﻿The 
  Fauna 
  of 
  the 
  Niagara 
  Group. 
  141 
  

  

  drical 
  for 
  some 
  distance 
  below 
  ; 
  composed 
  of 
  thin 
  plates, 
  each 
  

   fourth 
  plate 
  being 
  thicker 
  and 
  armed 
  with 
  a 
  row 
  of 
  strong 
  

   nodes. 
  

  

  In 
  general 
  form 
  and 
  the 
  symmetrical 
  arrangement 
  of 
  plates, 
  

   this 
  species 
  has 
  much 
  the 
  appearance 
  of 
  Eucalyptocrintjs 
  ; 
  

   but 
  the 
  subradial 
  plates 
  and 
  greater 
  number 
  of 
  interradials, 
  

   and 
  the 
  absence 
  of 
  the 
  elongate 
  plates 
  separating 
  the 
  pairs 
  of 
  

   arms 
  as 
  in 
  that 
  genus, 
  are 
  distinguishing 
  characters. 
  In 
  the 
  

   flatness 
  of 
  the 
  plates, 
  their 
  peculiar 
  surface 
  markings, 
  and 
  

   their 
  arrangement, 
  this 
  species 
  diners 
  from 
  all 
  others 
  of 
  the 
  

   genus 
  Rhodocrinus 
  described. 
  

  

  The 
  relation 
  of 
  this 
  species 
  to 
  Lyriocrinus 
  [Rhodocrinus] 
  

   dactylus 
  of 
  the 
  Niagara 
  formation 
  in 
  New 
  York 
  (Pal. 
  N. 
  Y., 
  

   vol. 
  ii, 
  p. 
  197, 
  plate 
  44) 
  is 
  very 
  obvious, 
  though 
  there 
  are 
  

   differences 
  which 
  make 
  it 
  desirable 
  to 
  continue 
  the 
  specific 
  

   distinction. 
  

  

  The 
  difference 
  between 
  the 
  species 
  here 
  noticed 
  and 
  the 
  typ- 
  

   ical 
  forms 
  of 
  Rhodocrinus 
  seem 
  to 
  me 
  to 
  warrant 
  the 
  con- 
  

   tinued 
  use 
  of 
  the 
  designation 
  Lyriocrinus, 
  at 
  least 
  as 
  a 
  sub- 
  

   generic 
  term. 
  

  

  EUCALYPTOCRINUS 
  Goldfuss. 
  

   Eucalyptocrinus 
  crassus. 
  

  

  Plate 
  17, 
  Figs. 
  1-11 
  ; 
  PL 
  18, 
  Figs. 
  1-9 
  ; 
  Plate 
  19, 
  Figs. 
  2, 
  4, 
  5. 
  

  

  Eucalyptocrinus 
  crassus 
  Hall.. 
  Trans. 
  Alb. 
  Inst., 
  vol. 
  iv, 
  p. 
  197. 
  Abstract, 
  p. 
  3; 
  

  

  May, 
  1863. 
  

   E. 
  crassus 
  Hall,. 
  20th 
  Rep. 
  St. 
  Cab. 
  Nat. 
  Hist., 
  p. 
  323, 
  pi. 
  11, 
  figs. 
  2, 
  3. 
  Rev. 
  Edit., 
  

  

  p. 
  365. 
  

  

  Body 
  massive, 
  turbinate 
  from 
  the 
  base 
  to 
  the 
  arms, 
  and 
  

   with 
  the 
  interbrachial 
  plates 
  and 
  arms 
  attached, 
  it 
  has 
  a 
  gen- 
  

   eral 
  subovate 
  form 
  with 
  a 
  truncate 
  base, 
  which 
  in 
  most 
  speci- 
  

   mens 
  is 
  deeply 
  impressed 
  at 
  the 
  column 
  attachment. 
  Basal 
  

   plates 
  small, 
  concealed 
  in 
  the 
  basal 
  cavity. 
  First 
  radial 
  plates 
  

   much 
  larger 
  than 
  the 
  succeeding 
  ones, 
  height 
  and 
  width 
  sub- 
  

   equal 
  ; 
  second 
  radials 
  quadrangular, 
  length 
  and 
  breadth 
  

   equal, 
  the 
  greatest 
  width 
  at 
  the 
  base 
  ; 
  third 
  radials 
  hexagonal, 
  

   the 
  lower 
  lateral 
  and 
  upper 
  sides 
  shorter 
  than 
  the 
  other 
  three. 
  

   First 
  supraradials 
  somewhat 
  smaller 
  than 
  the 
  third 
  radials, 
  

   pentangular 
  in 
  well 
  formed 
  specimens 
  ; 
  second 
  supraradials 
  

   less 
  than 
  half 
  as 
  large 
  as 
  the 
  first, 
  pentangular, 
  supporting 
  on 
  

  

  