﻿556 
  J. 
  BUBTLAND 
  FARMBIl 
  AND 
  J. 
  E. 
  S. 
  MOORE. 
  

  

  Fig. 
  32. 
  — 
  The 
  spirem 
  tliread 
  is 
  split. 
  

  

  Fig. 
  33. 
  — 
  The 
  chromosomes 
  are 
  delimited, 
  lougitudiaal 
  fission 
  obvious 
  in 
  

   some 
  of 
  them. 
  

  

  Figs. 
  34, 
  35. 
  — 
  Chromosomes 
  contracting 
  to 
  their 
  definite 
  form. 
  The 
  

   quadripolar 
  achromatic 
  figure 
  visible 
  in 
  Figs. 
  31 
  — 
  35, 
  especially 
  in 
  Fig. 
  34. 
  

  

  Fig. 
  36. 
  — 
  The 
  equatorial 
  plate 
  stage. 
  

  

  Fig. 
  37. 
  — 
  The 
  homotype 
  mitosis, 
  equatorial 
  plate 
  stage, 
  one 
  spindle 
  in 
  

   profile, 
  one 
  in 
  polar, 
  view. 
  

  

  Fig. 
  38. 
  — 
  Anaphase 
  of 
  the 
  homotype 
  mitoses. 
  

  

  PERIPLA.NETA. 
  

  

  Fig. 
  40. 
  — 
  Resting 
  pre-maiotic 
  cell 
  from 
  the 
  testis. 
  

  

  Figs. 
  41 
  — 
  44. 
  — 
  Early 
  stages 
  in 
  the 
  formation 
  of 
  the 
  pre-maiotic 
  chromo- 
  

   somes. 
  

  

  Figs. 
  45—48. 
  — 
  Still 
  later 
  stages 
  in 
  the 
  formation 
  of 
  the 
  pre-maiotic 
  

   chromosomes. 
  

  

  Figs. 
  49, 
  50.— 
  Early 
  stages 
  in 
  the 
  formation 
  of 
  the 
  pre-maiotic 
  spindle 
  

   figure. 
  

  

  Fig. 
  51. 
  — 
  Cell 
  in 
  the 
  "equatorial 
  plate" 
  stage. 
  

  

  Fig. 
  52. 
  — 
  Cell 
  showing 
  the 
  separation 
  of 
  the 
  daughter 
  chromosomes 
  in 
  an 
  

   ordinary 
  pre-maiotic 
  division. 
  

  

  Fig. 
  53. 
  — 
  Cell 
  in 
  a 
  very 
  early 
  stage 
  of 
  the 
  first 
  maiotic 
  (heterotype) 
  pro- 
  

   phase. 
  

  

  Fig. 
  54. 
  — 
  Cell 
  a 
  little 
  later, 
  showing 
  the 
  polarisation 
  of 
  the 
  chromatin, 
  and 
  

   the 
  first 
  contraction 
  of 
  the 
  chromatin 
  from 
  the 
  nuclear 
  wall. 
  

  

  Fig. 
  55.— 
  a 
  later 
  stage 
  in 
  which 
  both 
  the 
  polarisation 
  and 
  contraction 
  is 
  

   more 
  strongly 
  marked. 
  

  

  Fig. 
  56. 
  — 
  A 
  cell 
  in 
  which 
  the 
  chromatic 
  loops 
  characteristic 
  of 
  the 
  hetero- 
  

   type 
  division 
  have 
  become 
  differentiated. 
  

  

  Fig. 
  57. 
  — 
  A 
  later 
  stage 
  during 
  the 
  differentiation 
  of 
  the 
  loops. 
  In 
  this 
  cell 
  

   the 
  contraction 
  of 
  the 
  chromatin 
  has 
  about 
  reached 
  its 
  maximum. 
  

  

  Fig. 
  58. 
  — 
  Cell 
  in 
  which 
  the 
  loops 
  are 
  beginning 
  to 
  open 
  out 
  again. 
  

  

  Figs. 
  59, 
  60. 
  — 
  Stages 
  in 
  this 
  process. 
  

  

  Figs. 
  61 
  — 
  63. 
  — 
  Still 
  later 
  stages, 
  in 
  which 
  the 
  loops 
  are 
  still 
  further 
  opened 
  

   out 
  to 
  form 
  the 
  coarse 
  spirem, 
  and 
  in 
  which 
  the 
  longitudinal 
  fission 
  of 
  the 
  

   thread-work 
  is 
  becoming 
  visible. 
  

  

  Figs. 
  64— 
  66.— 
  Coarse 
  spirem 
  stages. 
  

  

  Fig. 
  67. 
  — 
  Later 
  stage, 
  in 
  which 
  the 
  thread 
  is 
  again 
  becoming 
  polarised, 
  and 
  

   in 
  which 
  the 
  fission 
  is 
  well 
  seen. 
  

  

  