﻿art. 
  2i 
  CYCLOSTOMATOUS 
  BRYOZOA 
  CANU 
  AND 
  BASSLER 
  57 
  

  

  In 
  transverse 
  section 
  the 
  tubes 
  are 
  equally 
  rounded, 
  with 
  thick 
  

   walls. 
  In 
  longitudinal 
  sections 
  they 
  are 
  cylindrical, 
  with 
  peripheral 
  

   gemmation 
  oriented 
  around 
  an 
  imaginary 
  axis. 
  The 
  dorsal 
  tubes 
  

   are 
  closed 
  (intrazoarial 
  gemmation). 
  The 
  zooecial 
  walls 
  are 
  vesic- 
  

   ular, 
  with 
  very 
  small 
  elements. 
  This 
  is 
  very 
  much 
  like 
  the 
  section 
  

   in 
  Frondipora, 
  but 
  the 
  ovicell 
  is 
  altogether 
  different. 
  

  

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

   Switzerland. 
  

  

  Plesioty 
  pes. 
  —Cat. 
  No. 
  69905, 
  U.S.N.M. 
  

  

  Family 
  THEONOIDAE 
  Busk 
  

  

  The 
  family 
  Theonoidae, 
  as 
  defined 
  by 
  Gregory 
  in 
  1899 
  and 
  1909, 
  

   embraced 
  the 
  following 
  genera 
  : 
  

  

  Actinopora 
  D'Orbigny, 
  1853, 
  Conotubigera 
  D'Orbigny, 
  1853 
  (Serie- 
  

   tubigera 
  D'Orbigny, 
  1853), 
  Multitubigera 
  D'Orbigny, 
  1853, 
  Theonoa 
  

   Lamouroux, 
  1821, 
  and 
  Retenoa 
  Gregory, 
  1909, 
  with 
  Multifascigera 
  

   D'Orbigny, 
  1853 
  (= 
  Meandrocavea) 
  , 
  Lopholepis 
  Hagenow, 
  1851, 
  and 
  

   Radiofascigera 
  D'Orbigny, 
  1853, 
  probably 
  belonging 
  to 
  the 
  Osculi- 
  

   poridae. 
  In 
  its 
  ovicell 
  Retenoa 
  is 
  a 
  typical 
  member 
  of 
  the 
  Cytisidae. 
  

   Radiofascigera 
  in 
  its 
  ovicell, 
  classed 
  with 
  doubt 
  in 
  the 
  Osculiporidae, 
  

   ought 
  to 
  be 
  maintained 
  in 
  the 
  vicinity 
  of 
  Actinopora 
  (multiserial) 
  and 
  

   of 
  Multitubigera. 
  

  

  The 
  known 
  ovicells 
  are 
  close 
  to 
  those 
  of 
  the 
  Cytisidae 
  without 
  

   being 
  perfectly 
  identical. 
  The 
  family 
  of 
  Theonoidae 
  could 
  be 
  main- 
  

   tained 
  therefore 
  with 
  some 
  restrictions. 
  Unfortunately, 
  the 
  ovicell 
  

   of 
  the 
  type 
  genus 
  Theonoa 
  is 
  still 
  unknown. 
  On 
  the 
  other 
  hand, 
  the 
  

   uniserial 
  Actinopora 
  of 
  the 
  complanata 
  group 
  (^organisans) 
  have 
  a 
  

   different 
  ovicell 
  of 
  the 
  type 
  of 
  Plagioecia. 
  

  

  If 
  the 
  family 
  should 
  be 
  maintained 
  it 
  ought 
  to 
  contain 
  the 
  following 
  

   genera: 
  

  

  Actinopora 
  (multiserial) 
  D'Orbigny, 
  1853, 
  Radiofascigera 
  D'Orbigny, 
  

   1853, 
  Multitubigera 
  D'Orbigny, 
  1853, 
  and 
  probably 
  according 
  to 
  

   zoarial 
  resemblances 
  Multifascigera 
  D'Orbigny, 
  1853, 
  Lopholepis 
  

   Hagenow, 
  1851, 
  Theonoa 
  Lamouroux, 
  1821, 
  and 
  Serietubigera 
  

   D'Orbigny, 
  1853. 
  

  

  Although 
  established 
  on 
  simple 
  zoarial 
  appearances, 
  all 
  of 
  these 
  

   genera, 
  after 
  a 
  study 
  of 
  the 
  known 
  sections, 
  appear 
  to 
  have 
  an 
  evi- 
  

   dent 
  reality, 
  the 
  mode 
  of 
  gemmation 
  and 
  the 
  arrangement 
  of 
  the 
  

   tubes 
  serving 
  as 
  generic 
  characters. 
  

  

  Genus 
  ACTINOPORA 
  D'Orbigny, 
  1853 
  

  

  ACTINOPORA 
  STELLATA 
  Koch 
  and 
  Dunker, 
  1837 
  

  

  Plate 
  6, 
  figs. 
  1, 
  2 
  

  

  1909. 
  Actinopora 
  stellata 
  Gregory, 
  Catalogue 
  of 
  the 
  Cretaceous 
  Bryozoa, 
  vol. 
  2, 
  

   p. 
  21. 
  (Bibliography.) 
  (Actinopora 
  regularis 
  D'Orbigny, 
  1853.) 
  

  

  