﻿46 
  W. 
  B. 
  EANDLES. 
  

  

  The 
  right 
  kidney 
  is 
  much 
  larger 
  than 
  it 
  appears 
  to 
  be 
  

   from 
  a 
  superficial 
  examination 
  ; 
  it 
  extends 
  ventrally 
  under- 
  

   neath 
  tlie 
  pericardium, 
  and 
  approaches 
  very 
  closely 
  to 
  the 
  left 
  

   kidney, 
  though 
  there 
  is 
  no 
  trace 
  of 
  communication 
  between 
  

   the 
  two. 
  There 
  are 
  slight 
  differences 
  in 
  extent 
  of 
  this 
  kidney 
  

   in 
  the 
  various 
  species, 
  and 
  it 
  is 
  most 
  highly 
  developed 
  in 
  

   T. 
  7iizyphinus 
  (fig. 
  49) 
  and 
  its 
  allies. 
  Here 
  the 
  kidney 
  can 
  

   be 
  divided 
  into 
  a 
  large 
  posterior 
  lobe 
  {p.r. 
  k.), 
  present 
  in 
  all 
  

   species, 
  and 
  a 
  smaller 
  anterior 
  lobe 
  (a. 
  r. 
  k.) 
  lying 
  underneath 
  

   the 
  oesophagus, 
  and 
  extending 
  almost 
  as 
  far 
  as 
  the 
  ti^ansverse 
  

   pallial 
  vein 
  ; 
  this 
  anterior 
  lobe 
  is 
  very 
  feebly 
  represented 
  in 
  

   T. 
  magus, 
  and 
  almost, 
  if 
  not 
  entirely, 
  absent 
  in 
  T. 
  lineatus. 
  

   In 
  Turbo, 
  Haliotis, 
  and 
  Pleurotomaria 
  the 
  anterior 
  

   lobe 
  is 
  very 
  large, 
  and 
  forms 
  quite 
  a 
  conspicuous 
  feature 
  of 
  

   the 
  right 
  kidney. 
  

  

  T. 
  zizyphinus, 
  in 
  possessing 
  a 
  moderately 
  well-developed 
  

   anterior 
  lobe, 
  approximates 
  in 
  this 
  respect 
  very 
  closely 
  to 
  

   Pleurotomaria. 
  The 
  posterior 
  lobe 
  {ii.r.k.) 
  is 
  by 
  far 
  the 
  

   largest 
  and 
  most 
  important 
  part 
  of 
  the 
  kidney 
  of 
  Trochus, 
  

   and 
  can 
  be 
  divided 
  into 
  two 
  portions, 
  the 
  dorsal 
  portion, 
  con- 
  

   sisting 
  entirely 
  of 
  glandular 
  tissue, 
  extending 
  up 
  between 
  the 
  

   pericardium 
  and 
  the 
  stomach, 
  and 
  the 
  ventral 
  portion, 
  which 
  

   is 
  lined 
  by 
  a 
  thin 
  membranous 
  wall, 
  forming 
  a 
  kind 
  of 
  urinary 
  

   chamber 
  [k.c.) 
  into 
  which 
  the 
  excreted 
  products 
  of 
  the 
  gland 
  

   are 
  collected. 
  This 
  urinary 
  chamber 
  is 
  continued 
  on 
  as 
  a 
  

   thin-walled 
  ureter 
  (-?<) 
  lying 
  on 
  the 
  right 
  side 
  of 
  the 
  mantle- 
  

   cavity 
  to 
  the 
  right 
  of 
  the 
  rectum, 
  and 
  opening 
  to 
  the 
  exterior 
  

   by 
  an 
  aperture 
  situated 
  close 
  to 
  the 
  aperture 
  of 
  the 
  left 
  

   kidney. 
  

  

  In 
  all 
  the 
  species 
  of 
  the 
  sub-genus 
  Gibbula 
  (figs. 
  39 
  — 
  41) 
  

   the 
  external 
  aperture 
  of 
  the 
  right 
  kidney 
  is 
  bounded 
  by 
  

   tumid 
  lips, 
  the 
  borders 
  of 
  which 
  are 
  fringed. 
  This 
  swollen 
  

   expansion 
  of 
  the 
  terminal 
  portion 
  of 
  the 
  ureter 
  is 
  very 
  con- 
  

   spicuous 
  in 
  females, 
  more 
  especially 
  so 
  during 
  the 
  breeding- 
  

   season. 
  Numerous 
  mucus-secreting 
  cells 
  are 
  present 
  in 
  this 
  

   enlarged 
  portion. 
  

  

  In 
  T. 
  zizyphinus 
  (figs. 
  42, 
  49) 
  and 
  other 
  members 
  of 
  the 
  

  

  