﻿of 
  

  

  Merriman: 
  Conjugation 
  of 
  Spirogyra. 
  ternata 
  11 
  

  

  h 
  

  

  containing 
  several 
  cells 
  of 
  one 
  sex 
  and 
  then 
  several 
  cells 
  of 
  the 
  

   opposite 
  sex 
  a 
  zigzag 
  position 
  of 
  the 
  threads 
  might 
  be 
  expected, 
  

   instead 
  of 
  the 
  symmetrical 
  curves 
  found 
  in 
  such 
  a 
  t>'pically 
  dioe- 
  

  

  cious 
  form 
  as 
  S. 
  ternata. 
  

  

  It 
  would 
  seem 
  that 
  a 
  continuous 
  movement 
  of 
  contents 
  of 
  the 
  

   cT 
  cells 
  in 
  one 
  direction, 
  thereby 
  increasing 
  the 
  contents 
  of 
  the 
  

   $ 
  thread 
  as 
  the 
  zygospores 
  form 
  and 
  subjecting 
  it 
  to 
  a 
  greater 
  

   geotropic 
  stimulus, 
  would 
  cause 
  a 
  sagging 
  of 
  the 
  thread, 
  resultmg 
  

   in 
  its 
  taking 
  an 
  outer 
  or 
  lower 
  position 
  in 
  reference 
  to 
  the 
  cf 
  

   filament. 
  Yet, 
  in 
  the 
  majority 
  of 
  cases 
  where 
  the 
  curvature 
  was 
  

   extreme 
  and 
  where 
  the 
  $ 
  thread 
  uniformly 
  kept 
  its 
  position, 
  

   there 
  had 
  been 
  no 
  appreciable 
  movement 
  of 
  the 
  contents, 
  even 
  

   when 
  a 
  complete 
  formation 
  of 
  the 
  conjugating 
  tubes 
  had 
  taken 
  

   place. 
  This 
  was 
  evidenced 
  by 
  the 
  fact 
  that 
  the 
  chromatophores 
  

   were 
  unrelaxed 
  in 
  position 
  and 
  also 
  by 
  the 
  intact 
  connecting 
  walls 
  

   of 
  the 
  conjugating 
  tubes. 
  Since 
  a 
  large 
  amount 
  

   material 
  was 
  available 
  it 
  seemed 
  desirable 
  to 
  scrutinize 
  more 
  

   closely 
  this 
  relation 
  of 
  filaments 
  in 
  conjugation. 
  It 
  seemed 
  pos- 
  

   sible 
  that 
  the 
  degree 
  of 
  curvature 
  might 
  be 
  dependent 
  upon 
  the 
  

   amount 
  of 
  tumidity 
  of 
  the 
  cells 
  and 
  not 
  upon 
  the 
  degree 
  of 
  ad- 
  

   vancement 
  in 
  the 
  formation 
  of 
  the 
  zygospores. 
  It 
  was 
  hoped 
  

   also 
  to 
  bring 
  to 
  light 
  more 
  information 
  as 
  to 
  the 
  number 
  and 
  

   nature 
  of 
  the 
  sexually 
  potent 
  cells 
  and 
  the 
  manner 
  of 
  formation 
  

  

  of 
  the 
  conjugating 
  tubes. 
  

  

  Camera 
  drawings 
  were 
  made 
  of 
  many 
  pairs 
  of 
  filaments, 
  in 
  

   some 
  cases 
  numbering 
  over 
  fifty 
  cells. 
  A 
  magnification 
  of 
  140 
  

   diameters 
  was 
  used 
  in 
  order 
  to 
  have 
  as 
  many 
  cells 
  as 
  possible 
  

   in 
  the 
  field 
  of 
  view 
  and 
  yet 
  to 
  see 
  clearly 
  the 
  position 
  of 
  the 
  nuclei 
  

   and 
  chromatophores. 
  Measurements 
  of 
  the 
  drawings 
  for 
  length 
  

   of 
  the 
  cells 
  and 
  filaments 
  were 
  obtained 
  by 
  two 
  methods. 
  In 
  the 
  

   first 
  method 
  a 
  piece 
  of 
  thread 
  held 
  without 
  undue 
  tension, 
  fol- 
  

   lowing 
  the 
  curving 
  outer 
  walls 
  of 
  the 
  cells, 
  was 
  measured 
  with 
  the 
  

   metric 
  ruler. 
  Slight 
  discrepancies 
  in 
  this 
  method 
  would 
  be 
  due 
  to 
  

   the 
  varying 
  tension 
  of 
  the 
  measuring 
  thread. 
  The 
  other 
  method 
  

   employed, 
  when 
  it 
  was 
  desired 
  to 
  compare 
  cell 
  with 
  cell 
  instead 
  

   of 
  filaments 
  as 
  a 
  whole, 
  was 
  to 
  measure 
  the 
  distance 
  from 
  one 
  

   transverse 
  wall 
  to 
  the 
  next 
  with 
  the 
  ruler, 
  not 
  allowing 
  for 
  the 
  

   convexity 
  of 
  the 
  lateral 
  walls. 
  Such 
  distances 
  added 
  would 
  bring 
  

  

  