﻿368 
  Geological 
  Society. 
  

  

  species 
  represents 
  a 
  distinct 
  genus. 
  Archceocyathwi 
  'profundus, 
  

   having 
  been 
  selected 
  by 
  Mr. 
  Billings 
  in 
  1865 
  as 
  the 
  typical 
  species, 
  

   was 
  retained 
  as 
  such, 
  and 
  the 
  characters 
  of 
  the 
  genus, 
  as 
  shown 
  in 
  

   this 
  species 
  were 
  defined 
  : 
  Arch, 
  atlanticus, 
  Bill., 
  was 
  made 
  the 
  type 
  of 
  

   a 
  new 
  genus, 
  Spirocyathus 
  : 
  and 
  the 
  third 
  species, 
  Arch, 
  minga- 
  

   nensis, 
  which 
  proves 
  to 
  be 
  a 
  siliceous 
  sponge, 
  was 
  included 
  in 
  a 
  

   new 
  genus, 
  Archceoscyphia. 
  

  

  Including 
  the 
  genera 
  allied 
  to 
  Archasoeyathus, 
  described 
  by 
  Meek 
  

   and 
  Bornemann, 
  the 
  following 
  constitute 
  the 
  family 
  ArcH-E0cya- 
  

   thinjg, 
  proposed 
  by 
  this 
  last-named 
  author; 
  Archceocyathus, 
  Bill.; 
  

   EthmophyUum, 
  Meek: 
  Coscinocyathm, 
  Born.; 
  Anthomorpha, 
  

   Born.; 
  Protopharetra, 
  Born.; 
  and 
  Spirocyathus, 
  g. 
  n. 
  

  

  The 
  genera 
  of 
  this 
  family 
  are 
  characterized 
  for 
  the 
  most 
  pari 
  by 
  

   turbinate 
  or 
  subcylindrical 
  forms 
  with 
  stoul 
  Avails 
  enclosing 
  an 
  

   interior 
  tubular 
  or 
  cup-shaped 
  cavity. 
  Their 
  skeletons 
  are 
  of 
  car- 
  

   bonate 
  of 
  lime 
  in 
  a 
  minutely 
  granular 
  condition. 
  The 
  walls 
  in 
  the 
  

   first 
  four 
  of 
  the 
  above-named 
  genera 
  consist 
  of 
  au 
  outer 
  and 
  an 
  inner 
  

   lamina 
  connected 
  by 
  vertical 
  and 
  radial 
  septa 
  ; 
  dissepiments 
  are 
  

   generally 
  present 
  between 
  the 
  septa: 
  save 
  in 
  the 
  genus 
  Antho- 
  

   morpha, 
  the 
  outer 
  lamina 
  of 
  the 
  wall 
  is 
  regularly 
  and 
  minutely 
  

   perforate, 
  and 
  the 
  inner 
  lamina 
  ami 
  septa 
  are 
  like-wise 
  cribriform 
  ; 
  

   EthmophyUum 
  is 
  particularly 
  distinguished 
  by 
  oblique 
  canals 
  cou- 
  

   necting 
  the 
  interspaces 
  of 
  the 
  wall 
  with 
  the 
  central 
  cavity, 
  

   Ooscinocyathus 
  by 
  transverse, 
  perforate 
  tabulae, 
  and 
  Anthomorpha 
  

   by 
  the 
  apparently 
  imperforate 
  character 
  of 
  the 
  surface-laminae 
  and 
  

   septa. 
  Protopharetra 
  and 
  Spirocyathus 
  are 
  either 
  non-septate 
  or 
  

   very 
  obscurely 
  septate; 
  their 
  skeleton 
  consists 
  of 
  anastomosing 
  

   laminae 
  and 
  fibres 
  ; 
  in 
  the 
  latter 
  genus 
  the 
  lamina- 
  are 
  remarkably 
  

   thickened 
  by 
  successive 
  secondary 
  deposits 
  of 
  calcareous 
  material. 
  

  

  The 
  Arclueocyathime 
  are 
  regarded 
  as 
  a 
  special 
  family 
  of 
  the 
  

   Zoaniharia 
  sclerodermata, 
  in 
  some 
  features 
  allied 
  to 
  the 
  group 
  of 
  

   perforate 
  corals. 
  The 
  family 
  is 
  restricted, 
  so 
  far 
  as 
  is 
  known 
  at 
  

   present, 
  to 
  the 
  lowest 
  fossiliferous 
  zone 
  of 
  the 
  Cambrian 
  strata, 
  that 
  

   characterized 
  by 
  the 
  genus 
  Olenellus, 
  Hall, 
  and 
  it 
  occurs 
  at 
  Anse-au- 
  

   loup, 
  Labrador; 
  Troy, 
  New 
  York 
  State; 
  Nevada; 
  in 
  the 
  Sierra 
  

   Morena, 
  Spain 
  : 
  and 
  in 
  the 
  south-west 
  of 
  the 
  Island 
  of 
  Sardinia. 
  

  

  The 
  genus 
  Archceoscyphia, 
  based 
  on 
  Archosoeyathus 
  minganensis, 
  

   Bill., 
  is 
  shown 
  to 
  be 
  a 
  lithistid 
  spouge, 
  and 
  Nipterella, 
  g. 
  n., 
  based 
  

   on 
  Oalathium 
  (?) 
  paradoxicum, 
  Bill., 
  belongs 
  likewise 
  to 
  the 
  same 
  

   group 
  of 
  sponges. 
  The 
  genera 
  Calaihium, 
  Bill., 
  and 
  Trichospongia, 
  

   Bill., 
  are 
  also 
  undoubted 
  siliceous 
  sponges. 
  These 
  various 
  sponges, 
  

   which 
  were 
  either 
  included 
  in 
  Archceocyathus 
  by 
  Mr. 
  Billings, 
  or 
  

   regarded 
  as 
  allied 
  thereto, 
  have 
  no 
  relation 
  whatever 
  to 
  the 
  genus, 
  

   or 
  to 
  any 
  member 
  of 
  the 
  family 
  in 
  which 
  it 
  is 
  included. 
  They 
  come 
  

   from 
  a 
  higher 
  geological 
  horizon, 
  the 
  Calciferous 
  formation 
  of 
  the 
  

   Canadian 
  geologists, 
  which 
  is 
  probably 
  the 
  summit 
  of 
  the 
  Cambrian. 
  

   They 
  occur 
  in 
  the 
  Mingan 
  Islands 
  and 
  in 
  Newfoundland. 
  Archceo- 
  

   scyphia 
  and 
  Calathium 
  are 
  present 
  in 
  the 
  Durness 
  limestones. 
  

  

  