﻿390 
  JOHN 
  RENNIE. 
  

  

  up 
  a 
  deeper 
  tint 
  than 
  the 
  cells 
  of 
  the 
  lighter 
  areas, 
  though 
  

   no 
  structural 
  differences 
  were 
  made 
  out 
  in 
  this 
  region 
  of 
  the 
  

   cell. 
  Capillaries 
  are 
  only 
  fairly 
  numerous 
  in 
  this 
  type 
  

   (fig.4)._ 
  

  

  Pholis 
  gunnellus. 
  — 
  The 
  two 
  islets 
  referred 
  to 
  in 
  an 
  

   earlier 
  part 
  of 
  this 
  paper 
  possess 
  the 
  same 
  structure, 
  except 
  

   that 
  the 
  principal 
  has 
  a 
  very 
  definite 
  capsule 
  not 
  apparent 
  in 
  

   the 
  other, 
  and 
  its 
  relation 
  to 
  the 
  pancreas 
  is 
  less 
  intimate. 
  

   The 
  structure 
  is 
  similar 
  to 
  that 
  described 
  for 
  Zeus, 
  but 
  the 
  

   cells 
  are 
  smaller 
  and 
  more 
  cylindrical. 
  Cell-walls 
  are 
  less 
  

   easily 
  seen, 
  but 
  are 
  present. 
  In 
  parts 
  the 
  capillaries 
  run 
  in 
  

   nearly 
  parallel 
  rows, 
  and 
  the 
  cells 
  are 
  arranged 
  in 
  bands 
  

   between. 
  The 
  cytoplasm 
  shows 
  a 
  delicate 
  network, 
  which, 
  in 
  

   contrast 
  to 
  that 
  visible 
  in 
  the 
  neighbouring 
  acini, 
  is 
  very 
  

   fine. 
  Differently 
  staining 
  areas, 
  as 
  noted 
  in 
  Zeus, 
  were 
  not 
  

   observed. 
  

  

  Anarrhichas 
  lupus. 
  — 
  The 
  principal 
  islet 
  is 
  a 
  large 
  

   body 
  with 
  a 
  well-defined 
  capsule 
  which 
  sends 
  in 
  numerous 
  

   supporting 
  partitions 
  (fig. 
  5). 
  It 
  is 
  surrounded 
  by 
  a 
  very 
  

   thin 
  band 
  of 
  zymogenous 
  tissue, 
  from 
  which 
  portions 
  pene- 
  

   trate 
  within 
  the 
  islet. 
  This 
  feature 
  is 
  not 
  uncommon 
  in 
  the 
  

   case 
  of 
  large 
  islets 
  in 
  fishes 
  ; 
  Diamare 
  noted 
  it 
  in 
  some 
  of 
  the 
  

   species 
  examined 
  by 
  him, 
  and 
  I 
  have 
  met 
  with 
  several 
  

   instances, 
  as 
  will 
  be 
  seen. 
  The 
  tissue 
  of 
  the 
  islet 
  proper 
  pre- 
  

   sented 
  similar 
  features 
  to 
  that 
  seen 
  in 
  Zeus. 
  Light 
  and 
  

   dark 
  areas 
  were 
  observable, 
  and 
  they 
  were 
  respectively 
  

   traceable 
  through 
  series 
  of 
  sections. 
  In 
  the 
  main 
  the 
  nuclei 
  

   of 
  the 
  lightly 
  staining 
  areas 
  were 
  seen 
  to 
  be 
  irregular 
  in 
  

   outline, 
  while 
  those 
  of 
  the 
  dark 
  areas 
  were 
  circular 
  or 
  oval. 
  

   There 
  was 
  also 
  a 
  difference 
  in 
  size, 
  the 
  former 
  being 
  

   larger. 
  

  

  In 
  Ones 
  mustela 
  a 
  large 
  islet 
  of 
  very 
  irregular 
  out- 
  

   line 
  was 
  examined. 
  It 
  occurred 
  in 
  a 
  mass 
  of 
  pancreatic 
  

   tissue 
  adherent 
  to 
  the 
  intestine 
  at 
  the 
  pylorus. 
  In 
  some 
  

   sections 
  it 
  appeared 
  as 
  two 
  separate 
  bodies, 
  but 
  examination 
  

   of 
  the 
  series 
  showed 
  a 
  connection. 
  This 
  islet 
  had 
  no 
  limiting 
  

   capsule, 
  it 
  was 
  invested 
  by 
  the 
  connective 
  tissue 
  of 
  the 
  

  

  