﻿Studies 
  on 
  Synapsis. 
  

  

  311 
  

  

  indicated, 
  their 
  number 
  should 
  be 
  tetraploid, 
  whereas 
  if 
  they 
  represent 
  whole 
  

   chromosomes, 
  their 
  number 
  should 
  be 
  diploid." 
  

  

  As 
  already 
  stated, 
  there 
  is 
  no 
  evidence 
  of 
  cleavage 
  in 
  the 
  telophase 
  of 
  the 
  

   later 
  oogonial 
  divisions 
  studied 
  ; 
  and 
  a 
  preliminary 
  examination 
  of 
  the 
  early 
  

   nuclear 
  history 
  of 
  the 
  oocyte 
  made 
  it 
  abundantly 
  evident 
  that 
  stages 
  which 
  

   are 
  obscure 
  and 
  difficult 
  to 
  interpret 
  in 
  the 
  male 
  sex 
  cells 
  display 
  a 
  remark- 
  

   able 
  clarity 
  in 
  the 
  ovarioles, 
  where 
  the 
  fixation 
  is 
  facilitated 
  by 
  the 
  small 
  

   diameter 
  of 
  the 
  terminal 
  chamber. 
  In 
  the 
  earliest 
  stages 
  (fig. 
  8) 
  the 
  nucleus 
  of 
  

   the 
  oocyte 
  is 
  readily 
  distinguishable 
  from 
  the 
  confused 
  reticulum 
  of 
  the 
  oogonial 
  

   resting 
  nuclei 
  by 
  the 
  organisation 
  of 
  the 
  chromatin 
  as 
  a 
  dense 
  tangle 
  of 
  

   finely 
  beaded, 
  single, 
  convoluted 
  and 
  none 
  the 
  less 
  definitive 
  threads 
  which 
  

   at 
  first 
  exhibit 
  no 
  sign 
  of 
  polarisation, 
  and 
  lie 
  in 
  contact 
  with 
  the 
  nuclear 
  

   membrane 
  ; 
  this 
  condition 
  corresponds 
  with 
  what 
  is 
  now 
  generally 
  described 
  

   as 
  the 
  early 
  leptotene 
  stage. 
  The 
  paired 
  accessory 
  chromosomes 
  which 
  are 
  

   indistinguishable 
  from 
  the 
  autosomes 
  on 
  the 
  equatorial 
  plate 
  of 
  the 
  oogonial 
  

   mitoses 
  behave, 
  as 
  will 
  be 
  seen 
  later, 
  like 
  their 
  fellows 
  in 
  the 
  ensuing 
  stages 
  ; 
  

   in 
  this 
  respect 
  they 
  resemble 
  those 
  of 
  the 
  Orthopteran 
  Leptophytes 
  recently 
  

   described 
  by 
  Mohr 
  (13).* 
  Very 
  soon 
  the 
  irregularly 
  disposed 
  filaments 
  of 
  

   the 
  early 
  leptotene 
  stage 
  assume 
  the 
  characteristic 
  polar 
  arrangement 
  which 
  

   marks 
  the 
  formation 
  of 
  the 
  bouquet 
  (fig. 
  9). 
  In 
  the 
  early 
  bouquet 
  the 
  

   filaments 
  are 
  seen 
  in 
  the 
  form 
  of 
  loops 
  polarised 
  at 
  both 
  ends 
  ; 
  and 
  not 
  as 
  

   yet 
  withdrawn 
  from 
  the 
  nuclear 
  membrane. 
  In 
  the 
  preparations 
  examined 
  

   a 
  number 
  of 
  such 
  nuclei 
  were 
  cut 
  in 
  the 
  plane 
  at 
  right 
  angles 
  to 
  the 
  axis 
  

   about 
  which 
  the 
  leptotene 
  loops 
  are 
  orientated 
  ; 
  and 
  it 
  was 
  thus 
  possible 
  to 
  

   count 
  the 
  number 
  of 
  the 
  latter, 
  each 
  of 
  which 
  would 
  in 
  median 
  section 
  be 
  cut 
  

   twice. 
  In 
  several 
  cases 
  the 
  number 
  of 
  points 
  was 
  so 
  clearly 
  between 
  sixty-six 
  

   and 
  sixty-nine, 
  as 
  to 
  leave 
  no 
  doubt 
  that 
  the 
  full 
  diploid 
  number 
  is 
  here 
  

   represented 
  (fig. 
  10). 
  The 
  attenuated, 
  single 
  and 
  finely 
  beaded 
  filaments 
  of 
  

   the 
  early 
  leptotene 
  bouquet 
  now 
  contract 
  away 
  from 
  the 
  nuclear 
  membrane 
  

   become 
  shorter 
  and 
  more 
  closely 
  approximated. 
  As 
  the 
  process 
  of 
  contrac- 
  

   tion 
  continues, 
  the 
  filaments 
  are 
  brought 
  into 
  closer 
  union 
  in 
  pairs, 
  and 
  it 
  

   appears 
  that 
  the 
  paired 
  association 
  of 
  the 
  loops 
  begins 
  at 
  the 
  polar 
  ends, 
  

   extending 
  to 
  their 
  distal 
  extremities, 
  until 
  the 
  whole 
  bouquet 
  is 
  formed 
  of 
  

   intimately 
  associated 
  loops 
  (fig. 
  11). 
  By 
  the 
  time 
  maximal 
  contraction 
  has 
  

   been 
  effected 
  the 
  interspace 
  between 
  the 
  conjugating 
  filaments 
  is 
  hardly 
  

   recognisable 
  ; 
  but 
  in 
  the 
  best 
  preparations 
  it 
  can 
  be 
  seen 
  that 
  even 
  in 
  this 
  

   stage, 
  the 
  pachytene 
  threads 
  retain 
  their 
  double 
  character 
  with 
  sufficient 
  

   clarity 
  to 
  indicate 
  the 
  nature 
  of 
  the 
  cleavage 
  which 
  follows 
  (fig. 
  12). 
  When 
  

   it 
  is 
  borne 
  in 
  mind 
  that 
  most 
  of 
  the 
  available 
  data 
  relating 
  to 
  the 
  synaptic 
  

   * 
  Cf. 
  Winiwarter 
  and 
  Sainmont 
  (34). 
  

  

  2 
  B 
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