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Isabel McCracken 



to be either the newest type or an atavistic form. Upon the 

 assumption that it is a new type, we would expect its behavior to 

 S and to B to parallel that of B to S. Our expectation is in the main 

 fulfilled. Inspection of Table II shows that in the progeny of 

 ABxB (category h) all the offspring are B. In the progeny of 



TABLE II {Third Genercuon) 



AB xS (category c) all the offspring are S. That is, both S and 

 B dominate AB completely in crosses between S and AB or B and 

 AB. In these two categories AB is completely recessive, in the 

 sense that it does not appear in the soma of any of the offspring. 



In BxB matings, extracted B (category d, Table II), both 

 parents having been born of AB parents, two kinds of broods are 



