﻿242 
  Prof. 
  Carl 
  Chun 
  on 
  the 
  

  

  increases 
  continuously, 
  but 
  at 
  the 
  same 
  time 
  new 
  bud-groups 
  

   appeal' 
  between 
  the 
  oldest 
  approximated 
  groups 
  of 
  the 
  internode. 
  

   In 
  our 
  case 
  the 
  oldest 
  approximated 
  groups 
  are 
  represented 
  by 
  

   a. 
  A; 
  consequently 
  we 
  obtain 
  for 
  a 
  further 
  developed 
  inter- 
  

   node 
  the 
  following 
  formula 
  (the 
  newly-formed 
  groups 
  being 
  

   indicated 
  by 
  a 
  . 
  /3 
  . 
  . 
  .) 
  : 
  — 
  

  

  B 
  . 
  i 
  . 
  h 
  . 
  g 
  .f.e 
  . 
  d 
  . 
  c 
  .b 
  . 
  a 
  a 
  A. 
  

  

  The 
  group 
  a 
  is 
  in 
  this 
  case 
  as 
  far 
  developed 
  as 
  the 
  group 
  i 
  

   formed 
  in 
  regular 
  sequence. 
  

  

  By 
  further 
  growth 
  a 
  secondary 
  internode 
  may 
  be 
  inter- 
  

   calated 
  between 
  a 
  . 
  A, 
  which, 
  in 
  its 
  growth, 
  behaves 
  exactly 
  

   like 
  the 
  primary 
  internode, 
  in 
  so 
  far 
  as 
  in 
  it 
  also 
  the 
  groups 
  

   are 
  new-formed 
  in 
  a 
  proximal 
  direction. 
  At 
  the 
  same 
  time, 
  

   however, 
  new 
  bud-groups 
  again 
  appear, 
  in 
  accordance 
  with 
  

   the 
  law 
  above 
  mentioned, 
  between 
  the 
  oldest 
  approximated 
  

   groups 
  of 
  the 
  primary 
  internode, 
  i. 
  e. 
  between 
  b 
  and 
  a. 
  We 
  

   should 
  therefore 
  obtain, 
  for 
  a 
  later 
  stage, 
  the 
  following 
  

   formula 
  : 
  — 
  

  

  B 
  .Jc.t.h.g 
  ./. 
  e.d.c.bu'afiuA. 
  

  

  The 
  latest 
  formed 
  bud-groups 
  of 
  the 
  same 
  size 
  are 
  here 
  

   h 
  } 
  «', 
  and 
  /3. 
  

  

  These 
  formulas 
  may 
  easily 
  be 
  further 
  developed, 
  if 
  we 
  keep 
  

   in 
  our 
  eye 
  the 
  law 
  that 
  new 
  bud-groups 
  always 
  originate 
  only 
  

   between 
  the 
  oldest 
  approximated 
  groups 
  of 
  the 
  primary 
  inter- 
  

   node, 
  and 
  that 
  the 
  intercalated 
  secondary 
  internodes, 
  as 
  well 
  

   as 
  the 
  primary 
  ones, 
  form 
  new 
  groups 
  in 
  the 
  proximal 
  

   direction. 
  

  

  Only 
  in 
  one 
  case 
  I 
  have 
  also 
  observed 
  in 
  the 
  last 
  internode 
  

   of 
  a 
  very 
  large 
  Halistemma 
  the 
  rudiment 
  of 
  an 
  intercalated 
  ter- 
  

   tiary 
  internode 
  (between 
  a 
  and 
  A). 
  

  

  I 
  may 
  observe 
  expressly 
  that 
  I 
  have 
  found 
  the 
  law 
  of 
  

   growth 
  of 
  the 
  stem 
  here 
  developed 
  to 
  hold 
  good 
  without 
  

   exception 
  in 
  all 
  the 
  specimens 
  examined, 
  and 
  that 
  the 
  formulas 
  

   above 
  given 
  are 
  taken 
  from 
  actual 
  examples. 
  When 
  super- 
  

   ficially 
  examined, 
  indeed, 
  the 
  last 
  and 
  longest 
  internodes 
  

   present 
  a 
  puzzling 
  picture, 
  and 
  may 
  give 
  rise 
  to 
  the 
  erroneous 
  

   notion 
  that 
  the 
  bud-groups 
  have 
  originated 
  irregularly 
  on 
  the 
  

   stem 
  ; 
  but 
  so 
  soon 
  as 
  the 
  regular 
  plan 
  has 
  been 
  recognized, 
  it 
  

   is 
  extraordinarily 
  pleasing 
  to 
  trace 
  it 
  through 
  all 
  the 
  internodes 
  

   of 
  the 
  elongated 
  stem 
  of 
  a 
  quietly 
  suspended 
  Halistemma. 
  

  

  I 
  must 
  leave 
  it 
  to 
  Hackel 
  to 
  say 
  how 
  such 
  regularly 
  ordered 
  

   gemmation 
  on 
  the 
  Physophorid 
  stem 
  is 
  to 
  be 
  reconciled 
  to 
  his 
  

   theory 
  of 
  the 
  multiplication 
  and 
  dislocation 
  of 
  the 
  Medusan 
  

   organs 
  on 
  the 
  Siphonophoran 
  stock. 
  

  

  