﻿The 
  Fauna 
  of 
  the 
  Niagaea 
  Group. 
  107 
  

  

  the 
  rays 
  ; 
  epitheca 
  rarely 
  covering 
  the 
  base, 
  leaving 
  the 
  rays 
  

   exsert 
  ; 
  these, 
  to 
  the 
  number 
  of 
  nine 
  or 
  ten, 
  and 
  sometimes 
  

   twelve, 
  coalesce 
  in 
  the 
  center, 
  gradually 
  increasing 
  in 
  number 
  

   with 
  the 
  growth 
  of 
  the 
  coral 
  till 
  there 
  are 
  from 
  seventeen 
  to 
  

   nineteen 
  at 
  the 
  margin 
  of 
  the 
  calyx. 
  Length, 
  20 
  mm. 
  

  

  With 
  the 
  exception 
  of 
  the 
  exsert 
  septa 
  at 
  the 
  base, 
  this 
  

   coral 
  has 
  all 
  the 
  characteristics 
  of 
  Streptelasma 
  in 
  the 
  

   arrangement 
  of 
  the 
  radiating 
  septa 
  which 
  coalesce 
  near 
  the 
  

   base 
  and 
  for 
  some 
  distance 
  upwards, 
  above 
  which 
  the 
  lamellae 
  

   approach 
  the 
  center, 
  leaving 
  a 
  cylindrical 
  cavity 
  which 
  grad- 
  

   ually 
  expands 
  above. 
  

  

  ZAPHKENTIS 
  Raflnesque. 
  

   Zaphrentis 
  celator. 
  

  

  Plate 
  5, 
  Figs, 
  5, 
  6. 
  

  

  Zaphrentis? 
  celator 
  Hall. 
  Doc. 
  Edit. 
  28th 
  Rep. 
  St. 
  Mus. 
  Nat. 
  Hist. 
  Explanation 
  

   of 
  pi. 
  5, 
  figs. 
  5, 
  6. 
  1876. 
  

  

  Corallum 
  turbinate, 
  rapidly 
  expanding 
  from 
  below, 
  with 
  

   irregularities 
  of 
  growth, 
  producing 
  expansion 
  and 
  contrac- 
  

   tion 
  of 
  the 
  cup. 
  Calyx 
  deep 
  and 
  broadly 
  expanded, 
  the 
  width 
  

   of 
  the 
  specimen 
  figured 
  nearly 
  as 
  great 
  as 
  the 
  height. 
  Dissepi- 
  

   ments, 
  sixty 
  or 
  more. 
  

  

  This 
  species 
  is 
  of 
  rare 
  occurrence 
  in 
  the 
  collections 
  from 
  the 
  

   Waldron 
  locality. 
  

  

  AULOPORA 
  Goldfuss. 
  

   Attlopora 
  precius. 
  

  

  Plate 
  9, 
  Figs. 
  5, 
  6. 
  

  

  Aulopora 
  precius 
  Hall. 
  Hoc. 
  Edit. 
  28th 
  Rep. 
  St. 
  Mus. 
  Nat. 
  Hist. 
  Explanation 
  

   . 
  of 
  pi. 
  9, 
  figs. 
  5, 
  6. 
  1876. 
  

  

  Corallum 
  parasitic, 
  consisting 
  of 
  elongate 
  tubular 
  cells, 
  

   which 
  in 
  their 
  progress 
  of 
  growth 
  usually 
  conform 
  to 
  the 
  sur- 
  

   face 
  on 
  which 
  they 
  grow, 
  somewhat 
  gradually 
  enlarging 
  to 
  

   the 
  aperture. 
  Calyces 
  budding 
  laterally 
  in 
  a 
  direct 
  line 
  or 
  

   sometimes 
  geminating 
  and 
  diverge 
  at 
  an 
  angle 
  of 
  from 
  45 
  to 
  

   80 
  degrees. 
  After 
  budding, 
  the 
  parent 
  cup 
  turns 
  upwards 
  

   and 
  ceases 
  to 
  grow 
  in 
  that 
  direction. 
  The 
  corallum 
  sometimes 
  

  

  