﻿The 
  Fauna 
  oe 
  the 
  Niagaea 
  Gtkoup. 
  133 
  

  

  GrLYPTASTEB, 
  Hall. 
  

   (xlyptaster 
  occidentalis. 
  

  

  Plate 
  13, 
  Figs. 
  7-11. 
  

  

  Glyptaster 
  occidentalis 
  Hall. 
  Trans. 
  Alb. 
  lust., 
  vol. 
  iv, 
  p. 
  204. 
  Abstract 
  p. 
  10 
  ; 
  

   May, 
  1863. 
  

  

  Body 
  of 
  medium 
  size, 
  broadly 
  subturbinate 
  ; 
  basal 
  plates 
  

   small, 
  distinctly 
  developed 
  ; 
  subradial 
  plates 
  comparatively 
  

   large, 
  marked 
  by 
  a. 
  single 
  rounded 
  ridge 
  which, 
  bifurcates 
  in 
  

   the 
  middle 
  of 
  the 
  plate, 
  the 
  divisions 
  passing 
  to 
  the 
  sutures 
  of 
  

   the 
  radial 
  plates. 
  First 
  radial 
  plate 
  large, 
  the 
  lower 
  half 
  

   marked 
  by 
  two 
  rounded 
  ridges 
  which 
  are 
  continued 
  from 
  the 
  

   two 
  adjacent 
  subradials, 
  and 
  unite 
  on 
  the 
  middle 
  of 
  this 
  plate, 
  

   continuing 
  along 
  the 
  second 
  and 
  third 
  radials, 
  and 
  bifurcating 
  

   on 
  the 
  latter, 
  following 
  the 
  subdivisions 
  of 
  the 
  ray. 
  Interra- 
  

   dials 
  about 
  three, 
  with 
  one 
  interradial 
  space 
  (the 
  anal) 
  larger 
  

   and 
  containing 
  a 
  greater 
  number 
  of 
  plates. 
  

  

  Surface 
  of 
  the 
  ridge 
  on 
  the 
  subradial 
  and 
  radial 
  plates, 
  

   marked 
  by 
  longitudinal 
  strise. 
  while 
  all 
  the 
  plates 
  are 
  marked 
  

   by 
  sharp 
  radiating 
  lines, 
  which 
  are 
  continuous 
  or 
  interrupted 
  

   and 
  granulose, 
  the 
  granules 
  being 
  often 
  arranged 
  in 
  more 
  or 
  

   less 
  confluent 
  lines 
  ; 
  intermediate 
  surface 
  of 
  plates 
  granulose. 
  

  

  Column 
  round 
  above 
  ; 
  arms 
  unknown. 
  

  

  Glyptaster 
  occidentalis 
  var. 
  crebescens 
  n. 
  var. 
  

  

  A 
  specimen 
  of 
  somewhat 
  more 
  robust 
  character 
  than 
  those 
  

   described, 
  has 
  the 
  ridges 
  of 
  the 
  rays 
  marked 
  with 
  undulating, 
  

   subgranulose 
  striae, 
  and 
  the 
  plates 
  more 
  distinctly 
  striate, 
  

   while 
  the 
  anal 
  area 
  is 
  large 
  and 
  subventricose, 
  showing 
  three 
  

   ranges 
  of 
  plates 
  in 
  the 
  order 
  of 
  one, 
  three 
  and 
  four, 
  with 
  a 
  

   more 
  numerous 
  fourth 
  range. 
  The 
  anterior 
  ray 
  gives 
  some 
  

   evidence 
  of 
  a 
  second 
  bifurcation 
  before 
  becoming 
  free 
  from 
  

   the 
  body. 
  

  

  Having 
  but 
  a 
  single 
  specimen 
  of 
  this 
  character, 
  I 
  hesitate 
  at 
  

   present 
  to 
  designate 
  it 
  as 
  a 
  distinct 
  species. 
  

  

  