﻿The 
  Fauna 
  of 
  the 
  Niagaka 
  Group. 
  135 
  

  

  The 
  surface 
  has 
  no 
  peculiar 
  markings. 
  The 
  column 
  in 
  its 
  

   upper 
  part 
  is 
  cylindrical, 
  composed 
  of 
  unequal 
  joints, 
  which 
  

   often 
  appear 
  to 
  be 
  made 
  up 
  of 
  unequal 
  or 
  irregular 
  plates. 
  

  

  This 
  species 
  differs 
  from 
  G. 
  occidentalis 
  and 
  from 
  G. 
  bra- 
  

   cMatus 
  {Pal. 
  N. 
  Y., 
  vol. 
  2, 
  p. 
  197) 
  in 
  the 
  absence 
  of 
  surface 
  

   sculpturing, 
  nodes, 
  or 
  granules; 
  in 
  the 
  greater 
  development 
  

   of 
  basal 
  plates, 
  and 
  the 
  quadrangular 
  form 
  of 
  the 
  second 
  

   radials. 
  

  

  CYATHOCRINUS 
  Miller. 
  

   Cyathocrinus 
  Polyxo. 
  

  

  Plate 
  15, 
  Figs. 
  10-17. 
  

  

  Cyathocrinus 
  Polyxo 
  Hall. 
  Trans. 
  Alb. 
  lust., 
  vol. 
  iv, 
  p. 
  199. 
  Abstract 
  p. 
  5; 
  May, 
  

   1863. 
  

  

  Body 
  broadly 
  turbinate, 
  base 
  large 
  and 
  somewhat 
  protub- 
  

   erant, 
  sides 
  angular 
  from 
  the 
  prominence 
  of 
  the 
  centers 
  of 
  the 
  

   subradial 
  and 
  radial 
  plates. 
  Basal 
  plates 
  wider 
  than 
  high, 
  the 
  

   basal 
  margins 
  expanded 
  at 
  the 
  junction 
  with 
  the 
  column. 
  

   Subradials 
  large, 
  wider 
  than 
  high 
  ; 
  radials 
  large, 
  hexagonal, 
  

   much 
  wider 
  than 
  high, 
  deeply 
  notched 
  on 
  the 
  upper 
  margin 
  ; 
  

   the 
  articular 
  scar 
  is 
  comparatively 
  small 
  and 
  indenting 
  the 
  

   plate 
  to 
  about 
  one-fourth 
  of 
  its 
  depth. 
  First 
  anal 
  plate 
  quad- 
  

   rangular, 
  nearly 
  equal 
  sided, 
  resting 
  upon 
  two 
  subradials, 
  and 
  

   supporting 
  on 
  one 
  of 
  its 
  upper 
  sides 
  one 
  end 
  of 
  the 
  adjacent 
  

   radial 
  plate 
  ; 
  second 
  anal 
  plate 
  larger 
  than 
  the 
  subradials, 
  

   resting 
  upon 
  one 
  subradial 
  and 
  the 
  first 
  anal, 
  and 
  between 
  

   the 
  radial 
  plates 
  of 
  the 
  adjacent 
  rays. 
  

  

  The 
  subradials, 
  first 
  radials 
  and 
  anal 
  plates 
  are 
  prominent 
  

   in 
  the 
  center, 
  with 
  low 
  angular 
  ridges 
  extending 
  to 
  the 
  su- 
  

   tures, 
  the 
  intermediate 
  spaces 
  being 
  depressed, 
  giving 
  a 
  

   strongly 
  angular 
  appearance 
  to 
  the 
  cup. 
  Entire 
  surface 
  

   smooth 
  or 
  very 
  finely 
  granulose. 
  Summit, 
  arms, 
  and 
  column 
  

   unknown. 
  

  

  The 
  body 
  of 
  this 
  species 
  is 
  usually 
  somewhat 
  unsymmetri- 
  

   cal 
  from 
  the 
  anal 
  side 
  being 
  more 
  elongated 
  or 
  higher, 
  and 
  

   less 
  ventricose 
  than 
  the 
  other 
  sides. 
  The 
  very 
  large 
  second 
  

   anal 
  plate, 
  the 
  protuberant 
  base 
  and 
  large 
  cicatrice 
  for 
  the 
  

   column 
  attachment, 
  are 
  distinguishing 
  features 
  of 
  the 
  calyx. 
  

  

  