492 E. ELEANOR CAROTHERS 



number of possible combinations of the morphologically differ- 

 ent gametes of the parents. 



In the second case, any variation found in the group might 

 occur in the offspring of a single pair. 



The first explanation is a simple, logical one which meets 

 all known facts; hence, in accordance with scientific custom, 

 we are justified in accepting it for the present. 



VI. BIBLIOGRAPHY . 



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