﻿G. 
  W. 
  SHRTJBSOLE 
  ON 
  THAMNISCUS. 
  311 
  

  

  34. 
  Thamniscus 
  : 
  Permian, 
  Carboniferous, 
  and 
  Silurian. 
  By 
  

   George 
  W. 
  Shrubsole, 
  Esq., 
  E.G.S. 
  (Read 
  April 
  26, 
  1882.) 
  

  

  The 
  genus 
  Thamniscus 
  was 
  founded 
  in 
  1819 
  by 
  Prof. 
  King 
  for 
  a 
  

   Polyzoan 
  of 
  large 
  size 
  found 
  in 
  the 
  Permian 
  beds 
  of 
  the 
  north 
  of 
  

   England. 
  The 
  main 
  interest 
  of 
  the 
  genus 
  consisted 
  in 
  Prof. 
  King 
  

   claiming 
  for 
  the 
  type 
  species 
  the 
  possession 
  of 
  certain 
  " 
  denticles," 
  

   " 
  vesicles," 
  and 
  " 
  hemispherical 
  bodies 
  " 
  similar 
  to 
  those 
  observed 
  in 
  

   " 
  certain 
  Lunulites 
  and 
  Cellaria 
  salicornia 
  "*. 
  Prof. 
  King 
  further 
  

   institutes 
  comparisons 
  between 
  these 
  peculiarities 
  in 
  his 
  genus 
  and 
  

   some 
  of 
  the 
  recent 
  forms 
  of 
  Polyzoa 
  formerly 
  included 
  among 
  

   Elasmopora, 
  Escharina, 
  and 
  Celleporaf. 
  It 
  is 
  needless 
  to 
  say 
  that 
  

   these 
  features 
  at 
  once 
  assign 
  the 
  genus 
  to 
  the 
  order 
  of 
  Chilosto- 
  

   matous 
  Polyzoa; 
  and 
  as 
  such 
  it 
  is 
  entitled 
  to 
  rank 
  as 
  the 
  most 
  

   pronounced 
  type 
  of 
  its 
  class 
  found 
  among 
  the 
  Palaeozoic 
  Polyzoa. 
  

   How 
  far 
  these 
  characters 
  can 
  be 
  sustained 
  will 
  be 
  the 
  subject 
  of 
  

   after 
  inquiry. 
  The 
  next 
  reference 
  to 
  the 
  gen 
  as 
  that 
  I 
  find 
  is 
  in 
  

   1874, 
  when 
  Mr. 
  R. 
  Etheridge, 
  Jun., 
  described, 
  as 
  found 
  in 
  some 
  

   Scottish 
  Carboniferous 
  Limestone 
  shale, 
  a 
  fragment 
  of 
  a 
  Polyzoan 
  

   which 
  he 
  thought 
  might 
  be 
  a 
  new 
  species 
  of 
  Polypora, 
  at 
  the 
  same 
  

   time 
  remarking 
  that 
  the 
  disposition 
  of 
  the 
  cells 
  and 
  the 
  mode 
  of 
  

   branching 
  were 
  exceedingly 
  like 
  those 
  seen 
  in 
  the 
  type 
  species 
  of 
  

   Thamniscus 
  (T. 
  dubius, 
  King), 
  and 
  suggesting 
  that 
  it 
  might 
  be 
  a 
  

   species 
  of 
  that 
  genus 
  J. 
  

  

  In 
  1875 
  the 
  Messrs. 
  Young, 
  of 
  Glasgow, 
  described 
  (under 
  the 
  

   name 
  of 
  Thamniscus 
  Eanhini) 
  a 
  free, 
  robust, 
  branching 
  Polyzoan 
  

   which 
  they 
  had 
  received 
  from 
  Dr. 
  Eankin 
  of 
  Carluke, 
  and 
  which 
  

   is 
  probably 
  identical 
  with 
  the 
  species 
  referred 
  to 
  by 
  Mr. 
  R. 
  Etheridge, 
  

   Jun. 
  At 
  the 
  same 
  time 
  they 
  remark 
  that 
  the 
  generic 
  position 
  of 
  

   the 
  fossil 
  is 
  uncertain 
  ; 
  and 
  if 
  the 
  " 
  gemmuliferous 
  vesicles 
  " 
  described 
  

   by 
  Prof. 
  King 
  are 
  essential 
  to 
  Thamniscus, 
  this 
  character 
  is 
  wanting 
  

   in 
  their 
  species, 
  even 
  in 
  the 
  best-preserved 
  specimens 
  §. 
  After 
  

   further 
  discussing 
  its 
  position 
  they 
  conclude 
  by 
  saying, 
  " 
  we 
  think 
  

   it 
  safer 
  to 
  leave 
  it 
  in 
  the 
  Palaeozoic 
  genus 
  Thamniscus. 
  ," 
  There 
  is 
  

   very 
  little 
  doubt 
  about 
  the 
  correctness 
  of 
  this 
  reference, 
  since 
  it 
  is 
  an 
  

   undoubted 
  Thamniscus, 
  

  

  As 
  yet 
  I 
  have 
  no 
  record 
  or 
  trace 
  of 
  Thamniscus 
  being 
  found 
  in 
  

   the 
  Devonian 
  rocks, 
  and 
  therefore 
  pass 
  on 
  to 
  the 
  Silurian 
  species. 
  

  

  I 
  have 
  long 
  been 
  familiar 
  with 
  fragments 
  of 
  a 
  Polyzoan 
  in 
  the 
  

   Dudley 
  Limestone 
  which 
  bear 
  a 
  general 
  resemblance 
  to 
  the 
  Permian 
  

   Thamniscus 
  ; 
  but 
  the 
  fragmentary 
  condition 
  of 
  the 
  remains 
  forbade 
  

   description. 
  Recently 
  I 
  have 
  found 
  in 
  the 
  Woodwardian 
  Museum, 
  

   labelled 
  by 
  Salter 
  Ceriopora, 
  a 
  fine 
  specimen 
  of 
  the 
  same, 
  in 
  

   which 
  the 
  growth, 
  habit, 
  and 
  cell-pore 
  are 
  sufficiently 
  displayed 
  to 
  

  

  * 
  Perm. 
  Foss. 
  England, 
  p. 
  45. 
  t 
  Ibid. 
  p. 
  40. 
  

  

  \ 
  Mem. 
  Geol. 
  Surv. 
  Scotland, 
  Explan. 
  Sh. 
  23, 
  p. 
  102. 
  

   § 
  Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  1875, 
  vol. 
  xv. 
  p. 
  336. 
  

   Q.J.G.S. 
  No. 
  151. 
  2 
  a 
  

  

  