553 
in Pinus and Thuja . 
ii. The second division is probably qualitative, since the chromosomes 
are not conceived of as being capable of complete rehabilitation and it 
seems reasonable that the material entities become rearranged during the 
rest period. 
I am indebted to Prof. D. M. Mottier for kind criticism and helpful 
advice during the progress of this work. 
Bloomington, Indiana, 
March 25, 1908. 
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