﻿MATURATION, 
  ETC., 
  OF 
  THE 
  EGG 
  OF 
  THE 
  AXOLOTL. 
  437 
  

  

  appearance 
  is 
  certainly 
  not 
  found, 
  except 
  for 
  a 
  few 
  sparse 
  

   granules, 
  about 
  tlie 
  fully 
  formed 
  centrospheres. 
  Some 
  of 
  

   this 
  original 
  pigment, 
  that 
  between 
  the 
  pronuclei, 
  seems 
  

   simply 
  to 
  disappear 
  in 
  situ, 
  but 
  the 
  remainder 
  is 
  probably 
  

   carried 
  to 
  the 
  periphery. 
  

  

  We 
  may 
  noAv 
  return 
  to 
  the 
  consideration 
  of 
  the 
  spindle. 
  

  

  At 
  present 
  we 
  have 
  only 
  described 
  that 
  portion 
  which 
  lies 
  

   extra-nuclear 
  — 
  between 
  the 
  centrosome 
  and 
  the 
  pronuclei, 
  

   and 
  arises 
  by 
  outgrowth 
  from 
  the 
  former. 
  These 
  polar 
  

   portions 
  increase 
  considerably 
  in 
  length 
  before 
  the 
  equatorial 
  

   part 
  is 
  formed. 
  The 
  extreme 
  polar 
  ends 
  of 
  the 
  fibres 
  become 
  

   merged 
  in 
  the 
  centrospheres. 
  

  

  The 
  equatorial 
  portion 
  is 
  most 
  distinctly 
  intra-nuclear 
  in 
  

   origin. 
  The 
  two 
  pronuclei, 
  greatly 
  increased 
  in 
  volume 
  and 
  

   elongated 
  in 
  the 
  direction 
  of 
  the 
  spindle 
  axis, 
  are 
  closely 
  

   applied 
  to 
  one 
  another. 
  In 
  a 
  stage 
  when 
  the 
  chromosomes 
  

   are 
  being 
  formed 
  the 
  nuclear 
  membrane 
  appears 
  indented 
  at 
  

   the 
  ends, 
  apparently 
  by 
  the 
  growth 
  of 
  the 
  extra-nuclear 
  

   fibres. 
  Soon 
  openings 
  appear 
  in 
  the 
  membrane 
  (fig. 
  38), 
  and 
  

   through 
  these 
  the 
  extra-nuclear 
  fibres 
  and 
  inter-fibrillar 
  spaces 
  

   become 
  continuous 
  with 
  a 
  similar 
  set 
  of 
  fibres 
  and 
  spaces, 
  

   each 
  with 
  each, 
  which 
  are 
  formed 
  inside 
  the 
  nucleus 
  by 
  a 
  re- 
  

   arrangement 
  of 
  the 
  achromatic 
  reticulum. 
  In 
  other 
  words, 
  the 
  

   threads 
  of 
  this 
  reticulum, 
  previously 
  irregularly 
  distributed, 
  

   became 
  now 
  parallel 
  to 
  the 
  axis 
  of 
  the 
  spindle, 
  and 
  continuous 
  

   through 
  the 
  openings 
  in 
  the 
  membrane 
  with 
  the 
  fibres 
  outside. 
  

  

  This 
  is, 
  I 
  think, 
  a 
  fair 
  account 
  of 
  the 
  appearances 
  of 
  

   sections 
  ; 
  whether 
  it 
  is 
  a 
  true 
  description 
  of 
  what 
  actually 
  

   occurs 
  is 
  another 
  matter. 
  I 
  have 
  indicated 
  briefly 
  above 
  that 
  

   the 
  inner 
  rays 
  of 
  the 
  aster 
  and 
  the 
  extra-nuclear 
  spindle 
  

   fibres 
  may 
  possibly 
  be 
  regarded 
  as 
  produced 
  by 
  the 
  precipita- 
  

   tion 
  of 
  the 
  albumins 
  of 
  the 
  cell 
  by 
  a 
  substance 
  derived 
  from 
  

   the 
  centrosome 
  ; 
  in 
  the 
  same 
  way 
  these 
  intra-nuclear 
  fibres 
  

   may 
  be 
  regarded 
  as 
  produced 
  by 
  an 
  extension 
  of 
  the 
  process, 
  

   that 
  is 
  to 
  say 
  by 
  the 
  precipitation 
  through 
  the 
  same 
  agent 
  of 
  

   the 
  albumins 
  of 
  the 
  pronuclei 
  themselves. 
  I 
  shall 
  discuss 
  the 
  

   point 
  in 
  greater 
  detail 
  further 
  on. 
  

  

  