﻿58 
  G. 
  K. 
  VINE 
  ON 
  THE 
  WENLOCK 
  POLYZOA. 
  

  

  Cyclostomata. 
  In 
  the 
  Silurian 
  species 
  there 
  is 
  not 
  the 
  least 
  indi- 
  

   cation 
  of 
  these 
  markings 
  or 
  punctures. 
  

  

  Good 
  specimens 
  of 
  the 
  species 
  are 
  comparatively 
  rare. 
  I 
  have 
  only 
  

   found 
  about 
  twenty 
  specimens 
  ; 
  and 
  no 
  two 
  of 
  these 
  are 
  exactly 
  

   alike. 
  Yet 
  there 
  is 
  a 
  general 
  likeness 
  in 
  the 
  whole 
  group 
  of 
  speci- 
  

   mens 
  ; 
  and 
  in 
  the 
  character 
  and 
  structure 
  of 
  the 
  cell 
  an 
  easy 
  com- 
  

   parison 
  may 
  be 
  made 
  with 
  Spiropora 
  regular 
  is. 
  It 
  seems 
  to 
  me 
  

   that 
  the 
  species 
  I 
  am 
  now 
  describing 
  is 
  to 
  some 
  extent 
  an 
  abnormal 
  

   form, 
  which 
  has 
  become 
  constant 
  within 
  a 
  very 
  limited 
  area, 
  and 
  

   taken 
  the 
  place 
  of 
  S. 
  regidaris 
  in 
  these 
  beds, 
  to 
  some 
  extent 
  at 
  least. 
  

   I 
  found 
  a 
  few 
  small 
  fragments 
  of 
  this 
  last 
  species 
  in 
  this 
  and 
  in 
  

   another 
  washing 
  ; 
  but 
  the 
  specimens 
  are 
  true 
  to 
  the 
  characters 
  

   already 
  ascribed 
  to 
  the 
  species. 
  It 
  would 
  perhaps 
  be 
  better 
  to 
  speak 
  

   of 
  S. 
  intermedia 
  as 
  a 
  variety 
  of 
  the 
  other. 
  In 
  this 
  case 
  it 
  would 
  be 
  

   necessary 
  to 
  have 
  some 
  indication 
  that 
  such 
  was 
  the 
  fact 
  ; 
  but 
  of 
  this 
  

   I 
  have 
  no 
  evidence, 
  except 
  that 
  the 
  non-exserted 
  cells 
  have 
  a 
  specific 
  

   likeness 
  in 
  some 
  parts 
  of 
  the 
  zoarium. 
  Both 
  in 
  the 
  general 
  habit 
  

   and 
  the 
  characters 
  of 
  the 
  two 
  species 
  they 
  are 
  individually 
  and 
  

   collectively 
  distinct. 
  S. 
  regularis 
  hardly 
  ever 
  varies 
  either 
  in 
  the 
  

   arrangement 
  of 
  the 
  cells 
  or 
  in 
  the 
  mode 
  of 
  branching. 
  This 
  one 
  

   varies 
  considerably 
  in 
  the 
  cell-arrangement; 
  and 
  the 
  branching, 
  when 
  

   present, 
  is 
  different. 
  

  

  Locality. 
  No. 
  25. 
  Tickwood 
  Beds. 
  

  

  9. 
  Diastopora 
  consimilis, 
  Lonsd. 
  

  

  Aulopora 
  consimilis, 
  Lonsd. 
  Silurian 
  Syst. 
  pi. 
  15. 
  fig. 
  7. 
  

  

  Diastopora 
  consimilis, 
  Lonsd. 
  Siluria, 
  1859, 
  3rd 
  ed. 
  

  

  In 
  plate 
  15. 
  fig. 
  7, 
  of 
  the 
  ' 
  Silurian 
  System,' 
  Lonsdale 
  placed 
  amongst 
  

   the 
  corals 
  the 
  above 
  species, 
  leaving 
  the 
  genus 
  as 
  doubtful 
  (Aulo- 
  

   pora 
  ?) 
  with 
  the 
  remark 
  " 
  probably 
  a 
  Bryozoon." 
  His 
  description 
  

   of 
  the 
  species 
  is 
  : 
  — 
  

  

  ' 
  ; 
  Encrusting, 
  tubes 
  round, 
  close 
  together, 
  radiated, 
  bifurcated 
  ; 
  

   opening 
  circular, 
  raised, 
  margins 
  thick." 
  

  

  " 
  Similar 
  to 
  Aulopora 
  compressa, 
  Goldf., 
  found 
  in 
  the 
  Oolitic 
  

   series 
  of 
  Germany. 
  Locality 
  and 
  formation, 
  Wenlock 
  Limestone 
  " 
  *. 
  

  

  This 
  comparison 
  with 
  the 
  species 
  of 
  Goldfuss 
  is 
  very 
  exact 
  ; 
  and 
  

   if 
  I 
  were 
  dealing 
  with 
  an 
  Oolitic 
  Diastopora 
  I 
  should 
  have 
  little 
  

   hesitation 
  in 
  confirming 
  Lonsdale's 
  reference. 
  

  

  In 
  my 
  British-Association 
  Report 
  on 
  Silurian 
  Polyzoaf, 
  I 
  have 
  

   made 
  a 
  reference 
  to 
  Lonsdale's 
  species, 
  and 
  I 
  have 
  also 
  described 
  a 
  

   specimen 
  submitted 
  to 
  me 
  by 
  Mr. 
  Longe. 
  Since 
  this 
  was 
  written 
  I 
  

   have 
  discovered 
  a 
  fragment 
  of 
  shell 
  nearly 
  triangular 
  in 
  shape, 
  three 
  

   and 
  a 
  half 
  lines 
  in 
  breadth 
  by 
  three 
  lines 
  long, 
  covered 
  by 
  a 
  portion 
  

   of 
  what 
  has 
  apparently 
  been 
  a 
  large 
  colony. 
  I 
  have 
  therefore 
  made 
  

   the 
  following 
  diagnosis 
  from 
  that 
  fragment 
  alone. 
  

  

  Zoarium 
  of 
  unknown 
  dimensions, 
  in 
  crusting 
  by 
  a 
  single 
  layer 
  a 
  

  

  fragment 
  of 
  shell. 
  Zooecia 
  tubular, 
  regular, 
  elongate, 
  in 
  series, 
  the 
  

  

  proximal 
  end 
  of 
  the 
  cell 
  rather 
  narrower 
  than 
  the 
  distal; 
  cells 
  

  

  contiguous, 
  but 
  each 
  separated 
  by 
  its 
  own 
  wall. 
  Orifice 
  circular 
  ; 
  

  

  * 
  ' 
  Silurian 
  System,' 
  descriptive 
  text 
  of 
  pi. 
  15. 
  t 
  York, 
  1881. 
  

  

  

  