﻿33S 
  Farr: 
  Pollen-mother-cell 
  of 
  Cobaea 
  scandens 
  alba 
  

  

  Kxplauatlon 
  of 
  plate 
  14- 
  

  

  4 
  

  

  The 
  figures 
  were 
  drawn 
  with 
  a 
  Spencer 
  i.S 
  objective 
  and 
  ocular 
  4, 
  with 
  a 
  tube 
  

   length 
  of 
  170 
  mm. 
  The 
  magnification 
  is 
  about 
  1,971 
  diameters. 
  

  

  Fig. 
  I. 
  Mother-cell 
  after 
  second 
  nuclear 
  .division. 
  Nuclei 
  are 
  organized, 
  

   spindles 
  inflated, 
  and 
  wall 
  thickened. 
  

  

  Fig. 
  2. 
  An 
  earij- 
  stage 
  in 
  the 
  furrowing 
  process, 
  showing 
  thickened 
  fibers 
  and 
  

   the 
  first 
  appearance 
  of 
  less 
  dense 
  areas. 
  

  

  Fig. 
  3. 
  Furrows 
  penetrating 
  deeper, 
  fibers 
  undisturbed 
  in 
  position, 
  and 
  tips 
  of 
  

   furrows 
  between 
  fibers. 
  

  

  Fig. 
  4. 
  . 
  A 
  section 
  with 
  deeper 
  furrows, 
  showing 
  no 
  penetrating 
  tips 
  in 
  the 
  less 
  

   dense 
  areas. 
  

  

  Fig. 
  5. 
  Another 
  section 
  from 
  the 
  cell 
  represented 
  in 
  Fig. 
  4, 
  between 
  that 
  section 
  

   and 
  the 
  fourth 
  nucleus, 
  showing 
  penetrating 
  tips 
  of 
  furrows 
  between 
  the 
  fibers. 
  

  

  Fig. 
  6. 
  Narrow 
  continuous 
  furrows, 
  tips 
  of 
  furrows, 
  and 
  the 
  beginning 
  of 
  a 
  

   central 
  triangular 
  area. 
  

  

  Fig. 
  7. 
  Late 
  stage 
  in 
  division, 
  showing 
  continuous 
  fibers, 
  surrounded 
  fibers, 
  

   central 
  triangular 
  area, 
  and 
  the 
  rounding 
  up 
  of 
  the 
  daughter-cells. 
  

  

  