﻿408 
  ^- 
  T. 
  Young, 
  

  

  plasm 
  and 
  the 
  achromatic 
  part 
  of 
  the 
  nucleus 
  stain 
  in 
  this 
  triple 
  

   stain, 
  whether 
  with 
  safranin 
  or 
  not. 
  

  

  My 
  present 
  study 
  increases 
  the 
  doubt 
  previously 
  expressed 
  by 
  

   me 
  (Young, 
  1910) 
  as 
  to 
  the 
  completeness 
  of 
  the 
  nuclear 
  membrane, 
  

   the 
  latter 
  in 
  many 
  cases 
  showing 
  evident 
  breaks, 
  while 
  in 
  both 
  

   early 
  spermatogonia 
  and 
  oogonia 
  a 
  membrane 
  is 
  often 
  not 
  demon- 
  

   strable. 
  A 
  comparison 
  of 
  resting 
  with 
  kinetic 
  oocytes 
  (cf. 
  Fig. 
  32 
  

   with 
  Fig. 
  52) 
  suggests 
  very 
  strongly 
  the 
  participation 
  of 
  the 
  skeins 
  

   of 
  the 
  latter 
  in 
  the 
  formation 
  of 
  the 
  membranes 
  of 
  the 
  former, 
  a 
  

   careful 
  study 
  of 
  these 
  suggesting 
  further 
  that 
  their 
  membranes 
  are 
  

   not 
  specific 
  structures, 
  but 
  merely 
  peripheral 
  condensations 
  of 
  the 
  

   nuclear 
  reticula. 
  

  

  In 
  two 
  previous 
  papers 
  (1908, 
  1910) 
  I 
  have 
  suggested 
  a 
  common 
  

   origin 
  for 
  membrane 
  and 
  reticulum. 
  I 
  have 
  however 
  (1910) 
  pointed 
  

   out 
  that 
  in 
  the 
  adult 
  nuclei 
  of 
  Taenia 
  crassicoUis 
  micro-chemical 
  

   tests 
  revealed 
  an 
  apparent 
  difference 
  betAveen 
  the 
  former 
  and 
  the 
  

   chromatin 
  granules 
  of 
  the 
  latter. 
  Whether 
  this 
  be 
  so 
  or 
  not 
  the 
  

   two 
  structures 
  are 
  probably 
  very 
  closely 
  related 
  in 
  their 
  origin 
  

   at 
  least. 
  

  

  The 
  apparently 
  simple 
  structure 
  of 
  the 
  spermatozoon 
  is 
  possibly 
  

   a 
  further 
  expression 
  of 
  cestode 
  degeneracy, 
  in 
  which 
  connection 
  it 
  

   is 
  worthy 
  of 
  note 
  that 
  their 
  development 
  is 
  much 
  abbreviated, 
  

   arising 
  as 
  they 
  appear 
  to 
  do 
  in 
  many 
  cases, 
  in 
  T. 
  pisiformis 
  at 
  least, 
  

   either 
  directly 
  from 
  spermatogenic 
  cytoplasm 
  or 
  from 
  chromidial 
  

   remains 
  of 
  spermatocytes, 
  rather 
  than 
  by 
  the 
  modification 
  of 
  a 
  sper- 
  

   matogenic 
  cell. 
  

  

  The 
  abbreviated 
  development 
  of 
  the 
  sex 
  cells 
  may 
  also 
  be 
  cor- 
  

   related 
  with 
  the 
  great 
  number 
  of 
  these 
  produced, 
  the 
  developmental 
  

   energy 
  possessed 
  by 
  the 
  primitive 
  sex 
  cells 
  being 
  used 
  in 
  the 
  pro- 
  

   duction 
  of 
  a 
  large 
  number 
  of 
  simple 
  cells 
  rather 
  than 
  a 
  smaller 
  

   number 
  of 
  specialized 
  ones. 
  

  

  The 
  occurrence 
  of 
  polar 
  bodies 
  in 
  cestodes 
  is 
  exceedingly 
  doubt- 
  

   ful. 
  The 
  views 
  of 
  different 
  authors 
  regarding 
  them 
  are 
  widely 
  

   different 
  and 
  there 
  is 
  as 
  yet 
  no 
  sufficient 
  evidence 
  to 
  show 
  that 
  

   they 
  occur. 
  Developmental 
  phenomena 
  have 
  never 
  been 
  observed 
  

   in 
  living 
  material 
  in 
  this 
  class 
  and 
  it 
  is 
  doubtful 
  if 
  they 
  ever 
  will 
  

   be. 
  And 
  preserved 
  material 
  has 
  not, 
  so 
  far 
  as 
  I 
  am 
  aware, 
  shown 
  

   any 
  stages 
  in 
  the 
  actual 
  extrusion 
  of 
  these 
  bodies. 
  The 
  stages 
  de- 
  

   scribed 
  are 
  either 
  precedent 
  or 
  successive 
  to 
  the 
  critical 
  moment, 
  

   which 
  raises 
  the 
  question 
  as 
  to 
  whether 
  this 
  moment 
  ever 
  actually 
  

  

  