﻿436 
  E. 
  E. 
  TOMES 
  ON 
  LOWER-OOLITE 
  MADEEPOEAEIA. 
  

  

  present 
  species 
  bears 
  the 
  nearest 
  resemblance 
  ; 
  but 
  it 
  differs 
  there- 
  

   from 
  in 
  having 
  the 
  calices 
  nearer 
  together 
  and 
  smaller, 
  and 
  in 
  having 
  

   the 
  mural 
  costae 
  much 
  more 
  delicate, 
  further 
  apart, 
  and 
  their 
  synap- 
  

   ticulae 
  more 
  uniform. 
  In 
  T. 
  arachnoides 
  these 
  costae 
  are 
  continuous 
  

   with 
  the 
  septa, 
  and 
  of 
  the 
  same 
  thickness 
  where 
  they 
  pass 
  over 
  the 
  

   edge 
  of 
  the 
  corallum 
  : 
  but 
  in 
  T. 
  cricJclei/ensis 
  they 
  are 
  not 
  half 
  the 
  

   thickness 
  of 
  the 
  septa. 
  

  

  Thamnastejea 
  (Synaste^a) 
  Duncani, 
  n. 
  sp. 
  

  

  This 
  is 
  a 
  small 
  and 
  turbinate 
  species, 
  which 
  bears 
  a 
  little 
  re- 
  

   semblance 
  to 
  the 
  Thamnastroea 
  Dwmonti 
  of 
  MM. 
  Chapuis 
  and 
  De- 
  

   walque 
  *, 
  but 
  differs 
  from 
  it 
  in 
  having 
  the 
  calices 
  further 
  apart, 
  

   and 
  in 
  having 
  thin 
  flexuous 
  septal 
  costae, 
  which 
  anastomose 
  ex- 
  

   ceedingly. 
  To 
  Thamnastrcea 
  Manseli 
  it 
  also 
  bears 
  a 
  little 
  resem- 
  

   blance, 
  but 
  differs 
  essentially 
  in 
  having 
  a 
  large 
  spongy 
  columella, 
  

   and 
  furcate 
  and 
  bifurcate 
  septal 
  costae, 
  and 
  in 
  having 
  smaller 
  calices 
  

   and 
  thinner 
  septa. 
  

  

  The 
  corallum 
  is 
  somewhat 
  turbinate, 
  and 
  was 
  attached 
  by 
  a 
  small 
  

   space. 
  It 
  exhibits 
  periods 
  of 
  growth, 
  and 
  has 
  the 
  outer 
  margin 
  

   of 
  the 
  calicular 
  surface 
  a 
  little 
  everted. 
  

  

  The 
  epitheca 
  is 
  thick 
  and 
  rather 
  rugose, 
  but 
  of 
  intermittent 
  

   growth, 
  showing 
  itself 
  as 
  irregular 
  rings 
  around 
  the 
  corallum. 
  

  

  The 
  mural 
  costae 
  are 
  straight, 
  thin, 
  and 
  appear 
  to 
  be 
  wholly 
  with- 
  

   out 
  synapticulae. 
  

  

  The 
  calicular 
  surface 
  is 
  rather 
  convex 
  ; 
  and 
  the 
  calices 
  are 
  scat- 
  

   tered 
  over 
  it 
  without 
  order, 
  and 
  are 
  rather 
  far 
  apart 
  in 
  relation 
  to 
  

   their 
  size. 
  

  

  They 
  are 
  small, 
  round, 
  shallow, 
  and 
  have 
  a 
  spongy 
  columella, 
  

   which 
  is 
  nearly 
  half 
  their 
  own 
  breadth. 
  

  

  The 
  septa 
  are 
  thin, 
  flexuous, 
  and 
  join 
  the 
  columella. 
  Their 
  

   margins 
  are 
  irregularly 
  papillatcd. 
  

  

  The 
  septal 
  costae 
  are 
  long, 
  flexuous, 
  and 
  anastomose 
  a 
  good 
  deal. 
  

   They 
  have 
  a 
  radiate 
  arrangement 
  without 
  any 
  tendency 
  to 
  the 
  

   parallel 
  disposition 
  observable 
  in 
  so 
  many 
  Thamnastrcea. 
  Their 
  

   margins 
  have 
  regular 
  papilllae. 
  Where 
  they 
  join 
  those 
  from 
  other 
  

   calices 
  they 
  are 
  very 
  crooked. 
  They 
  have 
  numerous 
  but 
  small 
  syn- 
  

   apticulae, 
  which 
  are 
  not 
  cuneiform 
  and 
  do 
  not 
  approach 
  very 
  near 
  

   to 
  the 
  columella. 
  

  

  There 
  are 
  two 
  complete 
  cycles 
  of 
  septa 
  and 
  part 
  of 
  a 
  third. 
  

  

  The 
  calices 
  are 
  about 
  1 
  line 
  in 
  diameter, 
  and 
  2 
  lines 
  from 
  centre 
  

   to 
  centre. 
  

  

  The 
  height 
  of 
  the 
  corallum 
  is 
  1 
  inch, 
  and 
  its 
  diameter 
  1| 
  inch. 
  

  

  I 
  have 
  met 
  with 
  only 
  one 
  specimen 
  of 
  this 
  coral 
  ; 
  and 
  that 
  was 
  

   taken 
  by 
  Mr. 
  W. 
  Jenkins, 
  of 
  Cheltenham, 
  from 
  the 
  lower 
  reef 
  at 
  

   Crickley 
  Hill. 
  

  

  Thamnaste^ea 
  (Synastejla) 
  Manseli, 
  Duncan, 
  Supp. 
  Brit. 
  Foss. 
  Cor. 
  

   pt. 
  iii. 
  p. 
  20, 
  pi. 
  iv. 
  figs. 
  11-14 
  (1872). 
  

  

  Of 
  this 
  well-marked 
  species 
  I 
  have 
  as 
  yet 
  only 
  seen 
  one 
  speci- 
  

  

  * 
  Foss. 
  Ter. 
  Sec. 
  de 
  Luxeuib. 
  p. 
  270, 
  pi. 
  xxxviii. 
  fig. 
  11. 
  

  

  