

 relation resulting from a 3 : 1 ratio is less than the prob- 

 able error. The deviation for the total is less than 

 three times the probable error, and might readily be 

 only a chance deviation. In two of the ears, however 

 (Nos. 303 and 325), the deviations are rather large to be 

 ascribed to chance. 



In view of the fact that previously reported experi- 

 ments fail to show an equally close approximation to 

 other members of the proposed series, there is no ade- 

 quate reason for assuming that the present approxima- 

 tion to the numbers of a 3 : 1 ratio belongs to a series of 

 formulae represented by the powers of 2. That no such 

 regularity exists in the interrelation of different char- 

 acter pairs is more definitely demonstrated by the ex- 

 periments described below. These results indicate that 

 the association of characters may be determined after 

 the conjugation of the gametes. 



Coherence of Characters not Always the Result of 



If correlations are in all cases due to gametic differ- 

 ences, there should be no correlations exhibited in a 

 cross with a Mendelian formula AabbXaabB. In our 

 experiments with corn this would be represented by a 

 cross between colored- waxy and white-horny, where the 

 first is heterozygous in aleurone color and the second 

 heterozygous in endosperm texture. The colored aleu- 

 rone is dominant to white, and the horny endosperm to- 

 the waxy. If colored aleurone is represented by C, 

 white aleurone by c, horny endosperm by H, and waxy 

 endosperm by h, the gametic structure would be as fol- 

 lows: Female parent, cchH, producing two classes of 

 gametes, ch and cH; male parent, Cchh, producing gam- 

 etes Ch and ch. In neither case is there opportunity for 

 coupling in the gametes since in the female parent all 

 of the gametes should bear the white character, and 

 those of the male parent the waxy character. The sig~ 



