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  PALEONTOLOGY 
  OF 
  ILLINOIS. 
  

  

  Ambnlacra 
  linear, 
  comparatively 
  aborter 
  and 
  probably 
  wider 
  than 
  

   in 
  any 
  other 
  of 
  ELzacriniu; 
  Ian 
  I 
  within 
  the 
  

  

  food 
  groove, 
  but 
  only 
  at 
  the- 
  apper 
  end 
  of 
  the 
  plat 
  t 
  half 
  

  

  i- 
  perfectly 
  i 
  by 
  the 
  aide-plates. 
  There 
  are 
  86 
  aide 
  

  

  pieces, 
  (outer 
  -ide 
  pieces 
  cannot 
  be 
  distingaished 
  in 
  the 
  Bp 
  

   with 
  a 
  deep 
  Bockel 
  to 
  each 
  plate. 
  The 
  hydroepire-por 
  only 
  

  

  seen 
  when 
  the 
  Bide 
  plates 
  aiv 
  broken 
  away. 
  

  

  Spiracles 
  ten, 
  one 
  to 
  each 
  side 
  of 
  the 
  ambulacrum; 
  slit-sha] 
  

   placed 
  like 
  those 
  of 
  the 
  preoedin 
  a 
  within 
  the 
  projecting 
  

  

  lateral 
  edges 
  of 
  the 
  orals: 
  those 
  of 
  the 
  anal 
  Bid 
  influent 
  with 
  

  

  the 
  anal 
  aperture. 
  The 
  hydro*] 
  unknown. 
  

  

  The 
  Bummit 
  (which 
  in 
  both 
  type 
  specimens 
  has 
  bun 
  preserved) 
  

   is 
  composed 
  of 
  but 
  few 
  comparatively 
  thick 
  pieces 
  which 
  are 
  simi- 
  

   larly 
  arranged 
  as 
  in 
  Elaacrinvs 
  obovatut. 
  Column 
  round, 
  central 
  

   perforation 
  very 
  small. 
  

  

  Obeervations: 
  This 
  species 
  has 
  its 
  closest 
  affinity 
  with 
  El 
  

   (Nucleocrinus) 
  elegant 
  Conrad, 
  from 
  which 
  it 
  differ^ 
  in 
  the 
  more 
  

   elongate 
  form, 
  in 
  the 
  mode 
  of 
  ornamentation, 
  in 
  havii. 
  

   straight 
  in 
  place 
  of 
  concave 
  interradial 
  sides, 
  and 
  in 
  

   trading 
  and 
  comparatively 
  Bhorter 
  ambulacra. 
  Th 
  

  

  . 
  reach 
  to 
  the 
  tin' 
  D 
  of 
  the 
  body. 
  \\h 
  

  

  /•.'. 
  meloniformit 
  they 
  occupy 
  only 
  five-sixths 
  of 
  that 
  length. 
  It 
  dif- 
  

   Erom 
  E. 
  VerneuUli 
  in 
  being 
  a 
  much 
  Bmaller 
  sp 
  ad 
  in 
  the 
  

  

  entirely 
  different 
  ornamentation; 
  from 
  I 
  - 
  angulai 
  

  

  /•.'. 
  hit-in, 
  i 
  Hall 
  and 
  our 
  /.. 
  • 
  i 
  - 
  lacking 
  that 
  mai 
  alar- 
  

  

  ity 
  of 
  the 
  body 
  so 
  conspicuous 
  in 
  each 
  of 
  th< 
  Then 
  is 
  

  

  aeral 
  resemblance 
  to 
  tin 
  figure 
  given 
  by 
  M 
  ery 
  ol 
  A 
  

  

  ocrinue 
  Conn 
  I 
  >ut 
  no 
  direct 
  row,-, 
  b, 
  made 
  a> 
  liis 
  

  

  1 
  deals 
  in 
  gem 
  ric 
  rather 
  than 
  Bpecific 
  only 
  

  

  Bpeoific 
  characteristic 
  dearly 
  brought 
  out, 
  "the 
  pn 
  

   illy 
  inapplii 
  

   logical 
  position, 
  etc.: 
  In 
  the 
  shales 
  of 
  tl 
  Group, 
  

  

  Buffalo, 
  towa, 
  and 
  at 
  the 
  t 
  . 
  » 
  i 
  ■ 
  of 
  the 
  same 
  group 
  in 
  the 
  Thunder 
  

  

  B 
  v} 
  r. 
  ion 
  of 
  Northern 
  Michigan. 
  

  

  