﻿ANATOMY 
  AND 
  AFFINITIES 
  OF 
  THE 
  TKOOHID.'E. 
  71 
  

  

  of 
  Tx'ochus, 
  and 
  having 
  similar 
  functions 
  and 
  relationships. 
  

   Burne 
  (10) 
  has 
  recently 
  shown 
  that 
  a 
  reno-pericardial 
  canal 
  

   is 
  present 
  in 
  Anipnllaria. 
  

  

  One 
  of 
  the 
  chief 
  objections 
  to 
  regarding 
  the 
  Monotocardian 
  

   kidney 
  as 
  homologous 
  to 
  the 
  right 
  kidney 
  of 
  the 
  Diotocardia 
  

   was 
  the 
  supposed 
  absence 
  of 
  any 
  communication 
  between 
  

   this 
  kidney 
  and 
  the 
  pericardium. 
  This 
  objection 
  has^ 
  liow- 
  

   ever, 
  been 
  removed, 
  for 
  Pelseneer 
  (36) 
  has 
  shown 
  that 
  a 
  right 
  

   reno-pericardial 
  canal 
  does 
  exist 
  in 
  Trochus. 
  I 
  have 
  been 
  

   able 
  to 
  confirm 
  his 
  observation. 
  

  

  In 
  Fissnrella, 
  though 
  this 
  is 
  undoubtedly 
  a 
  specialised 
  

   form, 
  the 
  only 
  reno-pericardial 
  canal 
  present 
  is 
  between 
  the 
  

   right 
  kidney 
  and 
  the 
  pericardium, 
  and 
  this 
  right 
  kidney 
  is 
  

   larger 
  and 
  of 
  more 
  functional 
  importance 
  than 
  the 
  left. 
  Again, 
  

   in 
  Patella 
  there 
  are 
  reno-pericardial 
  canals 
  between 
  the 
  

   pericai'dium 
  and 
  both 
  kidneys, 
  though 
  with 
  regard 
  to 
  this 
  

   genus 
  there 
  has 
  been 
  considerable 
  diversity 
  of 
  opinion, 
  some 
  

   observers 
  maintaining 
  the 
  presence 
  of 
  a 
  right 
  reno-pericardial 
  

   canal 
  only, 
  others 
  a 
  left; 
  while 
  v. 
  Erlanger 
  (14) 
  denies 
  the 
  

   existence 
  of 
  any 
  canal 
  whatever. 
  

  

  Cunningham 
  (12) 
  was 
  the 
  first 
  to 
  describe 
  the 
  presence 
  of 
  

   two 
  canals, 
  and 
  lately 
  Goodrich 
  (18) 
  has 
  confirmed 
  this 
  

   observ^ation 
  by 
  means 
  of 
  the 
  examination 
  of 
  serial 
  sections, 
  

   and 
  still 
  more 
  recently 
  I 
  have 
  been 
  sufficiently 
  fortunate 
  to 
  

   obtain 
  exactly 
  the 
  same 
  results 
  as 
  Goodrich, 
  also 
  by 
  means 
  of 
  

   serial 
  sections 
  through 
  the 
  pericardium 
  and 
  kidueys. 
  

  

  In 
  Haliotis 
  the 
  left 
  kidney 
  is 
  relatively 
  very 
  small, 
  and, 
  

   according 
  to 
  Perrier 
  (37), 
  Wegmann 
  (44), 
  and 
  v. 
  Erlanger 
  

   (14), 
  it 
  is 
  this 
  kidney 
  alone 
  which 
  communicates 
  with 
  the 
  

   pericardium. 
  In 
  a 
  recent 
  paper 
  on 
  the 
  kidneys 
  of 
  Haliotis 
  

   Fleure 
  (16) 
  finds 
  that 
  a 
  reno-pericardial 
  canal 
  exists 
  between 
  

   the 
  right 
  kidney 
  and 
  the 
  pericardiun], 
  but 
  denies 
  the 
  existence 
  

   of 
  a 
  left 
  reno-pericardial 
  canal. 
  

  

  With 
  regard 
  to 
  Pleurotomaria, 
  Woodward 
  (45) 
  has 
  

   described 
  a 
  left 
  reno-pericardial 
  canal 
  only. 
  I 
  have 
  examined 
  

   liis 
  preparations 
  of 
  the 
  kidneys 
  and 
  pericardium, 
  and 
  failed 
  

   to 
  find 
  any 
  communication 
  between 
  the 
  right 
  kidney 
  and 
  

  

  