﻿d9 
  

  

  more, 
  when 
  it 
  becomes 
  gradually 
  opaque 
  and 
  disintegrates. 
  

   During 
  this 
  period 
  of 
  disintegration, 
  masses, 
  larger 
  or 
  

   smaller, 
  will 
  protrude 
  from 
  the 
  surface 
  of 
  the 
  vjtellus, 
  and 
  

   oftentimes 
  of 
  very 
  fantastic 
  shape, 
  Fig. 
  10, 
  PL 
  VI. 
  The 
  

   remainder 
  of 
  the 
  vitellus, 
  during 
  this 
  early 
  limbed 
  condi- 
  

   tion, 
  remains 
  very 
  much 
  as 
  in 
  those 
  ova 
  wliich 
  show 
  no 
  

   "rising" 
  phase; 
  i. 
  e., 
  with 
  oil-globules 
  scattered 
  through- 
  

   out 
  a 
  granular 
  matrix. 
  The 
  unimpregnated 
  ova 
  which 
  do 
  

   not 
  swell 
  at 
  all, 
  and 
  those 
  which 
  partially 
  swell, 
  but 
  in 
  

   which 
  no 
  " 
  limb 
  " 
  is 
  formed, 
  disintegrate 
  much 
  more 
  rapidly 
  

   than 
  those 
  which 
  pass 
  through 
  the 
  "limbed" 
  condition. 
  

   In 
  their 
  disintegration 
  there 
  is 
  a 
  certain 
  amount 
  of 
  glomer- 
  

   ation, 
  but 
  this 
  is 
  not 
  as 
  distinct 
  as 
  in 
  the 
  others, 
  on 
  account 
  of 
  

   the 
  closely 
  investing 
  vitelline 
  membrane. 
  The 
  vitelline 
  mem- 
  

   brane 
  has 
  no 
  raicropyle, 
  and 
  is 
  apparently 
  without 
  pores. 
  

  

  Ijipregnated 
  Ovum. 
  

  

  The 
  most 
  noticeable 
  difference, 
  to 
  the 
  eye, 
  between 
  a 
  pan 
  

   of 
  impregnated 
  and 
  one 
  of 
  unimpregnated 
  ova, 
  is 
  in 
  the 
  

   very 
  much 
  greater 
  proportion 
  of 
  swollen 
  eggs 
  in 
  the 
  pan 
  to 
  

   which 
  milt 
  has 
  been 
  added. 
  This 
  is 
  not 
  so 
  noticeable, 
  un- 
  

   less 
  the 
  impregnation 
  has 
  been 
  performed 
  by 
  the 
  dry 
  

   method. 
  This 
  has 
  a 
  certain 
  limit, 
  to 
  be 
  sure, 
  since 
  the 
  

   eggs 
  are 
  quite 
  a 
  little 
  time 
  in 
  absorbing 
  water, 
  and 
  if 
  the 
  ova 
  

   are 
  placed 
  in 
  water 
  as 
  soon 
  as 
  stripped 
  from 
  the 
  fish, 
  and 
  

   within 
  -half 
  a 
  minute 
  afterward 
  the 
  milt 
  is 
  added, 
  the 
  result 
  

   will 
  be 
  pretty 
  satisfactory. 
  But 
  the 
  best 
  results 
  will 
  be 
  

   reached 
  when 
  the 
  ova 
  and 
  milt 
  are 
  placed 
  in 
  the 
  water 
  

   simultaneously. 
  The 
  first 
  changes 
  which 
  take 
  place 
  in 
  the 
  

   impregnated 
  ova 
  are 
  similar 
  to 
  those 
  already 
  described 
  in 
  

   the 
  swollen 
  unimpregnated 
  egg. 
  First, 
  a 
  slight 
  swelling 
  

   out 
  or 
  distension 
  of 
  the 
  vitelline 
  membrane; 
  then, 
  while 
  

   the 
  distension 
  proceeds, 
  a 
  gathering 
  together 
  of 
  the 
  globules 
  

   to 
  one 
  side 
  of 
  the 
  vitellus, 
  and 
  a 
  drawing 
  up 
  of 
  the 
  granular 
  

   plasma 
  into 
  a 
  " 
  limb 
  " 
  or 
  blastodermic 
  protuberance. 
  Figa. 
  

  

  