﻿Reproductive 
  organs 
  of 
  Taenia 
  pisiformis. 
  385 
  

  

  size 
  and 
  structure 
  with 
  the 
  spermatogonia. 
  Indeed 
  at 
  an 
  early 
  

   stage 
  the 
  two 
  can 
  be 
  distinguished 
  from 
  each 
  other 
  chiefly 
  by 
  posi- 
  

   tion 
  (Figs. 
  33 
  — 
  34). 
  The 
  development 
  of 
  the 
  follicular 
  membrane 
  

   too 
  is 
  the 
  same 
  as 
  that 
  of 
  the 
  testis, 
  and 
  similar 
  differences 
  of 
  

   opinion 
  exist 
  regarding 
  its 
  structure. 
  Sommer 
  & 
  Landois 
  (1872) 
  

   in 
  Bothriocephalus 
  latus, 
  Sommer 
  (1874) 
  in 
  Taenia 
  mediocanellata 
  

   and 
  solium, 
  and 
  Leuckart 
  (1886) 
  etc. 
  regarding 
  it 
  as 
  a 
  structure- 
  

   less 
  membrane, 
  while 
  Schmidt 
  (1888) 
  in 
  Bothriocephalus 
  latus 
  and 
  

   Erlanger 
  (1890) 
  in 
  Taenia 
  ecJiinococcus 
  describe 
  it 
  as 
  cellular 
  in 
  

   structure. 
  Salensky 
  (1874) 
  in 
  Amphilina 
  and 
  Moniez 
  (1881) 
  in 
  

   Ahothrium 
  gadi 
  claim 
  that 
  the 
  ovary 
  lies 
  in 
  parenchyma 
  spaces, 
  

   unsurrounded 
  by 
  any 
  special 
  membrane. 
  According 
  to 
  Roboz 
  (1882) 
  

   germinal 
  epithelium 
  is 
  present 
  internal 
  to 
  the 
  membrane 
  in 
  the 
  

   ovary 
  of 
  Solenophorus 
  megalocephalus 
  , 
  but 
  most 
  authors 
  derive 
  the 
  

   ova 
  from 
  ordinary 
  parenchyma 
  cells. 
  The 
  same 
  difference 
  between 
  

   the 
  views 
  of 
  Child 
  (1907, 
  I) 
  and 
  myself 
  exists 
  here 
  as 
  in 
  the 
  case 
  

   of 
  the 
  testis 
  membrane. 
  

  

  Eegarding 
  the 
  structure 
  of 
  the 
  ovary 
  at 
  an 
  early 
  stage 
  Child 
  

   says 
  (1. 
  c, 
  p. 
  102). 
  "The 
  cytoplasm 
  is 
  usually 
  not 
  sharply 
  marked 
  

   off 
  from 
  the 
  parenchymal 
  substance 
  still 
  present 
  so 
  that 
  the 
  whole 
  

   often 
  appears 
  as 
  a 
  syncytium." 
  Gough 
  (1909) 
  also 
  describes 
  the 
  

   early 
  ovary 
  as 
  a 
  syncytium. 
  I 
  find 
  on 
  the 
  contrary 
  the 
  oogonia, 
  as 
  

   well 
  as 
  the 
  spermatogonia, 
  distinct 
  cells. 
  

  

  After 
  the 
  completion 
  of 
  oogonial 
  divisions 
  and 
  consequent 
  

   follicular 
  growth 
  there 
  ensues 
  an 
  abortive 
  mitosis 
  analogous 
  to 
  that 
  

   already 
  described 
  in 
  the 
  primary 
  spermatocytes, 
  and 
  the 
  primary 
  

   oocytes 
  as 
  they 
  may 
  now 
  be 
  called 
  enter 
  at 
  the 
  same 
  time 
  upon 
  

   the 
  growth 
  period.^) 
  The 
  chromatin 
  becomes 
  more 
  prominent, 
  forming 
  

   first 
  an 
  irregular, 
  deeply 
  staining 
  network 
  composed 
  of 
  granules 
  of 
  

  

  "pre-oogonia'' 
  to 
  these 
  cells, 
  distinguishing 
  as 
  such 
  the 
  ovarian 
  cells 
  

   previous 
  to 
  the 
  formation 
  of 
  the 
  ovarian 
  membrane, 
  which 
  "seems 
  to 
  

   mark 
  the 
  time 
  of 
  cessation 
  of 
  active 
  proliferation 
  on 
  the 
  part 
  of 
  the 
  

   oogonia. 
  I 
  have 
  seen 
  no 
  sign 
  whatever 
  of 
  cell 
  division 
  in 
  stages 
  following 
  

   this" 
  (1. 
  c, 
  p. 
  142), 
  and 
  yet 
  his 
  figures 
  16 
  and 
  20 
  represent 
  mitoses 
  in 
  

   oogonia 
  (presumably 
  following 
  the 
  "pre-oogonia" 
  which 
  are 
  represented 
  in 
  

   figures 
  9 
  — 
  14). 
  "The 
  convenience 
  of 
  the 
  use 
  of 
  this 
  term" 
  is 
  not 
  to 
  me 
  

   "apparent". 
  In 
  my 
  material 
  the 
  follicular 
  membrane 
  is 
  present 
  from 
  the 
  

   outset 
  and 
  a 
  distinction 
  between 
  oogonia 
  and 
  pre-oogonia 
  is 
  not 
  evident 
  

   in 
  any 
  way. 
  

  

  1) 
  The 
  oocytes 
  increase 
  during 
  this 
  period 
  from 
  3,4 
  to 
  7,6 
  fx 
  and 
  

   their 
  nuclei 
  from 
  2,2 
  to 
  4,8 
  (X 
  (average 
  of 
  eight 
  measurements). 
  

  

  