﻿G. 
  R. 
  VINE 
  ON 
  THE 
  WENLOCK 
  POLYZOA. 
  61 
  

  

  author. 
  M'Coy 
  says 
  : 
  — 
  " 
  Interstices 
  [branches] 
  connected 
  by 
  thin, 
  

   transverse, 
  non-poriferous 
  dissepiments 
  " 
  *. 
  This 
  is 
  the 
  distinctive 
  

   feature 
  of 
  Carboniferous 
  and 
  Devonian 
  species, 
  but 
  not 
  of 
  the 
  type 
  

   included 
  in 
  the 
  genus 
  found 
  in 
  the 
  Silurian 
  rocks 
  and 
  shales. 
  The 
  

   Silurian 
  Hornera 
  ?, 
  then, 
  of 
  Lonsdale, 
  is 
  clearly 
  not 
  a 
  Polypora. 
  

  

  The 
  genus 
  Thamniscus, 
  King, 
  in 
  the 
  absence 
  of 
  fossils 
  on 
  which 
  I 
  

   could 
  more 
  safely 
  rely, 
  I 
  cannot 
  understand. 
  If 
  fig. 
  9, 
  pi. 
  5, 
  of 
  

   his 
  Permian 
  Fossils, 
  stood 
  alone, 
  I 
  should 
  have 
  no 
  difficulty 
  in 
  

   identifying 
  H. 
  crassa, 
  Lonsdale, 
  as 
  a 
  species 
  of 
  the 
  genus 
  Thamniscus, 
  

   King 
  : 
  fig. 
  8 
  is 
  a 
  worn 
  specimen 
  ; 
  but 
  that 
  too 
  is 
  pretty 
  clear. 
  If, 
  

   however, 
  we 
  are 
  obliged 
  to 
  accept 
  the 
  anomalous 
  characters 
  depicted 
  

   in 
  figs. 
  10, 
  11, 
  12 
  as 
  types 
  also 
  of 
  the 
  genus, 
  then 
  we 
  have 
  clearly 
  to 
  

   deal 
  with 
  more 
  than 
  one 
  suborder. 
  As 
  at 
  present 
  understood, 
  it 
  is 
  

   not 
  wise 
  to 
  place 
  the 
  species 
  described 
  by 
  Lonsdale 
  in 
  the 
  genus 
  

   Thamniscus, 
  King. 
  

  

  In 
  describing 
  Carboniferous 
  Polyzoa, 
  Messrs. 
  Young 
  of 
  Glasgow 
  

   have 
  placed 
  in 
  this 
  genus 
  a 
  species 
  f 
  having 
  a 
  very 
  peculiar 
  branching. 
  

   In 
  doing 
  this 
  they 
  must 
  rely 
  upon 
  evidence 
  that, 
  unfortunately, 
  I 
  

   do 
  not 
  possess. 
  I 
  have 
  therefore 
  figured 
  my 
  best 
  fragments 
  in 
  the 
  

   hope 
  that 
  better 
  specimens 
  than 
  I 
  possess 
  will 
  be 
  forthcoming, 
  and 
  

   that 
  the 
  characters 
  of 
  both 
  the 
  genus 
  and 
  the 
  species 
  may 
  be 
  

   redefined 
  %. 
  

  

  Locality. 
  Dudley, 
  Tickwood 
  beds. 
  

  

  I 
  have 
  several 
  fragments 
  of 
  another 
  very 
  delicate 
  species 
  belonging 
  

   to 
  the 
  same 
  genus, 
  whatever 
  it 
  may, 
  in 
  the 
  future, 
  be 
  called 
  ; 
  I 
  can- 
  

   not 
  regard 
  this 
  delicate 
  species 
  as 
  the 
  same, 
  even 
  in 
  a 
  young 
  state, 
  

   as 
  the 
  one 
  described 
  by 
  Lonsdale. 
  I 
  have 
  fragments 
  of 
  both 
  ; 
  and 
  

   they 
  differ 
  in 
  many 
  particulars. 
  I 
  shall 
  therefore 
  temporarily 
  place 
  

   it 
  in 
  the 
  same 
  genus 
  which 
  Lonsdale 
  gives. 
  

  

  13. 
  HoRKERA 
  ? 
  DELICATULA, 
  Sp. 
  n. 
  

  

  Zoarium 
  delicate 
  and 
  irregularly 
  branching 
  dichotomously, 
  but 
  

   not 
  in 
  one 
  plane. 
  Zocecia 
  disposed 
  in 
  diagonal 
  lines, 
  but 
  rarely 
  

   exceeding 
  three 
  ; 
  the 
  marginal 
  cells 
  slightly 
  indent 
  the 
  margin. 
  

   Orifice 
  of 
  cells 
  round 
  when 
  perfect, 
  pyriform 
  or 
  oval 
  when 
  worn 
  ; 
  

   peristomes 
  raised, 
  and 
  the 
  interspaces 
  between 
  the 
  cells 
  filled 
  up 
  

   apparently 
  with 
  wavy 
  lines 
  ; 
  but 
  in 
  section 
  the 
  ccencecium 
  is 
  filled 
  

   in 
  the 
  interspaces 
  between 
  cell 
  and 
  cell 
  with 
  minute 
  pores. 
  Zocecia 
  

   rather 
  more 
  separated, 
  comparatively 
  speaking, 
  than 
  in 
  H. 
  ? 
  crassa 
  ; 
  

   and 
  six 
  cells 
  occupy 
  one 
  line 
  measured 
  perpendicular 
  to 
  the 
  base. 
  

  

  Locality. 
  Basement 
  beds 
  of 
  Buildwas 
  beds, 
  no. 
  22. 
  

  

  This 
  very 
  minute 
  species 
  is 
  the 
  smallest 
  in 
  individual 
  character 
  of 
  

   all 
  the 
  Palaeozoic 
  branching 
  Polyzoa 
  with 
  which 
  I 
  am 
  acquainted. 
  

   The 
  character 
  of 
  the 
  zoarium, 
  the 
  mode 
  of 
  branching, 
  and 
  general 
  

   habit 
  of 
  the 
  species 
  is 
  well 
  shown. 
  I 
  have 
  not 
  found 
  the 
  larger 
  

  

  * 
  Syn. 
  Carb. 
  Foss. 
  of 
  Ireland. 
  t 
  T. 
  Bankini, 
  Y. 
  and 
  Y 
  

  

  X 
  Since 
  this 
  was 
  written, 
  I 
  learn 
  from 
  Mr. 
  Shrubsole, 
  F.G-.S., 
  that 
  in 
  all 
  

   probability 
  he 
  will 
  be 
  able 
  to 
  establish 
  the 
  genus 
  Thamniscus, 
  King, 
  on 
  a 
  more 
  

   solid 
  basis 
  than 
  it 
  rests 
  upon 
  at 
  present. 
  If 
  so, 
  then 
  the 
  species 
  described 
  by 
  

   me 
  as 
  Hornera 
  ? 
  crassa 
  and. 
  H. 
  ? 
  delicatula, 
  Vine, 
  may 
  find 
  a 
  proper 
  resting-place 
  

   in 
  the 
  family 
  Thamniscidse, 
  King. 
  

  

  