﻿DEVELOPMENT 
  OF 
  THE 
  SPERMATOZOA. 
  205 
  

  

  Let 
  us 
  now 
  return 
  to 
  the 
  examination 
  of 
  an 
  isolated 
  tube. 
  In 
  it 
  also 
  

   we 
  can 
  recognize 
  the 
  single 
  cysts, 
  and 
  we 
  perceive 
  at 
  once 
  that 
  each 
  cyst 
  

   pursues 
  its 
  independent 
  development, 
  and 
  gradually 
  changes 
  into 
  one 
  of 
  

   the 
  bundles 
  that 
  appear 
  so 
  very 
  plainly 
  in 
  the 
  second 
  segment, 
  Fig. 
  25 
  II. 
  

   It 
  will 
  next 
  be 
  noticed 
  that 
  the 
  further 
  we 
  descend 
  the 
  more 
  numerous 
  

   and 
  the 
  smaller 
  the 
  spermatoblasts 
  in 
  each 
  cyst, 
  the 
  nucleus 
  diminish- 
  

   ing 
  in 
  size 
  with 
  especial 
  rapidity. 
  The 
  nature 
  of 
  these 
  changes 
  appears 
  

   in 
  Figs. 
  26, 
  28, 
  29. 
  Fig. 
  26 
  represents 
  a 
  few 
  spermatoblasts 
  from 
  the 
  

   upper 
  portion 
  of 
  segment 
  I; 
  their 
  characters 
  have 
  been 
  already 
  de- 
  

   scribed. 
  Fig. 
  28 
  is 
  taken 
  from 
  lower 
  down. 
  Fig. 
  29 
  is 
  taken 
  from 
  a 
  

   transverse 
  section 
  of 
  one 
  of 
  the 
  upper 
  bundles 
  of 
  the 
  second 
  segment. 
  

   The 
  cells 
  have 
  begun 
  to 
  lengthen, 
  but 
  the 
  nuclei 
  have 
  not 
  changed 
  much. 
  

   To 
  this 
  fact 
  I 
  shall 
  recur 
  directly. 
  

  

  Segments 
  I 
  and 
  II, 
  Fig. 
  25, 
  correspond 
  to 
  two 
  natural 
  stages 
  in 
  the 
  

   development 
  of 
  the 
  spermatozoa 
  ; 
  first, 
  the 
  multiplication 
  of 
  the 
  sperm- 
  

   atoblasts; 
  second, 
  the 
  metamorphosis 
  of 
  the 
  spermatoblasts 
  into 
  the 
  

   spermatic 
  threads 
  (Samenfaden). 
  It 
  is 
  therefore 
  only 
  in 
  the 
  first 
  seg- 
  

   ment 
  that 
  we 
  find 
  the 
  signs 
  of 
  division, 
  which 
  have 
  been 
  frequently 
  

   noticed 
  in 
  the 
  development 
  of 
  the 
  male 
  products 
  in 
  various 
  animals 
  (I 
  

   may 
  mention 
  the 
  Batrachians 
  in 
  particular 
  285 
  ), 
  but 
  have, 
  I 
  believe, 
  hith- 
  

   erto 
  puzzled 
  all 
  naturalists, 
  without 
  exception. 
  These 
  signs 
  of 
  division 
  

   are 
  the 
  cells, 
  such 
  as 
  are 
  shown 
  in 
  Fig. 
  27, 
  which, 
  instead 
  of 
  the 
  ordinary 
  

   nuclei, 
  contain 
  a 
  number 
  of 
  very 
  dark 
  and 
  very 
  large 
  granules, 
  often 
  

   somewhat 
  irregularly 
  distributed. 
  I 
  have 
  been 
  so 
  fortunate 
  as 
  to 
  obtain 
  

   some 
  of 
  these 
  cells 
  isolated, 
  and 
  saw 
  at 
  once 
  that 
  they 
  were 
  in 
  process 
  

   of 
  division, 
  and 
  upon 
  closer 
  examination, 
  with 
  a 
  very 
  high 
  power 
  (Toilers 
  

   immersion 
  iVth), 
  I 
  ^as 
  able 
  to 
  see 
  that 
  many 
  of 
  them 
  were 
  in 
  the 
  condi- 
  

   tion 
  indicated 
  by 
  Fig. 
  27 
  A, 
  elongated, 
  constricted 
  in 
  the 
  middle, 
  the 
  

   granules 
  accumulated 
  at 
  the 
  two 
  opposite 
  poles, 
  and 
  running 
  between 
  

   the 
  two 
  accumulations 
  a 
  faint 
  striation. 
  There 
  can 
  be 
  no 
  doubt 
  that 
  

   this 
  represents 
  the 
  last 
  stage 
  of 
  the 
  division 
  of 
  the 
  nuclei, 
  by 
  the 
  forma- 
  

   tion 
  of 
  a 
  Kernspindelj 
  that 
  remarkable 
  phenomenon 
  which 
  has 
  been 
  so 
  

   actively 
  studied 
  in 
  Germany 
  and 
  Switzerland 
  during 
  the 
  last 
  two 
  years 
  

   by 
  so 
  many 
  distinguished 
  observers. 
  286 
  This 
  discovery 
  naturally 
  leads 
  to 
  

   a 
  variety 
  of 
  theoretical 
  considerations, 
  which 
  cannot 
  be 
  appropriately 
  

   introduced 
  here. 
  I 
  will 
  add 
  that 
  I 
  have 
  observed 
  several 
  other 
  stages 
  in 
  

   the 
  formation 
  of 
  the 
  Kernspindel, 
  but 
  as 
  my 
  investigations 
  on 
  this 
  point 
  

   are 
  still 
  incomplete, 
  I 
  will 
  reserve 
  further 
  details 
  for 
  another 
  occasion. 
  

  

  ^Spcngel: 
  Urogenital 
  System 
  der 
  Amphibien. 
  Semper's 
  Arbeiten, 
  iii, 
  p. 
  1, 
  plate 
  ii, 
  figs. 
  27-34, 
  

   Spermatozoa 
  of 
  Epicrium 
  glutinosum. 
  

  

  286 
  Biitschli 
  : 
  Studien 
  iiber 
  die 
  ersten 
  Entwickelungsvorgiinge 
  der 
  Eizelle, 
  etc. 
  Senkberg. 
  Natf. 
  Ges., 
  

   i 
  Frankfort, 
  Bd. 
  x, 
  p. 
  1. 
  

  

  Zur 
  Kenntniss 
  der 
  Theilungsprocess 
  der 
  Knorpelzellen. 
  Zeitsch. 
  Wiss. 
  Zool., 
  xxix, 
  p. 
  206. 
  

  

  Entrmckelungsgescbicbtliche 
  Beitrage. 
  Zur 
  Kenntniss 
  der 
  Furcbungsprocess 
  bei 
  STepbelis. 
  

  

  Z. 
  Z. 
  xxix, 
  p, 
  239. 
  

  

  O. 
  Hertwig 
  : 
  Befrncbtung, 
  etc. 
  Morpb. 
  Jabrb. 
  i, 
  p. 
  347 
  ; 
  iii, 
  p. 
  1 
  and 
  p. 
  271. 
  

  

  H. 
  Fol: 
  Sur 
  le 
  Developpement 
  des 
  Pt6ropodes. 
  Arcb. 
  Zool. 
  Expt. 
  G6n. 
  (1875), 
  Tome 
  iii, 
  p. 
  104 
  ; 
  also, 
  

   same 
  journal, 
  T. 
  V, 
  Fasaii. 
  

  

  Compare 
  also 
  tbe 
  "writings 
  of 
  Auerbacb, 
  Strassburger, 
  Balfour, 
  et 
  aL 
  

  

  