﻿1863.] 
  DUNCAN 
  — 
  WEST 
  INDIAN 
  CORALS. 
  39 
  

  

  24. 
  Plesiastrjea 
  spongiformis, 
  spec. 
  nov. 
  PL 
  IY. 
  figs. 
  6 
  a, 
  6 
  5. 
  

  

  Corallum 
  globose, 
  or 
  globose 
  above, 
  and 
  having 
  a 
  truncated 
  pe- 
  

   duncle 
  below. 
  Calices 
  very 
  close 
  and 
  crowded, 
  barely 
  projecting 
  

   above 
  the 
  surface. 
  Fossa 
  very 
  shallow, 
  especially 
  in 
  aged 
  corallites. 
  

   Septa 
  subequal, 
  and 
  resembling 
  those 
  of 
  the 
  former 
  species. 
  In 
  six 
  

   systems 
  of 
  three 
  cycles. 
  Pali 
  before 
  the 
  primary 
  and 
  secondary 
  orders. 
  

   Columella 
  cylindrical 
  or 
  flattened 
  in 
  the 
  younger 
  specimens, 
  and 
  

   almost 
  styliform 
  in 
  the 
  older. 
  Costse 
  subequal, 
  more 
  projecting 
  

   laterally 
  than 
  in 
  P. 
  c/lobosa 
  or 
  P. 
  distans, 
  and, 
  being 
  well 
  separated 
  

   on 
  the 
  free 
  surface, 
  and 
  not 
  covered 
  by 
  epitheca, 
  they 
  often 
  appear 
  

   to 
  end 
  in 
  a 
  line 
  of 
  exotheca. 
  Exotheca 
  cellular 
  and 
  tolerably 
  deve- 
  

   loped. 
  Endotheca 
  scanty. 
  Epitheca 
  rudimentary. 
  Height 
  1 
  t 
  4 
  q- 
  

   inch 
  to 
  2^- 
  inches 
  ; 
  diameter 
  of 
  calice 
  rather 
  less 
  than 
  -jL- 
  inch. 
  

  

  From 
  the 
  silt 
  of 
  the 
  Sandstone 
  plain, 
  San 
  Domingo. 
  Coll. 
  Geol. 
  

   Soc. 
  

  

  25. 
  Plesiastr^a 
  ramea, 
  spec. 
  nov. 
  PI. 
  V. 
  figs. 
  1 
  a, 
  1 
  b. 
  

  

  Corallum 
  in 
  gibbous 
  masses 
  or 
  more 
  or 
  less 
  cylindrical 
  processes 
  

   with 
  irregular 
  swellings. 
  Calices 
  distant, 
  very 
  slightly 
  exsert, 
  cir- 
  

   cular, 
  and 
  unequal 
  in 
  size. 
  Septa 
  thick 
  at 
  the 
  wall, 
  thin 
  internally, 
  

   unequal 
  in 
  size 
  according 
  to 
  the 
  orders 
  ; 
  finely 
  dentate 
  above, 
  but 
  

   sparely 
  granular 
  laterally. 
  In 
  six 
  systems 
  of 
  three 
  cycles, 
  with 
  occa- 
  

   sionally 
  an 
  additional 
  order 
  in 
  one 
  half 
  of 
  a 
  system. 
  Pali 
  very 
  small. 
  

   Columella 
  lax, 
  papillated, 
  and 
  small. 
  Fossa 
  moderately 
  deep. 
  Costae 
  

   well 
  developed, 
  subequal, 
  and 
  marked 
  by 
  three 
  or 
  four 
  dentate 
  pro- 
  

   jections 
  ; 
  they 
  are 
  evidently 
  covered 
  with 
  a 
  fine 
  epitheca, 
  which 
  is 
  

   not 
  granular 
  ; 
  where 
  the 
  epitheca 
  is 
  worn 
  the 
  costae 
  are 
  seen 
  to 
  be 
  

   smaller, 
  the 
  tertiary 
  being 
  much 
  smaller 
  than 
  the 
  others; 
  all 
  project, 
  

   however. 
  Exotheca 
  moderately 
  developed, 
  and 
  often 
  becoming 
  indu- 
  

   rated. 
  Endothecal 
  dissepiments 
  fragile, 
  but 
  horizontal 
  and 
  frequent. 
  

   Height 
  some 
  inches 
  ; 
  diameter 
  of 
  branches 
  1 
  inch, 
  more 
  or 
  less 
  ; 
  

   diameter 
  of 
  the 
  corallites 
  -fa 
  inch 
  ; 
  distance 
  between 
  the 
  corallites 
  

   about 
  -fij 
  inch. 
  

  

  From 
  the 
  silt 
  of 
  the 
  Sandstone 
  plain, 
  San 
  Domingo. 
  Coll. 
  Geol. 
  

   Soc. 
  

  

  P. 
  ramea, 
  var. 
  

  

  Calices 
  large 
  and 
  deep. 
  Three 
  cycles 
  of 
  septa. 
  Pali 
  small, 
  but 
  evi- 
  

   dently 
  arising 
  from 
  the 
  bottom 
  of 
  the 
  corallite, 
  often 
  only 
  before 
  the 
  

   primary 
  septa 
  ; 
  but 
  although 
  the 
  secondary 
  do 
  not 
  reach 
  the 
  colu- 
  

   mella, 
  still 
  the 
  opposing 
  pali 
  are 
  attached 
  to 
  that 
  structure, 
  which, 
  

   although 
  papillose 
  above, 
  is 
  seen 
  to 
  be 
  well 
  developed 
  in 
  longitudinal 
  

   sections. 
  Exotheca 
  generally 
  indurated. 
  Endothecal 
  dissepiments 
  

   stout 
  and 
  horizontal. 
  

  

  From 
  the 
  silt 
  of 
  the 
  Sandstone 
  plain, 
  San 
  Domingo. 
  Coll. 
  Geol. 
  

   Soc. 
  

  

  This 
  fossil 
  is 
  worn, 
  but 
  is 
  intensely 
  hard 
  ; 
  and 
  another 
  in 
  the 
  col- 
  

   lection, 
  which 
  belongs 
  to 
  the 
  typical 
  specific 
  form, 
  and 
  is 
  from 
  the 
  

   same 
  locality, 
  is 
  nearly 
  silicified, 
  and 
  has 
  attached 
  to 
  it 
  the 
  common 
  

   Foraminifera 
  of 
  the 
  Nivaje 
  deposit. 
  

  

  