﻿MATURATION, 
  ETC., 
  OF 
  TH 
  K 
  EGG 
  OF 
  THE 
  AXOLOTL. 
  407 
  

  

  Observations 
  on 
  the 
  Maturation 
  and 
  Fertilisation 
  

   of 
  the 
  Egg 
  of 
  the 
  Axolotl. 
  

  

  By 
  

   J. 
  1¥. 
  Jcnkiiisoii, 
  M.A., 
  

  

  AssistMiit, 
  (o 
  I 
  lie 
  Liiiacie 
  rrofcssor 
  of 
  Comparative 
  Anatomy, 
  Oxforil. 
  

  

  With 
  Plates 
  29—33. 
  

  

  t 
  of 
  the 
  

  

  Contents. 
  

  

  I. 
  Introductory 
  

   II. 
  Descriptive 
  

  

  A. 
  Maturation 
  

  

  1. 
  Tlie 
  Orst 
  polar 
  division 
  . 
  

  

  2. 
  The 
  second 
  polar 
  division 
  

  

  3. 
  Further 
  history 
  of 
  the 
  polar 
  bodies 
  

  

  4. 
  The 
  direction 
  of 
  division 
  of 
  the 
  ehromosomei 
  

  

  5. 
  The 
  number 
  of 
  the 
  chromosomes 
  . 
  

  

  B. 
  Fertilization 
  . 
  

  

  1. 
  General 
  outline 
  

  

  2. 
  The 
  entry 
  of 
  the 
  spermatozoon 
  

  

  3. 
  Changes 
  in 
  the 
  spermatozoon 
  ; 
  developmei 
  

  

  sperm 
  aster; 
  disappearance 
  of 
  the 
  middle 
  piece 
  

  

  4. 
  Formation 
  of 
  the 
  pronuclei 
  ; 
  appearance 
  of 
  the 
  defini- 
  

  

  tive 
  centrosome 
  . 
  . 
  . 
  . 
  

  

  5. 
  Union 
  of 
  the 
  jn-onuclei 
  ; 
  the 
  fertilisation 
  spindle 
  

  

  6. 
  Remarks 
  on 
  the 
  work 
  of 
  Fick 
  and 
  Michaelis 
  

  

  III. 
  Historical 
  AND 
  Critical 
  . 
  . 
  . 
  . 
  

  

  A. 
  ]\Iaturation 
  . 
  . 
  . 
  . 
  . 
  

  

  1. 
  The 
  structure 
  of 
  the 
  polar 
  spindles 
  

  

  2. 
  The 
  reduction 
  of 
  the 
  chromosomes 
  

  

  B. 
  Fertilization 
  . 
  . 
  . 
  . 
  . 
  

  

  1. 
  The 
  entrance 
  of 
  the 
  spermatozoon 
  

  

  2. 
  The 
  centrosome 
  in 
  fertilization 
  

  

  a. 
  The 
  centrosome 
  as 
  an 
  organ 
  of 
  the 
  cell 
  . 
  

  

  i. 
  Intra-nuclear 
  origin 
  of 
  the 
  centrosome 
  

   ii. 
  Structure 
  and 
  functions 
  of 
  the 
  centrosome 
  

  

  b. 
  The 
  origin 
  of 
  tlie 
  cleavage 
  centrosomes 
  

  

  IV. 
  Experimental 
  . 
  . 
  . 
  . 
  . 
  

  

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  VOL. 
  48, 
  l^ART 
  3. 
  — 
  NEW 
  SERIE.S. 
  

  

  30 
  

  

  