﻿382 
  R- 
  T. 
  Young, 
  

  

  But 
  the 
  most 
  complete 
  account 
  of 
  this 
  process 
  which 
  I 
  have 
  

   seen 
  is 
  that 
  of 
  Child 
  (1907, 
  II). 
  He 
  has 
  described 
  the 
  development 
  

   of 
  the 
  testes 
  in 
  Monieda 
  hy 
  the 
  amitotic 
  division 
  of 
  parenchyma 
  

   cells. 
  His 
  observations 
  and 
  my 
  own 
  coincide 
  in 
  that 
  apparently 
  any 
  

   parenchyma 
  cell 
  may 
  form 
  the 
  parent 
  cell 
  of 
  the 
  testis. 
  I 
  have 
  not 
  

   however 
  verified 
  his 
  observations 
  regarding 
  the 
  development 
  of 
  testes 
  

   from 
  muscle 
  cells. 
  ^) 
  He 
  moreover 
  makes 
  no 
  mention 
  of 
  the 
  forma- 
  

   tion 
  of 
  new 
  nuclei 
  from 
  chromidia, 
  while 
  occasional 
  cases 
  of 
  mitosis 
  

   in 
  the 
  early 
  testes 
  are 
  mentioned 
  by 
  him. 
  Child 
  further 
  describes 
  

   the 
  early 
  testes 
  as 
  syncytial 
  in 
  character, 
  which 
  observation 
  I 
  can- 
  

   not 
  support 
  as 
  in 
  my 
  material 
  I 
  find 
  the 
  cells 
  distinct 
  previous 
  to 
  

   cytophore 
  formation. 
  In 
  later 
  stages 
  according 
  to 
  Child's 
  descrip- 
  

   tion 
  and 
  figures 
  the 
  spermatids 
  become 
  more 
  or 
  less 
  constricted 
  oif 
  

   from 
  the 
  cytophore, 
  usually 
  remaining 
  attached 
  thereto 
  however 
  by 
  

   narrow 
  strands 
  of 
  protoplasm. 
  This 
  I 
  have 
  only 
  occasionally 
  observed, 
  

   the 
  nuclei 
  in 
  my 
  material 
  usually 
  remaining 
  imbedded 
  in 
  the 
  

   cytophore 
  at 
  all 
  stages. 
  

  

  The 
  increase 
  in 
  the 
  cytoplasm 
  of 
  the 
  cytophore 
  accompanying 
  

   the 
  appearance 
  of 
  skeins 
  and 
  coincident 
  increase 
  of 
  chromatin 
  as 
  

   noted 
  above, 
  has 
  been 
  observed 
  both 
  by 
  Child 
  and 
  myself. 
  In 
  the 
  

   words 
  of 
  the 
  former, 
  "Here 
  . 
  . 
  . 
  the 
  apparent 
  connection 
  of 
  the 
  nu- 
  

   clear 
  changes 
  with 
  the 
  growth 
  of 
  the 
  cytoplasm 
  is 
  most 
  striking" 
  

   (1. 
  c, 
  p. 
  181). 
  He 
  does 
  not 
  however 
  offer 
  any 
  satisfactory 
  explana- 
  

   tion 
  of 
  it. 
  Similar 
  phenomena 
  have 
  been 
  noted 
  in 
  many 
  forms 
  by 
  

   other 
  authors, 
  but 
  as 
  yet 
  no 
  satisfactory 
  explanation 
  has 
  been 
  offered. 
  

   In 
  the 
  present 
  instance 
  I 
  do 
  not 
  believe 
  that 
  the 
  two 
  processes 
  are 
  

   necessarily 
  interdependent, 
  but 
  rather 
  coincident, 
  both 
  resulting 
  from 
  

   a 
  general 
  growth 
  stimulus 
  thruout 
  the 
  tissue. 
  The 
  appearance 
  of 
  

   skeins 
  at 
  this 
  stage, 
  rather 
  than 
  the 
  deposition 
  of 
  granular 
  chroma- 
  

   tin 
  in 
  the 
  nucleus 
  I 
  shall 
  discuss 
  below. 
  

  

  Regarding 
  the 
  further 
  development 
  of 
  the 
  testis 
  Child's 
  obser- 
  

   vations 
  and 
  mj 
  own 
  differ 
  considerably. 
  In 
  Moniezia 
  there 
  are 
  two 
  

   types 
  of 
  spermatocyte 
  nuclei. 
  "In 
  the 
  one 
  the 
  nucleolus 
  has 
  disap- 
  

   peared 
  and 
  the 
  spireme 
  is 
  very 
  dense 
  and 
  occupies 
  almost 
  the 
  whole 
  

   periphery 
  of 
  the 
  nucleus. 
  The 
  nuclei 
  of 
  the 
  other 
  sort 
  are 
  con- 
  

   siderably 
  larger, 
  the 
  spireme 
  is 
  much 
  less 
  dense 
  and 
  more 
  irregular 
  in 
  

   form 
  and 
  does 
  not 
  occupy 
  the 
  whole 
  periphery 
  but 
  is 
  still 
  massed 
  

   more 
  or 
  less 
  at 
  one 
  side 
  and 
  the 
  nucleolus 
  is 
  still 
  intact" 
  (1. 
  c. 
  

  

  1) 
  I 
  have 
  paid 
  no 
  especial 
  attention 
  to 
  this 
  point. 
  

  

  