﻿PALEOCRINOIDEA. 
  

  

  Genus 
  POTERIOCRINUS, 
  Miller. 
  

   Poteriocrinus 
  coxanus, 
  Worthen. 
  

  

  PI. 
  XXVII, 
  Fig. 
  1. 
  

  

  Poteriocrinus 
  Coxanus, 
  Woethen, 
  February, 
  1882. 
  

  

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

  

  Body 
  above 
  the 
  medium 
  size, 
  obconie, 
  gradually 
  swelling 
  from 
  a 
  

   truncated 
  base 
  to 
  the 
  summit 
  of 
  the 
  radial 
  plates, 
  where 
  it 
  is 
  about 
  

   one-fourth 
  wider 
  than 
  high. 
  Basal 
  plates 
  as 
  wide, 
  or 
  a 
  little 
  wider, 
  

   than 
  high, 
  forming 
  by 
  themselves 
  a 
  low 
  pentagonal 
  cup, 
  about 
  twice 
  

   as 
  wide 
  as 
  high. 
  One 
  subradial 
  on 
  the 
  anterior 
  side 
  is 
  longer 
  than 
  

   wide, 
  the 
  others 
  about 
  as 
  wide 
  as 
  long, 
  all 
  pentagonal, 
  there 
  being 
  

   but 
  two 
  distinct 
  angles 
  on 
  their 
  lower 
  margins. 
  

  

  Badials 
  nearly 
  once 
  and 
  a 
  half 
  as 
  wide 
  as 
  high 
  on 
  the 
  anterior 
  

   rays, 
  curving 
  in 
  on 
  their 
  lateral 
  borders 
  so 
  as 
  to 
  give 
  a 
  pentalobate 
  

   character 
  to 
  the 
  upper 
  part 
  of 
  the 
  body. 
  

  

  Brachials 
  two, 
  the 
  first 
  quadrangular, 
  and 
  the 
  second 
  pentangular, 
  

   and 
  both 
  more 
  than 
  twice 
  as 
  wide 
  as 
  long, 
  the 
  second 
  supporting 
  

   on 
  their 
  sloping 
  sides 
  the 
  first 
  divisions 
  of 
  the 
  rays. 
  Only 
  two 
  of 
  

   the 
  rays 
  and 
  a 
  part 
  of 
  the 
  third 
  are 
  to 
  be 
  seen, 
  the 
  others 
  being 
  

   concealed 
  in 
  the 
  rock. 
  In 
  one 
  of 
  these, 
  probably 
  the 
  anterior 
  ray, 
  

   a 
  second 
  bifurcation 
  takes 
  place 
  on 
  the 
  fifth 
  plate 
  in 
  each 
  division, 
  

   and 
  the 
  outer 
  branch 
  is 
  seen 
  to 
  divide 
  once 
  more 
  about 
  the 
  tenth 
  

   plate, 
  and 
  the 
  inner 
  division 
  on 
  the 
  twenty-fourth 
  to 
  the 
  twenty- 
  

   sixth 
  plate, 
  beyond 
  which 
  the 
  arms 
  of 
  this 
  ray 
  are 
  not 
  preserved. 
  

  

  On 
  the 
  right 
  antero-lateral 
  ray 
  the 
  second 
  bifurcation 
  takes 
  place 
  

   on 
  the 
  fourth 
  plate 
  in 
  each 
  division, 
  the 
  outer 
  branch 
  dividing 
  twice 
  

   more 
  on 
  the 
  eighth 
  and 
  twenty-second 
  plate, 
  and 
  the 
  inner 
  one 
  twice 
  

   on 
  the 
  twenty-fourth 
  to 
  the 
  twenty-sixth 
  plate, 
  beyond 
  which 
  they 
  

   are 
  not 
  preserved. 
  This 
  gives 
  twelve 
  visible 
  arms 
  to 
  this 
  ray, 
  and 
  

   it 
  is 
  quite 
  possible 
  there 
  were 
  other 
  divisions 
  beyond, 
  as 
  the 
  arms 
  

   extended 
  about 
  two 
  inches 
  beyond 
  the 
  last 
  divisions 
  that 
  are 
  pre- 
  

  

  