﻿316 
  

  

  Mr. 
  L. 
  T. 
  Hogben. 
  

  

  this 
  manner, 
  new 
  vacuoles 
  appear 
  within 
  the 
  plasmosome, 
  and 
  a 
  similar 
  

   metamorphosis 
  ensues, 
  until 
  the 
  deposition 
  of 
  yolk 
  is 
  nearing 
  completion. 
  

  

  In 
  examining 
  preparations 
  of 
  the 
  eggs 
  of 
  Periplaneta, 
  the 
  observer 
  cannot 
  

   fail 
  to 
  be 
  impressed 
  with 
  two 
  facts, 
  namely, 
  that 
  the 
  inception 
  of 
  yolk 
  

   formation, 
  on 
  the 
  one 
  hand, 
  bears 
  no 
  relation 
  to 
  the 
  size 
  and 
  shape 
  of 
  the 
  

   egg, 
  while, 
  on 
  the 
  other, 
  the 
  first 
  appearance 
  of 
  the 
  deutoplasmic 
  spheres 
  

   clearly 
  synchronises 
  with 
  the 
  vacuolation 
  of 
  the 
  plasmosome 
  and 
  the 
  changes 
  

   consequent 
  tbereon. 
  The 
  first 
  indication 
  of 
  the 
  onset 
  of 
  yolk 
  deposition 
  is 
  

   the 
  formation 
  of 
  vacuolar 
  areas 
  in 
  the 
  periphery 
  of 
  egg 
  ; 
  within 
  these 
  are 
  

   often 
  seen 
  the 
  minute 
  chromatic 
  granules 
  first 
  emitted 
  by 
  the 
  plasmosome, 
  

   as 
  already 
  described. 
  An 
  exactly 
  similar 
  process 
  precedes 
  the 
  formation 
  of 
  

   the 
  remarkable 
  secondary 
  nuclei 
  of 
  certain 
  Hymenoptera, 
  described 
  in 
  a 
  

   previous 
  communication 
  (11). 
  True 
  secondary 
  nuclei, 
  however, 
  are 
  not 
  

   formed 
  in 
  the 
  Orthopteran 
  species 
  examined 
  (fig. 
  22). 
  Nor 
  do 
  these 
  events 
  

   appear 
  to 
  be 
  directly 
  related 
  to 
  the 
  formation 
  of 
  the 
  deutoplasmic 
  spheres. 
  

   The 
  first 
  yolk 
  is 
  deposited 
  at 
  the 
  outer 
  boundary 
  of 
  the 
  egg 
  in 
  the 
  form 
  of 
  

   spherical 
  globules 
  that 
  are 
  not 
  homogeneous, 
  and 
  are, 
  in 
  fact, 
  both 
  as 
  regards 
  

   size 
  and 
  appearance, 
  precisely 
  like 
  the 
  intranucleolar 
  deutosomes. 
  The 
  latter 
  

   break 
  up 
  into 
  several 
  homogeneous 
  globules, 
  which 
  are 
  the 
  yolk 
  spheres 
  

   sensu 
  stricto 
  (fig. 
  31). 
  Thus 
  it 
  seems 
  probable 
  that 
  the 
  nuclear 
  appearance 
  

   presented 
  by 
  the 
  intranucleolar 
  bodies 
  is 
  the 
  result 
  of 
  adsorption 
  to 
  the 
  

   surface 
  layers 
  of 
  an 
  internally 
  heterogeneous 
  mass 
  in 
  process 
  of 
  dissolution. 
  

  

  That 
  the 
  plasmosome 
  stands 
  in 
  an 
  intimate 
  functional 
  relation 
  to 
  the 
  

   formation 
  of 
  yolk 
  will 
  not 
  be 
  regarded 
  as 
  improbable 
  by 
  those 
  who 
  have 
  

   studied 
  oogenesis 
  in 
  insects, 
  and 
  many 
  investigators 
  of 
  this 
  problem 
  have 
  

   recognised 
  the 
  synchronism 
  of 
  yolk 
  formation 
  . 
  and 
  the 
  ejection 
  of 
  nuclear 
  

   granules. 
  In 
  tracing 
  the 
  yolk 
  spheres 
  of 
  Periplaneta 
  to 
  an 
  intraplasmosomal 
  

   origin, 
  the 
  present 
  author 
  has 
  not 
  arrived 
  at 
  this 
  solution 
  without 
  consider- 
  

   able 
  diffidence, 
  and, 
  were 
  it 
  not 
  for 
  the 
  possession 
  of 
  a 
  very 
  complete 
  series, 
  

   would 
  hesitate 
  to 
  advocate 
  such 
  a 
  conclusion. 
  It 
  may 
  be 
  said, 
  however, 
  

   that 
  very 
  similar 
  events 
  were 
  observed 
  in 
  certain 
  Hymenoptera, 
  although 
  no 
  

   account 
  was 
  given, 
  in 
  view 
  of 
  the 
  desirability 
  of 
  examining 
  more 
  favourable 
  

   material 
  with 
  more 
  suitable 
  technique. 
  The 
  seriation 
  of 
  stages 
  in 
  Periplaneta 
  

   is 
  facilitated 
  in 
  this 
  matter 
  by 
  the 
  independence 
  of 
  deutoplasmic 
  differentia- 
  

   tion 
  and 
  cytoplasmic 
  bulk, 
  while 
  the 
  relation 
  of 
  the 
  former 
  to 
  the 
  vacuolation 
  

   of 
  the 
  plasmosome 
  is 
  too 
  striking 
  to 
  escape 
  notice, 
  even 
  when 
  the 
  attention 
  is 
  

   primarily 
  focussed 
  on 
  other 
  questions. 
  

  

  Prom 
  the 
  heterochromosomes 
  in 
  the 
  synaptic 
  period 
  and 
  the 
  facts 
  

   elucidated 
  above, 
  it 
  might 
  well 
  be 
  surmised 
  that 
  the 
  accessory 
  body 
  

   described 
  by 
  Buchner 
  (96) 
  in 
  Gryllus 
  as 
  the 
  equivalent 
  of 
  the 
  male 
  hetero- 
  

  

  