﻿Reproductive 
  organs 
  of 
  Taenia 
  pisiformis. 
  379 
  

  

  lying 
  in 
  the 
  cytophore, 
  while 
  at 
  x 
  is 
  shown 
  the 
  very 
  indistinct 
  out- 
  

   line 
  of 
  a 
  second 
  spermatocyte 
  and 
  its 
  "nucleolus". 
  Careful 
  focussing 
  

   revealed 
  a 
  very 
  probable 
  connection 
  between 
  the 
  sperm 
  filament 
  and 
  

   the 
  spermatocyte 
  "nucleolus", 
  such 
  as 
  is 
  described 
  by 
  Child 
  (1907, 
  II) 
  

   as 
  typical 
  in 
  Moniezia\ 
  but 
  the 
  delicacy 
  of 
  these 
  structures 
  and 
  the 
  

   different 
  focal 
  levels 
  at 
  which 
  they 
  lay 
  rendered 
  it 
  impossible 
  to 
  

   bring 
  these 
  points 
  out 
  clearly 
  in 
  the 
  photograph. 
  In 
  Fig. 
  46 
  is 
  

   shown 
  much 
  better 
  the 
  connection 
  between 
  a 
  sperm 
  and 
  a 
  second 
  

   spermatocyte. 
  The 
  sperm 
  here 
  has 
  reached 
  a 
  fairly 
  advanced 
  stage 
  

   of 
  development 
  and 
  yet 
  the 
  spermatocyte 
  shows 
  absolutely 
  no 
  sign 
  

   of 
  elongation 
  to 
  form 
  a 
  head 
  or 
  other 
  part 
  of 
  the 
  sperm. 
  In 
  the 
  

   photograph 
  the 
  sperm 
  appears 
  to 
  be 
  attached 
  to 
  two 
  nuclei; 
  this 
  is 
  

   however 
  not 
  the 
  case. 
  That 
  there 
  is 
  no 
  fixity 
  in 
  the 
  number 
  of 
  

   sperms 
  attached 
  to 
  any 
  spermatocyte 
  is 
  shown 
  in 
  Fig. 
  44 
  where 
  two 
  

   sperms 
  may 
  be 
  seen 
  attached 
  to 
  one 
  spermatoc5^te 
  at 
  x 
  and 
  x^. 
  Here 
  

   again 
  there 
  is 
  no 
  evidence 
  of 
  any 
  modification 
  of 
  the 
  nucleus 
  to 
  con- 
  

   tribute 
  to 
  the 
  sperm. 
  

  

  In 
  many 
  cases 
  however 
  I 
  do 
  find 
  an 
  elongation 
  of 
  the 
  second 
  

   spermatocyte 
  in 
  the 
  formation 
  of 
  the 
  sperms, 
  as 
  is 
  shown 
  in 
  Figs. 
  48 
  

   and 
  49 
  x}) 
  In 
  these 
  cases 
  it 
  is 
  very 
  difficult 
  to 
  determine 
  the 
  

   relative 
  roles 
  of 
  nucleus 
  and 
  cytoptasm 
  in 
  sperm 
  development. 
  In 
  

   the 
  two 
  cases 
  figured 
  the 
  nuclei 
  apparently 
  take 
  little 
  or 
  no 
  part, 
  

   the 
  cytoplasm 
  functioning 
  chiefly, 
  if 
  not 
  entirely, 
  in 
  this 
  process. 
  

   In 
  many 
  cases 
  however 
  it 
  is 
  not 
  unlikely 
  that 
  the 
  nucleus 
  itself 
  

   elongates 
  to 
  form 
  at 
  least 
  a 
  part 
  of 
  the 
  sperm. 
  If 
  the 
  view 
  advanced 
  

   by 
  me 
  in 
  previous 
  papers 
  (Young, 
  1908 
  and 
  1910), 
  that 
  in 
  cestodes 
  

   nucleus 
  and 
  cytoplasm 
  are 
  essentially 
  the 
  same, 
  be 
  correct, 
  then 
  

   the 
  question 
  as 
  to 
  the 
  relative 
  roles 
  of 
  nucleus 
  and 
  cytoplasm 
  in 
  

   spermatogenesis 
  is 
  of 
  but 
  minor 
  importance. 
  

  

  There 
  are 
  two 
  kinds 
  of 
  developing 
  sperms 
  which 
  ultimately 
  

   form 
  the 
  same 
  adult 
  type. 
  One 
  of 
  these 
  is 
  a 
  filamentous, 
  the 
  other 
  

   a 
  tubular 
  type. 
  The 
  former 
  arises 
  as 
  a 
  simple 
  filament 
  increasing 
  

   somewhat 
  in 
  diameter 
  during 
  development, 
  while 
  the 
  latter 
  arises 
  

   first 
  as 
  a 
  delicate 
  tube 
  which 
  later 
  condenses 
  to 
  a 
  solid 
  filament. 
  

   Both 
  arise 
  in 
  the 
  same 
  region 
  of 
  the 
  same 
  cytophore, 
  the 
  earliest 
  

   stages 
  in 
  the 
  development 
  of 
  the 
  tubular 
  type 
  being 
  probably 
  repre- 
  

  

  1) 
  From 
  a 
  casual 
  inspection 
  of 
  some 
  Moniezia 
  slides 
  kindly 
  loaned 
  

   me 
  by 
  Dr. 
  Richards 
  this 
  is 
  apparently 
  the 
  method 
  of 
  sperm 
  formation 
  in 
  

   that 
  genus. 
  

  

  