﻿398 
  R. 
  T. 
  Young, 
  

  

  tures 
  which 
  he 
  labels 
  polar 
  bodies 
  are 
  not 
  also 
  ''?"s. 
  He 
  himself 
  admits 
  

   that 
  „Ich 
  habe 
  die 
  genannten 
  Erscheinungen 
  nicht 
  in 
  erschöpfender 
  

   Weise 
  studiert", 
  and 
  „Die 
  Abschnürung 
  des 
  I. 
  ßichtungskörperchens 
  

   selbst 
  habe 
  ich 
  niemals 
  beobachtet" 
  etc. 
  (1. 
  c, 
  p. 
  704—705). 
  The 
  

   view 
  of 
  Child 
  (1907 
  III) 
  and 
  Richards 
  (1909, 
  1911) 
  has 
  already 
  

   been 
  discussed. 
  "Pole 
  bodies" 
  are 
  mentioned 
  but 
  not 
  described 
  by 
  

   GouGH 
  (1911) 
  in 
  Avitellina 
  centripimdata. 
  Their 
  fate 
  is 
  not 
  clear 
  

   ^•but 
  when 
  the 
  eggs 
  pass 
  into 
  the 
  oviduct 
  they 
  are 
  no 
  longer 
  to 
  be 
  

   found" 
  (1. 
  c, 
  p. 
  374). 
  

  

  In 
  my 
  own 
  material 
  I 
  find 
  structures 
  which 
  are 
  quite 
  similar 
  

   to 
  those 
  figured 
  hj 
  St. 
  Eemy 
  and 
  v. 
  Janicki. 
  -) 
  I 
  find 
  however 
  no 
  

   evidence 
  for 
  considering 
  them 
  as 
  polar 
  bodies. 
  That 
  they 
  are 
  

   chromatin 
  extrusions 
  from 
  the 
  male 
  or 
  female 
  pronuclei 
  is 
  most 
  

   probable, 
  but 
  the 
  absence 
  of 
  all 
  evidence 
  showing 
  a 
  participation 
  

   of 
  the 
  maturation 
  spindle 
  in 
  their 
  formation, 
  the 
  inconstancy 
  of 
  their 
  

   occurrence, 
  and 
  their 
  irregularity 
  of 
  form, 
  and 
  variation 
  in 
  number 
  

   lead 
  me 
  to 
  believe 
  that 
  these 
  authors 
  were 
  mistaken 
  in 
  their 
  iden- 
  

   tification 
  of 
  these 
  bodies, 
  which 
  in 
  my 
  opinion 
  are 
  merely 
  chromidial 
  

   extrusions 
  lying 
  on 
  or 
  near 
  the 
  surface 
  of 
  the 
  egg. 
  This 
  extrusion 
  

   of 
  chromidia 
  from 
  the 
  oocyte 
  nucleus 
  has 
  been 
  described 
  by 
  Spat- 
  

   LiCH 
  (1909) 
  in 
  Tetrabothriiis 
  and 
  Gough 
  (1911) 
  in 
  AviteUina 
  centri- 
  

   punctata. 
  The 
  former 
  finds 
  the 
  yolk 
  nuclei 
  developing 
  in 
  relation 
  to 
  

   these 
  chromidia, 
  while 
  another 
  type 
  of 
  yolk 
  nucleus 
  apparently 
  

   develops 
  from 
  an 
  extruded 
  part 
  of 
  the 
  "nucleolus". 
  According 
  to 
  the 
  

   latter 
  they 
  appeal' 
  to 
  be 
  absorbed 
  by 
  the 
  cytoplasm, 
  for 
  in 
  their 
  

   place 
  "one 
  now 
  finds 
  a 
  mass 
  of 
  fine 
  granules, 
  and 
  finally 
  the 
  only 
  

   remaining 
  trace 
  is 
  a 
  darker 
  staining 
  of 
  the 
  plasma 
  in 
  the 
  vicinity 
  

   ot 
  the 
  place 
  they 
  had 
  occupied'' 
  (1. 
  c, 
  p. 
  373). 
  The 
  observations 
  

   above 
  cited 
  support 
  the 
  view 
  that 
  polar 
  bodies 
  are 
  not 
  formed 
  and 
  

   that 
  maturation 
  of 
  both 
  sperm 
  and 
  egg 
  are 
  degenerating 
  in 
  cestodes. 
  

  

  Fertilization. 
  There 
  is 
  here 
  likewise 
  but 
  little 
  information 
  

   available. 
  With 
  the 
  exception 
  of 
  Child's 
  paper 
  on 
  Moniesia 
  (1907, 
  III) 
  

   and 
  that 
  of 
  v. 
  Janicki 
  on 
  Taenia 
  serrata 
  (1907) 
  there 
  is 
  almost 
  

   nothing 
  in 
  the 
  literature 
  concerning 
  it. 
  As 
  I 
  have 
  already 
  indicated, 
  

   the 
  intimate 
  structure 
  of 
  the 
  spermatozoon 
  is 
  not 
  yet 
  understood, 
  

   hence 
  naturally 
  its 
  role 
  in 
  fertilization 
  is 
  doubtful, 
  at 
  least 
  as 
  to 
  

   details, 
  v. 
  Janicki 
  (1907) 
  found 
  fertilization 
  in 
  Taenia 
  serrata 
  

  

  2) 
  Compare 
  my 
  Figs. 
  80 
  and 
  81 
  with 
  figs. 
  7 
  a 
  — 
  f, 
  8 
  a 
  — 
  c, 
  e 
  — 
  h 
  etc., 
  

   of 
  V. 
  Janicki 
  and 
  2 
  — 
  9 
  of 
  St. 
  IIemy. 
  

  

  