﻿842 
  PALEONTOLOGY 
  OF 
  ILLINOIS. 
  

  

  of 
  from 
  eight 
  to 
  ten 
  simple 
  joints, 
  the 
  lir-t 
  join! 
  one-half 
  higher 
  

   than 
  wide, 
  and 
  differing 
  from 
  the 
  others 
  by 
  being 
  flattened 
  at 
  the 
  

  

  dorsal 
  side, 
  all 
  succeeding 
  ones 
  rounded 
  at 
  the 
  outer 
  side, 
  with 
  

   slightly 
  expanded 
  ends; 
  apper 
  and 
  lower 
  sides 
  almost 
  parallel. 
  The 
  

  

  •li 
  of 
  the 
  joints 
  is 
  somewhat 
  irregular, 
  varying 
  from 
  tin- 
  

   four 
  times 
  their 
  width, 
  hut 
  in 
  proportion 
  to 
  the 
  width 
  of 
  the 
  arm 
  : 
  

   ventral 
  groove 
  wide 
  and 
  deep. 
  No 
  pinnules 
  have 
  been 
  observed, 
  and 
  

   the 
  construction 
  of 
  the 
  vault 
  is 
  unknown. 
  

  

  Column 
  circular 
  very 
  Btrong 
  at 
  the 
  basal 
  disk, 
  hut 
  tap. 
  ring 
  so 
  

   dly 
  in 
  its 
  course 
  downward 
  that 
  at 
  ahout 
  one-fourth 
  of 
  an 
  inch 
  

   it 
  is 
  reduced 
  to 
  less 
  than 
  one-third 
  its 
  greatest 
  width. 
  whenC4 
  

   mains 
  stationary 
  as 
  far 
  as 
  it 
  is 
  preserved 
  in 
  the 
  specimen. 
  Tin- 
  

   segments 
  of 
  the 
  upper 
  or 
  conical 
  part 
  are 
  short, 
  aharply 
  edged, 
  and 
  

   of 
  the 
  same 
  height, 
  but 
  as 
  soon 
  ae 
  the 
  column 
  attains 
  its 
  ordinary 
  

   size, 
  the 
  joints 
  beconu 
  abruptly 
  higher, 
  more 
  cylindrical, 
  and 
  tl. 
  

   and 
  thinner 
  joints 
  alternate 
  in 
  the 
  usual 
  way. 
  Central 
  perforation 
  

   small. 
  

  

  The 
  specific 
  name 
  is 
  given 
  in 
  honor 
  of 
  1'. 
  Illicit 
  (': 
  

   Assistant 
  Masfr 
  r 
  at 
  Eaton 
  College, 
  England, 
  one 
  of 
  the 
  founders 
  of 
  

   the 
  genus 
  AUagecrinus.* 
  

  

  logical 
  position, 
  etc: 
  From 
  the 
  Chester 
  or 
  Kaskaskia 
  lii 
  

   .Monroe 
  county. 
  Illinois. 
  

  

  Illinois 
  State 
  collection. 
  

  

  genua 
  wee 
  proposed 
  bj 
  P, 
  .in., 
  lor 
  a 
  

  

  small 
  si 
  i'~ 
  fr<.m 
  the 
  Oarbonlforoo 
  - 
  and. 
  Lunate 
  and 
  H 
  

  

  April 
  1881, 
  p. 
  J- 
  1. 
  

  

  