﻿Report 
  of 
  the 
  State 
  Geologist. 
  895 
  

  

  of 
  two 
  and 
  three 
  ranges 
  are 
  more 
  nearly 
  equal 
  I 
  should 
  place 
  

   in 
  Polyp 
  orella. 
  

  

  In 
  recognizing 
  Polypora 
  to 
  be 
  consistent 
  several 
  new 
  genera 
  

   must 
  be 
  formed, 
  for 
  in 
  Reteporella, 
  Lyropora, 
  Archimedes 
  and 
  

   other 
  genera 
  there 
  are 
  forms 
  differing 
  from 
  each 
  other 
  in 
  

   exactly 
  the 
  same 
  manner 
  as 
  do 
  Fenestella 
  and 
  Polypora 
  ; 
  that 
  is, 
  

   some 
  forms 
  have 
  two 
  ranges 
  of 
  cell 
  apertures, 
  while 
  others 
  have 
  

   three 
  or 
  more. 
  Those 
  forms 
  with 
  only 
  two 
  ranges 
  of 
  apertures 
  

   have 
  usually 
  a 
  median 
  carina, 
  but 
  sometimes 
  only 
  a 
  median 
  row 
  

   of 
  nodes. 
  

  

  The 
  typical 
  species 
  Lyrojpora 
  lyra, 
  Hall, 
  1857 
  (Proc. 
  Amer. 
  

   Assoc. 
  Ad. 
  Sci.) 
  has 
  three 
  ranges 
  of 
  cell 
  apertures 
  and, 
  there- 
  

   fore, 
  corresponds 
  to 
  Polypora. 
  For 
  those 
  forms 
  having 
  only 
  

   two 
  ranges 
  of 
  cell 
  apertures, 
  corresponding 
  to 
  Fenestella, 
  I 
  

   propose 
  the 
  name 
  Lyroporella. 
  

  

  The 
  typical 
  species 
  of 
  Archimedes, 
  Retepora 
  Archimedes, 
  

   Le 
  Sueur, 
  1842, 
  Amer. 
  Jour. 
  Science, 
  vol. 
  43, 
  p. 
  19, 
  has 
  only 
  

   two 
  ranges 
  of 
  cell 
  apertures. 
  To 
  those 
  forms 
  having 
  three 
  or 
  

   more 
  ranges 
  of 
  apertures 
  it 
  is 
  proposed 
  to 
  apply 
  the 
  name 
  

   Archimedipora, 
  D'Orbigny, 
  (Prod, 
  de 
  Pal. 
  t. 
  1., 
  p. 
  102) 
  which 
  

   has 
  been 
  considered 
  a 
  synonym 
  for 
  Archimedes. 
  

  

  Reteporella 
  and 
  Reteporina 
  differ 
  in 
  the 
  same 
  manner 
  as 
  do 
  

   also 
  Ptiloporina 
  and 
  Ptiloporella. 
  

  

  Erecting 
  these 
  genera 
  will 
  make 
  uniform 
  the 
  practice 
  of 
  sepa- 
  

   rating 
  the 
  forms 
  having 
  three 
  or 
  more 
  ranges 
  of 
  apertures 
  from 
  

   those 
  which 
  have 
  only 
  two 
  ranges 
  of 
  cell 
  apertuies, 
  usually 
  

   separated 
  by 
  a 
  carina. 
  If 
  species 
  analogous 
  to 
  Polyporella 
  are 
  

   found 
  new 
  sub-genera 
  should 
  be 
  formed 
  in 
  accordance. 
  

  

  Though 
  this 
  multiplicity 
  of 
  genera 
  or 
  sub-genera 
  may 
  at 
  first 
  

   view 
  seem 
  cumbersome, 
  it 
  will 
  on 
  further 
  study 
  be 
  found 
  to 
  

   really 
  add 
  simplicity 
  to 
  the 
  arrangement 
  of 
  genera 
  and 
  will 
  

   greatly 
  aid 
  in 
  the 
  easy 
  identification 
  of 
  species. 
  

  

  FEXESTRAPORA, 
  Hall. 
  

   (See 
  Pal. 
  K 
  Y., 
  vol. 
  YI, 
  pi. 
  lxvi, 
  figs. 
  34-39.) 
  

   This 
  plate 
  with 
  several 
  others 
  in 
  the 
  volume 
  has 
  been 
  badly 
  

   printed, 
  but 
  a 
  faint 
  idea 
  of 
  the 
  appearance 
  of 
  the 
  genus 
  may 
  be 
  

   obtained 
  from 
  the 
  illustrations. 
  

  

  