﻿MATUKATION, 
  ETC., 
  OF 
  THE 
  EGG 
  OF 
  THE 
  AXOLOTL. 
  423 
  

  

  transformation 
  of 
  the 
  sperm-liead 
  into 
  the 
  sperm-nucleus. 
  I 
  

   believe, 
  however, 
  that 
  the 
  tapering 
  apical 
  extremity 
  of 
  the 
  

   sperm-head 
  is 
  not 
  used 
  in 
  this 
  process, 
  but 
  is 
  cast 
  off, 
  and 
  

   degenerates 
  in 
  the 
  cytoplasm. 
  At 
  any 
  rate 
  I 
  have 
  noticed 
  

   in 
  some 
  of 
  my 
  preparations 
  a 
  chromatic 
  body 
  placed 
  near 
  the 
  

   sperm-head, 
  or 
  in 
  the 
  sperm 
  path, 
  sometimes 
  filamentous 
  

   and 
  twisted, 
  sometimes 
  rounded 
  and 
  vacuolated, 
  which 
  seems 
  

   to 
  be 
  the 
  remnant 
  of 
  this 
  portion 
  of 
  the 
  spermatozoon. 
  

  

  The 
  sperm-head 
  lies 
  a 
  little 
  to 
  one 
  side 
  of 
  the 
  sperm 
  sphere, 
  

   sometimes 
  just 
  outside 
  the 
  sphere 
  between 
  the 
  yolk-granules. 
  

   The 
  tail 
  makes 
  an 
  angle 
  with 
  it 
  as 
  before, 
  but 
  is 
  completely 
  

   severed 
  from 
  it, 
  and 
  there 
  is 
  no 
  trace 
  whatever 
  of 
  the 
  middle- 
  

   piece. 
  Instead 
  the 
  centre 
  of 
  the 
  sphere 
  is 
  occupied 
  by 
  a 
  

   spherical 
  vacuolated 
  mass 
  in 
  which 
  no 
  pigment 
  granules 
  are 
  

   found. 
  

  

  The 
  sphere 
  itself 
  has 
  meanwhile 
  assumed 
  a 
  radial 
  struc- 
  

   ture. 
  Arising 
  from 
  the 
  outer 
  surface 
  of 
  the 
  central 
  vacuolated 
  

   mass 
  are 
  numerous 
  filainentous 
  processes 
  — 
  as 
  they 
  appear 
  in 
  

   sections. 
  These 
  processes 
  radiate 
  in 
  all 
  directions, 
  and 
  are 
  

   continued 
  outwards 
  for 
  some 
  distance 
  between 
  the 
  yolk- 
  

   granules 
  beyond 
  the 
  limits 
  of 
  the 
  sphere, 
  disappearing 
  finally 
  

   into 
  the 
  general 
  cytoplasm 
  of 
  the 
  egg. 
  They 
  constitute 
  the 
  

   well-known 
  sperm-aster. 
  These 
  filamentous 
  rays 
  are 
  united 
  

   to 
  one 
  another 
  by 
  frequent 
  anastomoses, 
  and 
  the 
  structure 
  

   presented 
  by 
  the 
  whole 
  is 
  that 
  of 
  a 
  large 
  number 
  of 
  elongated 
  

   chambers, 
  or 
  alveoli, 
  radially 
  arranged 
  ; 
  this 
  interpretation 
  is 
  

   borne 
  out 
  by 
  the 
  appearance 
  of 
  a 
  section 
  tangential 
  to 
  the 
  

   sphere, 
  which 
  is 
  that 
  of 
  a 
  polygonal 
  meshwork, 
  thickened 
  at 
  

   the 
  nodes. 
  The 
  spaces 
  — 
  whether 
  alveoli 
  or 
  not 
  — 
  between 
  the 
  

   rays 
  and 
  their 
  anastomoses 
  are 
  filled 
  with 
  a 
  faintly- 
  staining 
  

   coagulum. 
  Pigment 
  granules 
  are 
  scattered 
  freely, 
  but 
  not 
  

   abundantly 
  throughout 
  the 
  sperm-aster, 
  as 
  in 
  the 
  stage 
  last 
  

   described, 
  but 
  are 
  absent 
  from 
  the 
  vacuolated 
  central 
  mass. 
  

  

  I 
  believe, 
  though 
  I 
  cannot 
  positively 
  assert, 
  that 
  this 
  

   central 
  mass 
  originates 
  from 
  the 
  dissolution 
  of 
  the 
  middle- 
  

   piece 
  ; 
  I 
  have 
  one 
  preparation 
  (fig. 
  17) 
  in 
  which 
  a 
  small 
  faintly 
  

   staining 
  irregular 
  vacuolated 
  body 
  is 
  found 
  near 
  the 
  centre 
  of 
  

  

  VOL. 
  48, 
  PART 
  3. 
  — 
  NEW 
  SERIES. 
  31 
  

  

  