﻿A 
  Discussion 
  of 
  the 
  Different 
  Genera 
  of 
  

   Fenestellidae. 
  

  

  By 
  GEORGE 
  B. 
  SIMPSON. 
  

  

  FENESTELLA, 
  Miller. 
  

  

  This 
  genus 
  was 
  first 
  proposed 
  in 
  manuscript 
  by 
  J. 
  S. 
  Miller 
  of 
  

   Bristol, 
  England, 
  but 
  the 
  first 
  published 
  description 
  of 
  it 
  was 
  

   given 
  by 
  Mr. 
  W. 
  Lonsdale, 
  F. 
  G. 
  S., 
  in 
  his 
  description 
  of 
  the 
  

   fossil 
  corals, 
  in 
  Murchison's 
  Silurian 
  System 
  (Pt. 
  II, 
  p. 
  677, 
  

   1839), 
  as 
  follows 
  : 
  

  

  " 
  Fenestella, 
  Miller, 
  Gen. 
  Char. 
  - 
  A 
  stony 
  coral 
  fixed 
  at 
  the 
  

   base 
  and 
  composed 
  of 
  branches 
  which 
  unite 
  by 
  growth 
  and 
  form 
  

   a 
  cup. 
  

  

  Externally 
  the 
  branches 
  anastomose 
  or 
  regularly 
  bifurcate 
  ; 
  

   internally 
  they 
  form 
  a 
  network, 
  the 
  intervals 
  being 
  generally 
  

   oval. 
  

  

  One 
  row 
  of 
  pores 
  on 
  each 
  side 
  of 
  the 
  branches 
  externally, 
  the 
  

   openings 
  being 
  circular 
  and 
  projecting 
  when 
  perfect. 
  

  

  The 
  branches, 
  when 
  regularly 
  bifurcated, 
  are 
  connected 
  by 
  

   distant 
  transverse 
  processes 
  in 
  which 
  no 
  projecting 
  pores 
  are 
  

   visible. 
  In 
  well-preserved 
  specimens 
  of 
  the 
  base 
  of 
  apparently 
  

   old 
  corals, 
  the 
  pores 
  or 
  foramina 
  on 
  the 
  side 
  of 
  one 
  branch 
  have 
  

   united 
  by 
  growth 
  to 
  those 
  on 
  the 
  side 
  of 
  the 
  adjoining 
  branch, 
  

   and 
  constitute 
  solid 
  bars, 
  either 
  stretching 
  transversely 
  and 
  

   simply 
  across 
  the 
  intervals, 
  or 
  uniting 
  obliquely 
  three, 
  or 
  some- 
  

   times 
  more 
  together.*' 
  The 
  characters 
  here 
  described 
  were 
  illus- 
  

   trated 
  on 
  pi. 
  15, 
  figs. 
  15 
  to 
  19, 
  of 
  the 
  work 
  cited. 
  

  

  In 
  1841 
  Prof. 
  John 
  Phillips 
  (Palaeozoic 
  Fossils 
  of 
  Cornwall 
  

   Devon 
  and 
  West 
  Somerset) 
  formed 
  a 
  new 
  genus 
  based 
  upon 
  the 
  

   character 
  of 
  the 
  carinae 
  and 
  their 
  connecting 
  processes. 
  

   Ill 
  

  

  