﻿566 
  J. 
  V,. 
  FARMER 
  AND 
  D. 
  SHOVK. 
  

  

  at 
  the 
  equatorial 
  plane 
  of 
  the 
  spindle 
  that 
  their 
  real 
  form 
  is 
  

   not 
  easy 
  to 
  discern. 
  At 
  this 
  period 
  all 
  trace 
  of 
  the 
  longi- 
  

   tudinal 
  fission 
  is 
  obliterated 
  — 
  at 
  least 
  we 
  have 
  never 
  been 
  

   able 
  to 
  recognise 
  it 
  with 
  certainty, 
  even 
  in 
  the 
  best 
  prO' 
  

   parations. 
  

  

  The 
  chromosomes 
  next 
  enter 
  on 
  the 
  stage 
  of 
  the 
  diaster. 
  

   The 
  ring-like 
  ones 
  sometimes 
  break 
  across 
  the 
  middle, 
  leaving 
  

   two 
  half 
  rings 
  to 
  travel 
  to 
  each 
  pole. 
  Often 
  only 
  one 
  of 
  two 
  

   sides 
  breaks 
  at 
  firsts 
  and 
  then 
  this 
  frequently 
  becomes 
  almost 
  

   straightened 
  out, 
  as 
  though 
  it 
  were 
  being 
  forcibly 
  pulled 
  to 
  

   the 
  pole. 
  There 
  are 
  many 
  differences 
  in 
  the 
  exact 
  mode 
  of 
  

   division 
  pursued, 
  as 
  might 
  have 
  been 
  anticipated 
  when 
  dealing 
  

   with 
  viscous 
  structures, 
  but 
  in 
  principle 
  the 
  result 
  is 
  invari- 
  

   ably 
  the 
  same. 
  The 
  chromosome, 
  as 
  representing 
  a 
  continuous 
  

   length 
  of 
  the 
  S])ireme, 
  breaks 
  transversely, 
  and 
  so 
  different 
  

   entire 
  segments 
  of 
  the 
  spireme 
  are 
  distributed 
  between 
  the 
  

   two 
  daughter 
  nuclei. 
  

  

  Immediately 
  after 
  the 
  separation 
  of 
  the 
  daughter 
  chromo- 
  

   somes 
  from 
  each 
  other, 
  they 
  undergo 
  a 
  change 
  which 
  admits 
  

   of 
  the 
  I'eappearance 
  of 
  the 
  longitudinal 
  fission. 
  This 
  was 
  

   figured 
  and 
  described 
  by 
  Strasburger^ 
  some 
  years 
  ago, 
  and 
  

   we 
  are 
  quite 
  in 
  agreement 
  with 
  his 
  statement 
  of 
  the 
  facts 
  

   (see 
  our 
  figs. 
  45 
  — 
  48). 
  This 
  peculiar 
  occurrence 
  has 
  been 
  

   several 
  times 
  observed 
  in 
  various 
  animals, 
  but 
  its 
  significance 
  

   was 
  not, 
  until 
  recently, 
  properly 
  appreciated. 
  It 
  is 
  also 
  of 
  

   wider 
  occurrence 
  in 
  plants 
  than 
  is 
  often 
  supposed. 
  

  

  A 
  remarkable 
  irregularity, 
  similar 
  to 
  that 
  described 
  by 
  

   JueP 
  for 
  Hemerocallis, 
  has 
  been 
  found 
  by 
  us^ 
  to 
  occur 
  in 
  

   Tradescantia. 
  This 
  irregularity 
  consists 
  in 
  the 
  frequent 
  

   omission 
  of 
  some 
  of 
  the 
  chromosomes 
  to 
  reach 
  the 
  daughter 
  

   nuclei 
  with 
  the 
  rest 
  of 
  their 
  fellows. 
  Consequently 
  they 
  get 
  

   left 
  out 
  in 
  the 
  cytoplasm 
  when 
  the 
  two 
  daughter 
  nuclei 
  

  

  1 
  Strasburger, 
  " 
  Reductions 
  Tbeilung," 
  etc., 
  ' 
  Histologische 
  Beitriige,' 
  vi, 
  

   p. 
  51. 
  

  

  * 
  Juel, 
  ' 
  Pringsheim's 
  Jahrb. 
  wiss. 
  Bot.,' 
  Bd. 
  92. 
  

  

  2 
  Prof. 
  Marcus 
  Hartog 
  has 
  also 
  observed 
  the 
  phenomeuon 
  in 
  question, 
  and 
  

   kindly 
  communicated 
  his 
  results 
  to 
  us. 
  

  

  