﻿J863.] 
  . 
  DUNCAN 
  — 
  WEST 
  INDIAN 
  CORA.LS, 
  23 
  

  

  and 
  bounded 
  below 
  by 
  the 
  lamellar 
  columella. 
  The 
  margin 
  is 
  

   straight, 
  and 
  the 
  calice 
  rather 
  shallow. 
  Septa 
  about 
  210, 
  or 
  six 
  

   complete 
  cycles 
  and 
  part 
  of 
  a 
  seventh 
  ; 
  their 
  distribution 
  is 
  irregular. 
  

   The 
  lamellae 
  of 
  the 
  first 
  three 
  cycles, 
  and 
  a 
  portion 
  of 
  the 
  fourth 
  » 
  

   are 
  of 
  equal 
  dimensions, 
  and 
  range 
  to 
  the 
  fossula 
  \ 
  those 
  of 
  the 
  fifth 
  

   are 
  much 
  shorter, 
  and 
  the 
  rest 
  are 
  rudimentary. 
  All 
  the 
  upper 
  

   extremities 
  are 
  free 
  and 
  boldly 
  arched, 
  the 
  largest 
  projecting 
  up- 
  

   wards 
  y 
  1 
  ^ 
  inch 
  beyond 
  the 
  calicular 
  margin. 
  The 
  lamella? 
  of 
  the 
  first 
  

   four 
  cycles 
  are 
  nearly 
  equal 
  in 
  thickness, 
  and 
  the 
  thickness 
  does 
  not 
  

   vary 
  in 
  any 
  part 
  of 
  their 
  course. 
  The 
  sides 
  are 
  minutely 
  papillated 
  

   with 
  unequal 
  and 
  irregular 
  granules 
  ; 
  sometimes 
  they 
  are 
  arranged 
  

   in 
  rows 
  .parallel 
  to 
  the 
  outline 
  of 
  the 
  lamellae, 
  and 
  adjacent 
  to 
  the 
  

   edge 
  they 
  are 
  very 
  frequently 
  in 
  short, 
  close 
  -set, 
  minute 
  ridges. 
  The 
  

   papillae 
  on 
  the 
  edges 
  are 
  the 
  upper 
  extremities 
  of 
  these 
  ridges. 
  

   Pali 
  occur 
  as 
  rounded 
  lobes 
  in 
  front 
  of 
  the 
  lamellae 
  referable 
  to 
  the 
  

   penultimate 
  and 
  antepenultimate 
  cycles, 
  but 
  there 
  is 
  some 
  want 
  of 
  

   uniformity 
  ; 
  they 
  vary 
  in 
  size, 
  and 
  are 
  solidly 
  united 
  to 
  the 
  lamellae, 
  

   with 
  which 
  they 
  agree 
  in 
  structure. 
  Columella 
  thin, 
  lamelliform, 
  

   essential, 
  and 
  continuous 
  ; 
  the 
  upper 
  edge 
  is 
  lobed 
  and 
  sharp. 
  Epi- 
  

   theca 
  pellicular, 
  smooth, 
  glistening, 
  and 
  consisting 
  of 
  " 
  delicate 
  

   superimposed 
  laminae, 
  flakes 
  of 
  which 
  may 
  be 
  detached 
  mechanically. 
  

   It 
  permits 
  the 
  costae 
  to 
  be 
  faintly 
  seen, 
  and 
  is 
  minutely 
  granulated 
  at 
  

   the 
  upper 
  extremity." 
  Costae 
  faintly 
  visible, 
  except 
  close 
  to 
  the 
  

   calicular 
  margin 
  ; 
  at 
  that 
  part 
  they 
  exhibit 
  " 
  a 
  thin 
  granulated 
  edge 
  

   with 
  clear 
  interspaces; 
  but 
  a 
  little 
  lower 
  the 
  edge 
  thickens, 
  be- 
  

   comes 
  nearly, 
  and 
  the 
  sides 
  are, 
  contiguous." 
  "Throughout 
  the 
  

   remainder 
  of 
  the 
  specimen 
  the 
  costae 
  may 
  be 
  traced, 
  maintaining 
  a 
  

   slightly 
  convex 
  outline." 
  Instead 
  of 
  conforming 
  to 
  the 
  shape 
  of 
  

   the 
  corallum 
  and 
  radiating 
  from 
  the 
  pedicel 
  to 
  the 
  calice, 
  the 
  costae, 
  

   both 
  before 
  and 
  behind, 
  are 
  straight, 
  parallel, 
  and 
  run 
  at 
  right 
  angles 
  

   to 
  its 
  margin. 
  The 
  lateral 
  costae 
  incline 
  to 
  the 
  pedicel, 
  as 
  is 
  usual 
  in 
  

   flabelliform 
  Corals, 
  and 
  the 
  most 
  external 
  of 
  the 
  parallel 
  series 
  joins 
  

   them. 
  Wall 
  very 
  dense 
  and 
  thick. 
  Interior 
  much 
  filled 
  up 
  below 
  

   by 
  hard 
  coral-salts. 
  Height 
  1 
  T 
  ^- 
  inch 
  ; 
  length 
  of 
  long 
  axis 
  ^, 
  of 
  

   short 
  T 
  7 
  ¥ 
  inch 
  ; 
  breadth 
  of 
  fossula 
  Jjj 
  inch 
  and 
  more, 
  depth 
  -^ 
  3 
  (J 
  inch 
  ; 
  

   Locality, 
  Nivaje 
  shale. 
  Coll. 
  Geol. 
  Soc. 
  

  

  Variety 
  1*. 
  Plate 
  II. 
  figs. 
  2 
  a-2c. 
  — 
  Corallum 
  flabelliform, 
  much 
  

   compressed, 
  marked 
  by 
  growth-rings 
  ; 
  pedicel 
  sharp 
  and 
  curved. 
  

   Calice 
  long, 
  straight, 
  and 
  without 
  indentation. 
  Costae 
  parallel 
  to 
  a 
  

   slight 
  extent, 
  but 
  only 
  for 
  a 
  short 
  distance 
  downwards, 
  thence 
  they 
  

   converge 
  to 
  the 
  base, 
  and 
  some 
  join 
  the 
  lateral 
  costae. 
  The 
  costae 
  are 
  

   alternately 
  large 
  and 
  small, 
  and 
  are 
  granulated 
  on 
  the 
  free 
  margin, 
  

   there 
  being 
  two 
  or 
  three 
  series 
  of 
  granules 
  on 
  the 
  larger 
  and 
  one 
  on 
  

   the 
  smaller. 
  Epitheca 
  badly 
  developed, 
  and 
  deficient 
  in 
  some 
  places 
  

   where 
  the 
  costae 
  project. 
  Height 
  ly 
  2 
  ^ 
  inch 
  ; 
  length 
  ly 
  6 
  ^ 
  inch 
  ; 
  breadth 
  

  

  A 
  inch 
  - 
  

  

  From 
  the 
  Mvaje 
  shale. 
  Coll. 
  Geol. 
  Soc. 
  

  

  Variety 
  2. 
  — 
  Corallum 
  very 
  solid 
  and 
  heavy 
  from 
  filling 
  up. 
  Calice 
  

   * 
  This 
  and 
  the 
  three 
  following 
  varieties 
  are 
  not 
  described 
  in 
  Mr. 
  Lonsdale's 
  MS. 
  

  

  