﻿284 
  W. 
  lUiAXLANI) 
  HENIIAM. 
  

  

  Reddard's 
  memoir, 
  illustrating 
  tlie 
  external 
  anatomy 
  accom- 
  

   panying 
  the 
  description 
  of 
  P. 
  snbterraneiis 
  is 
  misleading, 
  

   for, 
  although 
  he 
  rightly 
  states 
  in 
  his 
  text 
  that 
  the 
  pore 
  is 
  

   in 
  Segment 
  XIII, 
  it 
  is 
  unfortunately 
  figured 
  in 
  Segment 
  

   XIV. 
  

  

  In 
  external 
  features, 
  then, 
  this 
  new 
  species 
  agrees 
  with 
  

   Beddard's 
  account 
  of 
  his 
  species. 
  

  

  So 
  far 
  as 
  the 
  internal 
  anatomy 
  is 
  concerned, 
  my 
  further 
  

   notes 
  deal 
  only 
  with 
  the 
  reproductive 
  organs, 
  to 
  which 
  my 
  

   attention 
  was 
  more 
  specially 
  directed. 
  

  

  There 
  is 
  no 
  sperm-sac, 
  but 
  the 
  Segments 
  VIII, 
  IX, 
  X, 
  XI 
  

   are 
  filled 
  with 
  developing 
  spermatozoa. 
  

  

  The 
  spermatheca 
  (fig. 
  14a) 
  extends 
  through 
  Segments 
  

   XIII 
  to 
  XVITI, 
  as 
  in 
  P. 
  kerguelenensis 
  and 
  P. 
  albus. 
  

  

  The 
  slit-like 
  apei-ture 
  leads 
  into 
  the 
  broader 
  end 
  of 
  a 
  large 
  

   pyriform 
  sac 
  with 
  very 
  thick 
  muscular 
  wall; 
  near 
  the 
  hinder 
  

   end 
  of 
  the 
  segment 
  the 
  neck 
  of 
  the 
  sac 
  passes 
  gradually 
  

   into 
  a 
  narrow 
  duct, 
  also 
  with 
  muscular 
  wall 
  and 
  tall 
  epithelial 
  

   lining; 
  this 
  duct 
  (a.) 
  passes 
  backwards 
  through 
  Segments 
  

   XIV, 
  XV, 
  XVI, 
  lying 
  either 
  above 
  or 
  below 
  the 
  gut, 
  

   undulating 
  slightly, 
  and 
  then 
  opens 
  into 
  a 
  much 
  dilated, 
  

   thin-walled 
  sac 
  (c.),the 
  "^ 
  ampulla" 
  of 
  Michaelsen, 
  which 
  lies 
  

   in 
  Segments 
  XVII, 
  XVIII, 
  the 
  septum 
  between 
  which 
  nips 
  

   tlie 
  ampulla 
  which 
  is 
  filled 
  with 
  ripe 
  sperms. 
  There 
  is 
  no 
  sign 
  

   of 
  any 
  spcrmatophore, 
  the 
  absence 
  of 
  which 
  seems 
  to 
  charac- 
  

   terise 
  the 
  genus. 
  

  

  We 
  do 
  not 
  know 
  the 
  fully 
  developed 
  spermatheca 
  of 
  

   P. 
  sub 
  terraneus, 
  but 
  that 
  of 
  the 
  present 
  species 
  differs 
  

   from 
  that 
  of 
  P. 
  lacustris 
  in 
  the 
  absence 
  of 
  the 
  glandular 
  

   region 
  of 
  the 
  duct 
  and 
  in 
  the 
  extraordinary 
  thickness 
  of 
  the 
  

   muscular 
  coat 
  near 
  the 
  pore 
  (fig. 
  15), 
  in 
  which 
  both 
  longi- 
  

   tudinal 
  and 
  circular 
  fibres 
  take 
  a 
  share. 
  

  

  The 
  Male 
  Efferent 
  Apparatus. 
  — 
  For 
  the 
  purpose 
  

   of 
  studying 
  this, 
  I 
  had 
  bisected, 
  the 
  worm 
  in 
  the 
  neighbour- 
  

   hood 
  of 
  the 
  reproductive 
  organs; 
  from 
  one 
  side 
  of 
  the 
  body 
  

   I 
  dissected 
  away 
  the 
  male 
  apparatus 
  ; 
  the 
  other 
  side, 
  with 
  

   apparatus 
  uninjured, 
  was 
  cut 
  into 
  a 
  series 
  of 
  transverse 
  

  

  