﻿134 
  DK. 
  G. 
  J. 
  HINDE 
  ON 
  AECH^OCYATHTJS 
  AND 
  OTHEE 
  GENEEA 
  

  

  but 
  subsequently, 
  in 
  the 
  belief 
  that 
  the 
  internal 
  structure 
  of 
  the 
  

   type 
  forms 
  was 
  similar 
  to 
  that 
  of 
  Archceocyathus 
  profundus, 
  Bill., 
  

   he 
  proposed 
  to 
  include 
  them 
  in 
  this 
  latter 
  genus. 
  In 
  1866, 
  how- 
  

   ever 
  *, 
  Mr. 
  C. 
  D. 
  Walcott 
  resuscitated 
  the 
  genus 
  and 
  gave 
  a 
  defini- 
  

   tion 
  of 
  it, 
  much 
  wider 
  in 
  certain 
  respects 
  than 
  can 
  be 
  sustained 
  by 
  the 
  

   type 
  species, 
  E. 
  Whitneyi, 
  so 
  that 
  it 
  also 
  includes 
  other 
  forms, 
  such 
  as 
  

   Archceocyathus 
  minganensis, 
  which 
  are 
  not 
  related 
  thereto. 
  The 
  

   type 
  form 
  of 
  Ethmophyllum, 
  as 
  described 
  by 
  Meek, 
  does, 
  however, 
  

   possess 
  one 
  feature 
  which 
  serves 
  to 
  mark 
  it 
  off 
  very 
  clearly 
  from 
  

   Archceocyathus, 
  Bill., 
  as 
  defined 
  above. 
  This 
  is 
  the 
  character 
  of 
  the 
  

   inner 
  lamina 
  of 
  the 
  wall, 
  which 
  instead 
  of 
  communicating 
  with 
  the 
  

   interior 
  of 
  the 
  cup 
  or 
  tube 
  by 
  simple 
  perforations, 
  consists 
  of 
  a 
  series 
  of 
  

   relatively 
  large 
  canals 
  directed 
  obliquely 
  upward 
  and 
  inward, 
  so 
  

   that 
  in 
  transverse 
  section 
  they 
  present 
  the 
  appearance 
  of 
  one 
  or 
  more 
  

   rows 
  of 
  vesicles 
  cut 
  across 
  (PI. 
  Y. 
  fig. 
  7). 
  (See 
  also 
  Walcott's 
  

   figure 
  in 
  Bull. 
  No. 
  30, 
  pi. 
  iv. 
  fig. 
  1 
  c.) 
  In 
  the 
  type 
  of 
  Archceo- 
  

   cyathus 
  marianus, 
  Bomer, 
  so 
  carefully 
  described 
  by 
  this 
  author 
  f 
  , 
  

   the 
  same 
  structural 
  feature 
  occurs 
  ; 
  but 
  in 
  this 
  form 
  only 
  a 
  single 
  

   incomplete 
  row 
  of 
  canals 
  is 
  shown 
  in 
  transverse 
  section 
  of 
  the 
  cup. 
  

   This 
  species 
  will 
  therefore 
  be 
  included 
  under 
  Ethmophyllum. 
  

  

  In 
  the 
  description 
  of 
  E. 
  Whitneyi 
  no 
  mention 
  is 
  made 
  of 
  perfo- 
  

   rations 
  i 
  in 
  the 
  septa, 
  but 
  they 
  are 
  very 
  distinctly 
  shown 
  in 
  the 
  

   septa 
  of 
  E. 
  marianum. 
  Dissepimental 
  tissue 
  is 
  not 
  developed 
  either 
  

   in 
  the 
  Nevada 
  or 
  in 
  the 
  Spanish 
  form 
  ; 
  and 
  in 
  this 
  latter 
  the 
  other 
  

   structures 
  are 
  so 
  well 
  preserved, 
  that 
  it 
  may 
  be 
  presumed 
  that 
  dis- 
  

   sepiments 
  were 
  not 
  originally 
  present. 
  Prof. 
  Meek 
  does, 
  indeed, 
  

   mention 
  transverse 
  plates 
  in 
  another 
  specimen 
  which 
  he 
  examined 
  ; 
  

   but 
  as 
  the 
  interior 
  cavity 
  of 
  this 
  was 
  likewise 
  occupied 
  by 
  a 
  dense 
  

   vesicular 
  tissue, 
  it 
  is 
  probable 
  that 
  it 
  belonged 
  either 
  to 
  Archceocya- 
  

   thus 
  or 
  Protopharetra. 
  

  

  In 
  other 
  respects 
  Ethmophyllum 
  approaches 
  closely 
  to 
  Archceo- 
  

   cyathus, 
  Bill., 
  and 
  its 
  characters 
  may 
  be 
  thus 
  defined 
  : 
  — 
  Funnel- 
  

   shaped 
  or 
  subcylindrical 
  forms 
  with 
  a 
  finely 
  perforate 
  outer 
  surface 
  ; 
  

   septa 
  well 
  developed 
  ; 
  dissepimental 
  tissue 
  apparently 
  wanting 
  ; 
  the 
  

   inner 
  surface 
  of 
  the 
  wall 
  consisting 
  of 
  a 
  series 
  of 
  obliquely 
  directed 
  

   canals 
  which 
  open 
  into 
  the 
  central 
  cavity. 
  

  

  At 
  present 
  only 
  two 
  species 
  of 
  this 
  genus 
  are 
  known, 
  E. 
  Whit- 
  

   neyi, 
  Meek, 
  from 
  the 
  Lower 
  Cambrian 
  (Olenellus-zone) 
  of 
  Nevada, 
  

   and 
  E. 
  marianum, 
  F. 
  Bomer, 
  from 
  an 
  apparently 
  corresponding 
  

   horizon 
  near 
  Cazalla, 
  Seville, 
  Spain. 
  

  

  Genus 
  Coscinocyathus, 
  Bornemann. 
  

  

  (1884. 
  Zeitschr. 
  d. 
  deutsch. 
  geol. 
  Gesellsch. 
  p. 
  704 
  ; 
  Versteine- 
  

  

  rungen 
  Sardiniens, 
  p. 
  59.) 
  

   Turbinate, 
  open 
  saucer-shaped, 
  or 
  subcylindrical 
  forms, 
  resembling 
  

  

  * 
  Bulletin 
  U. 
  S. 
  Geol. 
  Surv. 
  no. 
  30, 
  p. 
  75. 
  

   t 
  'Lethal 
  Palseozoica,' 
  lste 
  Lief. 
  (1880), 
  p. 
  301, 
  fig. 
  55. 
  

   I 
  They 
  are 
  not 
  present 
  in 
  the 
  beautifully 
  preserved 
  specimens 
  of 
  this 
  form 
  

   sent 
  me 
  by 
  Mr. 
  Walcott. 
  

  

  