﻿ANATOMY 
  AND 
  AFFINITIES 
  OF 
  THE 
  TRO0HID.E. 
  47 
  

  

  sub-genus 
  Calliostoma 
  the 
  terminal 
  portion 
  of 
  tlie 
  ureter 
  

   becomes 
  very 
  much 
  enlarged, 
  forming 
  what 
  Perrier 
  terms 
  an 
  

   ampulla 
  {anq).). 
  This 
  enlargement 
  is 
  present 
  only 
  in 
  the 
  

   female, 
  and 
  the 
  lumen 
  of 
  the 
  ureter 
  is 
  here 
  very 
  small, 
  

   becoming 
  almost 
  obliterated 
  by 
  the 
  relatively 
  enormous 
  thick- 
  

   ness 
  of 
  the 
  walls 
  (fig. 
  49). 
  The 
  external 
  aperture 
  of 
  the 
  

   ureter 
  is 
  placed 
  at 
  the 
  termination 
  of 
  this 
  thickening. 
  The 
  

   walls 
  of 
  the 
  ampulla 
  contain 
  numerous 
  mucus 
  cells, 
  which 
  

   swell 
  up 
  enormously 
  when 
  they 
  come 
  in 
  contact 
  with 
  water. 
  A 
  

   similar 
  enlargement 
  of 
  the 
  ureter 
  has 
  been 
  described 
  by 
  Wood- 
  

   ward 
  as 
  occurring 
  in 
  the 
  female 
  of 
  Pleurotomaria 
  B 
  ey 
  ri- 
  

   ch 
  ii. 
  It 
  is 
  undoubtedly 
  an 
  accessory 
  to 
  the 
  female 
  genital 
  

   organs, 
  and 
  from 
  its 
  very 
  glandular 
  nature 
  it 
  seems 
  probable 
  

   that 
  it 
  is 
  concerned 
  in 
  the 
  seci-etion 
  of 
  the 
  albuminous 
  material 
  

   in 
  which 
  the 
  eggs 
  are 
  enveloped 
  prior 
  to 
  their 
  discharge. 
  

   Though 
  this 
  structure 
  is 
  by 
  no 
  means 
  so 
  highly 
  developed 
  in 
  

   the 
  members 
  of 
  the 
  sub-genus 
  Gibbula, 
  it 
  is 
  undoubtedly 
  

   represented 
  by 
  the 
  tumid 
  and 
  fringed 
  lips 
  at 
  the 
  anterior 
  

   extremity 
  of 
  the 
  ureter. 
  

  

  The 
  presence 
  of 
  an 
  anterior 
  lobe 
  to 
  the 
  right 
  kidney 
  and 
  

   the 
  accessory 
  genital 
  organ 
  in 
  the 
  female 
  of 
  certain 
  species 
  of 
  

   Trochus 
  undoubtedly 
  proves 
  the 
  very 
  close 
  affinities 
  of 
  the 
  

   Trochidee 
  to 
  Pleurotomaria, 
  in 
  which 
  identically 
  the 
  same 
  

   structures 
  are 
  present. 
  Also 
  the 
  presence 
  of 
  these 
  two 
  

   structures 
  in 
  certain 
  species 
  and 
  their 
  almost 
  entire 
  absence 
  

   in 
  others 
  serve 
  very 
  well 
  as 
  a 
  basis 
  upon 
  which 
  we 
  can 
  

   definitely 
  separate 
  the 
  species 
  enumerated 
  into 
  the 
  two 
  well- 
  

   marked 
  sub-genera 
  Calliostoma 
  and 
  Clibbula. 
  

  

  Until 
  quite 
  recently 
  no 
  connection 
  had 
  been 
  traced 
  between 
  

   the 
  right 
  kidney 
  and 
  the 
  pericardium, 
  and 
  it 
  was 
  thought 
  

   that 
  the 
  right 
  reno-pericardial 
  canal 
  had 
  been 
  lost. 
  Pekeneer, 
  

   hoAvever, 
  in 
  1898 
  (36, 
  p. 
  53), 
  desciibed 
  a 
  right 
  reno-peri- 
  

   cardial 
  canal 
  in 
  Trochus 
  cinerarius. 
  My 
  own 
  researches 
  

   confirm 
  this 
  observation, 
  as 
  I 
  have 
  been 
  able 
  to 
  demonstrate, 
  

   both 
  by 
  dissection 
  in 
  T. 
  liueatus 
  (fig. 
  48, 
  r.p. 
  c.) 
  and 
  by 
  the 
  

   examination 
  of 
  serial 
  sections 
  in 
  T. 
  magus 
  (fig. 
  35, 
  r.p.c), 
  

   that 
  such 
  a 
  communication 
  does 
  exist. 
  The 
  right 
  reno- 
  

  

  