﻿148 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  careous 
  material 
  or 
  sclerenchyma, 
  which 
  increases 
  in 
  amount 
  

   toward 
  the 
  calyxes. 
  Calyxes 
  in 
  the 
  form 
  of 
  circular 
  apertures 
  sur- 
  

   rounded 
  by 
  a 
  cup-shaped, 
  thickened 
  margin, 
  the 
  floor 
  of 
  which 
  

   is 
  striated 
  by 
  rudimentary 
  septal 
  ridges. 
  Septal 
  spines 
  in 
  vertical 
  

   rows 
  occasionally 
  present. 
  Tabulae 
  few, 
  widely 
  separated, 
  but 
  ex- 
  

   tending 
  completely 
  across. 
  Mural 
  pores 
  comparatively 
  numerous, 
  

   circular, 
  and 
  irregularly 
  distributed. 
  

  

  Striatopora 
  flexuosa 
  Hah 
  (Fig. 
  45) 
  (1852. 
  Pal. 
  N. 
  Y. 
  2:156,. 
  

   pi. 
  40B) 
  

  

  Distinguishing 
  characters. 
  Bifurcating 
  or 
  irregularly 
  ramose 
  

   stems 
  with 
  teretely 
  terminating 
  branches; 
  calyxes 
  circular, 
  sur- 
  

   rounded 
  by 
  large 
  depressed 
  cells, 
  polygonal 
  in 
  outline 
  and 
  bounded 
  

   by 
  angular 
  ridges; 
  calycinal 
  orifice 
  in 
  lower 
  part 
  of 
  polygonal 
  cell,, 
  

   vertically 
  striate, 
  the 
  stria 
  continuing 
  upward 
  in 
  the 
  surrounding 
  

   cell. 
  

  

  Fig. 
  45 
  Striatopora 
  flexuosa 
  with 
  an 
  enlargement 
  of 
  several 
  calyxes 
  

  

  Found 
  not 
  uncommonly 
  in 
  the 
  Bryozoan 
  bed 
  of 
  the 
  Rochester 
  

   shale 
  at 
  Niagara, 
  generally 
  well 
  weathered 
  out. 
  Also 
  in 
  the 
  same 
  

   shale 
  at 
  Lockport 
  (Hall). 
  

  

  Class 
  CYSTOIDEA 
  von 
  Buch 
  

  

  The 
  cystoids 
  are 
  entirely 
  extinct 
  marine 
  invertebrates 
  which 
  

   flourished 
  only 
  during 
  Paleozoic 
  time. 
  Most 
  of 
  them 
  lived 
  during 
  

   the 
  Ordovicic 
  or 
  Siluric 
  eras, 
  but 
  Cambric 
  and 
  Carbonic 
  forms 
  

   are 
  also 
  known. 
  They 
  were 
  mostly 
  stemmed 
  organisms 
  with 
  a 
  

   calyx 
  and 
  imperfect 
  arms 
  like 
  the 
  crinoids, 
  but 
  a 
  few 
  of 
  them 
  were 
  

   stemless. 
  The 
  calyx, 
  which 
  varies 
  in 
  form, 
  is 
  composed 
  of 
  poly- 
  

   gonal 
  plates 
  which 
  are 
  united 
  by 
  close 
  sutures. 
  The 
  plates 
  vary 
  

   in 
  number 
  in 
  different 
  species, 
  from 
  13 
  to 
  several 
  hundred, 
  and 
  only 
  

   exceptionally 
  exhibit 
  a 
  regular 
  arrangement. 
  A 
  radial 
  arrange- 
  

   ment 
  of 
  plates, 
  like 
  that 
  of 
  the 
  Crinoidea 
  occurs 
  rarely, 
  and 
  the 
  

  

  