﻿56 
  

  

  Lot 
  C. 
  — 
  Yei", 
  cold 
  ; 
  hail 
  and 
  rain. 
  The 
  eggs 
  from 
  several 
  

   ripe 
  females 
  v 
  jre 
  fertilized, 
  but 
  no 
  changes 
  followed, 
  and 
  all 
  

   the 
  eggs 
  soc 
  .1 
  decayed. 
  

  

  Anoth' 
  1- 
  lot 
  of 
  embryos, 
  which 
  were 
  about 
  three 
  days 
  old, 
  

   and 
  in 
  ilie 
  stage 
  shown 
  in 
  Plate 
  III, 
  Figure 
  38, 
  also 
  died. 
  

  

  Lcr. 
  D. 
  — 
  Day 
  quite 
  cold. 
  The 
  eggs 
  from 
  three 
  females 
  

   were 
  very 
  carefully 
  fertilized 
  with 
  a 
  mixture 
  of 
  the 
  semen 
  

   from 
  tiiree 
  males 
  at 
  IDA. 
  M. 
  About 
  one 
  in 
  one 
  hundred 
  

   commenced 
  segmentation 
  between 
  1 
  and 
  6 
  P. 
  M 
  , 
  and 
  devel- 
  

   oped 
  very 
  slowly. 
  The 
  next 
  day 
  all 
  were 
  dead. 
  As 
  the 
  eggs 
  

   were 
  perfectly 
  ripe, 
  and 
  became 
  covered 
  with 
  active 
  sperma- 
  

   tozoa, 
  their 
  failure 
  to 
  develop 
  must 
  have 
  been 
  due 
  to 
  the 
  low 
  

   temperature. 
  

  

  Lot 
  E. 
  — 
  Quite 
  cool 
  in 
  the 
  morning 
  ; 
  warm 
  aiid 
  sultry 
  in 
  

   the 
  afternoon. 
  Eggs 
  fertilized 
  at 
  noon, 
  and 
  segmentation 
  

   commenced 
  in 
  about 
  two 
  hours. 
  At 
  7.30 
  P. 
  M. 
  about 
  half 
  of 
  

   them 
  had 
  finished 
  segmentation, 
  and 
  at 
  11.15 
  P. 
  M. 
  most 
  of 
  

   them 
  were 
  in 
  the 
  stage 
  shown 
  in 
  Figure 
  32. 
  On 
  the 
  fourth 
  

   day 
  most 
  of 
  them 
  were 
  doing 
  well, 
  and 
  had 
  reached 
  the 
  stage 
  

   sliowm 
  in 
  Figure 
  42, 
  when 
  a 
  fall 
  in 
  the 
  temperature 
  killed 
  all 
  

   of 
  them. 
  

  

  Lot 
  F.— 
  Kather 
  warm. 
  Eggs 
  fertilized 
  at 
  6 
  P. 
  M., 
  and 
  the 
  

   next 
  morning 
  at 
  5, 
  or 
  eleven 
  hours 
  after 
  fertilization, 
  some 
  

   were 
  in 
  the 
  stage 
  32, 
  and 
  some 
  in 
  the 
  stages 
  36 
  and 
  37. 
  

  

  Lot 
  G. 
  — 
  Day 
  quite 
  warm. 
  Eggs 
  fertilized 
  at 
  S 
  P. 
  M. 
  At 
  

   10.15 
  P. 
  M., 
  or 
  a 
  little 
  more 
  than 
  two 
  hours 
  after 
  fertilization, 
  

   nearly 
  all 
  of 
  them 
  were 
  in 
  the 
  early 
  stages 
  of 
  segmentation, 
  

   and 
  at 
  5 
  A. 
  M., 
  or 
  nine 
  hours 
  after 
  fertilization, 
  they 
  were 
  in 
  

   the 
  stage 
  shown 
  in 
  Figure 
  37, 
  and 
  in 
  forty-eight 
  hours 
  they 
  

   were 
  in 
  the 
  stajce 
  42. 
  

  

  Lot 
  H. 
  — 
  Ver}^ 
  hot 
  day. 
  Segmentation 
  was 
  completed 
  two 
  

   hours 
  after 
  fertilization, 
  and 
  in 
  two 
  hours 
  and 
  a 
  half 
  the 
  em- 
  

   bryos 
  were 
  in 
  the 
  stage 
  32, 
  and 
  in 
  forty-eight 
  hours 
  in 
  the 
  

   stage 
  shoM'n 
  in 
  43. 
  

  

  I 
  was 
  so 
  far 
  from 
  the 
  water 
  during 
  my 
  investigations 
  that 
  I 
  

   was 
  not 
  able 
  to 
  make 
  any 
  observations 
  upon 
  the 
  temperature 
  

   of 
  the 
  oyster 
  beds 
  during 
  the 
  spawning 
  season, 
  but 
  the 
  case* 
  

  

  