﻿418 
  J. 
  W. 
  JENKINSON. 
  

  

  ii'regular 
  clumps. 
  The 
  polar 
  body 
  is 
  in 
  a 
  slight 
  depressioa 
  

   at 
  the 
  surface 
  of 
  the 
  egg. 
  It 
  persists 
  for 
  some 
  time 
  and 
  may 
  

   be 
  found 
  throughout 
  the 
  earlier 
  stages 
  of 
  fertilization. 
  

  

  The 
  second 
  polar 
  body 
  also 
  persists 
  for 
  a 
  considerable 
  time. 
  

   Like 
  the 
  first 
  it 
  contains 
  pigment 
  and 
  agglomei'ated 
  yoiie- 
  

   granules. 
  In 
  it, 
  however, 
  the 
  nucleus 
  is 
  very 
  frequently 
  

   reconstituted. 
  A 
  clear 
  vacuole 
  is 
  formed 
  round 
  the 
  chro- 
  

   mosomes 
  (figs. 
  11 
  and 
  12) 
  ; 
  these 
  send 
  out 
  little 
  processes 
  

   towards 
  the 
  wall 
  of 
  this 
  vacuole 
  (fig. 
  13), 
  which 
  thus 
  forms 
  

   the 
  nuclear 
  membrane, 
  and 
  to 
  one 
  another. 
  The 
  chromo- 
  

   somes 
  then 
  break 
  up 
  into 
  irregular 
  coarse 
  fragments 
  (fig. 
  14); 
  

   but 
  I 
  have 
  never 
  observed 
  the 
  formation 
  of 
  a 
  completely 
  

   reticular 
  nucleus. 
  These 
  changes 
  in 
  the 
  nucleus 
  of 
  the 
  

   second 
  polar 
  body 
  do 
  not 
  necessarily 
  keep 
  pace 
  with 
  the 
  

   similar 
  changes 
  iu 
  the 
  chromosomes 
  which 
  remain 
  in 
  the 
  &gg. 
  

  

  4. 
  The 
  direction 
  of 
  division 
  of 
  the 
  chromosomes. 
  

  

  It 
  is 
  perfectly 
  clear 
  that 
  in 
  the 
  second 
  polar 
  spindle 
  the 
  

   chromosomes 
  are 
  divided 
  longitudinally, 
  that 
  is 
  quantitatively 
  

   in 
  Weismann's 
  sense. 
  Bnt 
  in 
  the 
  case 
  of 
  the 
  fir&t 
  maturation 
  

   division 
  I 
  have 
  not 
  the 
  material 
  for 
  deciding 
  this 
  point. 
  

   The 
  chromosomes 
  are 
  plnced 
  on 
  the 
  spindle 
  in 
  the 
  form 
  of 
  

   rings, 
  broken 
  into 
  two 
  half- 
  rings 
  at 
  the 
  equator. 
  This 
  arrange- 
  

   ment 
  certainly 
  reminds 
  one 
  at 
  fii-st 
  sight 
  very 
  strongly 
  of 
  the 
  

   heterotypical 
  spindles 
  of 
  the 
  Salamander, 
  Amphiuma., 
  and 
  

   Batrachoseps, 
  in 
  which, 
  according 
  to 
  Flemming, 
  Meves 
  (1896), 
  

   McGregor, 
  and 
  Eisen 
  the 
  chromosomes 
  are 
  longitudinally 
  

   split. 
  But 
  it 
  will 
  be 
  impossible 
  to 
  determine 
  whether 
  this 
  is 
  

   so 
  in 
  the 
  first 
  maturation 
  division 
  of 
  the 
  ova 
  of 
  these 
  

   Amphibia 
  until 
  we 
  know 
  accurately 
  the 
  mode 
  of 
  formation 
  of 
  

   the 
  chromosomes 
  themselves 
  in 
  the 
  interior 
  of 
  the 
  germinal 
  

   vesicle. 
  

  

  •5. 
  The 
  number 
  of 
  the 
  chromosomes. 
  

  

  I 
  have 
  not 
  paid 
  a 
  very 
  great 
  deal 
  of 
  attention 
  to 
  this 
  point, 
  

   but 
  I 
  believe 
  the 
  number 
  to 
  be 
  fifteen 
  in 
  each 
  of 
  the 
  two 
  polar 
  

  

  