﻿art. 
  21 
  CYCLOSTOMATOUS 
  BRYOZOA 
  CANU 
  AND 
  BASSLER 
  93 
  

  

  The 
  longitudinal 
  section 
  is 
  that 
  characteristic 
  of 
  the 
  Corymbopori- 
  

   dae 
  as 
  Canu 
  has 
  figured 
  in 
  1919. 
  The 
  walls 
  of 
  the 
  tubes 
  are 
  monili- 
  

   form. 
  The 
  gemmation 
  is 
  incomprehensible 
  and 
  the 
  nature 
  of 
  the 
  

   pores 
  remains 
  still 
  doubtful. 
  Gregory's 
  hypothesis 
  is 
  not 
  clear. 
  " 
  The 
  

   pores 
  seem 
  to 
  be 
  due 
  to 
  the 
  nearly 
  complete 
  filling 
  of 
  the 
  aperture 
  

   of 
  the 
  dead 
  zoaria 
  by 
  epizoarial 
  material." 
  

  

  In 
  transverse 
  section 
  the 
  tubes 
  are 
  polygonal, 
  with 
  adjacent 
  walls; 
  

   they 
  are 
  larger 
  at 
  the 
  zoarial 
  center. 
  

  

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

   land. 
  

  

  Plesioty 
  pes. 
  —Cat. 
  No. 
  69948, 
  U.S.N.M. 
  

  

  CORYMBOPORA 
  (?) 
  CUPULA 
  D'Orbigny, 
  1853 
  

  

  Plate 
  8, 
  figs. 
  1-7 
  

  

  1853. 
  Reptomulticava 
  cupula 
  D'Orbigny, 
  Pal^ontologie 
  franchise, 
  Terrain 
  Cre- 
  

   tan, 
  vol. 
  5, 
  p. 
  1037, 
  pi. 
  792, 
  figs. 
  6-11. 
  

  

  Our 
  determination 
  is 
  possibly 
  incorrect, 
  for 
  D'Orbigny's 
  figures 
  

   do 
  not 
  indicate 
  smaller 
  tubes 
  at 
  the 
  center 
  of 
  the 
  zoarium 
  nor 
  col- 
  

   onies 
  so 
  thick. 
  We 
  maintain 
  our 
  determination, 
  however, 
  because 
  

   specimens 
  of 
  D'Orbigny's 
  species 
  as 
  figured 
  by 
  him 
  have 
  never 
  been 
  

   rediscovered 
  at 
  Le 
  Mans. 
  

  

  Our 
  specimens 
  are 
  capitate, 
  simple 
  or 
  agglomerate. 
  The 
  ovicel 
  

   is 
  that 
  of 
  the 
  Corymboporidae, 
  absolutely 
  analogous 
  with 
  that 
  o 
  

   the 
  genotype 
  figured 
  by 
  Canu. 
  Exteriorily 
  the 
  zoarium 
  appears 
  to 
  

   be 
  formed 
  of 
  superposed 
  lamellae 
  in 
  which 
  the 
  tubes 
  are 
  much 
  

   smaller 
  at 
  the 
  center 
  and 
  on 
  the 
  margin. 
  This 
  is 
  an 
  illusion 
  result- 
  

   ing 
  from 
  the 
  special 
  mode 
  of 
  gemmation 
  in 
  Corymbopora. 
  Thin 
  

   sections 
  confirm 
  this 
  observation. 
  

  

  Occurrence. 
  — 
  Cretaceous 
  (Cenomanian) 
  : 
  Le 
  Mans 
  (Sarthe), 
  France. 
  

  

  Plesiotypes.— 
  Oat. 
  No. 
  69949, 
  U.S.N.M. 
  

  

  