﻿PALAEONTOLOGY 
  OP 
  ILLINOIS. 
  

  

  The 
  Bpine 
  under 
  consideration 
  ia, 
  perhaps, 
  less 
  intimately 
  allied 
  

   to 
  CUnacanthus 
  gemmai 
  St. 
  J. 
  and 
  W.. 
  than 
  with 
  C. 
  deft 
  

  

  bed, 
  both 
  from 
  the 
  same 
  formation, 
  [noertain 
  features 
  

   of 
  Burfaci 
  ornamentation 
  it 
  resembles 
  the 
  former, 
  but 
  in 
  

   form 
  it 
  is 
  apparently 
  allied 
  to 
  the 
  latter; 
  while 
  in 
  the 
  

   ornamentation 
  it 
  possesses 
  features 
  readily 
  distinguishing 
  it 
  

  

  - 
  of 
  the 
  genus. 
  Thi 
  fragment 
  lure 
  alluded 
  to 
  

   rare 
  acquisition 
  at 
  the 
  locality 
  where 
  it 
  was 
  found, 
  which 
  lias 
  

   thus 
  far 
  afforded 
  very 
  few 
  specimens 
  of 
  ichthyodorulib 
  

  

  logical 
  pontion 
  and 
  locality: 
  St. 
  Lotus 
  formation, 
  calcareous 
  

   Bhal< 
  - 
  : 
  Pella, 
  towa. 
  

  

  \. 
  and 
  \N 
  . 
  

  

  PL 
  W 
  IV. 
  lit:. 
  1. 
  

  

  .„.! 
  Woi.iiiFN. 
  ISM. 
  Hi. 
  (...■]. 
  Bum 
  >. 
  II. 
  

  

  I- 
  . 
  .in 
  ' 
  

  

  n..n.p. 
  iis.pl 
  mi 
  

  

  WOBTHn 
  WR. 
  iK. 
  M 
  I'. 
  *3S. 
  

  

  above 
  species 
  is, 
  perhaps, 
  the 
  mosl 
  frequently 
  Diet 
  with 
  of 
  

  

  al! 
  the 
  ichthyodorulites 
  occurring 
  in 
  the 
  St. 
  Louis 
  formation. 
  The 
  

  

  fine 
  example 
  now 
  illustrated, 
  and 
  which 
  was 
  kindly 
  loaned 
  us 
  for 
  

  

  ■ 
  ,,n 
  by 
  Dr. 
  George 
  Bambach, 
  i 
  to 
  the 
  Bhumard 
  

  

  a 
  in 
  Washington 
  University 
  al 
  St. 
  ! 
  and 
  is 
  unquestionably 
  

  

  the 
  tin. 
  isi 
  specimen 
  of 
  the 
  Bpi 
  • 
  '•• 
  

  

  It 
  i- 
  interesting 
  to 
  note 
  the 
  wide 
  distribution 
  of 
  this 
  iohthyodorulite. 
  

   We 
  have 
  been 
  favored 
  with 
  the 
  loan 
  of 
  a 
  Bpecimen 
  from 
  equivalent 
  

   deposits 
  al 
  Grand 
  Bapids, 
  M 
  , 
  bj 
  Prof. 
  E. 
  \. 
  Btrong, 
  which 
  

  

  undoubtedly 
  is 
  identical 
  with 
  the 
  present 
  - 
  

   The 
  fin-spine 
  originally 
  described 
  onder 
  the 
  name 
  /■ 
  **•? 
  

  

  ,. 
  \. 
  and 
  W., 
  and 
  Bubsequentlj 
  referred 
  by 
  the 
  authors 
  

   t() 
  t 
  | 
  :.\ 
  but 
  convi 
  

  

  oifioally 
  distinct 
  from 
  the 
  above 
  spe< 
  atter 
  spines 
  an 
  

  

  doubtless 
  the 
  worn 
  upper 
  portion 
  of 
  thai 
  in 
  which 
  the 
  

  

  dorsal 
  keel 
  and 
  the 
  first 
  hm 
  la 
  

  

  od 
  tlu 
  i 
  the 
  

  

  dentiolea 
  are 
  ondiatinguishable 
  from 
  that 
  obtained 
  in 
  the 
  

  

  rticularlj 
  n 
  f< 
  rred 
  to. 
  

  

  ormation 
  3t 
  I 
  

   Irand 
  Rapids, 
  Miehij 
  

  

  