﻿•27.; 
  PALAEONTOLOGY 
  OF 
  ILLINOIS. 
  

  

  . 
  i.iuim'um 
  s 
  i'i:Nhii.i.iri)i.Mi> 
  t 
  Worthen. 
  

  

  1-1. 
  XXYI1I. 
  rig. 
  9. 
  

  

  .ry. 
  1*82. 
  

  

  No. 
  i. 
  ■■'. 
  ■■ 
  ;-8. 
  

  

  Body 
  small, 
  forming 
  In-low 
  the 
  summit 
  of 
  tin- 
  radial 
  plates 
  a 
  low 
  

   cup, 
  about 
  twice 
  as 
  wide 
  as 
  high. 
  Baaala, 
  and 
  the 
  lower 
  angle 
  of 
  

   the 
  Bubradials, 
  oonoealed 
  ondei 
  the 
  lir-t 
  columnar 
  joints. 
  

  

  Subradiala 
  about 
  as 
  long 
  as 
  wide, 
  exoepl 
  the 
  one 
  on 
  the 
  posterior 
  

   aide, 
  which 
  is 
  a 
  little 
  longer 
  than 
  the 
  others, 
  Badials 
  aboat 
  twice 
  

   as 
  la: 
  tin- 
  baaala, 
  wider 
  than 
  long, 
  and 
  truncated 
  squi 
  

  

  across 
  their 
  opper 
  margina 
  for 
  tin- 
  reception 
  of 
  the 
  bracl 
  

   Brachials 
  twice 
  as 
  long 
  as 
  wide, 
  four 
  of 
  them 
  pentagonal, 
  co 
  

   in 
  the 
  middle, 
  and 
  supporting 
  two 
  arms 
  which 
  continue 
  simple 
  to 
  

   their 
  extremities. 
  The 
  anterior 
  ray 
  has 
  a 
  long 
  quadrangular 
  brachial 
  

   plate 
  supporting 
  a 
  single 
  arm, 
  making 
  nine 
  arms 
  altogether 
  for 
  this 
  

   species. 
  

  

  Arms 
  composed 
  of 
  rounded 
  joints 
  that 
  arc 
  generally 
  longer 
  than 
  

   wide, 
  hut 
  slightly 
  wedge-shaped, 
  giving 
  off 
  >tron^ 
  pinnules 
  from 
  

   their 
  tongesl 
  >ides. 
  

  

  Column 
  slightly 
  larger 
  at 
  it> 
  junction 
  with 
  the 
  body 
  than 
  below, 
  

   composed 
  of 
  alternately 
  thiokex 
  and 
  thinner 
  job 
  

  

  Firai 
  anal 
  plate 
  longer 
  than 
  wide, 
  pentagonal, 
  and 
  rests 
  partly 
  

   between 
  two 
  of 
  the 
  aubradiala 
  and 
  under 
  the 
  right 
  t 
  radial. 
  

  

  Above 
  lliis 
  a 
  double 
  series 
  of 
  small 
  anal 
  plates 
  can 
  . 
  the 
  

  

  Brat 
  of 
  which 
  rests 
  on 
  top 
  of 
  the 
  1. 
  ft 
  ibradial, 
  and 
  the 
  

  

  s. 
  oond 
  on 
  tlie 
  first 
  anal. 
  

  

  This 
  little 
  orinoid 
  is 
  related 
  to 
  that 
  described 
  by 
  Meek 
  and 
  Wor- 
  

  

  theii 
  iu 
  the 
  second 
  volume 
  of 
  the 
  Gcol. 
  Survey 
  of 
  111 
  

  

  pi, 
  17, 
  fig. 
  6, 
  under 
  the 
  name 
  of 
  Scaphu 
  crintu 
  deeadaetyUu, 
  hut 
  differs 
  

  

  from 
  it 
  in 
  the 
  prop. 
  of 
  the 
  body 
  plates, 
  and 
  I] 
  in 
  its 
  

  

  brachials 
  and 
  arm 
  plat* 
  

  

  / 
  ition 
  and 
  locality: 
  Upper 
  part 
  of 
  tin 
  Keokuk 
  1 
  Hamil- 
  

  

  ton. 
  Qlinois. 
  

  

  I 
  ..f 
  Mr. 
  I.. 
  \. 
  ( 
  Mection. 
  

  

  