﻿276 
  

  

  Mr. 
  L. 
  T. 
  Hogben. 
  

  

  to 
  a 
  thin 
  lamella, 
  while 
  the 
  nurse 
  cells 
  are 
  no 
  longer 
  seen. 
  The 
  egg 
  then 
  is 
  

   elongated, 
  slightly 
  pointed 
  at 
  each 
  end, 
  and 
  tapering 
  off 
  into 
  a 
  stalk 
  at 
  the 
  

   anterior 
  extremity 
  (fig. 
  31). 
  At 
  the 
  posterior 
  pole, 
  in 
  preparations 
  that 
  have 
  

   been 
  decolorised 
  so 
  as 
  to 
  remove 
  the 
  stain 
  from 
  the 
  yolk, 
  there 
  is 
  seen 
  to 
  

   be 
  a 
  region 
  of 
  deeply 
  staining 
  granules. 
  The 
  presence 
  of 
  this 
  body 
  was 
  

   originally 
  noticed 
  by 
  Weismann 
  (1882), 
  who 
  applied 
  to 
  it 
  the 
  term 
  

   " 
  Furchungskern 
  " 
  ; 
  needless 
  to 
  say, 
  it 
  is 
  not 
  the 
  cleavage 
  nucleus, 
  nor 
  is 
  

   there 
  any 
  reason 
  to 
  suppose 
  that 
  it 
  is 
  of 
  nuclear 
  origin. 
  Tanquary, 
  curiously, 
  

   applied 
  the 
  same 
  term 
  to 
  a 
  similar 
  collection 
  of 
  granules 
  in 
  the 
  egg 
  of 
  

   the 
  ant 
  Camponotus. 
  Hegner, 
  who 
  has 
  not 
  examined 
  the 
  egg 
  of 
  Rhoclites 
  

   himself, 
  has 
  suggested 
  that 
  these 
  granules 
  are 
  of 
  the 
  nature 
  of 
  what 
  he 
  calls 
  

   " 
  germ-cell 
  determinants." 
  Their 
  later 
  history 
  has 
  not 
  yet 
  been 
  followed, 
  nor 
  

   has 
  that 
  of 
  the 
  more 
  definitive 
  body 
  described 
  in 
  the 
  Cynipid 
  Diastrophus 
  ; 
  

   and 
  in 
  view 
  of 
  the 
  conflicting 
  accounts 
  that 
  have 
  been 
  given 
  by 
  Martin, 
  

   Silvestri, 
  Hegner, 
  and 
  others 
  as 
  regards 
  both 
  origin 
  and 
  fate 
  of 
  the 
  " 
  germ- 
  

   cell 
  determinants 
  " 
  in 
  Hymenoptera, 
  it 
  might 
  be 
  advisable 
  for 
  the 
  present 
  to 
  

   refrain 
  from 
  using 
  this 
  term 
  until 
  a 
  more 
  precise 
  acquaintance 
  with 
  their 
  

   genetic 
  and 
  developmental 
  significance 
  is 
  forthcoming. 
  

  

  Nuclear 
  Phenomena 
  in 
  the 
  Late 
  Ovarian 
  Oocyte. 
  

  

  About 
  the 
  time 
  that 
  the 
  gallfly 
  emerges, 
  the 
  oocyte 
  nucleus 
  is 
  large 
  and 
  

   conspicuous, 
  occupying 
  a 
  position 
  about 
  midway 
  from 
  either 
  pole. 
  It 
  has 
  

   been 
  said 
  that, 
  towards 
  the 
  end 
  of 
  the 
  growth 
  period, 
  the 
  chromosomes 
  

   regain 
  their 
  visible 
  identities, 
  and 
  appear 
  in 
  the 
  diploid 
  number 
  (fig. 
  32). 
  

   What 
  follows 
  has 
  been 
  described 
  by 
  Schleip, 
  thus 
  : 
  " 
  Zuerst 
  sind 
  sie 
  

   Fadchen 
  mit 
  den 
  bekaimten 
  Knotchen-formigen 
  Verdickungen 
  und 
  einer 
  

   allerding 
  nicht 
  sehr 
  deutlichen 
  Langspalte. 
  Der 
  relativ 
  kleine 
  Nucleolus 
  

   bleibt 
  erhalten 
  bis 
  etwas 
  zu 
  der 
  Zeit 
  wo 
  die 
  Kernmembran 
  sich 
  auflost. 
  

   Dann 
  werden 
  die 
  Chromosomen 
  dicker 
  und 
  erscheinen 
  im 
  Praparat 
  

   schliesslich 
  als 
  unregelmassig 
  geformte 
  Kliimpchen. 
  Einige 
  von 
  ihnen 
  

   sind 
  deutlich 
  ringformig." 
  

  

  There 
  are 
  two 
  points 
  in 
  this 
  short 
  account 
  which 
  compel 
  comment. 
  

   First, 
  the 
  chromosomes 
  are 
  not 
  at 
  this 
  stage 
  irregular. 
  Originally 
  in 
  the 
  

   form 
  of 
  filaments 
  which 
  are 
  clearly 
  double, 
  like 
  those 
  of 
  Cynips 
  or 
  

   Copidosoma, 
  they 
  shorten 
  up 
  into 
  dumb-bell 
  shaped 
  bodies, 
  that 
  still 
  

   preserve 
  their 
  bivalent 
  character 
  (figs. 
  33, 
  34). 
  The 
  only 
  conclusion 
  

   that 
  can 
  be 
  drawn 
  from 
  Schleip's 
  figures 
  is 
  either 
  that 
  they 
  are 
  very 
  

   diagrammatic, 
  or 
  that 
  they 
  illustrate 
  preparations 
  imperfectly 
  fixed. 
  In 
  

   the 
  second 
  place, 
  none 
  of 
  the 
  chromosomes 
  are 
  ring-shaped 
  ; 
  at 
  this 
  

  

  