INHERITANCE OF SEX 



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FIG. 100. Diagram illustrating the history of the sex chromosome when 

 accompanied by a smaller x or Y chromosome, as in Lygaeus bicrucis. The male 

 cells have twelve ordinary chromosomes and two sex chromosomes, one larger 

 (X} than the other (F). The resulting spermatozoa from each primordial cell 

 differ; two have X and produce females on uniting with eggs, two have no X and 

 produce males. (From Morgan.) 



