﻿Studies 
  on 
  Synapsis. 
  

  

  323 
  

  

  become 
  stretched 
  lengthwise 
  of 
  the 
  spindle 
  and 
  divide 
  transversely. 
  Two 
  

   rings 
  in 
  their 
  account 
  remain 
  open 
  at 
  one 
  side 
  and 
  retain 
  evidence 
  of 
  the 
  

   diplotene 
  cleavage 
  ; 
  they 
  are 
  stated 
  to 
  divide 
  in 
  the 
  same 
  way 
  as 
  the 
  remainder. 
  

   According 
  to 
  Morse, 
  on 
  the 
  other 
  hand, 
  the 
  polarised 
  loops 
  straighten 
  out 
  

   and 
  proceed 
  to 
  division 
  in 
  the 
  following 
  manner 
  : 
  " 
  The 
  chromosomes 
  come 
  

   to 
  lie 
  in 
  the 
  equator 
  of 
  the 
  cell 
  with 
  their 
  longitudinal 
  axes 
  in 
  that 
  plane. 
  

   Some 
  of 
  the 
  bodies 
  precociously 
  arrange 
  themselves 
  for 
  division, 
  while 
  others 
  

   lag 
  behind. 
  For 
  this 
  reason 
  one 
  cell 
  may 
  present 
  an 
  almost 
  complete 
  history 
  

   of 
  the 
  division 
  of 
  the 
  chromosomes. 
  The 
  attachment 
  of 
  the 
  spindles 
  fibres. 
  . 
  . 
  . 
  

   may 
  be 
  in 
  the 
  middle 
  thus 
  pulling 
  the 
  daughter 
  chromosomes 
  apart 
  sym- 
  

   metrically 
  to 
  form 
  a 
  ring 
  ; 
  or 
  the 
  attachment 
  may 
  be 
  nearer 
  one 
  end 
  of 
  the 
  

   chromosome 
  than 
  the 
  other, 
  so 
  that 
  the 
  daughter 
  chromosomes 
  are 
  pulled 
  

   out 
  at 
  first 
  into 
  a 
  bracket 
  figure 
  . 
  . 
  ." 
  

  

  These 
  two 
  descriptions, 
  the 
  one 
  telosynaptic, 
  the 
  other 
  parasynaptic, 
  are 
  

   needless 
  to 
  say 
  mutually 
  exclusive 
  ; 
  moreover, 
  neither 
  is 
  adequate. 
  The 
  

   inadequacy 
  of 
  the 
  last 
  is 
  indicated 
  by 
  the 
  sentence 
  italicised, 
  since 
  if 
  the 
  

   chromosomes 
  of 
  the 
  heterotype 
  mitosis 
  differ 
  inter 
  se, 
  as 
  regards 
  the 
  actual 
  

   form 
  of 
  the 
  cleavage, 
  a 
  complete 
  history 
  can 
  obviously 
  only 
  be 
  obtained 
  by 
  

   tracing 
  out 
  the 
  genesis 
  of 
  each 
  chromosome 
  individually. 
  As 
  regards 
  Farmer 
  

   and 
  Moore's 
  interpretation, 
  it 
  is 
  only 
  necessary 
  to 
  say 
  that 
  they 
  only 
  figure 
  

   two 
  chromosomes 
  giving 
  any 
  iudication 
  of 
  the 
  method 
  of 
  transformation 
  

   which 
  they 
  describe 
  in 
  the 
  text. 
  

  

  A 
  sequential 
  analysis 
  of 
  the 
  chromosome 
  complex 
  in 
  the 
  heterotype 
  

   metaphase 
  is 
  a 
  matter 
  of 
  great 
  difficulty, 
  where 
  the 
  number 
  of 
  chromosomes 
  

   is 
  as 
  large 
  as 
  in 
  Periplaneta, 
  and 
  since 
  it 
  may 
  be 
  stated 
  without 
  exaggeration 
  

   that 
  of 
  the 
  sixteen 
  bivalents, 
  no 
  two 
  pass 
  through 
  all 
  stages 
  of 
  the 
  trans- 
  

   formation 
  from 
  the 
  diplotene 
  threads 
  (and 
  loops) 
  synchronously, 
  space 
  does 
  

   not 
  permit 
  the 
  illustration 
  of 
  a 
  complete 
  series 
  of 
  nuclei 
  demonstrating 
  

   every 
  detail 
  of 
  the 
  transition 
  from 
  the 
  post-synaptic 
  bouquet 
  to 
  the 
  

   heterotype 
  telophase. 
  In 
  the 
  present 
  investigation 
  it 
  was 
  possible 
  to 
  obtain 
  

   a 
  series 
  of 
  reconstructions 
  of 
  whole 
  nuclei 
  representing 
  some 
  fifteen 
  stages 
  : 
  

   in 
  the 
  interpretation 
  of 
  these 
  a 
  certain 
  element 
  of 
  error 
  may 
  arise 
  in 
  

   consequence 
  of 
  the 
  fact 
  that 
  the 
  form 
  attributed 
  to 
  a 
  particular 
  chromosome 
  

   of 
  necessity 
  depends 
  on 
  whether 
  it 
  is 
  superimposed 
  upon 
  another, 
  the 
  plane 
  

   in 
  which 
  it 
  is 
  viewed, 
  and 
  like 
  considerations. 
  So 
  that 
  no 
  single 
  cell 
  from 
  

   section 
  or 
  smear 
  preparation 
  is 
  adequate 
  for 
  a 
  given 
  stage, 
  while 
  it 
  is 
  not 
  

   always 
  possible 
  to 
  find 
  another 
  cell 
  at 
  exactly 
  the 
  same 
  stage 
  to 
  settle 
  

   a 
  doubtful 
  point. 
  However, 
  after 
  a 
  prolonged 
  and 
  somewhat 
  tedious 
  com- 
  

   parison 
  of 
  a 
  very 
  large 
  number 
  of 
  nuclei, 
  it 
  is 
  possible 
  to 
  record 
  with 
  

   assurance 
  the 
  main 
  facts. 
  At 
  the 
  inception 
  of 
  the 
  metaphase 
  fourteen 
  out 
  of 
  

  

  