﻿9 
  7 
  

  

  The 
  Fatoa 
  of 
  the 
  Niagara 
  Group. 
  137 
  

  

  one-half 
  their 
  length 
  by 
  the 
  column. 
  Subradials 
  proportion- 
  

   ally 
  large, 
  three 
  hexagonal 
  and 
  two 
  larger 
  and 
  heptagonal. 
  

   First 
  radials 
  short, 
  broad, 
  pentangular, 
  the 
  width 
  twice 
  the 
  

   height 
  ; 
  the 
  second 
  radial 
  is 
  a 
  short 
  plate 
  having 
  a 
  width 
  ^ve 
  

   times 
  as 
  great 
  as 
  the 
  height, 
  curving 
  gently 
  downward 
  in 
  

   the 
  middle, 
  and 
  succeeded 
  by 
  a 
  short 
  pentangular 
  plate 
  

   supporting 
  on 
  its 
  upper 
  sloping 
  sides 
  a 
  series 
  of 
  short 
  lin- 
  

   ear 
  arm 
  plates 
  ; 
  in 
  some 
  of 
  the 
  rays 
  there 
  is 
  a 
  second 
  sub- 
  

   division 
  on 
  the 
  fourth 
  plate 
  above. 
  First 
  anal 
  plate 
  quad- 
  

   rangular, 
  a 
  little 
  longer 
  than 
  wide, 
  resting 
  obliquely 
  upon 
  

   the 
  two 
  heptagonal 
  subradials, 
  and 
  supporting 
  upon 
  its 
  

   upper 
  side 
  one 
  end 
  of 
  the 
  adjoining 
  first 
  radial 
  plate 
  ; 
  the 
  

   second 
  anal 
  plate, 
  which 
  is 
  larger 
  than 
  the 
  first, 
  hexagonal, 
  

   resting 
  upon 
  the 
  top 
  of 
  a 
  subradial 
  and 
  against 
  the 
  upper 
  end 
  

   of 
  the 
  first 
  anal, 
  supported 
  on 
  the 
  sides 
  by 
  the 
  first 
  radial 
  

   plates 
  of 
  the 
  postero 
  -lateral 
  rays. 
  Column 
  small, 
  round 
  at 
  its 
  

   junction 
  with 
  the 
  body. 
  Entire 
  surface 
  finely 
  granulose. 
  

  

  This- 
  species 
  was 
  originally 
  described 
  from 
  the 
  calyx, 
  includ- 
  

   ing 
  the 
  first 
  radials, 
  and 
  its 
  relations 
  to 
  Lecanocrinus 
  were 
  not 
  

   fully 
  apparent. 
  A 
  more, 
  extensive 
  collection 
  from 
  the 
  locality 
  

   has 
  brought 
  a 
  considerable 
  number 
  of 
  specimens 
  in 
  the 
  same 
  

   state 
  as 
  the 
  one 
  figured, 
  including 
  a 
  single 
  individual 
  retain- 
  

   ing 
  the 
  arms. 
  In 
  this 
  condition 
  its 
  relations 
  with 
  the 
  above 
  

   genus 
  are 
  very 
  apparent. 
  The 
  base 
  is 
  more 
  spreading 
  and 
  

   more 
  symmetrical 
  than 
  in 
  the 
  New 
  York 
  species 
  of 
  the 
  genus, 
  

   and 
  the 
  subdivision 
  of 
  the 
  arms 
  is 
  likewise 
  different. 
  The 
  

   form 
  of 
  the 
  calyx 
  corresponds 
  to 
  Poteriocrinus 
  pisiformis 
  

   of 
  Roemer, 
  from 
  the 
  Niagara 
  formation 
  of 
  Tennessee, 
  but 
  in 
  

   the 
  figure 
  of 
  that 
  species 
  there 
  is 
  no 
  indication 
  of 
  an 
  anal 
  

   plate 
  corresponding 
  to 
  the 
  first 
  anal 
  plate 
  of 
  this 
  fossil, 
  

   though 
  the 
  figure 
  is 
  otherwise 
  very 
  similar. 
  

  

  ICHTHYOCRINUS 
  Conrad. 
  

  

  ICHTHYOCRINUS 
  SUBANGULARIS. 
  

   Plate 
  16, 
  Figs. 
  11-13. 
  

  

  Ichthyocrinus 
  subangularis 
  Hall. 
  Trans. 
  Alb. 
  lust., 
  vol. 
  iv, 
  p. 
  201. 
  Abstract, 
  p. 
  

  

  7; 
  May, 
  1863. 
  

   I. 
  subangularis 
  Hall. 
  20th 
  Rep. 
  St. 
  Cab. 
  Nat. 
  Hist., 
  p. 
  325, 
  pi. 
  11, 
  figs. 
  15, 
  16; 
  

  

  pp. 
  867, 
  429, 
  of 
  Revised 
  Edit. 
  [1870.] 
  

   I. 
  corbis 
  W. 
  & 
  M. 
  Mem. 
  Bost. 
  Soc. 
  Nat. 
  Hist., 
  vol. 
  i, 
  p. 
  89. 
  1865. 
  

  

  Body 
  elongate, 
  narrowly 
  turbinate 
  or 
  obconic 
  below, 
  becom- 
  

  

  