﻿528 
  J. 
  BRETLANU 
  FAKIMER 
  AND 
  J. 
  E. 
  8. 
  MOOHE. 
  

  

  the 
  spindle, 
  recalling" 
  the 
  corresponding 
  figures 
  that 
  are 
  so 
  

   much 
  more 
  frequently 
  to 
  be 
  seen 
  in 
  Trades 
  cant 
  ia. 
  But 
  

   as 
  a 
  general 
  rule 
  the 
  V 
  shape 
  of 
  the 
  daughter 
  chromosome 
  is 
  

   not 
  easy 
  to 
  identify. 
  They 
  are 
  swollen 
  and 
  stumpy 
  structures, 
  

   and 
  very 
  seldom 
  show 
  the 
  reopening 
  of 
  the 
  fission 
  that 
  is 
  so 
  

   conclusively 
  exhibited 
  in 
  Tradescantia 
  and 
  sometimes 
  also 
  

   in 
  Lilium. 
  

  

  A 
  wall 
  is 
  formed 
  across 
  the 
  interzonal 
  fibres 
  at 
  the 
  close 
  of 
  

   the 
  heterotype 
  mitosis, 
  and 
  the 
  daughter 
  nuclei 
  at 
  once 
  divide 
  

   again, 
  the 
  new 
  spindles 
  being 
  formed 
  close 
  together, 
  but 
  

   their 
  axes 
  not 
  being 
  in 
  the 
  same 
  plane. 
  The 
  fission 
  of 
  these 
  

   (homotype) 
  chromosomes 
  is 
  clearly 
  longitudinal 
  (Fig. 
  37), 
  and 
  

   seems 
  beyond 
  doubt 
  to 
  correspond 
  with 
  the 
  hitherto 
  obliter- 
  

   ated 
  primary 
  fission 
  of 
  the 
  spirem 
  thread 
  of 
  the 
  previous 
  

   karyokinesis. 
  

  

  The 
  four 
  nuclei 
  are 
  thus 
  distributed 
  to 
  the 
  four 
  lobes 
  of 
  the 
  

   original 
  inother-cell 
  (fig. 
  38), 
  and 
  the 
  respective 
  lobes 
  are 
  

   delimited 
  from 
  each 
  other, 
  at 
  the 
  centre 
  of 
  the 
  original 
  cell, 
  

   by 
  walls 
  that 
  take 
  up 
  the 
  same 
  position 
  as 
  do 
  soap 
  films 
  when 
  

   placed 
  in 
  boxes 
  of 
  corresponding 
  form. 
  Ultimately 
  fresh 
  

   walls 
  are 
  formed 
  around 
  the 
  contents 
  of 
  each 
  cell 
  (special 
  

   mother-cell) 
  and 
  the 
  spores 
  separate 
  by 
  the 
  solution 
  of 
  the 
  

   original 
  walls. 
  But 
  this 
  process 
  need 
  not 
  be 
  described 
  here, 
  

   as 
  it 
  is 
  not 
  pertinent 
  to 
  the 
  main 
  objects 
  of 
  this 
  memoir. 
  

  

  IV. 
  Periplaneta 
  Americana. 
  

   (a) 
  The 
  pre-maiotic 
  period. 
  

  

  As 
  an 
  illustration 
  of 
  the 
  manner 
  in 
  which 
  the 
  sexual 
  cells 
  

   become 
  matured 
  among 
  the 
  metozoa, 
  no 
  individual 
  type 
  

   appears 
  to 
  be 
  inore 
  suitable, 
  or 
  on 
  the 
  whole 
  more 
  interesting, 
  

   than 
  the 
  common 
  cockroach. 
  

  

  In 
  this 
  insect, 
  as 
  in 
  so 
  many 
  other 
  cases, 
  the 
  male 
  gland 
  

   consists 
  of 
  numerous 
  small 
  spaces 
  filled 
  with 
  cells 
  in 
  different 
  

   stages 
  of 
  development; 
  and 
  as 
  in 
  all 
  cases 
  among 
  the 
  metozoa, 
  

   these 
  generative 
  cells 
  have 
  themselves 
  arisen 
  through 
  the 
  

  

  