﻿300 
  PALEONTOLOGY 
  OF 
  ILLINOIS. 
  

  

  oates 
  th. 
  Beeond 
  time 
  on 
  the 
  eight 
  or 
  ninth 
  plate, 
  the 
  right 
  branch 
  

  

  tiding 
  off 
  two 
  additional 
  arms 
  on 
  the 
  seventh, 
  and 
  again 
  on 
  the 
  

   fourteenth 
  plate, 
  while 
  the 
  left 
  branch 
  gives 
  off 
  another 
  arm 
  on 
  the 
  

  

  hth 
  or 
  ninth 
  plate, 
  beyond 
  which 
  it 
  u 
  not 
  pn 
  

   probably 
  eight 
  arms 
  to 
  this 
  ray. 
  The 
  other 
  raj 
  

   beyond 
  the 
  Beeond 
  bifurcation. 
  The 
  arms 
  are 
  composed 
  of 
  rather 
  

   short, 
  wedge-formi 
  .1 
  joints, 
  that 
  give 
  off 
  Btrong 
  pinnules 
  from 
  their 
  

   longest 
  

  

  Anal 
  ana 
  unknown. 
  Column 
  round, 
  composed 
  at 
  first 
  of 
  rather 
  

   even 
  joints, 
  with 
  a 
  thicker 
  one 
  intercalated 
  at 
  .-hoit 
  intervals 
  below. 
  

   The 
  calyx 
  of 
  this 
  species 
  could 
  not 
  be 
  readily 
  distinguished 
  from 
  

  

  ■ 
  ral 
  others 
  that 
  are 
  found 
  in 
  the 
  Chester 
  limestone, 
  hut 
  its 
  long, 
  

   slender 
  arms, 
  and 
  their 
  mode 
  of 
  bifurcation, 
  are 
  its 
  distinc 
  

   characters. 
  

  

  Position 
  and 
  locality: 
  Chester 
  limestone, 
  Monroe 
  county. 
  111. 
  

   No. 
  -2. 
  i:>7. 
  Qlinois 
  State 
  collection. 
  

  

  POTBRIOOBIHUS 
  KaSI 
  -. 
  Wortlun. 
  

  

  PL 
  WIX. 
  Ha. 
  r. 
  

   PoUrloorinu* 
  KaMlcaskUniU, 
  Wobthkh, 
  Feb 
  . 
  i- 
  

  

  BaUetln 
  No. 
  l. 
  of 
  the 
  Illinois 
  - 
  

  

  Body 
  small, 
  bell-shaped, 
  nearly 
  twice 
  as 
  wid< 
  as 
  long 
  to 
  the 
  sum- 
  

   mit 
  of 
  the 
  radials, 
  composed 
  of 
  rather 
  thin, 
  smooth 
  plates, 
  ^o 
  

   anohylosed 
  together 
  that 
  their 
  relative 
  size 
  and 
  form 
  cannot 
  h. 
  dei 
  

  

  mined. 
  The 
  radials 
  air 
  nearly 
  as 
  long 
  as 
  wide, 
  pentagonal, 
  tlnck- 
  

  

  ened 
  on 
  their 
  upper 
  margins 
  with 
  a 
  lip-like 
  suture 
  between 
  them 
  

   and 
  the 
  first 
  brachial 
  plates. 
  

  

  Brachials 
  two, 
  the 
  firs! 
  quadrangular, 
  the 
  second 
  pentagonal; 
  

   length 
  and 
  breadth 
  about 
  equal, 
  both 
  rounded 
  externally, 
  and 
  oon- 
  

   Btrioted, 
  the 
  second 
  Bharply 
  angular 
  above, 
  and 
  supporting 
  on 
  

   Bloping 
  Bides 
  the 
  first 
  divisions 
  of 
  the 
  n 
  

  

  Ann- 
  OOmpoaed 
  <>f 
  rather 
  long. 
  \\, 
  i 
  p. 
  «1 
  joints, 
  that 
  pr 
  

  

  iitly 
  on 
  their 
  outer 
  margins, 
  giving 
  them 
  i 
  somewhat 
  

   appearance, 
  and 
  after 
  their 
  first 
  division 
  on 
  the 
  second 
  brachials 
  U 
  

   all 
  divide 
  again 
  on 
  the 
  eighth 
  to 
  the 
  tenth 
  plate 
  above 
  the 
  brachial 
  

   giving 
  four 
  arms 
  to 
  each 
  ray 
  as 
  the 
  normal 
  number. 
  In 
  ur 
  

  

  I 
  a 
  branoh 
  d< 
  ar 
  

   making 
  ti\« 
  

   Pinnules 
  rather 
  strong 
  and 
  atta.-h,,! 
  to 
  the 
  loi 
  arm 
  

  

  plat 
  • 
  unknown. 
  Vent] 
  li 
  I 
  idricnl. 
  an.l 
  about 
  

  

  