﻿70 
  PKOCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  ct 
  

  

  The 
  exterior 
  lamellae 
  could 
  become 
  elevated 
  to 
  form 
  false 
  

   ramifications. 
  

  

  The 
  longitudinal 
  section 
  shows 
  a 
  number 
  of 
  tubes 
  cut 
  tangentially 
  

   and 
  appearing 
  in 
  gray 
  or 
  in 
  black. 
  The 
  facettes 
  were 
  in 
  reality 
  

   arranged 
  regularly 
  in 
  transverse 
  rows. 
  

  

  In 
  Ceriocava 
  the 
  longitudinal 
  section 
  has 
  different 
  aspects 
  accord- 
  

   ing 
  as 
  the 
  facettes 
  are 
  arranged 
  in 
  quincunx 
  or 
  transversely. 
  This 
  

   obsvervation 
  was 
  known, 
  but 
  it 
  is 
  important 
  that 
  it 
  has 
  been 
  con- 
  

   firmed 
  on 
  the 
  same 
  species. 
  

  

  The 
  central 
  tubes 
  grow 
  by 
  axial 
  gemmation 
  around 
  a 
  single 
  tube 
  

   which 
  branches 
  only 
  at 
  the 
  bifurcations 
  of 
  the 
  branches. 
  This 
  tube 
  

   appears 
  in 
  transversal 
  sections 
  with 
  a 
  larger 
  diameter. 
  

  

  Occurrence. 
  — 
  Lower 
  Cretaceous 
  (Valangian) 
  : 
  Sainte-Croix 
  CVaud) 
  j 
  

   Switzerland 
  (common) 
  . 
  

  

  Cotypes.— 
  Cat. 
  No. 
  69922, 
  U.S.N.M. 
  

  

  CERIOCAVA 
  INGENS, 
  new 
  species 
  

  

  Plate 
  8, 
  figs. 
  8-12 
  

  

  Description. 
  — 
  The 
  zoarium 
  is 
  free, 
  large, 
  arborescent; 
  the 
  branches 
  

   are 
  compressed 
  or 
  cylindrical. 
  The 
  facettes 
  are 
  distinct, 
  separated 
  

   by 
  a 
  furrow 
  of 
  little 
  depth, 
  somewhat 
  convex, 
  smooth, 
  arranged 
  

   in 
  quincunx, 
  pierced 
  at 
  the 
  middle 
  by 
  the 
  aperture. 
  The 
  aper- 
  

   ture 
  is 
  orbicular 
  and 
  surrounded 
  by 
  a 
  thin, 
  little 
  salient 
  peristome. 
  

   The 
  orifices 
  of 
  the 
  tubes 
  without 
  facettes 
  are 
  large 
  and 
  irregularly 
  

   polygonal. 
  

  

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

   peristome, 
  0.17 
  mm.; 
  diameter 
  of 
  facettes, 
  0.30-0.40 
  mm.; 
  diameter 
  

   of 
  orifices 
  without 
  facettes, 
  0.20 
  mm.; 
  diameter 
  of 
  zoarium, 
  10 
  mm. 
  

  

  Affinities. 
  — 
  As 
  in 
  all 
  species 
  of 
  the 
  genus, 
  the 
  orifice 
  of 
  the 
  tubes 
  

   without 
  facettes 
  is 
  expanded; 
  it 
  measures 
  internally 
  at 
  the 
  base 
  of 
  

   the 
  visible 
  peristomie 
  0.17 
  mm., 
  but 
  externally 
  its 
  diameter 
  is 
  about 
  

   0.40 
  mm., 
  exactly 
  equal 
  to 
  that 
  of 
  the 
  tubes 
  with 
  facettes. 
  

  

  The 
  species 
  differs 
  from 
  Diplocava 
  inordinata 
  in 
  its 
  monomorphic 
  

   zooecia, 
  its 
  large 
  zoarium, 
  and 
  its 
  much 
  larger 
  micrometric 
  measure- 
  

   ments. 
  On 
  the 
  figured 
  specimen 
  the 
  tubes 
  with 
  facettes 
  are 
  at 
  the 
  

   bottom 
  of 
  the 
  zoarium; 
  the 
  branches 
  are 
  deprived 
  of 
  them. 
  

  

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

   Switzerland 
  (very 
  rare) 
  . 
  

  

  Cotype.— 
  Cat. 
  No. 
  69923, 
  U.S.N.M. 
  

  

  CERIOCAVA 
  TENUIRAMA, 
  new 
  species 
  

  

  Plate 
  10, 
  figs. 
  1-4 
  

  

  Description. 
  — 
  The 
  zoarium 
  is 
  free, 
  cylindrical, 
  bifurcated, 
  formed 
  

   of 
  small 
  branches. 
  The 
  orifices 
  of 
  the 
  tubes 
  without 
  facettes 
  are 
  

   lozenge-shaped, 
  elongated, 
  arranged 
  in 
  transverse 
  rows. 
  The 
  orifices 
  

  

  