﻿G. 
  K. 
  VINE 
  ON 
  THE 
  WEDLOCK 
  POLYZOA. 
  

  

  67 
  

  

  Localities. 
  Buildwas 
  beds, 
  No. 
  38 
  only 
  ; 
  Coalbrookdale 
  beds, 
  very 
  

   rare 
  fragments 
  ; 
  Tickwood 
  beds, 
  No. 
  25 
  and 
  No. 
  42. 
  

  

  Fig. 
  14. 
  — 
  Ptilodictya 
  interporosa, 
  Vine. 
  

  

  A 
  portion 
  of 
  the 
  branch 
  of 
  one 
  specimen, 
  showing 
  the 
  central 
  and 
  lateral 
  

   arrangement 
  of 
  cells 
  with 
  the 
  intercellular 
  spaces 
  filled 
  with 
  smaller 
  open- 
  

   ings: 
  X 
  12. 
  

  

  20. 
  Ptilodictya 
  intekpokosa, 
  sp. 
  n. 
  (Tig. 
  14.) 
  

  

  Zoarium 
  consisting 
  of 
  a 
  thin, 
  narrow, 
  branching 
  frond 
  of 
  unknown 
  

   extension. 
  Zocecia 
  arranged 
  in 
  two 
  orders 
  ; 
  the 
  median 
  row, 
  or 
  

   rows, 
  may 
  or 
  may 
  not 
  be 
  perpendicular 
  to 
  the 
  base, 
  and 
  may 
  con- 
  

   sist 
  of 
  from 
  one 
  to 
  four 
  rows 
  ; 
  for 
  this 
  character 
  is 
  very 
  variable 
  : 
  the 
  

   lateral 
  rows 
  are 
  oblique, 
  extending 
  to 
  the 
  margin 
  of 
  the 
  zoarium, 
  

   which 
  is 
  rather 
  sharp-edged, 
  but 
  without 
  any 
  marginal 
  striae 
  : 
  cells 
  

   oval, 
  slightly 
  compressed 
  in 
  the 
  middle, 
  rather 
  larger 
  towards 
  the 
  

   margin. 
  The 
  whole 
  of 
  the 
  cells 
  are 
  surrounded 
  by 
  minute 
  openings 
  

   ("interstitial 
  tubules"*) 
  which, 
  becoming 
  filled 
  in, 
  in 
  the 
  older 
  

   growth 
  of 
  the 
  colony 
  present 
  the 
  appearance 
  of 
  a 
  minutely 
  granular 
  

   peristome 
  to 
  the 
  cell. 
  About 
  four 
  cells, 
  with 
  their 
  "interstitial 
  

   tubules," 
  occupy 
  the 
  space 
  of 
  a 
  line 
  in 
  either 
  a 
  longitudinal 
  or 
  oblique 
  

   direction, 
  and 
  about 
  six 
  transversely. 
  The 
  compressed 
  character 
  of 
  

   the 
  median 
  rows 
  in 
  one 
  specimen 
  alters 
  this 
  measurement 
  slightly 
  ; 
  

   but 
  the 
  clearly 
  defined 
  character 
  of 
  the 
  cells 
  of 
  this 
  species 
  is 
  

   unmistakable. 
  

  

  Locality. 
  Tickwood 
  beds, 
  No. 
  42. 
  

  

  This 
  beautiful 
  species 
  is 
  founded 
  upon 
  ten 
  fragments, 
  the 
  longest 
  

   of 
  which 
  is 
  not 
  more 
  than 
  a 
  quarter 
  of 
  an 
  inch 
  in 
  length. 
  The 
  

   characters, 
  however, 
  are 
  so 
  distinct 
  and 
  so 
  unlike 
  those 
  of 
  any 
  other 
  

   Ptilodictya 
  that 
  I 
  know 
  of, 
  that 
  I 
  cannot 
  do 
  otherwise 
  than 
  describe 
  

   it 
  as 
  new. 
  At 
  first 
  sight 
  the 
  specimens 
  may 
  be 
  mistaken 
  for 
  a 
  Fis- 
  

   tulipora, 
  M 
  c 
  Coy 
  ; 
  but 
  although 
  hundreds 
  of 
  fragments 
  of 
  Fistulipora 
  

   are 
  found 
  in 
  the 
  same 
  beds, 
  only 
  the 
  ten 
  specimens 
  of 
  this, 
  as 
  above- 
  

   named, 
  have 
  been 
  found. 
  The 
  orifices 
  of 
  the 
  cells 
  of 
  P. 
  interporosa 
  

   are 
  distinctly 
  oval 
  ; 
  in 
  Fistulipora 
  they 
  are 
  circular 
  ; 
  and 
  in 
  the 
  

   zoarium 
  of 
  this 
  latter 
  species 
  there 
  are 
  non- 
  cellular 
  spaces 
  which 
  

   are 
  filled 
  in 
  with 
  interstitial 
  tubuli 
  of 
  a 
  most 
  marked 
  character. 
  In 
  

  

  Of 
  Nicholson. 
  

  

  j?2 
  

  

  