﻿4 
  

  

  Howe: 
  Monosporangial 
  discs 
  in 
  Liagora 
  

  

  k 
  

  

  wall 
  is 
  abjointed 
  as 
  a 
  one-celled 
  gemma, 
  but 
  when 
  abjointing 
  

   occurs 
  the 
  subjacent 
  cell 
  commonly 
  goes 
  with 
  it, 
  the 
  two 
  together 
  

   (Figs. 
  7 
  and 
  8) 
  constituting 
  a 
  two- 
  celled 
  gemma. 
  In 
  this 
  case, 
  

   the 
  lower 
  of 
  the 
  two 
  cells 
  seems 
  not 
  to 
  divide 
  but 
  to 
  persist 
  as 
  a 
  

   finally 
  inconspicuous 
  stalk 
  or 
  appendage 
  of 
  the 
  young 
  disc, 
  which 
  

   results 
  from 
  divisions 
  of 
  the 
  upper 
  cell 
  (Fig. 
  22). 
  Very 
  rarely 
  

   (Fig. 
  28), 
  one 
  finds 
  an 
  irregular 
  pluricellular 
  gemma 
  formed 
  with- 
  

   out 
  obvious 
  rejuvenescence 
  or 
  with 
  rejuvenescence 
  limited 
  to 
  one 
  

   or 
  two 
  of 
  its 
  cells. 
  Occasionally 
  (Fig. 
  9) 
  several 
  consecutive 
  

  

  Fig. 
  25. 
  Terminal 
  cells 
  of 
  an 
  assimilatory 
  filament 
  of 
  Liagora 
  ceranoides 
  (No 
  

   4778d, 
  from 
  Montego 
  Bay, 
  Jamaica), 
  showing 
  enlargement 
  and 
  rounding 
  oi 
  two 
  of 
  

   them 
  preparatory 
  to 
  their 
  division 
  to 
  form 
  multicellular 
  gemmae, 
  which 
  develop 
  

   into 
  monosporangium-bearing 
  discs. 
  X 
  510. 
  

  

  Fig. 
  26. 
  A 
  later 
  stage, 
  showing 
  young 
  disc, 
  still 
  attached, 
  disc 
  and 
  stalk-cell 
  

   together 
  corresponding 
  to 
  a 
  twice 
  forked 
  vegetative 
  branch 
  four 
  cells 
  long 
  (No. 
  

   477&d), 
  X 
  620. 
  

  

  Fig. 
  27. 
  Dorsal 
  view 
  of 
  a 
  young 
  disc, 
  slightly 
  smaller 
  than 
  that 
  shown 
  in 
  

   Fig. 
  26 
  (No. 
  4778d), 
  X 
  260. 
  

  

  Fig. 
  28. 
  Apex 
  of 
  an 
  assimilarity 
  filament 
  showing 
  irregular 
  division 
  to 
  form 
  a 
  

   gemma 
  (No. 
  574/. 
  L, 
  ceranoides. 
  Gun 
  Cay, 
  Bahama 
  Islands). 
  X 
  620. 
  

  

  Fig. 
  29. 
  A 
  gemma 
  in 
  a 
  three-celled 
  stage, 
  the 
  original 
  mother-cell 
  waU 
  gela- 
  

   tinizing 
  at 
  apex 
  (No. 
  j/4/). 
  X 
  510. 
  

  

  ft 
  

  

  cells 
  of 
  a 
  filament 
  are 
  converted 
  Into 
  aplanospores 
  with 
  evident 
  

   rejuvenescence 
  and 
  with 
  gelatinization 
  of 
  the 
  original 
  walls. 
  

   The 
  first 
  divisions 
  of 
  the 
  rejuvenated 
  cell 
  appear 
  to 
  occur 
  in 
  a 
  

   variety 
  of 
  ways. 
  Often 
  (Figs. 
  8 
  and 
  29) 
  thev 
  sueeest 
  the 
  "cru- 
  

  

  