﻿art. 
  2i 
  CYCLOSTOMATOUS 
  BKYOZOA 
  CANU 
  AND 
  BASSLER 
  85 
  

  

  Family 
  ASCOSOECIIDAE 
  Canu, 
  1919 
  

  

  Genus 
  LATEROCAVEA 
  D'Orbigny, 
  1853 
  

  

  1S53. 
  Laterocavea 
  D'Orbigny, 
  Pal6ontologie 
  frangaise, 
  Terrain 
  Cr6tac6, 
  vol. 
  5, 
  

   p. 
  933. 
  

  

  Original 
  diagnosis. 
  — 
  "Colonie 
  fixe 
  par 
  sa 
  base, 
  d'ou 
  partent 
  des 
  

   rameaux 
  tres 
  comprimes, 
  divises 
  par 
  des 
  dichotomisations 
  sur 
  le 
  

   menie 
  plan 
  et 
  representant 
  un 
  ensemble 
  flabelliforme 
  dendroide. 
  

   Chaque 
  branche 
  comprimee 
  est 
  pourvue, 
  sur 
  ses 
  deux 
  faces 
  larges 
  

   de 
  lignees 
  transversales 
  espacees, 
  composees 
  d'une 
  seule 
  rangee 
  de 
  

   cellules 
  tubuleuses; 
  entre 
  ces 
  lignees 
  sont 
  de 
  nombreux 
  pores 
  inter- 
  

   mediaires. 
  Sur 
  le 
  cote 
  etroit 
  des 
  branches 
  sont 
  des 
  surfaces 
  tres, 
  

   grandes, 
  couvertes 
  seulement 
  de 
  pores 
  opposes 
  epars, 
  on 
  par 
  lignes 
  

   longitudinales 
  bifurquees 
  dans 
  des 
  sillons." 
  

  

  Diagnosis. 
  — 
  The 
  zoarium 
  is 
  dichotomous 
  and 
  formed 
  of 
  compres- 
  

   sed 
  fronds. 
  The 
  tubes 
  are 
  oriented 
  toward 
  two 
  cellular 
  faces; 
  they 
  

   are 
  cylindrical, 
  with 
  peristome; 
  their 
  gemmation 
  is 
  axial 
  around 
  a 
  

   central 
  tube. 
  They 
  are 
  separated 
  by 
  parietal 
  mesopores. 
  The 
  two 
  

   noncellular 
  sides 
  are 
  forme;! 
  only 
  of 
  parietal 
  mesopores. 
  The 
  ovicell 
  

   is 
  placed 
  on 
  a 
  side 
  with 
  mesopores. 
  

  

  Genotype. 
  — 
  Laterocavea 
  dutempleana 
  D'Orbigny, 
  1853. 
  Cretaceous. 
  

  

  LATEROCAVEA 
  DUTEMPLEANA 
  D'Orbigny, 
  1853 
  

  

  Plate 
  15, 
  figs. 
  1-6 
  

  

  1853. 
  Laterocavea 
  dutempleana 
  D'Orbigny, 
  Pal6ontologie 
  frangaise, 
  Terrain 
  

   Cr<§tace, 
  vol. 
  5, 
  p. 
  933, 
  pi. 
  772, 
  figs. 
  7-10. 
  

  

  We 
  have 
  discovered 
  some 
  excellent 
  specimens 
  of 
  this 
  remarkable 
  

   species, 
  which 
  have 
  permitted 
  us 
  to 
  study 
  the 
  detailed 
  structure. 
  In 
  

   transverse 
  section 
  the 
  tubes 
  are 
  round 
  and 
  grouped 
  around 
  a 
  central 
  

   tube. 
  The 
  parietal 
  mesopores 
  have 
  very 
  thick 
  walls; 
  they 
  form 
  an 
  

   exterior 
  zone, 
  regular, 
  enlarged 
  laterally. 
  

  

  In 
  longitudinal 
  section 
  the 
  tubes 
  are 
  cylindrical, 
  short, 
  somewhat 
  

   narrowed 
  at 
  their 
  base. 
  The 
  gemmation 
  is 
  axial 
  around 
  a 
  central 
  

   tube, 
  which 
  ramifies 
  at 
  the 
  dichotomisations. 
  In 
  their 
  terminal 
  

   recurved 
  portion 
  the 
  tubes 
  are 
  separated 
  by 
  parietal 
  mesopores, 
  with 
  

   thickened 
  walls. 
  

  

  In 
  meridian 
  section 
  the 
  axial 
  tubes 
  have 
  the 
  lozenge-shape 
  derived 
  

   from 
  their 
  orientation 
  toward 
  the 
  broad 
  sides. 
  The 
  lateral 
  tubes 
  

   are 
  aborted 
  and 
  emit 
  only 
  parietal 
  mesopores 
  much 
  longer 
  than 
  the 
  

   others. 
  

  

  In 
  tangential 
  section 
  the 
  orifices 
  are 
  elliptical, 
  often 
  adjacent 
  later- 
  

   ally, 
  and 
  separated 
  in 
  the 
  longitudinal 
  direction 
  by 
  irregular 
  groups 
  

   of 
  4 
  or 
  5 
  mesopores. 
  

  

  