﻿The 
  Änatomy 
  of 
  the 
  Female 
  Genital 
  Tract 
  of 
  the 
  Pupipara 
  etc. 
  21 
  

  

  above 
  referred 
  to 
  shows 
  tliat 
  the 
  lumen 
  of 
  the 
  vagina 
  has 
  been 
  in- 
  

   creased 
  in 
  size 
  in 
  response 
  to 
  this 
  need 
  of 
  the 
  larva. 
  

  

  Another 
  important 
  group 
  of 
  muscle-fibres 
  is 
  the 
  thick 
  bunch 
  

   transverse 
  to 
  the 
  longitudinal 
  axis 
  of 
  the 
  body 
  which 
  Covers 
  the 
  

   dorsal 
  surface 
  of 
  the 
  ingrowth 
  of 
  the 
  body-wall 
  above 
  mentioned 
  

   (PI. 
  II, 
  Fig. 
  3 
  and 
  6 
  p.t.mus). 
  The 
  ends 
  of 
  the 
  fibres 
  are 
  attached 
  to 
  

   two 
  ridges 
  formed 
  in 
  the 
  body-cavity 
  by 
  the 
  two 
  grooves 
  (Fig. 
  6 
  gr) 
  

   which 
  form 
  the 
  lateral 
  boundaries 
  of 
  the 
  chitinous 
  plate 
  extending 
  

   from 
  the 
  vulva 
  to 
  the 
  anus 
  and 
  mentioned 
  above. 
  These 
  muscles 
  

   are, 
  perhaps, 
  the 
  largest 
  group 
  of 
  muscle-fibres 
  in 
  the 
  animal's 
  body. 
  

   Their 
  function 
  is 
  obvious: 
  by 
  their 
  contraction 
  they 
  raise 
  the 
  plate 
  

   forming 
  the 
  posterior 
  lip 
  of 
  the 
  vulva 
  and 
  thus 
  very 
  much 
  increase 
  

   the 
  capacity 
  of 
  that 
  slit-like 
  opening 
  during 
  a 
  birth. 
  Eeinforcing 
  

   these 
  muscles 
  are 
  also 
  a 
  number 
  of 
  fibres 
  which 
  pass 
  from 
  the 
  above- 
  

   mentioned 
  ridges 
  to 
  the 
  dorsal 
  body-wall. 
  

  

  The 
  ventral 
  wall 
  of 
  the 
  vagina 
  is 
  but 
  poorly 
  supplied 
  with 
  

   special 
  muscles, 
  there 
  being 
  here 
  no 
  extensive 
  bands 
  or 
  groups 
  of 
  

   fibres 
  but 
  only 
  a 
  few 
  scattered 
  fibres 
  which 
  pass 
  from 
  it 
  to 
  the 
  ven- 
  

   tral 
  body-wall 
  (PI. 
  II, 
  Fig. 
  3 
  vag.mus). 
  

  

  The 
  uterus. 
  

  

  The 
  uterus 
  is 
  a 
  broad, 
  dorso-ventrally 
  compressed 
  tube 
  stretching 
  

   from 
  the 
  anterior 
  end 
  of 
  the 
  vagina 
  forward 
  to 
  the 
  median 
  oviduct 
  

   (PI. 
  II, 
  Figs. 
  1, 
  2, 
  3, 
  4 
  U). 
  Its 
  actual 
  shape 
  and 
  size 
  are 
  entirely 
  

   dependant 
  upon 
  the 
  age 
  and 
  the 
  sexual 
  condition 
  of 
  the 
  animal. 
  The 
  

   virginal 
  uterus 
  represented 
  in 
  Fig. 
  3 
  has 
  a 
  length 
  of 
  about 
  1 
  mm, 
  

   which 
  is 
  about 
  half 
  the 
  length 
  of 
  the 
  abdomen, 
  and 
  extends 
  forward 
  

   to 
  within 
  0,8 
  mm 
  of 
  the 
  forward 
  end 
  of 
  the 
  abdomen. 
  The 
  presence 
  

   of 
  an 
  egg 
  (PI. 
  II, 
  Fig. 
  1) 
  in 
  the 
  uterus 
  changes 
  its 
  shape 
  but 
  slightly, 
  

   but 
  when 
  the 
  egg 
  hatches 
  and 
  the 
  young 
  larva 
  begins 
  to 
  grow, 
  the 
  

   uterus 
  rapidly 
  becomes 
  stretched 
  out 
  of 
  all 
  semblance 
  of 
  its 
  former 
  

   shape. 
  The 
  presence 
  of 
  the 
  full-grown 
  larva 
  in 
  the 
  uterus 
  distends 
  

   that 
  organ 
  forward 
  until 
  it 
  reaches 
  the 
  anterior 
  end 
  of 
  the 
  abdomen 
  

   (PI. 
  II, 
  Fig. 
  4). 
  The 
  small 
  intestine 
  of 
  the 
  mother 
  is 
  crowded 
  by 
  

   this 
  great 
  growth 
  of 
  the 
  larva 
  into 
  the 
  anterior, 
  dorsal 
  portion 
  of 
  

   the 
  abdominal 
  cavity, 
  and 
  the 
  voluminous 
  rectum 
  is 
  pressed 
  against 
  

   the 
  dorsal 
  body-wall. 
  The 
  larva, 
  which 
  at 
  this 
  time 
  occupies 
  with 
  

   the 
  uterus 
  half 
  the 
  Space 
  in 
  the 
  abdominal 
  cavity, 
  can 
  easily 
  be 
  seen 
  

   through 
  the 
  ventral 
  abdominal 
  wall. 
  It 
  appears 
  as 
  a 
  glistening, 
  

   white 
  object 
  occupying 
  the 
  entire 
  median 
  portion 
  of 
  the 
  abdomen. 
  

  

  