﻿THR 
  MATOTIO 
  PHASE 
  IN 
  ANIMALS 
  AND 
  PLANTS. 
  555 
  

  

  Fig. 
  1. 
  — 
  Very 
  early 
  stage 
  of 
  propliase 
  of 
  first 
  maiotic 
  (heterotype) 
  mitosis, 
  

   first 
  appearance 
  of 
  chromatic 
  fibrils. 
  

  

  Fig. 
  2. 
  — 
  Slightly 
  later 
  stage, 
  first 
  contraction 
  figure. 
  

  

  Fig. 
  3. 
  — 
  The 
  ojiening 
  out 
  of 
  spireni 
  after 
  the 
  first 
  contraction. 
  The 
  

   beginning 
  of 
  longitudinal 
  fission 
  is 
  shown. 
  

  

  Fig. 
  4. 
  — 
  Slightly 
  later 
  stage, 
  longitudinal 
  fission 
  completed. 
  

  

  Fig. 
  5. 
  — 
  The 
  divarication 
  of 
  the 
  longitudinal 
  halves 
  of 
  the 
  spirem. 
  The 
  

   second 
  co'itractiou 
  figure 
  is 
  just 
  commencing. 
  

  

  Figs. 
  6, 
  7, 
  8, 
  9, 
  10. 
  — 
  Stages 
  in 
  the 
  second 
  contraction 
  (synapsis). 
  The 
  

   longiLudinal 
  fission 
  still 
  clear, 
  but 
  the 
  thread 
  as 
  a 
  whole 
  is 
  contracting 
  and 
  

   thickening. 
  

  

  Fig. 
  11. 
  — 
  Still 
  later 
  stage, 
  showing 
  the 
  loops 
  and 
  parallel 
  arrangement 
  of 
  

   the 
  spirem, 
  with 
  indications 
  of 
  the 
  fission 
  now 
  almost 
  obliterated. 
  

  

  Figs. 
  12, 
  13. 
  — 
  The 
  chromosomes 
  rapidly 
  forming, 
  indications 
  (clear 
  in 
  one 
  

   of 
  fission 
  still 
  apparent. 
  

  

  Fig. 
  14. 
  — 
  The 
  congregation 
  of 
  the 
  chromosomes 
  just 
  before 
  the 
  formation 
  

   of 
  the 
  equatorial 
  plate. 
  

  

  Fig. 
  15. 
  — 
  The 
  chromosomes 
  on 
  the 
  equatorial 
  plate, 
  illustrating 
  some 
  of 
  

   the 
  various 
  shapes 
  commonly 
  present. 
  

  

  Figs. 
  16, 
  17. 
  — 
  Diaster 
  (heterotype). 
  The 
  chromosomes 
  show 
  the 
  re- 
  

   appearance 
  of 
  the 
  longitudinal 
  fission. 
  The 
  variation 
  depends 
  on 
  the 
  modes 
  

   in 
  which 
  they 
  are 
  arranged 
  on 
  the 
  spindle. 
  

  

  Fig. 
  18. 
  — 
  Late 
  anaphase 
  of 
  diaster 
  (polar 
  view). 
  

  

  Fig. 
  19. 
  — 
  Telophase 
  of 
  heterotype. 
  

  

  Fig. 
  20. 
  — 
  Homotype 
  diaster. 
  

  

  Fig. 
  21. 
  — 
  Homotype 
  telophase. 
  

  

  Fig. 
  22. 
  — 
  Early 
  spirem 
  of 
  Osmund 
  a. 
  

  

  Fig. 
  23. 
  — 
  Late 
  spirem, 
  showing 
  the 
  longitudinal 
  fission 
  and 
  the 
  looping 
  

   of 
  the 
  spirem. 
  

  

  Figs. 
  24, 
  25. 
  — 
  Later 
  stages, 
  the 
  chromosomes 
  definitely 
  isolated. 
  

  

  Figs. 
  26, 
  27. 
  — 
  The 
  various 
  forms 
  assumed 
  by 
  the 
  chromosomes 
  during 
  their 
  

   later 
  differentiation. 
  

  

  Fig. 
  2S. 
  — 
  The 
  heterotype 
  equatorial 
  plate 
  stage 
  of 
  Osmund 
  a. 
  

  

  FiG. 
  29. 
  — 
  Psilotum, 
  early 
  stage 
  in 
  developnieut 
  of 
  the 
  heterotype 
  chromo- 
  

   somes, 
  after 
  the 
  spirem 
  phase 
  is 
  over. 
  

  

  Fig. 
  30. 
  — 
  Psilotum, 
  heterotype 
  chronio30;n33" 
  corresponding 
  to 
  those 
  of 
  

   Osmunda 
  in 
  fig. 
  27. 
  

  

  Fig. 
  31.— 
  Aneura 
  pinguis. 
  Early 
  prophase. 
  In 
  each 
  of 
  the 
  cells 
  shown 
  

   a 
  centrosphere 
  is 
  figured. 
  

  

  