﻿F. 
  TF. 
  Sardeson 
  — 
  Lichenaria 
  tyjpa 
  W. 
  <& 
  S. 
  103 
  

  

  The 
  vertical, 
  intermiiral 
  canals 
  from 
  which 
  the 
  new 
  cells 
  ex- 
  

   pand, 
  arise 
  from 
  the 
  mnral 
  pores 
  or 
  transverse 
  canals, 
  and 
  hence 
  

   they 
  open 
  at 
  the 
  bottom 
  into 
  two, 
  rarely 
  into 
  three 
  or 
  one 
  

   parent 
  cell. 
  But 
  not 
  all 
  mural 
  pores 
  or 
  canals 
  give 
  rise 
  to 
  ver- 
  

   tical 
  canals 
  and 
  young 
  cells. 
  In 
  different 
  specimens 
  and 
  differ- 
  

   ent 
  stages 
  of 
  the 
  same, 
  mural 
  pores 
  of 
  both 
  kinds 
  are 
  apparently 
  

   proportionate 
  to 
  the 
  number 
  of 
  incipient 
  cells, 
  although 
  more 
  

   numerous 
  than 
  these. 
  

  

  Tabulae 
  are 
  few 
  and 
  thin, 
  and 
  like 
  the 
  walls 
  they 
  now 
  

   present 
  a 
  fine 
  crystalline 
  structure 
  onlj^ 
  There 
  is 
  no 
  evidence- 
  

   of 
  " 
  baculi 
  " 
  such 
  as 
  compose 
  the 
  walls 
  and 
  tabulae* 
  of 
  the 
  well 
  

   known 
  Protarcea. 
  Small 
  direct 
  mural 
  spines, 
  or 
  pseudosepta, 
  

   are 
  sometimes 
  present 
  but 
  are 
  not 
  distinguishably 
  arranged 
  in 
  

   continuous 
  rows. 
  

  

  Remarks. 
  The 
  presence 
  of 
  mural 
  pores 
  indicates 
  relation- 
  

   ship 
  to 
  such 
  Tabulate 
  corals 
  as 
  Favosites 
  and 
  especially 
  to 
  

   Michelinia 
  and 
  Fleurodictyum^ 
  but 
  the 
  transverse 
  pores 
  are 
  

   less 
  numerous 
  than 
  in 
  these. 
  The 
  vertical 
  pores 
  or 
  intermural 
  

   canals 
  are 
  like 
  those 
  of 
  Fleiirodictymn 
  et 
  cd.^ 
  and 
  may 
  be 
  

   interpreted 
  as 
  siphonopores 
  or 
  as 
  coenenchymal 
  coeca,t 
  if 
  indeed 
  

   these 
  be 
  not 
  homologous 
  structures. 
  From 
  them 
  budded 
  the 
  

   new 
  polyp-cells. 
  There 
  are 
  therefore 
  three 
  stages 
  of 
  structural 
  

   development 
  distinguishable, 
  viz. 
  a 
  pore, 
  i. 
  e. 
  transverse 
  canal, 
  

   h 
  vertical 
  canal, 
  i. 
  e. 
  siphonopore 
  or 
  coenenchymal 
  coecum, 
  and 
  c 
  

   polyp-cell 
  stage 
  ; 
  but 
  since 
  in 
  some 
  cases 
  a 
  complete 
  transverse 
  

   canal 
  is 
  not 
  developed, 
  and 
  in 
  others 
  such 
  canals 
  exist 
  without 
  

   accompanying 
  second 
  and 
  third 
  stages, 
  it 
  appears 
  most 
  probable 
  

   that 
  we 
  have 
  record 
  of 
  two 
  distinct 
  structures, 
  viz., 
  transverse 
  

   canals 
  and 
  polyps, 
  the 
  young 
  stage 
  of 
  the 
  latter 
  budding 
  often 
  

   but 
  not 
  always 
  from 
  the 
  former. 
  

  

  It 
  is 
  noteworthy, 
  however, 
  that 
  mural 
  pores 
  are 
  most 
  

   numerous 
  where 
  most 
  new 
  polyp 
  cells 
  are 
  developing. 
  

   Beecher's 
  conclusion 
  from 
  study 
  of 
  Fleurodictyum 
  lenticidare 
  

   (Hall), 
  " 
  that 
  primarily, 
  the 
  development 
  of 
  mural 
  pores 
  is 
  

   identical 
  or 
  homologous 
  with 
  the 
  process 
  of 
  gemmation,";}: 
  is 
  

   supported, 
  although 
  insufficiently, 
  by 
  this 
  last 
  mentioned 
  char- 
  

   acter 
  of 
  Lichenaria. 
  If 
  it 
  could 
  be 
  assumed 
  in 
  the 
  case 
  of 
  

   Lichenaria^ 
  that 
  there 
  wei'e 
  no 
  transverse 
  canals 
  developed 
  other 
  

   than 
  those 
  which 
  formed 
  the 
  mural 
  pores, 
  then 
  Lichenaria 
  

   would 
  offer 
  a 
  little 
  better 
  evidence 
  than 
  Plenrodictyuin 
  in 
  

   support 
  of 
  Beecher's 
  view, 
  since 
  it 
  might 
  be 
  said 
  that 
  non-pro- 
  

   ductive 
  mural 
  pores 
  were 
  developing 
  from 
  productive 
  ones 
  

   because 
  they 
  are 
  "developed 
  when 
  the 
  period 
  of 
  gemmation 
  is 
  

  

  *Full 
  grown, 
  fairly 
  well-preserved 
  specimens 
  of 
  Protarcea 
  do 
  have 
  tabulae, 
  

   Lindstrom, 
  op. 
  cit., 
  p. 
  110, 
  notwithstanding. 
  

  

  f 
  Bourne. 
  Philos. 
  Trans, 
  vol. 
  clxxxvi, 
  B.. 
  p. 
  455 
  (1895). 
  

   X 
  Trans. 
  Conn. 
  Acad., 
  vol. 
  viii, 
  p. 
  212 
  (1891). 
  

  

  