﻿INVERTEBRATES. 
  287 
  

  

  Poteriocrinus 
  Talboti, 
  Worthen. 
  

  

  PI. 
  XXX, 
  Pig. 
  7. 
  

  

  Poteriocrinus 
  Talboti, 
  "Worthen, 
  February, 
  1882. 
  

  

  Bulletin 
  No. 
  1, 
  of 
  the 
  Illinois 
  State 
  Museum 
  of 
  Natural 
  History, 
  p. 
  17. 
  

  

  Body 
  very 
  short, 
  basin-shaped, 
  base 
  depressed, 
  and 
  the 
  basals 
  

   hidden 
  in 
  the 
  basal 
  concavity. 
  

  

  Subradials 
  short, 
  curving 
  inward 
  below 
  to 
  form 
  by 
  their 
  lower 
  

   angles 
  part 
  of 
  the 
  basal 
  depression. 
  

  

  Radials 
  pantagonal, 
  twice 
  as 
  wide 
  as 
  high, 
  widest 
  at 
  their 
  upper 
  

   margins, 
  and 
  truncated 
  squarely 
  across 
  fur 
  the 
  reception 
  of 
  the 
  

   brachial 
  plates. 
  

  

  On 
  the 
  anterior 
  ray, 
  there 
  are 
  six 
  or 
  seven 
  brachials, 
  all 
  becoming 
  

   narrower 
  upward 
  so 
  that 
  the 
  last 
  is 
  only 
  about 
  half 
  as 
  wide 
  as 
  the 
  

   first. 
  The 
  last 
  one 
  is 
  an 
  axillary 
  plate, 
  and 
  supports 
  two 
  arms 
  that 
  

   continue 
  simple 
  to 
  their 
  extremities. 
  The 
  other 
  rays 
  have 
  but 
  a 
  

   single 
  brachial, 
  which 
  is 
  as 
  large 
  or 
  larger 
  than 
  the 
  radials 
  on 
  which 
  

   they 
  rest, 
  pentagonal 
  in 
  form, 
  and 
  give 
  support 
  on 
  their 
  upper 
  slop- 
  

   ing 
  sides 
  to 
  the 
  first 
  division 
  of 
  the 
  rays. 
  On 
  the 
  left 
  antero-lateral 
  

   ray 
  the 
  arms 
  divide 
  on 
  the 
  sixth 
  plate, 
  beyond 
  which 
  they 
  appear 
  

   to 
  be 
  simple, 
  which 
  would 
  give 
  four 
  arms 
  to 
  this 
  ray. 
  If 
  the 
  pos- 
  

   terior 
  rays, 
  which 
  are 
  concealed 
  in 
  the 
  rock 
  in 
  our 
  specimen, 
  cor- 
  

   respond 
  with 
  the 
  antero-lateral 
  ray, 
  it 
  would 
  give 
  eighteen 
  arms 
  to 
  

   the 
  entire 
  animal. 
  Anal 
  area 
  and 
  column 
  unknown. 
  

  

  I 
  take 
  pleasure 
  in 
  dedicating 
  this 
  species 
  to 
  my 
  esteemed 
  friend, 
  

   Henry 
  Talbot, 
  Esq., 
  of 
  Waterloo, 
  to 
  whom 
  I 
  am 
  indebted 
  for 
  many 
  

   acts 
  of 
  personal 
  kindness, 
  and 
  for 
  some 
  interesting 
  fossils. 
  

  

  Position 
  and 
  locality; 
  St. 
  Louis 
  limestone, 
  Monroe 
  county, 
  111. 
  

  

  No. 
  2,470, 
  Illinois 
  State 
  collection. 
  

  

  Poteriocrinus 
  validus, 
  "Worthen. 
  

  

  PI. 
  XXVIII, 
  Pig. 
  16. 
  

  

  Poteriocrinus 
  validus, 
  Worthen, 
  February, 
  1882. 
  

  

  Bulletin 
  No. 
  1, 
  of 
  the 
  Illinois 
  State 
  Museum 
  of 
  Natural 
  History, 
  p. 
  18. 
  

  

  Body 
  more 
  than 
  twice 
  as 
  wide 
  as 
  high, 
  forming 
  a 
  low, 
  shallow 
  

   cup. 
  Basals 
  small 
  and 
  concealed 
  by 
  the 
  first 
  columnar 
  joints. 
  

   Subradials 
  hexagonal 
  on 
  the 
  anterior 
  side, 
  strongly 
  protuberant 
  in 
  

   the 
  middle 
  and 
  depressed 
  at 
  the 
  angles, 
  giving 
  a 
  very 
  rugged 
  ap- 
  

  

  