﻿292 
  

  

  Mr. 
  L. 
  T. 
  Hogben. 
  

  

  Wilson, 
  E. 
  B., 
  "Studies 
  on 
  Chromosomes, 
  VIII 
  : 
  Observations 
  on 
  the 
  maturation 
  

   phenomena 
  in 
  certain 
  Hymenoptera 
  and 
  other 
  forms, 
  with 
  considerations 
  on 
  

   synapsis 
  and 
  reduction," 
  ' 
  .Tourn. 
  Exptl. 
  Zool., 
  5 
  vol. 
  13, 
  1912. 
  

  

  EXPLANATION 
  OF 
  PLATES. 
  

  

  Illustrations 
  were 
  outlined 
  with 
  camera 
  lucida 
  and 
  studied 
  with 
  Leitz 
  2 
  mm. 
  and 
  

   No. 
  12 
  apochrom. 
  Single 
  cells 
  of 
  individual 
  plates 
  are 
  drawn 
  at 
  the 
  same 
  

   magnification. 
  Figs. 
  96, 
  10, 
  30, 
  31, 
  39, 
  40, 
  41, 
  46, 
  52, 
  are 
  not 
  drawn 
  at 
  the 
  same 
  

   magnification. 
  

  

  Plate 
  4. 
  — 
  Cynips 
  Kollari. 
  

  

  Fig. 
  1, 
  a, 
  b, 
  c, 
  — 
  Cynips 
  Kollari 
  side 
  views 
  of 
  mitoses 
  in 
  somatic 
  tissues. 
  

  

  d, 
  e. 
  — 
  Anaphase 
  plates 
  from 
  gut 
  of 
  larva 
  : 
  20 
  chromosomes 
  visible. 
  

   Fig. 
  2. 
  — 
  Follicular 
  mitoses 
  with 
  20 
  chromosomes. 
  

   Fig. 
  3. 
  — 
  Cell 
  from 
  ovary 
  of 
  larva 
  during 
  resting 
  period. 
  

   Fig. 
  4. 
  — 
  Rosette 
  cell, 
  showing 
  irregular 
  clumps 
  of 
  chromatin 
  in 
  the 
  nucleus. 
  

   Fig. 
  5. 
  — 
  Leptonema. 
  Dense 
  tangle 
  of 
  pale 
  threads 
  in 
  the 
  nucleus. 
  

   Fig. 
  6, 
  a, 
  b, 
  c. 
  — 
  Stages 
  in 
  synizesis. 
  

   Fig. 
  7, 
  b, 
  c. 
  — 
  Young 
  nurse 
  cells. 
  

  

  Fig. 
  8. 
  — 
  Young 
  oocyte 
  showing 
  pachytene 
  threads 
  haploid 
  number. 
  

  

  Plate 
  5. 
  — 
  Cynips 
  Kollari 
  (continued). 
  

  

  Fig. 
  9, 
  a. 
  — 
  Young 
  oocyte, 
  " 
  diffuse 
  stage." 
  Chromosomes 
  with 
  reduced 
  staining 
  capacity, 
  

   identity 
  no 
  longer 
  traceable. 
  

   b. 
  — 
  Somewhat 
  later 
  oocyte 
  less 
  magnified, 
  showing 
  follicle 
  nurse 
  cells 
  and 
  proto- 
  

   plasmic 
  strand 
  of 
  egg 
  protruding 
  into 
  the 
  nurse 
  chamber. 
  

  

  Fig. 
  10. 
  — 
  -Diagrammatic 
  representation 
  of 
  the 
  full-grown 
  egg. 
  

  

  Fig. 
  11. 
  — 
  Nucleus 
  of 
  oocyte 
  at 
  end 
  of 
  the 
  growth 
  period. 
  Diploid 
  number 
  of 
  filaments 
  

   visible. 
  

  

  Fig. 
  12. 
  — 
  End 
  to 
  end 
  pairing 
  of 
  the 
  same. 
  

  

  Figs. 
  13, 
  14. 
  — 
  Maturation 
  spindle 
  of 
  the 
  late 
  ovarian 
  oocyte 
  with 
  10 
  doubles. 
  

   Figs. 
  15-17. 
  — 
  Stages 
  in 
  condensation 
  of 
  the 
  abortive 
  maturation 
  spindle 
  : 
  disappearance 
  

   of 
  spindle 
  fibres 
  and 
  reduction 
  of 
  the 
  nucleoplasmic 
  zone. 
  

  

  Plate 
  6. 
  — 
  Rhodites 
  Rosce. 
  

  

  Fig. 
  18.— 
  Follicular 
  mitoses. 
  

  

  Fig. 
  19. 
  — 
  Oogonial 
  mitoses 
  showing 
  18 
  chromosomes. 
  

  

  Fig. 
  20. 
  — 
  Rosette 
  from 
  ovary 
  of 
  late 
  larva 
  with 
  chromatin 
  of 
  nucleus 
  in 
  fprm 
  of 
  irregular 
  

   masses. 
  

  

  Figs. 
  21, 
  22. 
  — 
  Leptotene 
  nuclei. 
  

   Figs. 
  23-25. 
  — 
  Synizesis 
  figures. 
  

  

  Figs. 
  26, 
  27. 
  — 
  Post-synaptic 
  spireme 
  segmenting 
  into 
  9 
  pachytene 
  threads. 
  

   Fig. 
  28. 
  — 
  Diplotene 
  nucleus. 
  

  

  Fig. 
  29. 
  — 
  Late 
  diplotene 
  in 
  a 
  young 
  nurse 
  cell 
  comparable 
  to 
  that 
  described 
  by 
  Dederer 
  

   in 
  Philosamia. 
  

  

  Plate 
  7. 
  

  

  Fig. 
  30. 
  — 
  Very 
  young 
  oocyte 
  and 
  adjacent 
  nurse 
  chamber. 
  The 
  oocyte 
  nucleus 
  is 
  in 
  

   the 
  diffuse 
  stage, 
  with 
  chromatin 
  granules 
  in 
  the 
  surrounding 
  cytoplasm. 
  

   The 
  nuclei 
  of 
  the 
  nurse 
  cells 
  are 
  granular. 
  (Magnification 
  reduced.) 
  

  

  