﻿394 
  R- 
  T. 
  Young, 
  

  

  Taenia 
  serrata 
  consists 
  of 
  two 
  elements, 
  one, 
  the 
  larger, 
  with 
  a 
  

   large 
  nucleus, 
  enclosing 
  a 
  homogeneous 
  bod}^ 
  (yolk), 
  is 
  the 
  "cellule 
  

   embryogène"; 
  the 
  other 
  smaller, 
  containing 
  refractive 
  granulations 
  

   and 
  a 
  small 
  nucleus, 
  is 
  the 
  "cellule 
  granuleuse". 
  The 
  latter 
  persists 
  

   indefinitel}^ 
  and 
  enlarges 
  without 
  dividing, 
  meantime 
  becoming 
  filled 
  

   wdth 
  more 
  and 
  more 
  numerous 
  granulations, 
  which 
  are 
  insoluble 
  in 
  

   alcohol, 
  are 
  not 
  colored 
  by 
  osmic 
  acid, 
  and 
  hence 
  cannot 
  be 
  of 
  a 
  

   fatty 
  nature. 
  

  

  The 
  work 
  of 
  van 
  Beneden 
  and 
  St. 
  Eemy 
  was 
  done 
  on 
  isolated 
  

   eggs. 
  More 
  recently 
  v. 
  Janicki 
  (1907) 
  has 
  reviewed 
  the 
  same 
  study 
  

   on 
  Taenia 
  serrata 
  by 
  means 
  of 
  sections, 
  and 
  Child 
  (1907, 
  III) 
  and 
  

   EiCHARDS 
  (1911) 
  have 
  made 
  brief 
  surveys 
  of 
  the 
  same 
  field 
  in 
  

   sectioned 
  material 
  of 
  Moniezia. 
  The 
  first 
  has 
  described 
  and 
  figured 
  

   the 
  "cellule 
  granuleuse" 
  of 
  van 
  Beneden 
  and 
  St. 
  Remy 
  and 
  inter- 
  

   preted 
  it 
  as 
  a 
  yolk 
  cell, 
  the 
  interpretation 
  given 
  earlier 
  by 
  Leuckaet 
  

   (1856).^) 
  In 
  Moniesia 
  Child 
  (1. 
  c.) 
  has 
  figured 
  and 
  briefly 
  described 
  

   a 
  cell, 
  which, 
  to 
  judge 
  from 
  his 
  figures 
  in 
  comparison 
  with 
  those 
  of 
  

   V. 
  Janicki, 
  and 
  with 
  my 
  own 
  preparations 
  '^), 
  is 
  I 
  believe 
  undoubtedly 
  

   the 
  same 
  as 
  the 
  "cellule 
  granuleuse" 
  of 
  the 
  former 
  authors 
  and 
  the 
  

   "yolk 
  cell" 
  of 
  Leuckart 
  and 
  v. 
  Janickt. 
  He 
  has 
  however 
  interpreted 
  

   it 
  as 
  a 
  polar 
  body, 
  and 
  when 
  two 
  of 
  these 
  cells 
  are 
  present 
  they 
  

   are 
  according 
  to 
  him 
  the 
  two 
  polar 
  bodies. 
  Child's 
  interpretation 
  

   has 
  recently 
  been 
  accepted 
  by 
  Richards 
  (1909 
  and 
  1911) 
  for 
  

   Taenia 
  serrata 
  and 
  Moniesia, 
  and 
  I 
  at 
  first 
  accepted 
  this 
  interpretation 
  

   provisionally 
  myself^), 
  but 
  later 
  studies 
  have 
  convinced 
  me 
  of 
  the 
  

   correctness 
  of 
  v. 
  Janicki's 
  view. 
  My 
  reasons 
  for 
  this 
  conclusion 
  are 
  

   the 
  following: 
  

  

  First. 
  This 
  cell 
  does 
  not 
  appear 
  until 
  the 
  eggs 
  have 
  reached 
  

   the 
  uterus, 
  that 
  is 
  until 
  after 
  they 
  have 
  passed 
  the 
  yolk 
  duct, 
  altho 
  

   well 
  developed 
  spindles 
  are 
  found 
  in 
  oviduct 
  eggs.*) 
  

  

  Second. 
  The 
  absence 
  of 
  typical 
  anaphases 
  ^) 
  and 
  telophases. 
  

   Were 
  the 
  nucleus 
  of 
  this 
  cell 
  that 
  of 
  a 
  newly 
  formed 
  polar 
  body, 
  

  

  1) 
  In 
  his 
  later 
  Parasitenwerk 
  Leuckart 
  makes 
  no 
  reference 
  to 
  his 
  

   earlier 
  interpretation. 
  

  

  2) 
  Both 
  sections 
  and 
  isolated 
  eggs. 
  

  

  3) 
  Young 
  (1908, 
  p. 
  246). 
  

  

  4) 
  Child 
  (1. 
  c.) 
  says 
  that 
  the 
  egg 
  usually 
  reaches 
  the 
  uterus 
  before 
  

   the 
  appearance 
  of 
  the 
  first 
  maturation 
  spindle. 
  Thus 
  it 
  is 
  evident 
  from 
  

   his 
  account 
  that 
  in 
  Municzia 
  likewise 
  this 
  cell 
  does 
  not 
  appear 
  until 
  after 
  

   the 
  egg 
  has 
  passed 
  the 
  yolk 
  duct. 
  

  

  5) 
  With 
  one 
  exception, 
  see 
  footnote 
  2, 
  page 
  392. 
  

  

  