﻿26 
  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Nov. 
  18, 
  

  

  6. 
  TfiOCHOCYATHUS 
  ABNORMALIS., 
  Spec. 
  HOY. 
  PI. 
  II. 
  figS. 
  4 
  Cl-± 
  C. 
  

  

  New 
  genus, 
  Lonsdale 
  MS. 
  

  

  Corallum 
  simple, 
  long, 
  compressed, 
  strongly 
  curved 
  in 
  the 
  plane 
  of 
  

   the 
  minor 
  axis, 
  and 
  with 
  the 
  usual 
  shape 
  of 
  the 
  elongated 
  Trochocyaihi. 
  

   The 
  inferior 
  end 
  is 
  small 
  and 
  pedicellate, 
  and 
  presents 
  no 
  sign 
  of 
  ad- 
  

   hesion 
  ; 
  and 
  the 
  upper, 
  or 
  calicular 
  margin, 
  is 
  slightly 
  arched, 
  the 
  

   centre 
  of 
  the 
  large 
  axis 
  being 
  on 
  a 
  higher 
  plane 
  than 
  that 
  of 
  the 
  

   other. 
  The 
  corallum 
  diminishes 
  in 
  bulk 
  gradually 
  from 
  above 
  down- 
  

   wards. 
  The 
  calice 
  is 
  elliptical, 
  and 
  its 
  fossa 
  deep. 
  The 
  septa 
  

   are 
  numerous, 
  alternately 
  large 
  and 
  small, 
  in 
  six 
  systems; 
  there 
  

   are 
  two 
  perfect 
  systems 
  of 
  four 
  cycles 
  at 
  opposite 
  sides 
  of 
  the 
  great 
  

   axis 
  ; 
  and 
  in 
  full-grown 
  individuals 
  there 
  are 
  five 
  perfect 
  cycles 
  in 
  the 
  

   remaining 
  systems, 
  but 
  they 
  are 
  imperfect 
  in 
  small 
  specimens. 
  

   Septa 
  exsert, 
  rounded 
  and 
  arched 
  at 
  the 
  wall, 
  vertical 
  where 
  the 
  

   inner 
  edge 
  forms 
  the 
  boundary 
  of 
  the 
  fossa, 
  those 
  of 
  the 
  lateral 
  

   systems 
  being 
  most 
  developed 
  ; 
  below 
  the 
  margin, 
  in 
  sections, 
  the 
  

   primary 
  and 
  secondary 
  septa 
  are 
  nearly 
  alike, 
  and 
  the 
  tertiary 
  also 
  

   where 
  there 
  are 
  five 
  cycles. 
  Laminae 
  stout, 
  smooth 
  above, 
  granular, 
  

   showing 
  both 
  a 
  biplated 
  composition 
  and 
  a 
  small 
  groove, 
  which, 
  pass- 
  

   ing 
  through 
  the 
  wall, 
  is 
  continuous 
  with 
  the 
  interlaminar 
  space 
  of 
  

   the 
  septa 
  and 
  costae. 
  Columella 
  long 
  and 
  narrow, 
  sharp 
  and 
  uneven 
  

   on 
  the 
  free 
  surface 
  ; 
  it 
  is 
  composed 
  of 
  long 
  dissepiments 
  joining 
  the 
  

   pali 
  and 
  the 
  eudothecal 
  tissue 
  laterally. 
  Pali 
  stout, 
  and 
  remaining 
  

   attached 
  to 
  the 
  columella 
  (in 
  transverse 
  sections) 
  ; 
  they 
  are 
  granular, 
  

   rounded 
  above, 
  and 
  marked 
  by 
  one 
  or 
  more 
  lines 
  parallel 
  with 
  the 
  

   free 
  edge 
  ; 
  they 
  are 
  seen 
  before 
  all 
  the 
  septa, 
  except 
  those 
  of 
  the 
  last 
  

   or 
  rudimentary 
  cycle, 
  those 
  of 
  the 
  primary 
  and 
  secondary 
  septa 
  being 
  

   subequal, 
  and 
  larger 
  than 
  the 
  others. 
  The 
  costae 
  are 
  much 
  more 
  

   prominent 
  at 
  the 
  base 
  than 
  at 
  the 
  calicular 
  margin, 
  the 
  costa 
  of 
  

   the 
  great 
  curvature 
  being 
  more 
  or 
  less 
  crested 
  and 
  spined 
  below, 
  

   but 
  nearly 
  plane 
  above. 
  The 
  primary 
  costae 
  of 
  the 
  sides 
  are, 
  now 
  

   and 
  then, 
  slightly 
  crested 
  near 
  the 
  base, 
  as 
  is 
  also 
  the 
  costa 
  of 
  the 
  

   small 
  curvature. 
  The 
  intermediate 
  costae 
  are 
  small, 
  flat, 
  distinct, 
  and 
  

   granular. 
  Endotheca 
  exists 
  in 
  the 
  form 
  of 
  oblique 
  laminae, 
  which 
  

   extend 
  between 
  the 
  septa 
  and 
  close-in 
  the 
  interseptal 
  loculi, 
  more 
  or 
  

   less 
  ; 
  the 
  dissepiments 
  are 
  stout 
  and 
  inclined. 
  The 
  lower 
  part 
  of 
  

   the 
  interior 
  of 
  the 
  corallum 
  is 
  filled 
  up 
  and 
  is 
  solid. 
  

  

  Height 
  of 
  largest 
  specimen 
  2^ 
  inches, 
  of 
  smallest 
  ly 
  2 
  ^ 
  inch 
  ; 
  length 
  

   of 
  largest 
  calice 
  -f-§ 
  inch, 
  of 
  smallest 
  -^ 
  inch; 
  breadth 
  of 
  largest 
  

   calice 
  y^- 
  inch, 
  of 
  smallest 
  -j^- 
  inch. 
  

  

  Prom 
  the 
  Nivaje 
  shale, 
  San 
  Domingo. 
  Coll. 
  Geol. 
  Soc. 
  

  

  This 
  species 
  is 
  closely 
  allied 
  to 
  the 
  European 
  species 
  of 
  the 
  Turin 
  

   Miocene 
  with 
  crests, 
  except 
  with 
  regard 
  to 
  the 
  endotheca. 
  

  

  7. 
  Trochocyathtts 
  profundus, 
  spec. 
  nov. 
  PI. 
  Y. 
  figs. 
  3 
  a-3 
  c. 
  

   Corallum 
  simple, 
  tall, 
  subturbinate, 
  slightly 
  compressed, 
  with 
  a 
  

  

  twisted 
  pedicel, 
  which 
  presents 
  a 
  mark 
  of 
  former 
  adherence. 
  Coral- 
  

   lum 
  curved, 
  but 
  unevenly, 
  and 
  not 
  quite 
  in 
  the 
  plane 
  of 
  either 
  axis. 
  

   Calice 
  elliptical 
  and 
  open, 
  with 
  a 
  very 
  deep 
  fossa. 
  Septa 
  delicate, 
  

   but 
  little 
  exsert, 
  arched 
  at 
  the 
  wall, 
  and 
  with 
  their 
  inner 
  margin 
  

  

  