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  nutritive 
  pole, 
  and 
  two 
  of 
  the 
  three 
  nearly 
  equal 
  masses 
  into 
  

   which 
  the 
  egg 
  is 
  blocked 
  out 
  lie 
  at 
  the 
  formative 
  end, 
  and 
  

   one 
  at 
  the 
  nutritive 
  end 
  ; 
  the 
  latter 
  is 
  less 
  granular 
  than 
  the 
  

   pear. 
  The 
  three 
  furrows 
  do 
  not 
  tend 
  to 
  meet 
  exactly 
  at 
  the 
  

   centre, 
  but 
  as 
  shown 
  in 
  Figure 
  6, 
  two 
  minutes 
  later 
  than 
  

   Figure 
  5, 
  the 
  one 
  which 
  runs 
  down 
  from 
  the 
  polar 
  globule 
  

   inclines 
  to 
  one 
  side 
  so 
  as 
  to 
  meet 
  one 
  of 
  the 
  side 
  furrows 
  before 
  

   the 
  other. 
  During 
  the 
  stages 
  shown 
  in 
  this 
  and 
  the 
  preceding 
  

   and 
  succeeding 
  figures 
  the 
  protoplasm 
  of 
  the 
  whole 
  egg 
  is 
  

   violently 
  disturbed, 
  and 
  the 
  granular 
  matter 
  quivers 
  or 
  dances, 
  

   with 
  w'hat 
  would 
  be 
  called 
  " 
  Brownian 
  " 
  motion, 
  were 
  it 
  not 
  

   confined 
  to 
  this 
  particular 
  stage 
  of 
  development. 
  At 
  the 
  

   stage 
  shown 
  in 
  Figure 
  5, 
  the 
  three 
  lobes 
  «, 
  h 
  and 
  c 
  of 
  the 
  

   trefoil 
  are 
  nearly 
  equal 
  in 
  size, 
  but 
  at 
  the 
  present 
  stage, 
  

   Figure 
  6, 
  the 
  one 
  at 
  the 
  nutritive 
  end, 
  «, 
  is 
  the 
  largest, 
  and 
  the 
  

   one 
  which 
  is 
  most 
  perfectly 
  separated, 
  c, 
  the 
  smallest. 
  The 
  

   later 
  stages 
  show 
  that 
  this 
  smallest 
  spherule 
  is 
  posterior 
  to 
  the 
  

   larger 
  one, 
  and 
  this 
  figure 
  therefore 
  gives 
  a 
  view 
  of 
  the 
  left 
  

   ^ide 
  of 
  the 
  egg 
  or 
  embryo 
  with 
  its 
  dorsal 
  surface 
  below. 
  For 
  

   the 
  sake 
  of 
  brevity, 
  we 
  may 
  now 
  call 
  the 
  smallest 
  spherule, 
  c, 
  

   of 
  Figure 
  6, 
  the 
  first 
  micromere, 
  the 
  next 
  largest, 
  h, 
  the 
  second 
  

   micromere, 
  and 
  the 
  one 
  at 
  the 
  nutritive 
  pole, 
  a, 
  the 
  macromere. 
  

  

  In 
  one 
  minute 
  after 
  the 
  stage 
  shown 
  in 
  Figure 
  6 
  the 
  verti- 
  

   cal 
  furrow 
  has 
  united 
  with 
  one 
  of 
  the 
  lateral 
  furrows, 
  to 
  sep- 
  

   arate 
  ofi" 
  the 
  first 
  micromere, 
  and 
  the 
  second 
  lateral 
  furrow 
  

   has 
  run 
  in 
  and 
  united 
  with 
  the 
  line 
  thus 
  formed, 
  so 
  that 
  the 
  

   egg 
  is 
  now 
  divided 
  into 
  three 
  separate 
  masses, 
  each 
  of 
  which 
  

   now 
  becomes 
  spherical, 
  as 
  shown 
  in 
  Figure 
  7. 
  This 
  stage 
  ends 
  

   the 
  first 
  period 
  of 
  activity, 
  and 
  the 
  changes 
  which 
  follow 
  re- 
  

   sult 
  in 
  the 
  gradual 
  obliteration 
  of 
  the 
  sharply 
  defined 
  charac- 
  

   teristics 
  which 
  have 
  been 
  acquired. 
  

  

  In 
  forty-five 
  seconds 
  after 
  the 
  stage 
  shown 
  in 
  Figure 
  7 
  the 
  

   two 
  micromeres, 
  h 
  and 
  c, 
  have 
  approached 
  and 
  united 
  with 
  

   each 
  other, 
  as 
  shown 
  in 
  Figure 
  8, 
  and 
  the 
  second 
  micromere, 
  5, 
  

   ■has 
  also 
  become 
  fused 
  with 
  the 
  macromere, 
  a, 
  although 
  the 
  

   egg 
  still 
  has 
  its 
  trefoil 
  outline, 
  and 
  is 
  now 
  very 
  similar 
  to 
  the 
  

   stage 
  shown 
  in 
  Figure 
  5. 
  In 
  another 
  minute 
  Figure 
  9, 
  the 
  

   fusion 
  of 
  the 
  second 
  micromere, 
  h, 
  with 
  the 
  macromere, 
  a, 
  is 
  

  

  