﻿48 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  67 
  

  

  Genus 
  MESENTERIPORA 
  BJainville, 
  1834 
  

  

  MESENTERIPORA 
  MARGINATA 
  D'Orbigny, 
  1853 
  

  

  Plate 
  6, 
  fig. 
  3 
  

  

  1899. 
  Diastopora 
  marginata 
  Gregory, 
  Catalogue 
  of 
  the 
  Cretaceous 
  Bryozoa 
  in 
  

   the 
  British 
  Museum, 
  vol. 
  1, 
  p. 
  137. 
  (Bibliography 
  and 
  occurrence.) 
  

  

  Measurements. 
  — 
  Diameter 
  of 
  aperture, 
  0.14-0.16 
  mm.; 
  diameter 
  

   of 
  peristome, 
  0.22 
  mm.; 
  diameter 
  of 
  tubes, 
  0.27 
  mm.; 
  distance 
  of 
  

   peristomes, 
  2 
  mm.; 
  separation 
  of 
  peristomes, 
  0.64-0.72 
  mm. 
  

  

  Structure. 
  — 
  We 
  provisionally 
  place 
  this 
  beautiful 
  species 
  next 
  to 
  

   Nematifera 
  because 
  of 
  the 
  presence 
  of 
  separating 
  salient 
  threads, 
  bu 
  t 
  

  

  we 
  have 
  not 
  yet 
  been 
  able 
  to 
  

   discover 
  the 
  ovicell. 
  More- 
  

   over, 
  the 
  transverse 
  section 
  is 
  

   of 
  a 
  type 
  entirely 
  special. 
  

   There 
  is 
  no 
  basal 
  lamella, 
  

  

  Fig. 
  21.— 
  Mesenteripora 
  marginata 
  D'Orbigny, 
  1853. 
  , 
  . 
  . 
  . 
  . 
  , 
  ,. 
  

  

  Transverse 
  section, 
  X 
  16. 
  Lower 
  Cretaceous 
  (Val. 
  ^nd 
  although 
  the 
  lamellar 
  

   angian): 
  Sainte-Croix, 
  Switzerland 
  ZOarium 
  has 
  tWO 
  sides 
  they 
  

  

  are 
  not 
  formed 
  by 
  two 
  lamellae 
  placed 
  back 
  to 
  back. 
  The 
  tubes 
  

   are 
  polygonal, 
  with 
  thin 
  walls 
  arranged 
  in 
  quincunx 
  and 
  confused. 
  

  

  Occurrence. 
  — 
  Lower 
  Cretaceous 
  (Valangian) 
  : 
  Sainte-Croix 
  (Vaud), 
  

   Switzerland, 
  and 
  Villers-le-lac 
  (Jura), 
  France. 
  

  

  Plesioty 
  pes. 
  —Cat. 
  No. 
  69897, 
  U.S.N. 
  M. 
  

  

  Family 
  PLAGIOECIIDAE 
  Canu, 
  1918 
  

  

  Genus 
  NOTOPLAGIOECIA 
  Canu 
  and 
  Bassler, 
  1922 
  

  

  The 
  ovicell 
  is 
  an 
  irregular 
  convex 
  capsule, 
  replacing 
  many 
  peri- 
  

   stomes. 
  The 
  tubes 
  are 
  short, 
  club-shaped, 
  with 
  moniliform 
  walls 
  

   thickened 
  at 
  the 
  extremities. 
  The 
  gemmation 
  is 
  dorsal. 
  There 
  is 
  

   no 
  basal 
  lamella. 
  

  

  Provisional 
  genotype. 
  — 
  Notoplagioecia 
  faringdonensis 
  Canu 
  and 
  

   Bassler, 
  1922. 
  

  

  Range. 
  — 
  Cretaceous 
  (Aptian, 
  Coniacian). 
  

  

  NOTOPLAGIOECIA 
  FARINGDONENSIS 
  Canu 
  and 
  Bassler, 
  1922 
  

  

  Plate 
  5, 
  figs. 
  3-5 
  

  

  Description. 
  — 
  The 
  zoarium 
  is 
  free, 
  cylindrical 
  or 
  compressed. 
  The 
  

   tubes 
  are 
  indistinct, 
  very 
  little 
  convex, 
  smooth. 
  The 
  peristomes 
  are 
  

   orbicular, 
  thin, 
  arranged 
  in 
  quincunx 
  or 
  in 
  transverse 
  rows. 
  The 
  

   zone 
  of 
  growth 
  is 
  an 
  elevated 
  cone. 
  The 
  ovicell 
  is 
  an 
  irregular 
  sack 
  

   covering 
  many 
  adjacent 
  tubes. 
  

  

  