﻿71 
  

  

  eggs 
  exaiiiined 
  had 
  passed 
  through 
  the 
  first 
  stage 
  of 
  

   activity, 
  and 
  as 
  far 
  as 
  could 
  be 
  decided 
  had 
  reached 
  the 
  

   second 
  period 
  of 
  rest 
  — 
  resembling 
  Brook's 
  figs. 
  8, 
  9 
  and 
  

   10. 
  I 
  was 
  called 
  away 
  from 
  the 
  microscope 
  at 
  this 
  time 
  

   and 
  was 
  unable 
  to 
  trace 
  the 
  changes 
  during 
  the 
  second 
  

   period 
  of 
  rest 
  or 
  to 
  note 
  the 
  time 
  of 
  their 
  occurrence. 
  

  

  At 
  1.27 
  A. 
  M., 
  or 
  live 
  hours 
  and 
  fifteen 
  minutes 
  after 
  

   fertilization, 
  the 
  eggs 
  had 
  passed 
  through 
  the 
  second 
  

   period 
  of 
  activity 
  and 
  had 
  entered 
  upon 
  the 
  third 
  period 
  

   of 
  rest. 
  In 
  some 
  of 
  them 
  the 
  four 
  micromeres 
  were 
  

   easily 
  observed, 
  but 
  in 
  others 
  they 
  were 
  not 
  so 
  distinct 
  ; 
  

   a 
  few 
  were 
  as 
  figured 
  by 
  Brook's 
  (fig. 
  1(5), 
  but 
  tlie 
  ma- 
  

   jority 
  appeared 
  as 
  in 
  figs. 
  18 
  and 
  19. 
  

  

  I 
  was 
  unable 
  to 
  follow 
  the 
  intermediate 
  chfinges 
  be- 
  

   tween 
  those 
  of 
  the 
  third 
  period 
  of 
  rest 
  and 
  those 
  of 
  the 
  

   first 
  swimming 
  stage, 
  but 
  at 
  my 
  next 
  observation, 
  at 
  4.30 
  

   A. 
  M., 
  on 
  the 
  7th, 
  larger 
  nuuibers 
  of 
  eggs 
  had 
  reached 
  

   the 
  latter 
  stage 
  and 
  were 
  swimming 
  at 
  the 
  surface 
  of 
  the 
  

   water. 
  The 
  cilia 
  were 
  well 
  developed 
  and 
  the 
  movements 
  

   of 
  the 
  embryo 
  very 
  rapid 
  — 
  their 
  appearance 
  was 
  exactlj^ 
  

   as 
  figured 
  by 
  Brooks' 
  figs., 
  82, 
  33, 
  34 
  and 
  3;"). 
  The 
  water 
  

   in 
  the 
  glass 
  was 
  now 
  siphoned 
  off, 
  into 
  a 
  jar, 
  that 
  the 
  

   embryo 
  miglit 
  have 
  room 
  for 
  development 
  and 
  be 
  free 
  

   from 
  the 
  inliiience 
  of 
  decaying 
  eggs 
  ; 
  but 
  as 
  I 
  had 
  but 
  

   two 
  fruit 
  jars 
  holding 
  a 
  quart 
  each, 
  with 
  which 
  to 
  con- 
  

   duct 
  my 
  experiment, 
  I 
  was 
  forced 
  to 
  take 
  many 
  eggs 
  into 
  

   the 
  second 
  receptacle 
  before 
  they 
  had 
  developed 
  swim- 
  

   ming 
  powers, 
  or 
  else 
  sacrifice 
  them. 
  As 
  the 
  rate 
  of 
  seg- 
  

   mentation 
  was 
  very 
  irregular, 
  I 
  had 
  for 
  a 
  time, 
  what 
  was 
  

   to 
  me, 
  a 
  rather 
  confusing 
  mixture 
  of 
  eggs 
  in 
  the 
  process 
  

   of 
  segmentation 
  and 
  developing 
  embryos 
  ; 
  but 
  with 
  care 
  

   and 
  close 
  observaticm, 
  I 
  managed 
  to 
  follow 
  each 
  lot 
  initil 
  

   they 
  reached 
  the 
  swimming 
  stage 
  and 
  could 
  observe 
  no 
  

   difference 
  between 
  them 
  and 
  the 
  first, 
  except 
  in 
  the 
  rate 
  

   of 
  change 
  from 
  one 
  period 
  to 
  another. 
  

  

  At 
  12.30 
  P. 
  M., 
  June 
  7th, 
  or 
  sixteen 
  and 
  a-half 
  hours 
  

   after 
  fertilizaticm, 
  there 
  were 
  many 
  eggs 
  in 
  the 
  first 
  swim- 
  

  

  