﻿918 
  I 
  ORTY- 
  SEVENTH 
  REPORT 
  ON 
  THE 
  S 
  TATE 
  MUSEUM. 
  

  

  LYKOPOKELLA, 
  nov. 
  gen. 
  

  

  For 
  the 
  same 
  reasons 
  which 
  induced 
  me 
  to 
  propose 
  the 
  genus 
  

   Polyporella 
  for 
  the 
  forms 
  intermediate 
  between 
  Fenestella 
  and 
  

   Polypora, 
  I 
  propose 
  the 
  genus 
  or 
  sub-genus 
  Lyroporella 
  for 
  those 
  

   forms 
  intermediate 
  between 
  Lyropora 
  and 
  Lyroporina, 
  which 
  

   have 
  two 
  ranges 
  of 
  cell 
  apertures 
  on 
  the 
  narrower 
  portion 
  of 
  the 
  

   branches 
  and 
  three 
  or 
  more 
  on 
  the 
  wider 
  portions. 
  

  

  The 
  same 
  arguments 
  which 
  were 
  used 
  in 
  regard 
  to 
  the 
  genus 
  

   Polyporella 
  apply 
  with 
  equal 
  force 
  to 
  Lyroporella. 
  

  

  Lyropora, 
  Lyroporella 
  and 
  Lyroporina 
  differ 
  from 
  Polypora, 
  

   Polyporella 
  and 
  Fenestella 
  only 
  in 
  the 
  manner 
  of 
  growth. 
  

  

  It 
  is 
  necessary 
  that 
  the 
  thickened 
  margins 
  of 
  the 
  former 
  genera 
  

   should 
  be 
  present 
  to 
  distinguish 
  fragments 
  of 
  them 
  from 
  frag 
  

   ments 
  of 
  the 
  latter 
  genera. 
  

  

  Resume. 
  

  

  In 
  this 
  paper 
  the 
  following 
  genera 
  of 
  Fenestellidse 
  are 
  

   mentioned 
  : 
  

  

  Fenestella. 
  — 
  Forms 
  having 
  two 
  ranges 
  of 
  cell 
  apertures 
  

   under 
  the 
  following 
  groups 
  : 
  

  

  Group 
  a. 
  Fenestella 
  (humilis), 
  with 
  low, 
  smooth 
  carinae. 
  

   Group 
  /?. 
  Fenestella 
  (nodata), 
  with 
  nodes 
  or 
  low 
  nodose 
  carinae. 
  

  

  Group 
  y. 
  Fenestella 
  (laminata), 
  with 
  very 
  prominent 
  equal, 
  

   thin 
  carinae. 
  

  

  Group 
  d. 
  Fenestella 
  (mediadilata), 
  with 
  carinae 
  expanding 
  

   midway 
  of 
  their 
  height, 
  then 
  contracting, 
  the 
  expanded 
  portion 
  

   having 
  nodes 
  on 
  the 
  margin. 
  

  

  Group 
  e. 
  Fenestella 
  (summidilata), 
  with 
  prominent 
  carinae, 
  

   summits 
  expanded, 
  margins 
  smooth. 
  

  

  Group 
  C. 
  Fenestella 
  (praetexta), 
  with 
  prominent 
  carinae, 
  ex- 
  

   panded 
  at 
  the 
  summit, 
  margins 
  nodose. 
  

  

  Flabelliporina. 
  — 
  Branches 
  and 
  dissepiments 
  similar 
  to 
  

   Fenestella, 
  but 
  having 
  a 
  flabellate 
  mode 
  of 
  growth. 
  

  

  Fenestralia. 
  — 
  Forms 
  resembling 
  Fenestella, 
  but 
  having 
  two 
  

   ranges 
  of 
  cell 
  apertures 
  on 
  each 
  side 
  of 
  a 
  median 
  keel. 
  

  

  Polypora. 
  — 
  Similar 
  to 
  Fenestella, 
  but 
  having 
  three 
  or 
  more 
  

   ranges 
  of 
  cell 
  apertures 
  not 
  separated 
  by 
  a 
  carina. 
  

  

  