Cell Division and Heredity 63 



surrounding protoplasmic network. The waste 

 products from these groups will then constitute 

 the chromomeres which frequently occur along the 

 spireme thread and give to the latter a beaded 

 appearance. Each of these groups may be very 

 small, in fact, it may be submicroscopic, and the 

 spireme structure that is actually observed may 

 be only the protoplasmic envelope with which each 

 of these groups surrounds itself. The lengthen- 

 ing and shortening of the spireme thread during 

 the different stages of cell division may then in- 

 volve a deformation of only this protoplasmic 

 envelope and not of the individual spirazine clus- 

 ters within it. 



On the other hand, if we assume the spirazines 

 to extend longitudinally of the chromosomes, the 

 pattern which is characteristic of the species will 

 be disposed in a plane transverse thereto. The 

 two daughter chromosomes of each pair, at the 

 time when they separate from each other, must 

 then be assumed to possess duplicate patterns. 

 In order to replace the loss of germinal material 

 which was sustained by each daughter chromo- 

 some as the result of the preceding division, it 

 appears that each of them would have to fold over 

 on itself during the resting stage so as to produce 

 the duplicated or bilaterally symmetrical pattern 

 which will be necessary for the next cell division. 



