﻿JAN. 
  4, 
  1922 
  KENDALL 
  AND 
  CRAWFORD: 
  ARGENTINA 
  SILUS 
  11 
  

  

  spiral 
  valve 
  in 
  Argentina 
  silus 
  is 
  fully 
  as 
  well 
  developed 
  as 
  it 
  is 
  in 
  the 
  

   ganoids, 
  among 
  which 
  it 
  is 
  very 
  well 
  developed 
  in 
  Polypterus 
  and 
  

   the 
  Sturgeon, 
  but 
  vestigeal 
  in 
  Lepidosieous 
  and 
  Amia 
  (Amiatus).^ 
  

  

  It 
  is 
  generally 
  believed 
  that 
  the 
  spiral 
  valve 
  is 
  absent 
  in 
  the 
  more 
  

   specialized 
  Teleostei 
  with 
  the 
  possible 
  exceptions 
  of 
  Chirocentrus 
  

   and 
  possibly 
  some 
  Salmonidae. 
  In 
  making 
  the 
  latter 
  exception 
  

   reference 
  is 
  made 
  to 
  Rathke's 
  work 
  published 
  in 
  1824. 
  

  

  In 
  discussing 
  the 
  folds 
  of 
  the 
  mucous 
  membrane 
  lining 
  the 
  intestines 
  

   of 
  various 
  fishes, 
  Rathke^ 
  mentions 
  crossfolds 
  (Querfalten) 
  and 
  ring- 
  

   folds 
  (Ringfalten) 
  as 
  occurring 
  in 
  C/zi^eaa/csa, 
  the 
  grayling 
  {Thymallus), 
  

   whitefish 
  {Coregonus), 
  and 
  Salmo 
  trutta. 
  While 
  Rathke 
  evidently 
  

   was 
  aware 
  of 
  the 
  presence 
  of 
  these 
  folds, 
  it 
  is 
  clear 
  that 
  he 
  did 
  not 
  

   interpret 
  them 
  as 
  spiral 
  valves, 
  for 
  he 
  does 
  not 
  use 
  the 
  term 
  "Spiral- 
  

   falten" 
  in 
  this 
  connection 
  as 
  he 
  does 
  in 
  describing 
  the 
  spiral 
  valve 
  of 
  

   the 
  Sturgeon. 
  The 
  more 
  exact 
  meaning 
  of 
  the 
  term 
  "vestige" 
  still 
  

   remains 
  to 
  be 
  determined; 
  but 
  at 
  present 
  such 
  a 
  discussion 
  seems 
  to 
  

   be 
  extraneous. 
  As 
  a 
  matter 
  of 
  fact, 
  however, 
  the 
  writers 
  have 
  found 
  

   that 
  in 
  some 
  specimens 
  of 
  "Rainbow" 
  trout 
  {Salmo 
  sp.) 
  there 
  were 
  

   six 
  or 
  seven 
  well-developed 
  spiral 
  folds 
  in 
  the 
  posterior 
  end 
  of 
  the 
  

   intestine 
  which 
  will 
  be 
  discussed 
  more 
  fully 
  in 
  a 
  future 
  paper. 
  

  

  Of 
  the 
  remaining 
  Teleosts 
  in 
  which 
  there 
  are 
  so-called 
  rudiments 
  

   or 
  vestiges 
  of 
  spiral 
  valves, 
  Gymnarchus^ 
  apparently 
  possesses 
  a 
  

   slight 
  spiral 
  valve 
  which 
  disappears 
  43 
  days 
  after 
  hatching. 
  How- 
  

   ever, 
  according 
  to 
  Cuvier 
  and 
  Valenciennes,^ 
  there 
  is 
  a 
  well-developed 
  

   spiral 
  valve 
  in 
  Chirocentrus, 
  one 
  of 
  the 
  Physostomi. 
  It 
  is 
  described 
  

   as 
  follows: 
  "Upon 
  opening 
  the 
  intestine, 
  one 
  finds 
  a 
  mucous 
  lining 
  

   very 
  remarkable 
  for 
  its 
  exceedingly 
  numerous 
  and 
  close-set 
  folds, 
  

   which, 
  for 
  the 
  whole 
  extent 
  of 
  the 
  canal, 
  form 
  a 
  series 
  of 
  connivant 
  

   valves, 
  or 
  rather 
  an 
  internal 
  lamina 
  wound 
  in 
  a 
  very 
  compact 
  spiral 
  — 
  

   une 
  lame 
  sur 
  une 
  spirale 
  tres-seree 
  " 
  The 
  description 
  is 
  sup- 
  

   plemented 
  by 
  a 
  drawing 
  which 
  differs 
  from 
  other 
  drawings 
  ^° 
  of 
  the 
  

   spiral 
  valve 
  of 
  Chirocentrus. 
  However, 
  it 
  is 
  apparent 
  that 
  Chiro- 
  

  

  « 
  Parker 
  and 
  Haswell, 
  A 
  Text-Book 
  of 
  Zoology, 
  2: 
  218. 
  1897. 
  

  

  '' 
  Heinrich 
  Rathke, 
  Uher 
  den 
  Darmkanal 
  und 
  die 
  Zeugungsorgane 
  der 
  Fische, 
  62-65, 
  

   83. 
  1824. 
  

  

  * 
  R. 
  Assheton, 
  The 
  Development 
  of 
  Gymnarchus 
  niloticus. 
  The 
  Work 
  of 
  John 
  Samuel 
  

   Budgett. 
  Edited 
  by 
  J. 
  Graham 
  Verr. 
  P. 
  326. 
  

  

  » 
  Cuvier 
  and 
  Valenciennes, 
  Histoire 
  Naturelle 
  des 
  Poissons, 
  19: 
  117; 
  also 
  PI. 
  565 
  

   between 
  pp. 
  312-313. 
  1846. 
  

  

  1" 
  E. 
  S. 
  Goodrich, 
  A 
  Treatise 
  on 
  Zoology, 
  fig. 
  77A. 
  Edited 
  by 
  Sir 
  Ray 
  Lankester. 
  

  

  