﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  

  

  159 
  

  

  Order 
  flexibili^;^ 
  Zittel 
  

   Genus 
  ichthyocrinus 
  Conrad 
  

  

  [Ety. 
  : 
  ixdu^, 
  fish; 
  x/>j'vov, 
  lily] 
  

  

  (1842. 
  Acad. 
  nat. 
  sci. 
  Phil 
  Jour. 
  8:279) 
  

  

  Calyx 
  with 
  all 
  plates 
  above 
  the 
  radials 
  united 
  by 
  loose 
  suture 
  or 
  

   by 
  muscular 
  articulation. 
  Base 
  dicyclic; 
  infrabasals 
  three, 
  unequal, 
  

   very 
  small, 
  rarely 
  extending 
  beyond 
  the 
  top 
  stem 
  joint 
  with 
  which 
  

   they 
  are 
  fused. 
  Basals 
  five, 
  small. 
  Radials 
  and 
  lower 
  brachials 
  

   laterally 
  in 
  contact 
  on 
  all 
  sides; 
  no 
  interradials 
  or 
  anals. 
  Brachials 
  

   united 
  by 
  more 
  or 
  less 
  wavy 
  sutures 
  and 
  their 
  lower 
  edges 
  furnished 
  

   with 
  tooth-like 
  projections 
  which 
  fit 
  into 
  depressions 
  on 
  the 
  sub- 
  

   jacent 
  plates. 
  Tegmen 
  squamous, 
  composed 
  of 
  five 
  orals 
  and 
  

   numerous, 
  very 
  small, 
  movable 
  plates. 
  Arms 
  non-pinnulate, 
  with 
  

   a 
  wide, 
  shallow 
  ventral 
  groove. 
  -When 
  the 
  arms 
  are 
  folded, 
  the 
  

   crown 
  appears 
  like 
  a 
  perfectly 
  solid 
  body. 
  Stem 
  round, 
  the 
  upper 
  

   joints 
  extremely 
  short, 
  and 
  generally 
  wider 
  than 
  the 
  others. 
  

  

  Ichthyocrinus 
  laevis 
  Conrad 
  (Fig. 
  54) 
  (Hall. 
  1852. 
  Pal. 
  N. 
  Y. 
  

   2:195, 
  pi. 
  43) 
  

  

  Distinguishing 
  characters. 
  Stem 
  slender, 
  round 
  and 
  smooth, 
  grad- 
  

   ually 
  enlarging 
  to 
  the 
  base 
  of 
  the 
  calyx 
  

   and 
  composed 
  of 
  alternate 
  thick 
  and 
  thin 
  

   joints; 
  radials 
  five, 
  succeeded 
  by 
  two 
  to 
  

   four 
  costals 
  in 
  each 
  radius; 
  10 
  columns 
  of 
  

   distichals, 
  from 
  six 
  to 
  nine 
  plates 
  in 
  each, 
  

   an 
  unequal 
  number 
  in 
  the 
  two 
  columns 
  

   of 
  each 
  radius; 
  20 
  columns 
  of 
  palmars, 
  

   and 
  40 
  of 
  post-palmars, 
  the 
  number 
  of 
  

   plates 
  varying 
  in 
  the 
  columns 
  of 
  the 
  same 
  

   individual; 
  plates 
  with 
  lower 
  margins 
  ob- 
  

   tusely 
  triangular 
  and 
  upper 
  margins 
  with 
  

   a 
  corresponding 
  reentrant 
  angle; 
  axillary 
  

   plates 
  angular 
  above 
  and 
  below. 
  

  

  Found 
  in 
  certain 
  calcareous 
  layers 
  near 
  the 
  middle 
  of 
  the 
  lower 
  

   Rochester 
  shales 
  at 
  Niagara. 
  Also 
  in 
  the 
  same 
  shales 
  at 
  Lockport 
  

   (Hall). 
  

  

  Fig. 
  54 
  Ichthyocrinus 
  laevis 
  with 
  

   stem 
  enlarged 
  

  

  