﻿Report 
  of 
  the 
  State 
  Geologist. 
  897 
  

  

  la 
  Eeteporella 
  the 
  branches 
  anastomose, 
  as 
  is 
  shown 
  by 
  the 
  

   fact 
  that 
  when 
  the 
  branches 
  are 
  in 
  contact 
  (anastomosed) 
  the 
  

   number 
  of 
  ranges 
  of 
  cell 
  apertures 
  is 
  just 
  twice 
  as 
  great 
  as 
  on 
  

   other 
  portions 
  of 
  the 
  branches, 
  an 
  interstitial 
  series 
  never 
  

   occurring. 
  The 
  ranges 
  of 
  apertures 
  simply 
  approach 
  and 
  recede 
  

   from 
  each 
  other 
  on 
  account 
  of 
  the 
  sinuosity 
  of 
  the 
  branches. 
  

  

  Flat 
  Forms. 
  

  

  There 
  are 
  two 
  modes 
  of 
  growth, 
  flabellate 
  and 
  infundibuli- 
  

   form. 
  In 
  a 
  very 
  extended 
  observation 
  I 
  have 
  never 
  seen 
  the 
  

   same 
  species 
  assume 
  both 
  of 
  these 
  forms, 
  and 
  it 
  is 
  fair 
  to 
  infer 
  

   that 
  the 
  same 
  species 
  has 
  always 
  the 
  same 
  mode 
  of 
  growth, 
  that 
  

   is, 
  it 
  is 
  uniformly 
  flabellate, 
  or 
  uniformly 
  infundibuliform. 
  

  

  As 
  by 
  this 
  mode 
  of 
  growth 
  all 
  species 
  of 
  Fenestella 
  naturally 
  

   form 
  two 
  groups, 
  it 
  seems 
  to 
  me 
  that 
  they 
  are 
  worthy 
  of 
  generic 
  

   distinction. 
  

  

  The 
  typical 
  species 
  of 
  Fenestella 
  are 
  infundibuliform. 
  For 
  

   those 
  species 
  which 
  in 
  other 
  respects 
  are 
  the 
  same 
  as 
  Fenestella, 
  

   but 
  which 
  have 
  a 
  flabellate 
  growth, 
  I 
  propose 
  the 
  name 
  

   Flabelliporina. 
  

  

  For 
  those 
  species 
  which 
  in 
  other 
  respects 
  are 
  the 
  same 
  as 
  

   Polypora, 
  but 
  have 
  a 
  flabellate 
  mode 
  of 
  growth, 
  I 
  propose 
  the 
  

   name 
  Flabelliporella. 
  

  

  To 
  me 
  it 
  seems 
  that 
  the 
  marked 
  difference 
  in 
  the 
  mode 
  of 
  

   growth 
  as 
  is 
  exhibited 
  by 
  the 
  fan-shaped 
  and 
  cup- 
  shaped 
  forms 
  

   is 
  of 
  a 
  higher 
  generic 
  importance 
  than 
  the 
  difference 
  in 
  the 
  

   number 
  of 
  rows 
  of 
  cell 
  apertures 
  on 
  a 
  branch 
  or 
  the 
  height 
  and 
  

   shape 
  of 
  the 
  carinas, 
  both 
  of 
  which 
  features 
  have 
  been 
  deemed 
  of 
  

   generic 
  value. 
  

  

  The 
  genera 
  Lyropora, 
  Archimedes, 
  Helicopora 
  and 
  Ptilopora 
  

   have 
  all 
  been 
  formed 
  on 
  the 
  mode 
  of 
  growth. 
  It 
  may 
  be 
  

   objected 
  that 
  by 
  a 
  fragment 
  alone 
  it 
  can 
  not 
  be 
  determined 
  

   whether 
  a 
  species 
  is 
  flabellate 
  or 
  infundibuliform, 
  but 
  neither 
  

   can 
  it 
  be 
  determined 
  from 
  a 
  fragment 
  whether 
  it 
  belongs 
  to 
  

   Fenestella,, 
  Lyropora 
  or 
  Archimsdes. 
  In 
  all 
  these 
  genera 
  it 
  is 
  

   necessary 
  to 
  have 
  a 
  characteristic 
  portion 
  of 
  the 
  frond 
  in 
  order 
  

   to 
  determine 
  the 
  genus. 
  

   113 
  

  

  