﻿446 
  R. 
  E. 
  TOMES 
  ON 
  LOWER-OOLITE 
  MADREPORARIA. 
  

  

  Diameter 
  of 
  the 
  corallum 
  from 
  11 
  to 
  15 
  lines, 
  of 
  which 
  the 
  central 
  

   large 
  calice 
  takes 
  3 
  lines. 
  

  

  One 
  specimen 
  was 
  taken 
  by 
  me 
  from 
  the 
  lower 
  reef 
  at 
  the 
  

   Horse 
  Pools, 
  Brookthorpe, 
  near 
  Gloucester, 
  a 
  few 
  months 
  since 
  : 
  and 
  

   another 
  was 
  given 
  to 
  me 
  by 
  Dr. 
  Wright, 
  with 
  other 
  Inferior-Oolite 
  

   corals 
  from 
  near 
  Cheltenham 
  as 
  long 
  ago 
  as 
  1859. 
  I 
  have 
  met 
  

   with 
  no 
  others. 
  

  

  DiMOKPHARiE 
  a 
  Fromenteli, 
  Tonies. 
  

  

  Thamnastrod 
  Fromenteli, 
  Tomes, 
  Geol. 
  Mag. 
  vol. 
  v. 
  1878. 
  

  

  I 
  have 
  found 
  it 
  necessary 
  to 
  remove 
  this 
  species 
  from 
  the 
  genus 
  

   to 
  which 
  I 
  assigned 
  it, 
  and 
  to 
  place 
  it 
  with 
  other 
  species 
  in 
  the 
  

   genus 
  Dimorpharasa. 
  A 
  species 
  of 
  Thamnastrcea 
  from 
  the 
  Lias 
  had 
  

   already 
  been 
  named 
  after 
  M. 
  de 
  Fromentcl, 
  by 
  MM. 
  Tcrquem 
  and 
  

   Piette 
  ; 
  but 
  the 
  alteration 
  made 
  above 
  in 
  the 
  generic 
  name 
  renders 
  a 
  

   change 
  of 
  specific 
  name 
  unnecessary. 
  

  

  DiMOErnARjKA, 
  sp. 
  

  

  A 
  single 
  specimen 
  has 
  been 
  taken 
  by 
  myself 
  from 
  the 
  lower 
  reef 
  

   at 
  Crickley, 
  which 
  obviously 
  differs 
  from 
  all 
  the 
  others 
  here 
  given. 
  

   It 
  is 
  too 
  ill 
  preserved 
  to 
  admit 
  of 
  a 
  detailed 
  description, 
  but 
  may 
  be 
  

   briefly 
  characterized 
  as 
  turbinate, 
  higher 
  than 
  wide, 
  with 
  rather 
  

   coarse 
  rugged 
  septa, 
  and 
  caliccs 
  irregular 
  both 
  as 
  to 
  form 
  and 
  

   arrangement. 
  

  

  Genus 
  Phylloseris, 
  n. 
  g. 
  

  

  The 
  corallum 
  consists 
  of 
  one 
  or 
  more 
  upright 
  foliaceous 
  plates 
  or 
  

   fronds, 
  which 
  have 
  a 
  very 
  irregular 
  form, 
  and 
  are 
  thin 
  at 
  their 
  

   margin. 
  One 
  of 
  their 
  flat 
  and 
  upright 
  surfaces 
  is 
  furnished 
  with 
  

   calices, 
  which 
  are 
  arranged 
  in 
  transverse 
  lines 
  or 
  bands 
  running 
  

   from 
  side 
  to 
  side, 
  a 
  good 
  deal 
  as 
  in 
  the 
  genus 
  Agaricia. 
  The 
  spaces 
  

   dividing 
  these 
  lines 
  of 
  calices 
  from 
  each 
  other 
  aro 
  covered 
  by 
  a 
  

   membranous 
  and 
  wrinkled 
  epitheca, 
  which 
  extends 
  upwards 
  quite 
  

   to 
  the 
  margins 
  of 
  the 
  calices. 
  Generally 
  the 
  frond 
  towards 
  the 
  

   bottom 
  is 
  wholly 
  covered 
  by 
  epitheca. 
  

  

  The 
  other 
  surface 
  of 
  the 
  frond 
  is 
  wholly 
  covered 
  by 
  a 
  transversely 
  

   wrinkled 
  epitheca 
  without 
  any 
  trace 
  of 
  calices. 
  

  

  When 
  the 
  epitheca 
  of 
  the 
  last-named 
  surface 
  is 
  removed, 
  long 
  

   and 
  delicate 
  costae 
  are 
  exposed, 
  extending 
  from 
  the 
  bottom 
  to 
  the 
  

   top 
  of 
  the 
  frond, 
  and 
  having 
  a 
  somewhat 
  radiate 
  arrangement. 
  

  

  The 
  increase 
  in 
  the 
  size 
  of 
  the 
  fronds 
  takes 
  place 
  by 
  means 
  of 
  

   gemmation 
  from 
  their 
  margins 
  ; 
  but 
  the 
  increase 
  in 
  their 
  number 
  

   occurs 
  quite 
  differently. 
  

  

  They 
  are 
  produced 
  by 
  gemmation, 
  which 
  arises 
  at 
  variable 
  

   heights 
  on 
  their 
  calicular 
  surfaces, 
  generally 
  about 
  the 
  point 
  where 
  

   the 
  epitheca 
  ceases 
  to 
  be 
  uniform, 
  and 
  the 
  rows 
  of 
  calices 
  begin. 
  

   The 
  new 
  frond 
  is 
  speedily 
  covered 
  outwardly 
  by 
  a 
  wrinkled 
  epi- 
  

   theca, 
  its 
  upper 
  and 
  outer 
  part 
  being 
  calicular 
  ; 
  and 
  as 
  it 
  increases 
  

   in 
  size 
  by 
  gemmation 
  it 
  adapts 
  itself 
  closely 
  to 
  the 
  parent 
  frond, 
  

  

  