﻿210 
  PROCEEDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIETY. 
  

  

  its 
  ventral 
  wall 
  with 
  the 
  oviduct. 
  In 
  the 
  natural 
  position 
  the 
  

   receptaculum 
  is 
  spirally 
  twisted 
  at 
  its 
  origin, 
  and 
  lies 
  closely 
  applied 
  

   to 
  the 
  concave 
  surface 
  of 
  the 
  hermaphrodite 
  duct. 
  

  

  The 
  penis 
  opens 
  into 
  the 
  vestibule 
  opposite 
  the 
  mouth 
  of 
  the 
  vagina. 
  

   It 
  is 
  of 
  large 
  size, 
  swollen 
  in 
  the 
  middle, 
  and 
  enveloped 
  to 
  within 
  

   a 
  short 
  distance 
  of 
  its 
  retractor 
  muscle 
  by 
  a 
  loose 
  sheath 
  of 
  muscle. 
  

   At 
  the 
  point 
  of 
  attachment 
  of 
  its 
  retractor 
  muscle 
  it 
  is 
  sharply 
  bent 
  

   upon 
  itself, 
  but 
  cannot 
  be 
  said 
  to 
  form 
  a 
  cajcum. 
  The 
  segment 
  

   between 
  this 
  bend 
  and 
  the 
  vas 
  deferens 
  (epiphallus) 
  is 
  short, 
  and 
  at 
  its 
  

   distal 
  end 
  has 
  a 
  large 
  globular 
  and 
  intensely 
  white 
  kalk-sac. 
  The 
  

   vas 
  deferens 
  passes 
  forward 
  beneath 
  the 
  penis, 
  and 
  thence 
  in 
  a 
  

   mesentery 
  of 
  its 
  own 
  to 
  the 
  apex 
  of 
  the 
  cloaca. 
  At 
  this 
  point 
  it 
  is 
  

   reflected 
  around 
  the 
  anterior 
  aorta 
  and 
  pleural 
  nerves 
  upon 
  the 
  

   surface 
  of 
  the 
  vagina, 
  and 
  combines 
  with 
  the 
  oviduct 
  to 
  form 
  the 
  

   hermaphrodite 
  duct 
  in 
  the 
  usual 
  way. 
  

  

  The 
  penis, 
  when 
  exposed 
  by 
  dividing 
  the 
  loose 
  muscular 
  sheath 
  

   mentioned 
  above, 
  is 
  seen 
  to 
  owe 
  a 
  large 
  part 
  of 
  its 
  swollen 
  appearance 
  

   to 
  a 
  double 
  lobulated 
  glandular 
  development 
  of 
  its 
  convex 
  surface. 
  

   The 
  inner 
  surface 
  of 
  the 
  penis 
  is 
  grooved 
  dorsally 
  to 
  form 
  a 
  seminal 
  

   channel, 
  with 
  strongly 
  dentate 
  borders. 
  The 
  terminal 
  dentations 
  or 
  

   papillae 
  are 
  particularly 
  pronounced, 
  and 
  no 
  doubt 
  form 
  a 
  papillate 
  

   extremity 
  to 
  the 
  organ 
  when 
  everted. 
  

  

  The 
  retractor 
  penis 
  is 
  attached 
  to 
  the 
  right 
  side 
  of 
  the 
  body, 
  close 
  

   to 
  the 
  anterior 
  aorta, 
  and 
  directly 
  above 
  the 
  base 
  of 
  the 
  albumen 
  

   gland. 
  

  

  The 
  ovotestis 
  was 
  destroyed. 
  

  

  The 
  Retractor 
  Muscles. 
  Fig. 
  3. 
  

  

  The 
  buccal 
  retractor 
  is 
  completely 
  separate 
  from 
  the 
  rest, 
  except 
  at 
  

   its 
  actual 
  origin 
  from 
  the 
  shell. 
  Anteriorly 
  it 
  divides 
  into 
  two 
  slips 
  

   for 
  insertion 
  upon 
  the 
  buccal 
  mass. 
  

  

  The 
  tentacular 
  retractors 
  of 
  each 
  side 
  arise 
  as 
  a 
  single 
  strand 
  from 
  

   the 
  pedal 
  retractor 
  mass. 
  About 
  the 
  middle 
  of 
  its 
  length 
  the 
  strand 
  

   divides, 
  the 
  greater 
  part 
  passing 
  to 
  the 
  ocular 
  tentacle, 
  and 
  a 
  smaller 
  

   slip 
  to 
  the 
  anterior 
  tentacle. 
  

  

  Upon 
  anatomical 
  grounds, 
  and 
  leaving 
  the 
  shell 
  altogether 
  aside, 
  

   one 
  cannot 
  include 
  this 
  species 
  in 
  the 
  genus 
  Hemiplecta, 
  the 
  genus 
  

   to 
  which 
  the 
  shell 
  is 
  at 
  present 
  referred. 
  

  

  The 
  chief 
  characters 
  upon 
  which 
  this 
  conclusion 
  rests 
  are 
  the 
  

   absence 
  of 
  sliell 
  lobes, 
  the 
  absence 
  of 
  an 
  araatorial 
  organ, 
  the 
  papillate 
  

   condition 
  of 
  the 
  interior 
  of 
  the 
  penis, 
  and 
  the 
  needle-like 
  marginal 
  

   teeth 
  of 
  the 
  radula. 
  

  

  On 
  the 
  other 
  hand, 
  the 
  animal 
  in 
  the 
  broad 
  lines 
  of 
  its 
  structure 
  

   and 
  in 
  many 
  important 
  particulars 
  resembles 
  the 
  members 
  of 
  the 
  

   Philippine 
  genus 
  Rhysota. 
  This 
  is 
  the 
  case 
  as 
  regards 
  the 
  foot 
  and 
  

   mucous 
  pore, 
  the 
  condition 
  of 
  the 
  mantle-lobes, 
  the 
  general 
  form 
  of 
  

   the 
  genitalia 
  (compare 
  particularly 
  Semper' 
  s 
  figure 
  of 
  the 
  genitalia 
  

   of 
  Rhysota 
  ovum, 
  Eeisen 
  im 
  Archipel., 
  Philippinen 
  Landmoll., 
  p. 
  69, 
  

   pi. 
  iv, 
  fig. 
  1), 
  the 
  form 
  of 
  the 
  penis 
  and 
  receptaculum 
  seminis, 
  and 
  the 
  

   development 
  of 
  papillae 
  within 
  the 
  penis. 
  

  

  