﻿THE 
  ANATOMY 
  OF 
  rfEOILOCm^TUS, 
  CLAPAREDE. 
  135 
  

  

  is 
  well 
  marked. 
  Fig-. 
  56 
  shows 
  the 
  appearance 
  of 
  these 
  cells. 
  

   Their 
  protoplasm 
  is 
  clear, 
  staining 
  only 
  feebly, 
  and 
  contains 
  

   no 
  grannies 
  such 
  as 
  are 
  found 
  in 
  the 
  nepliridial 
  epithelium. 
  

   The 
  cilia 
  are 
  long- 
  and 
  their 
  bases 
  extend 
  into 
  the 
  cell-body 
  as 
  

   deeply 
  staining 
  rods. 
  

  

  The 
  funnels 
  as 
  well 
  as 
  the 
  nephridiostomes 
  and 
  upper 
  portions 
  

   of 
  the 
  nepliridial 
  tubes 
  are 
  often 
  filled 
  with 
  the 
  genital 
  products. 
  

  

  From 
  the 
  description 
  above 
  given 
  it 
  will 
  be 
  seen 
  that 
  in 
  

   these 
  genital 
  segments 
  we 
  have 
  to 
  do 
  with 
  a 
  compound 
  organ, 
  

   consisting* 
  of 
  a 
  nephridium 
  and 
  a 
  genital 
  funnel 
  combined, 
  

   which 
  Goodrich, 
  to 
  whose 
  very 
  valuable 
  papers 
  we 
  are 
  

   indebted 
  for 
  much 
  of 
  our 
  recent 
  knowledge 
  of 
  similar 
  struc- 
  

   tures 
  amongst 
  polychietes, 
  has 
  termed 
  nephromixia. 
  

  

  Genital 
  Products. 
  

  

  The 
  genital 
  products 
  in 
  Poecilochaetus 
  are 
  first 
  found 
  in 
  

   the 
  seventeenth 
  segment, 
  and 
  occur 
  in 
  every 
  segment 
  behind 
  

   that, 
  with 
  the 
  exception 
  of 
  the 
  segments 
  at 
  the 
  extreme 
  end 
  

   of 
  the 
  body. 
  

  

  Ova. 
  — 
  The 
  gonads 
  lie 
  along 
  the 
  inner 
  and 
  upper 
  sides 
  of 
  

   the 
  nephridial 
  tubes 
  (PI. 
  12, 
  figs. 
  58 
  (horizontal), 
  59 
  (trans- 
  

   verse) 
  and 
  GO). 
  As 
  the 
  ova 
  increase 
  in 
  size 
  they 
  separate 
  off 
  

   from 
  the 
  gonads 
  and 
  pass 
  upwards 
  into 
  the 
  general 
  bod}'- 
  

   cavity, 
  where 
  the 
  process 
  of 
  maturation 
  continues 
  (fig. 
  59). 
  

  

  In 
  their 
  earliest 
  recognisable 
  stages 
  (fig. 
  60) 
  the 
  developing 
  

   ova 
  appear 
  simply 
  as 
  a 
  number 
  of 
  enlarged 
  nuclei, 
  lying 
  in 
  a 
  

   mass 
  of 
  cell 
  substance 
  in 
  which 
  no 
  definite 
  cell 
  outlines 
  ai-e 
  

   shown 
  in 
  the 
  preparations. 
  As 
  the 
  nucleus 
  and 
  cell-body 
  

   enlarge, 
  the 
  individual 
  ova 
  become 
  clearly 
  marked 
  out 
  by 
  a 
  

   definite 
  cell 
  membrane, 
  although 
  for 
  a 
  time 
  they 
  continue 
  to 
  

   adhere 
  together. 
  The 
  nucleus 
  develops 
  one 
  large, 
  deeply 
  

   staining 
  nucleolus 
  and 
  a 
  number 
  of 
  smaller 
  granules 
  of 
  chro- 
  

   matin 
  (fig. 
  01). 
  A 
  Avell-developed 
  yolk 
  nucleus, 
  horse-shoe 
  

   shaped 
  in 
  section, 
  forms 
  a 
  cap 
  over 
  about 
  one 
  half 
  of 
  the 
  

   nucleus. 
  This 
  yolk 
  nucleus 
  consists 
  of 
  deeply 
  staining 
  

   granules 
  (fig. 
  60 
  and 
  61, 
  ijh.n.) 
  which 
  in 
  methyl-blue-eosin 
  

  

  