﻿562 
  J. 
  B. 
  FARMER 
  AND 
  D. 
  SHOVE. 
  

  

  there 
  can 
  exist 
  no 
  doubt 
  of 
  the 
  fact 
  during 
  this 
  part 
  of 
  the 
  

   prophase 
  (figs. 
  12 
  — 
  14j. 
  Careful 
  examination 
  of 
  the 
  free 
  

   ends 
  will 
  often 
  indicate 
  that 
  each 
  chromosome 
  is 
  really 
  split, 
  

   and 
  this 
  becomes 
  very 
  clear 
  as 
  the 
  equatorial 
  plate 
  stage 
  is 
  

   reached 
  (fig. 
  15). 
  

  

  The 
  diaster 
  is 
  formed 
  in 
  the 
  well-known 
  fashion, 
  by 
  the 
  

   separation 
  of 
  the 
  longitudinal 
  halves 
  of 
  the 
  individual 
  

   chromosomes 
  and 
  their 
  distribution 
  to 
  the 
  appropriate 
  pole. 
  

   During 
  the 
  anaphase 
  irregularities 
  are 
  often 
  encountered. 
  

   Some 
  chromosomes 
  often 
  seem 
  to 
  get 
  away 
  from 
  the 
  main 
  

   groups, 
  as 
  shown 
  in 
  figs. 
  17 
  and 
  18. 
  

  

  When 
  the 
  number 
  of 
  the 
  chromosomes 
  of 
  these 
  nuclei 
  is 
  

   estimated 
  one 
  soon 
  comes 
  to 
  realise 
  that 
  it 
  is 
  not 
  constant. 
  

   There 
  can 
  be 
  no 
  doubt 
  whatever 
  on 
  this 
  point, 
  and, 
  as 
  it 
  is 
  

   of 
  some 
  interest, 
  we 
  may 
  state 
  we 
  paid 
  special 
  attention 
  to 
  it, 
  

   and 
  made 
  a 
  very 
  large 
  series 
  of 
  drawings 
  and 
  countings 
  of 
  

   those 
  examples 
  that 
  admitted 
  of 
  a 
  reliable 
  estimate 
  being 
  

   arrived 
  at. 
  The 
  number 
  varies 
  from 
  about 
  twenty-six 
  to 
  

   thirty-three. 
  The 
  last 
  was 
  the 
  highest 
  number 
  observed. 
  

   As 
  regards 
  the 
  lower 
  numbers, 
  we 
  confined 
  ourselves 
  to 
  those 
  

   cases 
  in 
  which 
  the 
  razor 
  had 
  not 
  touched 
  the 
  nuclei, 
  in 
  order 
  

   to 
  exclude 
  the 
  possibility 
  of 
  accidental 
  removal 
  of 
  any 
  of 
  the 
  

   chromosomes. 
  

  

  As 
  the 
  anaphase 
  and 
  telophase 
  supervene, 
  the 
  chromosomes 
  

   pass 
  through 
  the 
  reverse 
  series 
  of 
  changes 
  already 
  observed 
  

   during 
  the 
  prophase. 
  The 
  vesiculation, 
  long 
  ago 
  noticed 
  by 
  

   van 
  Beneden, 
  and 
  since 
  then 
  confirmed 
  by 
  numerous 
  obser- 
  

   vers, 
  is 
  strikingly 
  shown 
  in 
  these 
  Tradescantia 
  nuclei. 
  The 
  

   chromosomes 
  become 
  thicker, 
  and 
  finally 
  the 
  chromatin 
  is 
  

   seen 
  to 
  be 
  distributed 
  as 
  a 
  cloud 
  of 
  fine 
  granules 
  through 
  the 
  

   liuin 
  band. 
  At 
  the 
  same 
  time 
  the 
  nucleoli 
  are 
  regenerated, 
  

   and 
  it 
  is 
  a 
  significant 
  fact 
  that 
  they 
  always 
  appear 
  in 
  the 
  first 
  

   instance 
  in 
  close 
  connection 
  with 
  the 
  chromatic 
  bauds, 
  aud 
  

   they 
  are 
  much 
  more 
  numerous 
  than 
  during 
  the 
  later 
  stages 
  

   of 
  telophase. 
  This 
  diminution 
  in 
  number 
  is 
  clearly 
  effected 
  

   by 
  fusion 
  or 
  running 
  together 
  of 
  the 
  previously 
  discrete 
  

   nucleolar 
  masses. 
  The 
  clear 
  area 
  that 
  surrounds 
  each 
  

  

  