﻿140 
  DE. 
  G. 
  J. 
  HISTDE 
  OlST 
  AECH^OCYATHTJS 
  AND 
  OTHEE 
  GENEEA 
  

  

  Billings 
  * 
  and 
  Meek 
  f 
  ; 
  Dr. 
  Bornemann 
  J 
  and 
  Prof. 
  Meneghini 
  § 
  also 
  

   for 
  some 
  time 
  regarded 
  the 
  Sardinian 
  examples 
  of 
  Archceocyathus 
  as 
  

   species 
  of 
  Cyathophyllum. 
  Their 
  form 
  and 
  mode 
  of 
  growth 
  so 
  pre- 
  

   cisely 
  simulate 
  turbinate 
  or 
  subcylindrical 
  specimens 
  of 
  Silurian 
  

   and 
  Devonian 
  genera 
  of 
  Rugose 
  Corals, 
  that 
  they 
  would 
  at 
  once 
  be 
  

   regarded 
  as 
  such 
  by 
  any 
  one 
  at 
  all 
  familiar 
  with 
  these 
  organisms, 
  

   and, 
  indeed, 
  in 
  some 
  weathered-out 
  specimens 
  of 
  Archceocyathus 
  

   the 
  differences 
  are 
  not 
  apparent 
  until 
  sections 
  have 
  been 
  made. 
  

  

  The 
  radiate 
  vertical 
  septa 
  in 
  Archceocyathus 
  and 
  its 
  allies 
  may 
  

   strictly 
  be 
  compared 
  with 
  the 
  same 
  structures 
  in 
  corals 
  ; 
  they 
  com- 
  

   mence 
  from 
  the 
  outer 
  surface- 
  wall 
  of 
  the 
  organism, 
  with 
  which 
  they 
  

   are 
  in 
  immediate 
  connexion, 
  and 
  extend 
  to 
  the 
  lamina 
  bounding 
  

   the 
  inner 
  tube 
  or 
  cup, 
  which, 
  indeed, 
  is 
  formed 
  in 
  some 
  cases 
  by 
  

   the 
  lateral 
  extension 
  and 
  union 
  of 
  proximate 
  septa. 
  In 
  their 
  per- 
  

   forate 
  character, 
  as 
  has 
  already 
  been 
  pointed 
  out 
  by 
  Mr. 
  Billings, 
  

   the 
  septa 
  resemble 
  those 
  of 
  perforate 
  corals, 
  which, 
  however, 
  are 
  

   of 
  rare 
  occurrence 
  in 
  Palaeozoic 
  strata 
  : 
  but 
  since 
  Mr. 
  Billings 
  wrote, 
  

   a 
  genus 
  of 
  corals 
  ||, 
  Calostylis, 
  Lindstr., 
  has 
  been 
  discovered 
  in 
  the 
  

   Silurian 
  strata 
  of 
  the 
  Isle 
  of 
  Gotland, 
  in 
  which 
  the 
  septa 
  are 
  markedly 
  

   perforate, 
  like 
  those 
  of 
  Archceocyathus. 
  

  

  The 
  regular 
  perforate 
  character 
  of 
  the 
  outer 
  surface 
  of 
  the 
  wall, 
  

   so 
  clearly 
  shown 
  in 
  some 
  of 
  the 
  Sardinian 
  specimens 
  of 
  Archceocyathus 
  

   and 
  in 
  Ethmophyllum 
  marianum, 
  Bom., 
  and 
  E. 
  Whitneyi, 
  from 
  Spain 
  

   and 
  Nevada 
  respectively, 
  cannot 
  find 
  a 
  parallel 
  in 
  any 
  palaeozoic 
  coral 
  

   with 
  which 
  I 
  am 
  acquainted 
  ; 
  but 
  some 
  tertiary 
  fossil 
  and 
  recent 
  

   deep-sea 
  forms 
  (such 
  as, 
  for 
  example, 
  Stephanojphylliaformosissima 
  9 
  ^, 
  

   Moseley) 
  have 
  their 
  basal 
  surface 
  perforated 
  in 
  a 
  manner 
  equally 
  

   delicate 
  as 
  in 
  the 
  Cambrian 
  Archaeocyathinae. 
  It 
  is 
  probable 
  that 
  

   there 
  may 
  have 
  been 
  in 
  Archceocyathus 
  profundus 
  an 
  outer 
  delicate 
  

   imperforate 
  lamina 
  of 
  an 
  epithecal 
  character, 
  the 
  same 
  as 
  in 
  the 
  

   majority 
  of 
  corals. 
  

  

  The 
  dissepiments 
  connecting 
  the 
  septa 
  in 
  Archceocyathus 
  and 
  in 
  

   some 
  of 
  the 
  allied 
  genera 
  bear 
  a 
  close 
  resemblance 
  to 
  the 
  same 
  

   structures 
  in 
  many 
  Bugose 
  Corals, 
  such 
  as 
  Cyathophyllum 
  and 
  

   Cystiphyllum. 
  The 
  tabulae 
  in 
  Coscinocyaihus, 
  though 
  comparable 
  

   in 
  position 
  to 
  those 
  of 
  Bugose 
  Corals, 
  differ 
  in 
  their 
  perforate 
  cha- 
  

   racter. 
  

  

  In 
  the 
  well- 
  developed 
  perforated 
  laminae 
  of 
  the 
  wall 
  bounding 
  

   the 
  inner 
  tube 
  or 
  cup, 
  Archceocyathus 
  and 
  some 
  of 
  the 
  allied 
  genera 
  

   differ 
  from 
  more 
  recent 
  corals, 
  and 
  the 
  peculiar 
  oblique 
  canals 
  

   which 
  characterize 
  the 
  genus 
  Ethmophyllum 
  are 
  also 
  without 
  a 
  

   counterpart 
  in 
  other 
  corals. 
  In 
  the 
  genus 
  Anthomorpha, 
  Bornem., 
  

  

  * 
  New 
  Species 
  of 
  Lower 
  Sil. 
  Fossils, 
  1861, 
  p. 
  3. 
  

  

  t 
  Amer. 
  Journ. 
  Sci. 
  and 
  Arts, 
  vol. 
  xliv. 
  1868, 
  p. 
  62. 
  

  

  \ 
  Extrait 
  du 
  Compte 
  Eendu 
  du 
  Congres 
  geol. 
  intern, 
  a 
  Bologne 
  (1881), 
  

   p. 
  3. 
  

  

  § 
  Atti 
  della 
  Societa 
  Toscana 
  di 
  Sc. 
  Nat. 
  (1881), 
  p. 
  201. 
  

  

  || 
  Ofrersigt 
  k. 
  Vetenskaps-Akad. 
  Forhandl. 
  1868, 
  p. 
  421. 
  The 
  same 
  genus 
  

   has 
  been 
  found 
  by 
  Nicholson 
  and 
  Etheridge 
  in 
  Scotland. 
  See 
  Mon. 
  Girvan 
  

   Fossils, 
  fasc. 
  1, 
  p. 
  65, 
  pi. 
  v. 
  figs. 
  2, 
  2 
  c. 
  It 
  also 
  occurs 
  in 
  the 
  Wenlock 
  district. 
  

  

  % 
  Eeport 
  on 
  ' 
  Challenger' 
  Corals, 
  p. 
  201, 
  pi. 
  xiii. 
  

  

  