﻿THE 
  MATOTIC 
  PHASE 
  IN 
  ANIMALS 
  AND 
  PLANTS. 
  519 
  

  

  in 
  the 
  angles 
  where 
  the 
  walls 
  meet; 
  whilst 
  at 
  other 
  times 
  

   these 
  granules 
  can 
  be 
  traced 
  as 
  lines 
  or 
  rows 
  for 
  short 
  dis- 
  

   stances 
  within 
  the 
  nuclear 
  cavity. 
  The 
  regular 
  spireme 
  

   arrangement 
  is 
  thus 
  the 
  result 
  of 
  a 
  progressive 
  differentiation^ 
  

   a 
  result 
  encountered 
  in 
  other 
  cases^ 
  e. 
  g. 
  in 
  Tradescantia, 
  

   and 
  less 
  prominently 
  perhaps 
  in 
  Lilium. 
  

  

  As 
  the 
  spore-mother-cells 
  approach 
  maturity 
  the 
  chromatin 
  

   assumes 
  a 
  more 
  regular 
  arrangement, 
  and 
  the 
  linin 
  frame- 
  

   work 
  begins 
  to 
  stand 
  out 
  more 
  clearly 
  from 
  the 
  paralinin 
  that 
  

   surrounds 
  and 
  encloses 
  it. 
  The 
  thread 
  now 
  forms 
  a 
  thin, 
  

   much 
  -convoluted 
  filament 
  which 
  seems 
  to 
  be 
  continuous, 
  

   though 
  free 
  from 
  the 
  cross 
  anastomoses 
  present 
  at 
  an 
  earlier 
  

   stage. 
  At 
  least 
  no 
  free 
  ends 
  could 
  be 
  with 
  any 
  certainty 
  dis- 
  

   covered. 
  The 
  chromatin 
  is 
  now 
  very 
  distinctly 
  arranged 
  in 
  

   a 
  single 
  serial 
  row 
  of 
  granules 
  in 
  the 
  linin. 
  At 
  this 
  stage 
  the 
  

   first 
  contraction 
  figure 
  is 
  to 
  be 
  met 
  with. 
  The 
  coils 
  of 
  the 
  

   spireme 
  are 
  densel}- 
  aggregated 
  at 
  one 
  side 
  of 
  the 
  nucleus, 
  

   but 
  some 
  parts 
  of 
  the 
  whole 
  thread 
  remain 
  free 
  from 
  the 
  

   general 
  tangle. 
  Gradually 
  the 
  dense 
  mass 
  again 
  becomes 
  

   looser, 
  and 
  the 
  thread 
  rapidly 
  shortens 
  and 
  thickens, 
  whilst 
  

   at 
  the 
  same 
  time 
  the 
  chromatin 
  granules 
  are 
  seen 
  to 
  

   be 
  larger, 
  though 
  whether 
  their 
  increase 
  in 
  size 
  is 
  due 
  to 
  

   fusion, 
  or, 
  as 
  seems 
  more 
  probable, 
  to 
  growth, 
  could 
  not 
  be 
  

   decided. 
  Here 
  and 
  there 
  signs 
  of 
  the 
  longitudinal 
  fission 
  

   become 
  apparent, 
  inasmuch 
  as 
  single 
  granules 
  are 
  replaced 
  by 
  

   double 
  ones 
  that 
  lie 
  in 
  pairs 
  along 
  limited 
  lengths 
  of 
  the 
  

   thread 
  (Fig. 
  22). 
  The 
  latter 
  is 
  still 
  much 
  convoluted, 
  and 
  its 
  

   windings 
  can 
  easily 
  be 
  traced 
  just 
  beneath 
  the 
  nuclear 
  wall. 
  

   The 
  longitudinal 
  fission 
  just 
  mentioned 
  does 
  not 
  become 
  

   emphasised 
  as 
  in 
  the 
  case 
  of 
  Lilium, 
  and 
  the 
  thread 
  does 
  not 
  

   separate 
  so 
  distinctly 
  into 
  two 
  longitudinal 
  halves 
  as 
  in 
  that 
  

   genus. 
  

  

  The 
  second 
  (synaptic) 
  contraction 
  figure 
  now 
  sets 
  in. 
  The 
  

   thickening 
  thread 
  gradually 
  becomes 
  massed 
  together 
  in 
  the 
  

   vicinity 
  of 
  the 
  nucleolus, 
  but 
  distal 
  loops 
  are 
  still 
  easily 
  seen 
  

   which 
  extend, 
  and 
  may 
  be 
  attached 
  to, 
  the 
  nuclear 
  wall. 
  In 
  

   these 
  looped 
  portions 
  the 
  signs 
  of 
  longitudinal 
  fission 
  are 
  very 
  

  

  