﻿18 
  Merriman; 
  Co^7UGATION 
  of 
  Spirqgyra 
  ternata 
  

  

  crease 
  of 
  22 
  //, 
  the 
  corresponding 
  cell 
  of 
  the 
  cf 
  filament 
  shows 
  a 
  

   reduction 
  of 
  22 
  \x 
  in 
  the 
  outer 
  wall. 
  This 
  equality 
  is 
  presumably 
  a 
  

   coincidence, 
  since 
  the 
  second 
  cf 
  cell 
  in 
  Table 
  IV 
  shows 
  a 
  similar 
  

   reduction 
  of 
  21 
  /x 
  in 
  the 
  outer 
  wall. 
  This 
  cell 
  is 
  not 
  conjugating 
  

   but 
  is 
  opposite 
  tumid 
  cells 
  of 
  the 
  9 
  thread 
  and 
  is 
  probably 
  in- 
  

   fluenced 
  by 
  them. 
  

  

  In 
  the 
  cT 
  filament 
  there 
  is 
  a 
  reduction 
  in 
  the 
  outer 
  wall 
  in 
  

   every 
  cell 
  but 
  the 
  second 
  from 
  the 
  end 
  A. 
  In 
  this 
  cell 
  it 
  is 
  to 
  be 
  

   seen 
  that 
  more 
  of 
  the 
  wall 
  than 
  is 
  usually 
  the 
  case 
  takes 
  part 
  in 
  

   the 
  formation 
  of 
  the 
  tube. 
  All 
  of 
  this 
  wall 
  is 
  elevated 
  from 
  the 
  

   level 
  of 
  a 
  straight 
  line 
  connecting 
  the 
  transverse 
  walls. 
  The 
  

   bulging 
  of 
  this 
  wall 
  has 
  probably 
  counteracted 
  the 
  usual 
  tendency 
  

   of 
  the 
  inner 
  parts 
  of 
  the 
  transverse 
  walls 
  to 
  spread 
  apart. 
  

  

  According 
  to 
  these 
  measurements, 
  then, 
  the 
  compression 
  in 
  the 
  

   filament, 
  as 
  revealed 
  in 
  the 
  breaking 
  and 
  subsequent 
  replacement 
  

   of 
  the 
  broken 
  parts, 
  does 
  not 
  involve 
  the 
  filaments 
  as 
  a 
  whole 
  but 
  

   is 
  restricted 
  in 
  its 
  extent 
  to 
  the 
  parts 
  of 
  the 
  cells 
  which 
  are 
  farthest 
  

   from 
  the 
  conjugating 
  tube. 
  Measurements 
  also 
  indicate 
  that 
  

   differences 
  in 
  tension 
  in 
  the 
  9 
  cells 
  are 
  not 
  so 
  different 
  from 
  those 
  

   occurring 
  in 
  vegetative 
  cells. 
  In 
  this 
  connection 
  it 
  is 
  to 
  be 
  

   remembered 
  that 
  all 
  the 
  cells 
  of 
  a 
  filament 
  are 
  in 
  a 
  state 
  of 
  slight 
  

   compression, 
  for 
  when 
  a 
  filament 
  is 
  broken 
  or 
  an 
  intervening 
  cell 
  

   dies 
  the 
  end 
  cell 
  extends 
  slightly, 
  rounding 
  off 
  and 
  assuming 
  the 
  

   regular 
  shape 
  of 
  an 
  ordinary 
  terminal 
  cell. 
  This 
  does 
  not 
  explain 
  

   the 
  striking 
  and 
  opposing 
  differences 
  in 
  tension 
  found 
  exclusively 
  

   in 
  cells 
  In 
  the 
  conjugating 
  state. 
  

  

  In 
  another 
  part 
  of 
  this 
  investigation 
  other 
  changes 
  in 
  the 
  

   conjugating 
  cells 
  will 
  be 
  considered, 
  especially 
  the 
  formation 
  of 
  

   the 
  tubes. 
  There 
  it 
  will 
  be 
  noted 
  that 
  more 
  of 
  the 
  inner 
  wall 
  of 
  

   the 
  9 
  cell 
  takes 
  part 
  in 
  the 
  formation 
  of 
  the 
  tube 
  than 
  is 
  the 
  

   case 
  with 
  the 
  cT 
  cell. 
  Hence, 
  as 
  in 
  Fig. 
  3, 
  where 
  E 
  and 
  F 
  of 
  the 
  9 
  

   cell 
  are 
  always 
  nearer 
  relatively 
  than 
  C 
  and 
  D 
  of 
  the 
  cf 
  cell, 
  the 
  

   linear 
  extension 
  of 
  the 
  conjugating 
  tube 
  of 
  the 
  9 
  cell 
  will 
  be 
  found 
  

   to 
  exceed 
  that 
  of 
  the 
  cf* 
  cell, 
  if 
  all 
  of 
  the 
  linear 
  extension 
  pressing 
  

   against 
  the 
  opposing 
  wall 
  is 
  considered. 
  However, 
  it 
  Is 
  the 
  

   bringing 
  together 
  of 
  the 
  transverse 
  walls 
  and 
  the 
  consequent 
  

   rectilinear 
  contraction 
  of 
  one 
  side 
  of 
  the 
  filament 
  at 
  the 
  beginning 
  

  

  A 
  

  

  of 
  conjugation 
  that 
  results 
  in 
  the 
  constant 
  relative 
  nosltive 
  of 
  the 
  

  

  