﻿134 
  K. 
  J. 
  Al.TiKN. 
  

  

  Ficr. 
  57 
  (PI. 
  12) 
  shows 
  the 
  appearance 
  pi^eseiited 
  hy 
  cells 
  of 
  

   the 
  nephridial 
  lip 
  niuler 
  a 
  high 
  power, 
  the 
  figure 
  being 
  drawn 
  

   from 
  a 
  section 
  of 
  material 
  preserved 
  in 
  Hermnnn's 
  fluid 
  and 
  

   stained 
  with 
  methyl-blue-eosin 
  solution. 
  The 
  cells 
  are 
  much 
  

   swollen 
  and 
  vacuolated, 
  and 
  contain, 
  in 
  addition 
  to 
  the 
  nuclei 
  

   (n.), 
  large 
  nunabers 
  of 
  granides 
  of 
  vainous 
  sizes, 
  which 
  stain 
  

   bright 
  red 
  in 
  the 
  preparations. 
  The 
  protoplasmic 
  ground 
  

   substance 
  of 
  the 
  cells 
  stains 
  blue, 
  but 
  the 
  cells, 
  being 
  highly 
  

   vacuolated, 
  this 
  bhie-staining 
  substance 
  is 
  not 
  uniformly 
  

   distributed 
  through 
  them. 
  The 
  red 
  grannies 
  ai^e 
  often 
  

   surrounded 
  by 
  a 
  spherical 
  mass 
  of 
  blue-staining 
  protoplasm, 
  

   in 
  the 
  case 
  of 
  the 
  smnller 
  grannies 
  two 
  or 
  three 
  being 
  found 
  

   within 
  each 
  sphere. 
  The 
  appearances 
  suggest 
  that 
  the 
  red 
  

   granules 
  are 
  first 
  formed 
  within 
  the 
  blue 
  spherical 
  masses, 
  

   that 
  they 
  gradually 
  increase 
  in 
  size 
  within 
  these 
  masses, 
  

   whilst 
  the 
  latter 
  subsequently 
  become 
  swollen 
  and 
  break 
  

   down, 
  giving 
  rise 
  to 
  the 
  vacuolated 
  appearance 
  of 
  the 
  general 
  

   cell 
  protoplasm 
  with 
  free 
  red 
  granules 
  floating 
  in 
  it. 
  

  

  In 
  the 
  segments 
  from 
  17 
  backwards 
  the 
  structure 
  and 
  

   general 
  shape 
  of 
  the 
  nephridia 
  themselves 
  (fig. 
  58) 
  remain 
  

   practically 
  the 
  same 
  as 
  in 
  the 
  anterior 
  segments, 
  excepting 
  

   for 
  the 
  fact 
  that 
  a 
  large 
  ciliated 
  genital 
  funnel 
  is 
  added 
  to 
  

   the 
  nephridiostome. 
  The 
  arrangement 
  of 
  this 
  genital 
  funnel 
  

   will 
  be 
  gathered 
  from 
  the 
  sagittal 
  section 
  shown 
  in 
  fig. 
  52 
  

   (PI. 
  12). 
  The 
  upper 
  portion 
  of 
  the 
  funnel 
  is 
  formed 
  by 
  a 
  

   great 
  development 
  of 
  the 
  cells 
  of 
  the 
  coclomic 
  ejiithelium 
  

   covering 
  the 
  face 
  of 
  the 
  septum, 
  which 
  are 
  much 
  increased 
  

   in 
  size 
  and 
  richly 
  ciliated 
  (Ij). 
  gst. 
  d.). 
  These 
  ciliated 
  cells 
  

   cover 
  a 
  large 
  part 
  of 
  the 
  anterior 
  face 
  of 
  the 
  posterior 
  

   septum. 
  The 
  lower 
  portion 
  of 
  the 
  genital 
  funnel 
  (/p. 
  gst. 
  v.) 
  is 
  

   composed 
  of 
  ciliated 
  cells 
  attached 
  to 
  the 
  lower 
  lip 
  of 
  the 
  

   nephridiostome, 
  which 
  form 
  a 
  membrane 
  hanging 
  freely 
  in 
  

   the 
  cavity 
  of 
  the 
  segment, 
  and 
  with 
  the 
  upper 
  lip 
  constituting 
  

   a 
  funnel-shaped 
  structure 
  surrounding 
  the 
  nephridiostome. 
  

   This 
  genital 
  funnel 
  (gonostome) 
  is 
  composed 
  of 
  cells 
  of 
  quite 
  

   different 
  structure 
  to 
  those 
  of 
  the 
  nephridium, 
  and 
  the 
  line 
  

   of 
  demarcation 
  between 
  the 
  nephridiostome 
  and 
  gonostome 
  

  

  