﻿56 
  W. 
  13. 
  HANDLES. 
  

  

  a 
  granulai- 
  appearance. 
  These 
  cells 
  are 
  manifestly 
  glandular, 
  

   and 
  present 
  a 
  very 
  sti'iking 
  resemblance 
  to 
  the 
  excretory 
  cells 
  

   of 
  the 
  riglit 
  kidney; 
  they 
  constitute 
  the 
  so-called 
  peri- 
  

   cardial 
  gland, 
  and 
  according 
  to 
  Grobbcn^ 
  and 
  Perrier 
  (37, 
  

   p. 
  127), 
  the 
  products 
  of 
  excretion 
  are 
  conveyed 
  out 
  of 
  the 
  

   pericardium 
  to 
  the 
  exterior 
  through 
  the 
  left 
  reno-pericardial 
  

   canal 
  and 
  papillary 
  sac. 
  

  

  The 
  posterior 
  aorta 
  (figs. 
  39, 
  47, 
  p. 
  ao.) 
  arises 
  from 
  the 
  

   aortic 
  bulb, 
  crosses 
  over 
  the 
  right 
  kidney 
  and 
  stomach, 
  giving 
  

   off 
  branches 
  to 
  the 
  latter; 
  it 
  then 
  curves 
  under 
  this 
  organ, 
  

   follows 
  the 
  inside 
  of 
  the 
  visceral 
  spire 
  to 
  its 
  apex, 
  and 
  dis- 
  

   tributes 
  branches 
  to 
  both 
  liver 
  and 
  gonad. 
  

  

  The 
  anterior 
  aorta 
  (a. 
  rto.), 
  which 
  also 
  arises 
  from 
  the 
  

   aortic 
  bulb, 
  is 
  situated 
  on 
  the 
  left 
  side 
  of 
  the 
  body 
  between 
  

   the 
  body-wall 
  and 
  the 
  ascending 
  portion 
  of 
  the 
  intestine. 
  It 
  

   follows 
  the 
  course 
  of 
  the 
  intestine 
  for 
  a 
  considerable 
  distance, 
  

   furnishing 
  it 
  with 
  several 
  branches, 
  crosses 
  to 
  the 
  right, 
  

   passing 
  over 
  the 
  crop, 
  and 
  penetrates 
  between 
  the 
  crop 
  

   and 
  radula-sac 
  ; 
  it 
  supplies 
  the 
  buccal 
  mass 
  with 
  vessels, 
  

   and 
  then 
  recurves 
  to 
  foim 
  a 
  sinus 
  situated 
  above 
  the 
  ventral 
  

   nerve-cords; 
  from 
  this 
  the 
  blood 
  penetrates 
  into 
  the 
  lacunas 
  of 
  

   the 
  foot. 
  

  

  The 
  venous 
  system 
  is 
  chiefly 
  lacunar, 
  sinuses 
  being 
  con- 
  

   spicuous 
  in 
  the 
  foot, 
  especially 
  in 
  the 
  glandular 
  portion 
  on 
  

   the 
  dorsal 
  surface. 
  The 
  blood 
  returning 
  from 
  the 
  posterior 
  

   region 
  of 
  the 
  visceral 
  mass 
  traverses 
  the 
  right 
  kidney 
  by 
  

   numerous 
  sinuses; 
  these 
  are 
  collected 
  into 
  a 
  large 
  vessel, 
  the 
  

   efferent 
  renal 
  vein 
  (fig. 
  48, 
  e.r. 
  c), 
  which 
  passes 
  into 
  the 
  

   mantle-cavity, 
  where 
  it 
  unites 
  with 
  a 
  vessel 
  bringing 
  blood 
  

   from 
  the 
  sinuses 
  of 
  the 
  anterior 
  portion 
  of 
  the 
  body; 
  the 
  vein 
  

   formed 
  by 
  the 
  union 
  of 
  these 
  vessels 
  crosses 
  over 
  the 
  rectum, 
  

   and, 
  emerging 
  from 
  between 
  the 
  apertures 
  of 
  the 
  right 
  and 
  

   left 
  kidneys, 
  traverses 
  the 
  mantle 
  from 
  right 
  to 
  left 
  as 
  the 
  

   transverse 
  pallial 
  vein 
  (figs. 
  39 
  — 
  43, 
  f. 
  j:». 
  t'.) 
  ; 
  it 
  receives 
  

  

  ' 
  Grol)beii, 
  C, 
  "Die 
  Pericardialdriise 
  der 
  Laniellibrancliiateu 
  (ein 
  Beit- 
  

   v&tj; 
  ziir 
  Keiitiiiss 
  der 
  Aualomie 
  dieser 
  Molluskeiiclasse)," 
  ' 
  Arb. 
  zool. 
  Inst. 
  

   Wieii.,' 
  Bd. 
  vii, 
  ISSS. 
  

  

  