﻿Studies 
  on 
  Synapsis. 
  

  

  271 
  

  

  into 
  the 
  adjacent 
  nurse 
  chamber 
  entering 
  into 
  relation 
  with 
  the 
  nurse 
  cells. 
  

   In 
  the 
  early 
  growth 
  period, 
  before 
  the 
  deposition 
  of 
  yolk 
  has 
  begun, 
  several 
  

   spherical 
  bodies 
  of 
  varying 
  sizes 
  staining 
  with 
  chromatin 
  dyes 
  are 
  found 
  

   lying 
  in 
  the 
  cytoplasm 
  ; 
  in 
  one 
  case 
  two 
  such 
  bodies, 
  one 
  at 
  the 
  anterior 
  end 
  

   and 
  one 
  at 
  the 
  opposite 
  pole 
  were 
  observed 
  (fig. 
  95). 
  In 
  other 
  cases 
  their 
  

   number 
  was 
  more 
  numerous 
  ; 
  they 
  appeared 
  to 
  increase 
  in 
  size 
  in 
  proportion 
  

   as 
  they 
  were 
  remotely 
  situated 
  from 
  the 
  nuclear 
  membrane. 
  Some 
  sections 
  

   showed 
  minute 
  granules 
  lying 
  within, 
  upon 
  and 
  just 
  outside 
  the 
  nuclear 
  

   membrane 
  ; 
  and 
  the 
  nucleus 
  in 
  such 
  may 
  show 
  several 
  karyosomes, 
  so 
  that 
  

   possibly 
  these 
  bodies 
  are 
  the 
  products 
  of 
  the 
  oocyte 
  nucleus. 
  As 
  in 
  Neuroterus 
  

   and 
  Andricus, 
  it 
  is 
  not 
  possible 
  to 
  detect 
  in 
  the 
  eggs 
  of 
  Cynips 
  any 
  region 
  

   which 
  can 
  be 
  said 
  to 
  correspond 
  with 
  the 
  " 
  germ-cell 
  determinants 
  " 
  of 
  

   Copidosoma. 
  The 
  full-grown 
  egg, 
  unlike 
  the 
  elongated 
  type 
  which 
  is 
  

   characteristic 
  of 
  the 
  Hymenoptera, 
  is 
  fusiform, 
  tapering 
  to 
  a 
  fine 
  stalk 
  at 
  one 
  

   extremity 
  (fig. 
  10). 
  

  

  Nuclear 
  Phenomena 
  in 
  the 
  late 
  Ovarian 
  Oocyte. 
  

  

  About 
  the 
  time 
  when 
  the 
  egg 
  reaches 
  its 
  maximum 
  dimensions, 
  i.e., 
  just 
  

   before 
  the 
  imago 
  bores 
  its 
  way 
  out 
  of 
  the 
  gall, 
  the 
  chromatin 
  of 
  the 
  nucleus 
  

   resolves 
  itself 
  into 
  long 
  filaments 
  of 
  which 
  about 
  20 
  can 
  be 
  counted 
  (fig. 
  11). 
  

   These 
  then 
  become 
  shorter 
  and 
  thicker, 
  preparatory 
  to 
  conjugation 
  in 
  pairs, 
  

   so 
  that 
  each 
  member 
  of 
  a 
  pair 
  is 
  in 
  contact 
  with 
  its 
  fellow 
  by 
  one 
  extremity 
  

   only. 
  Since 
  the 
  number 
  of 
  chromosomes 
  is 
  reduced 
  in 
  the 
  early 
  oocytes 
  of 
  

   the 
  young 
  pupa, 
  it 
  would 
  appear 
  that 
  the 
  chromosomes 
  pair 
  twice 
  in 
  the 
  forms 
  

   which 
  are 
  now 
  under 
  consideration. 
  Agar 
  has 
  described 
  a 
  reunion 
  of 
  univalents 
  

   after 
  a 
  period 
  of 
  temporary 
  separation 
  preparatory 
  to 
  the 
  formation 
  of 
  

   the 
  maturation 
  spindle 
  in 
  the 
  spermatogenesis 
  of 
  Lepidosiren. 
  Wilson 
  has 
  

   also 
  stated 
  that 
  in 
  the 
  spermatogenesis 
  of 
  certain 
  Hemiptera 
  the 
  X 
  and 
  Y 
  

   chromosomes 
  regularly 
  conjugate 
  at 
  the 
  poles 
  of 
  the 
  spindle 
  before 
  the 
  

   first 
  maturation 
  division 
  is 
  completed. 
  Hegner 
  believes 
  that 
  a 
  pairing 
  of 
  

   chromosomes 
  end 
  to 
  end 
  immediately 
  before 
  the 
  appearance 
  of 
  the 
  maturation 
  

   spindle 
  occurs 
  in 
  Copidosoma. 
  These 
  bivalent 
  elements, 
  which 
  are 
  distributed 
  

   at 
  first 
  without 
  any 
  definite 
  arrangement 
  (fig. 
  12), 
  betray 
  their 
  double 
  nature 
  

   by 
  a 
  deep 
  constriction 
  in 
  the 
  middle. 
  They 
  soon 
  begin 
  to 
  arrange 
  themselves 
  

   about 
  a 
  definite 
  axis, 
  and 
  spindle 
  fibres 
  make 
  their 
  appearance, 
  though 
  no 
  

   asters 
  or 
  centrosomes 
  are 
  visible. 
  The 
  number 
  of 
  doubles 
  present 
  at 
  this 
  

   stage 
  is 
  very 
  easy 
  to 
  count, 
  10 
  being 
  invariably 
  present 
  (fig. 
  13). 
  They 
  are 
  

   now 
  seen 
  to 
  array 
  themselves 
  in 
  a 
  parallel 
  series 
  upon 
  the 
  spindle 
  with 
  the 
  

   point 
  of 
  contact 
  of 
  their 
  univalent 
  constituents 
  in 
  the 
  equatorial 
  plane. 
  

   What 
  follows 
  corresponds 
  exactly 
  with 
  what 
  has 
  been 
  described 
  in 
  Copidosoma 
  

  

  vol. 
  xci. 
  — 
  B. 
  Y 
  

  

  