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THE AMERICAN NATURALIST [Vol. XL V 



Sutton, because, if it were true, there could be no more 

 Mendelian pairs in a given species than the number of 

 chromosomes present in that species. Even if this ob- 

 jection could be avoided 6 the more serious objection still 

 remained, namely, that with a small number of chromo- 

 somes present many characters should Mendelize to- 

 gether, but very few cases of this sort are known. De 

 Vries was the first, I believe, to point out that this objec- 

 tion could be met if the genes are contained in smaller 

 bodies that can pass between homologous pairs of chro- 

 mosomes ; and Boveri has admitted this idea as compat- 

 ible with his conception of the individuality of the 

 chromosomes. In the case of the inheritance of two sex- 

 limited characters in the same animal we have an experi- 

 mental verification of this hypothesis. 



show/that more dominant characters can occur in the same individual than 

 the number of chromosomes seems to me only to push back the difficulty. 



