20B • , • . 



Assuming the individuality of the chromosomes, and that one-half 

 is paternal and one-half maternal, Gregoire, Allen, Strasburger and others 

 claim that the double spirem, developing in the prophase of the first 

 mitosis, consists of the paternal and maternal spirems which have been 

 brought together side by side during synapsis. But according to the view 

 of Farmer and Moore and the writer, the double spirem is produced by a 

 longitudinal splitting, and that it is composed of paternal and maternal 

 chromosomes united end to end. 



