﻿PLATE 
  II. 
  

  

  Figure 
  10. 
  — 
  The 
  same 
  egg 
  one 
  minute 
  later. 
  The 
  line 
  be- 
  

   tween 
  the 
  second 
  micromere 
  and 
  macromere 
  has 
  disappeared, 
  

   and 
  the 
  first 
  micromere, 
  c, 
  now 
  projects 
  from 
  one 
  end 
  of 
  the 
  

   elongated 
  mass 
  formed 
  by 
  the 
  union 
  of 
  the 
  spherules 
  a 
  and 
  h. 
  

  

  Figure 
  11. 
  — 
  The 
  same 
  o,^^ 
  three 
  minutes 
  later. 
  The 
  fusion 
  

   of 
  a 
  and 
  h 
  is 
  now 
  complete, 
  and 
  a 
  large 
  transparent 
  vesicle 
  is 
  

   now 
  visible 
  in 
  the 
  first 
  micromere, 
  «?, 
  and 
  another 
  in 
  the 
  com- 
  

   pound 
  mass, 
  ab. 
  

  

  Figure 
  12. 
  — 
  The 
  same 
  q^^ 
  two 
  minutes 
  and 
  thirty 
  seconds 
  

   later. 
  

  

  Figure 
  13. 
  — 
  Another 
  egg, 
  about 
  two 
  minutes 
  later. 
  This 
  

   is 
  the 
  true 
  resting 
  stage, 
  at 
  the 
  end 
  of 
  the 
  second 
  period 
  of 
  

   rest. 
  Tlie 
  two 
  vesicles 
  have 
  become 
  irregular. 
  The 
  remains 
  

   of 
  an 
  external 
  membrane 
  adhere 
  to 
  one 
  side 
  of 
  the 
  egg. 
  

  

  Figure 
  14. 
  — 
  The 
  same 
  q^^ 
  seven 
  minutes 
  later 
  than 
  Figure 
  

   13. 
  The 
  compound 
  mass, 
  a 
  and 
  J, 
  is 
  elongated, 
  the 
  first 
  mi- 
  

   cromere, 
  c, 
  is 
  well 
  defined, 
  and 
  waves 
  travel 
  from 
  the 
  nutri- 
  

   tive 
  towards 
  the 
  formative 
  ends 
  of 
  the 
  two 
  masses. 
  Two 
  seg- 
  

   mentation 
  nuclei 
  occupy 
  the 
  positions 
  of 
  the 
  large 
  vesicles 
  of 
  

   earlier 
  stages. 
  This 
  stage 
  is 
  the 
  beginning 
  of 
  the 
  second 
  pe- 
  

   riod 
  of 
  activity. 
  

  

  Figure 
  15. 
  — 
  The 
  same 
  egg 
  one 
  minute 
  later. 
  The 
  second 
  

   micromere, 
  J, 
  is 
  now 
  well 
  defined, 
  as 
  well 
  as 
  the 
  first. 
  

  

  Figure 
  16. 
  — 
  The 
  same 
  egg 
  one 
  minute 
  later. 
  This 
  stage 
  

   marks 
  the 
  end 
  of 
  the 
  second 
  period 
  of 
  activity. 
  The 
  forma- 
  

   tive 
  end 
  of 
  the 
  egg 
  is 
  now 
  occupied 
  by 
  four 
  micromeres, 
  two 
  

   of 
  which 
  seem 
  to 
  be 
  the 
  products 
  of 
  the 
  division 
  of 
  the 
  first 
  

   micromere, 
  c, 
  and 
  two 
  of 
  them 
  the 
  products 
  of 
  the 
  second, 
  h. 
  

  

  Figure 
  17. 
  — 
  The 
  same 
  egg 
  two 
  minutes 
  later, 
  at 
  the 
  com- 
  

   mencement 
  of 
  the 
  tliird 
  period 
  of 
  rest. 
  The 
  second 
  micro- 
  

   mere, 
  J, 
  has 
  again 
  begun 
  to 
  fuse 
  with 
  the 
  macromere, 
  a. 
  

  

  Figure 
  IS. 
  The 
  same 
  egg 
  three 
  minutes 
  and 
  thirty 
  seconds 
  

   later. 
  The 
  second 
  micromere 
  is 
  no 
  longer 
  separated 
  from 
  the 
  

   macromere, 
  and 
  mass, 
  a 
  and 
  h^ 
  formed 
  by 
  their 
  union 
  is 
  nearlj 
  

   spherical. 
  

  

  