﻿HO 
  TWEXTY-EIGHTH 
  EEPOET 
  OX 
  THE 
  SlATE 
  MUSEUM. 
  

  

  presenting: 
  the 
  characters 
  of 
  the 
  older 
  individuals 
  represented 
  

   from 
  the 
  Wenlock 
  limestone, 
  though 
  the 
  few 
  larger 
  specimens 
  

   which 
  have 
  come 
  under 
  my 
  examination 
  do 
  not 
  show 
  the 
  

   great 
  diversity 
  in 
  the 
  size 
  of 
  the 
  calyces 
  which 
  appears 
  in 
  the 
  

   smaller 
  corals. 
  The 
  position 
  and 
  character 
  of 
  the 
  mural 
  pores 
  

   in 
  the 
  European 
  species 
  is 
  not 
  stated 
  in 
  the 
  description. 
  The 
  

   strongly 
  pustulose 
  character 
  of 
  the 
  cell-walls 
  as 
  represented 
  

   in 
  the 
  British 
  specimens 
  has 
  not 
  been 
  observed 
  in 
  the 
  Ameri- 
  

   can 
  forms. 
  

  

  CHJETETES 
  Fischer. 
  

   Chjetetes 
  coxsemilis. 
  

  

  Plate 
  9, 
  Figs. 
  T-14. 
  

  

  Compare 
  Trematopora 
  solida 
  Hall. 
  Pal. 
  X. 
  Y., 
  vol. 
  ii, 
  p. 
  153, 
  pi. 
  40 
  A, 
  figs. 
  6 
  a, 
  

   6 
  b, 
  6 
  c. 
  1852. 
  

  

  Chcetetes? 
  consimilis 
  Hall. 
  Doc. 
  Edit. 
  28tli 
  Rep. 
  St. 
  Mus. 
  Xat. 
  Hist. 
  Explana- 
  

   tion 
  of 
  pi. 
  9, 
  figs. 
  7-u. 
  isre. 
  

  

  Frond 
  solid, 
  ramose, 
  frequently 
  branching, 
  branches 
  in 
  the 
  

   larger 
  specimens 
  having 
  a 
  diameter 
  of 
  six 
  millimetres. 
  Cell- 
  

   tubes 
  polygonal 
  rising 
  from 
  the 
  center 
  of 
  the 
  branches 
  and 
  

   gradually 
  diverging 
  to 
  the 
  surface. 
  Cell-walls 
  thin, 
  strongly 
  

   corrugated, 
  transverse 
  diaphragms 
  extremely 
  rare 
  or 
  entirely 
  

   wanting. 
  Apertures 
  .35 
  mm. 
  in 
  diameter. 
  

  

  In 
  well-preserved 
  specimens 
  the 
  cell- 
  walls 
  at 
  the 
  apertures 
  

   are 
  granulose 
  and 
  have 
  minute 
  spines 
  at 
  the 
  angles 
  of 
  the 
  

   cells. 
  

  

  This 
  species 
  occurs 
  in 
  such 
  forms 
  as 
  are 
  figured 
  on 
  plate 
  9, 
  

   presenting 
  in 
  the 
  different 
  conditions 
  of 
  weathering, 
  the 
  phases 
  

   represented 
  in 
  the 
  enlarged 
  fig 
  ares 
  8, 
  10, 
  12 
  and 
  14. 
  

  

  TREMATOPORA 
  Hall. 
  

   Treaiatopora 
  osculum. 
  

  

  Plate 
  10. 
  Figs. 
  5-8. 
  11-11. 
  

  

  Trematopora 
  oscubun 
  Hall. 
  Doc. 
  Edit. 
  28th 
  Rep. 
  St. 
  Mus. 
  Nat. 
  Hist. 
  Explana- 
  

   tion 
  of 
  pi. 
  10, 
  figs. 
  3-12 
  (3 
  and 
  1 
  in 
  error). 
  1876. 
  

   Comp. 
  T. 
  ostiolata 
  Hall. 
  Pal. 
  X. 
  Y.. 
  vol. 
  ii. 
  p. 
  152. 
  pi. 
  10A. 
  figs. 
  5a-5n. 
  1852. 
  

  

  Frond 
  ramose, 
  hollow 
  with 
  an 
  interior 
  epitheca. 
  branching 
  

   infrequently 
  : 
  diameter 
  of 
  branches 
  from 
  one 
  and 
  a 
  half 
  to 
  

   two 
  millimetres 
  : 
  thickness 
  of 
  the 
  substance 
  of 
  the 
  bryozoum 
  

   .35 
  mm. 
  Cell-tubes 
  oval 
  : 
  apertures 
  .3 
  mm. 
  in 
  length, 
  closely 
  

   arranged 
  in 
  quincunx 
  order, 
  forming 
  oblique 
  rows, 
  opening 
  

  

  