﻿1863.] 
  DUNCAN 
  WEST 
  INDIAN 
  CORALS. 
  Si 
  

  

  bilobed. 
  Those 
  of 
  the 
  fourth 
  are 
  nearly 
  as 
  long; 
  their 
  internal 
  lobe 
  is 
  

   small 
  and 
  does 
  not 
  reach 
  to 
  the 
  fossula 
  ; 
  whilst 
  those 
  of 
  the 
  fifth 
  only 
  

   possess 
  the 
  external 
  lobe, 
  and 
  terminate 
  internally, 
  not 
  far 
  from 
  the 
  

   wall, 
  in 
  a 
  serrated 
  edge, 
  which 
  is 
  only 
  visible 
  in 
  sections. 
  There 
  

   are 
  six 
  systems 
  of 
  septa 
  of 
  five 
  cycles, 
  with 
  several 
  orders 
  of 
  a 
  sixth. 
  

   The 
  laminae 
  are 
  granular, 
  and 
  are 
  marked 
  by 
  the 
  endothecal 
  dissepi- 
  

   ments, 
  the 
  areas 
  enclosed 
  by 
  these 
  markings 
  being 
  granular. 
  Near 
  

   the 
  septal 
  margin 
  the 
  granules 
  are 
  ranged 
  in 
  linear 
  series, 
  and 
  often 
  

   merge 
  into 
  more 
  or 
  less 
  vertical 
  lines, 
  which 
  end 
  at 
  the 
  margin, 
  and 
  

   give 
  a 
  bluntly 
  toothed 
  appearance 
  to 
  the 
  inner 
  lobe. 
  The 
  granules 
  

   are 
  continued 
  up 
  to 
  the 
  sides 
  of 
  the 
  teeth 
  of 
  the 
  upper 
  lobe. 
  The 
  

   granules 
  near 
  the 
  margin 
  of 
  the 
  inner 
  lobe 
  are 
  often 
  smaller 
  and 
  

   more 
  closely 
  set 
  than 
  below. 
  Between 
  the 
  lobes 
  is 
  a 
  deep 
  depression, 
  

   which 
  separates 
  the 
  calice 
  with 
  the 
  fossula 
  into 
  three 
  distinct 
  parts, 
  

   an 
  inner, 
  middle, 
  and 
  outer. 
  In 
  large 
  specimens 
  the 
  laminae 
  are 
  

   often 
  a 
  little 
  curved, 
  but 
  in 
  all 
  there 
  is 
  a 
  little 
  greater 
  thickness 
  

   externally 
  than 
  at 
  the 
  fossula. 
  The 
  fossula 
  is 
  long, 
  deep, 
  and 
  nar- 
  

   row. 
  The 
  columella 
  is 
  essential, 
  but 
  its 
  bulk 
  is 
  composed 
  of 
  the 
  

   ends 
  of 
  the 
  septa 
  and 
  the 
  terminations 
  of 
  the 
  innermost 
  dissepiments. 
  

   Costae 
  produced 
  above, 
  and 
  less 
  so 
  below 
  ; 
  they 
  are 
  subequal 
  above, 
  

   but 
  midway 
  and 
  below 
  some 
  smaller 
  are 
  interpolated 
  ; 
  they 
  are 
  

   marked 
  with 
  transverse 
  tubercles 
  or 
  ridges, 
  generally 
  papillated 
  on 
  the 
  

   crest. 
  The 
  sides 
  of 
  the 
  costae 
  adjacent 
  to 
  the 
  margin 
  are 
  boldly 
  

   papillated 
  ; 
  the 
  intercostal 
  furrows 
  are 
  narrow, 
  and 
  diminish 
  in 
  

   depth 
  inferiorly. 
  The 
  endotheca 
  is 
  well 
  developed 
  and 
  vesicular. 
  

   The 
  exotheca 
  is 
  scantily 
  developed, 
  and 
  rarely 
  passes 
  to 
  the 
  costal 
  

   edge. 
  The 
  wall 
  is 
  much 
  thicker 
  near 
  the 
  base 
  than 
  above, 
  and 
  there 
  

   is 
  much 
  consolidation 
  of 
  the 
  lower 
  part 
  of 
  the 
  corallum. 
  The 
  epi- 
  

   theca 
  is 
  strong, 
  membraniform, 
  and 
  marked 
  by 
  transverse 
  ridges, 
  

   but 
  is 
  little 
  affected 
  by 
  the 
  costae 
  beneath 
  : 
  it 
  appears 
  often 
  to 
  wear 
  

   off 
  during 
  fossilization. 
  

  

  The 
  larger 
  specimens 
  are 
  rather 
  compressed, 
  and 
  have 
  a 
  tendency 
  

   to 
  be 
  grooved 
  in 
  front 
  and 
  behind. 
  The 
  columella 
  appears 
  to 
  dimi- 
  

   nish 
  in 
  development 
  as 
  the 
  Coral 
  grows 
  in 
  height. 
  The 
  septa 
  attain 
  

   a 
  high 
  numerical 
  development 
  early*. 
  Height 
  of 
  large 
  specimen 
  

   3 
  inches, 
  small 
  2 
  inches 
  ; 
  the 
  smallest 
  in 
  the 
  collection 
  l^j 
  inch 
  ; 
  

   length 
  2^, 
  1 
  T 
  9 
  ^, 
  ly 
  6 
  ^ 
  inches 
  ; 
  breadth 
  1-^j-t, 
  l-j%, 
  1^-inch 
  ; 
  height 
  of 
  

   inner 
  margin 
  of 
  septa 
  y^- 
  inch. 
  

  

  From 
  the 
  Mvaje 
  shale, 
  San 
  Domingo. 
  Coll. 
  Geol. 
  Soc. 
  

  

  16. 
  Antillia 
  bilobata, 
  spec. 
  nov. 
  PL 
  III. 
  fig. 
  3. 
  

  

  Circophyllia, 
  species 
  3, 
  Lonsdale 
  MS. 
  

  

  **Corallum 
  simple, 
  straight, 
  turbinate, 
  and 
  very 
  much 
  compressed, 
  

   so 
  as 
  to 
  appear 
  more 
  or 
  less 
  bilobate 
  ; 
  it 
  is 
  somewhat 
  constricted 
  above 
  

   and 
  pedicellate 
  below. 
  Calice 
  somewhat 
  like 
  the 
  figure 
  of 
  "8"; 
  its 
  area 
  

   is 
  sometimes 
  smaller 
  than 
  that 
  of 
  a 
  transverse 
  section 
  of 
  the 
  Coral 
  

   half 
  an 
  inch 
  below 
  the 
  calicular 
  margin; 
  it 
  is 
  constricted 
  centrally, 
  has 
  

  

  * 
  For 
  full 
  details 
  of 
  the 
  construction 
  see 
  Lonsdale's 
  MS. 
  

  

  t 
  The 
  constricted 
  calice 
  is 
  not 
  measured, 
  but 
  the 
  wall 
  just 
  below 
  it. 
  

  

  