﻿EPITHELIAL 
  ISLETS 
  OF 
  THE 
  PANCREAS 
  IN 
  TELEOSTEI. 
  397 
  

  

  Relation 
  of 
  the 
  Islets 
  to 
  the 
  Pancreatic 
  Acini. 
  

  

  From 
  the 
  foregoing 
  account 
  it 
  will 
  be 
  seen 
  that 
  in 
  bony 
  

   fishes 
  these 
  islets^ 
  though 
  undoubtedly 
  existing 
  under 
  con- 
  

   ditions 
  similar 
  to 
  those 
  met 
  with 
  in 
  higher 
  animals, 
  also 
  vei'y 
  

   commonly 
  occur 
  in 
  distinctly 
  less 
  intimate 
  morphological 
  

   relation 
  to 
  the 
  pancreatic 
  alveoli. 
  It 
  will 
  have 
  been 
  noted 
  

   that 
  various 
  conditions 
  have 
  been 
  observed, 
  from 
  that 
  where 
  

   the 
  tissue 
  of 
  the 
  islet 
  stands 
  in 
  the 
  same 
  relation 
  to 
  the 
  zymo- 
  

   genous 
  elements 
  as 
  the 
  sepai-ate 
  alveoli 
  of 
  the 
  latter 
  do 
  to 
  

   each 
  other 
  (figs. 
  4 
  and 
  6) 
  to 
  cases 
  where 
  a 
  thick 
  investing 
  

   capsule 
  exists 
  around 
  a 
  large 
  islet 
  with 
  no 
  alveoli 
  in 
  contact, 
  

   and 
  only 
  a 
  very 
  few 
  of 
  these 
  in 
  the 
  surrounding 
  parts, 
  e. 
  g. 
  

   Syn 
  gnat 
  bus 
  (fig. 
  3). 
  Indeed, 
  my 
  attention 
  in 
  the 
  first 
  

   instance 
  was 
  confined 
  to 
  these 
  latter 
  bodies 
  in 
  such 
  fishes 
  as 
  

   Pholis 
  gunnellus 
  and 
  Syngnathus 
  acus, 
  where 
  the 
  

   ordinary 
  pancreatic 
  tissue 
  is 
  in 
  no 
  more 
  intimate 
  relation 
  to 
  

   them 
  than 
  it 
  is 
  to 
  the 
  portal 
  vein 
  or 
  mesenteric 
  artery, 
  along 
  

   which 
  vessels 
  it 
  extends 
  as 
  narrow 
  bands. 
  Accordingly 
  I 
  

   hesitated 
  to 
  relate 
  these 
  distinctly 
  encapsuled 
  and 
  separate 
  

   glands 
  with 
  the 
  pancreatic 
  " 
  islet 
  ^' 
  of 
  the 
  usual 
  type 
  until 
  I 
  

   had 
  found 
  in 
  various 
  species 
  bodies 
  of 
  identical 
  structure 
  in 
  

   situations 
  which 
  left 
  no 
  further 
  room 
  for 
  doubt. 
  Amone-st 
  

   these 
  encapsuled 
  glands 
  there 
  is 
  included 
  the 
  body 
  already 
  

   noted 
  as 
  a 
  " 
  principal 
  islet." 
  Diamare, 
  without 
  making 
  any 
  

   reference 
  to 
  the 
  question 
  of 
  regular 
  occurrence, 
  describes 
  this 
  

   body 
  in 
  Orthagoriscus 
  mola. 
  Rhombus 
  Itevis, 
  and 
  

   Lophius 
  piscatorius 
  as 
  a 
  pancreatic 
  islet. 
  Indeed, 
  no 
  

   reasonable 
  doubt 
  can 
  be 
  raised 
  as 
  regards 
  the 
  homology 
  of 
  

   the 
  principal 
  islet. 
  

  

  A 
  feature 
  observed 
  in 
  the 
  islets 
  in 
  Hippoglossus 
  vul- 
  

   garis, 
  PJeuronectes 
  platessa, 
  and 
  Anarrhichas 
  lupus, 
  

   viz. 
  the 
  penetration 
  of 
  these 
  by 
  zymogenous 
  elements, 
  had 
  been 
  

   previously 
  noted 
  by 
  Diamare 
  in 
  other 
  species. 
  These 
  elements 
  

   may 
  appear 
  continuous 
  with 
  the 
  pancreatic 
  tissue 
  outside, 
  or 
  

   as 
  detached 
  alveoli 
  surrounded 
  by 
  the 
  islet. 
  In 
  the 
  latter 
  

  

  