SECT. I 



MORPHOLOGY 



Fin. 88.— Dividing pollen mother cells of a Lily, somewhat diagrammatic. 1. Mother cell with 

 resting nucleus ; 2, the separation of the chromosomes ; 3, the condition of contraction known 

 as synapsis ; 4, double filament in process of fusion ; 5, spirem consisting of an apparently 

 single filament derived from the fused double filament ; (>, reappearance of the longitudinal 

 split, the spirem still unsegmented ; 7, spirem transversely segmented, into paired chromo- 

 somes ; 8, diakinesis ; 0, multipolar spindle ; 10, spindle of the mother nucleus, the nuclear 

 plate composed of paired chromosomes ; U, reduction division, the separating chromosomes 

 showing partial sejjaration of their longitudinal halves ; 12, young daughter nuclei ; 13, the 

 longitudinal halves of the chromosomes (daughter chromosomes) are ananged in pairs on the 

 nuclear spindles ; 14, the spindles of the daughter nuclei ; 15, separation of the daughter 

 chromosomes ; 16, young stage of the grand-daughter nuclei. ( x about 800.) 



