﻿The 
  Anatomy 
  of 
  the 
  Feraale 
  Genital 
  Tract 
  of 
  the 
  Pnpipara 
  etc. 
  19 
  

  

  This 
  thickening 
  projects 
  into 
  the 
  vulva 
  in 
  the 
  form 
  of 
  a 
  spur 
  and 
  

   is 
  seen 
  especially 
  well 
  in 
  a 
  sagittal 
  section 
  (PL 
  II, 
  Fig. 
  3 
  spur). 
  The 
  

   anterior 
  edges 
  of 
  these 
  paired 
  plates 
  are 
  much 
  thickened 
  and 
  form 
  

   distinct 
  ridges. 
  The 
  posterior, 
  convex 
  lip 
  of 
  the 
  vulva 
  is 
  a 
  chitinous 
  

   plate 
  thickly 
  beset 
  with 
  spines 
  which, 
  as 
  above 
  mentioned, 
  extends 
  

   back 
  to 
  the 
  anus 
  (PL 
  II, 
  Figs. 
  1 
  and 
  3 
  ch.pl). 
  The 
  margin 
  of 
  this 
  

   plate 
  which 
  forms 
  the 
  lip 
  is 
  thickened 
  to 
  form 
  a 
  ridge 
  which 
  pro- 
  

   jects 
  eave-like 
  over 
  the 
  vulva 
  from 
  above 
  (PL 
  II, 
  Fig. 
  3 
  ch.pl). 
  The 
  

   continuity 
  of 
  this 
  ridge 
  is 
  broken 
  in 
  the 
  median 
  line 
  by 
  a 
  median 
  

   indentation 
  (PL 
  II, 
  Fig. 
  1 
  ch.pl). 
  The 
  plate 
  itself 
  is 
  bounded 
  on 
  both 
  

   the 
  right 
  and 
  left 
  sides 
  by 
  a 
  deep 
  groove 
  (PL 
  II, 
  Fig. 
  6 
  gr), 
  which 
  

   forms 
  a 
  ridge 
  in 
  the 
  body-cavity, 
  the 
  significance 
  of 
  which 
  for 
  the 
  

   attachment 
  of 
  muscles 
  for 
  the 
  control 
  of 
  the 
  vulva 
  will 
  be 
  explained 
  

   further 
  on. 
  

  

  The 
  vulva, 
  it 
  will 
  be 
  seen, 
  is 
  a 
  valve-like 
  slit 
  which 
  is 
  capable 
  

   of 
  great 
  distension. 
  The 
  larva, 
  at 
  the 
  time 
  of 
  birth 
  is 
  a 
  cylindrical 
  

   object 
  with 
  a 
  diameter 
  of 
  about 
  0,78 
  mm. 
  The 
  vulva, 
  thus, 
  through 
  

   which 
  it 
  must 
  pass, 
  must 
  Stretch 
  in 
  all 
  directions 
  and 
  more 
  than 
  

   double 
  its 
  capacity 
  at 
  the 
  time 
  of 
  a 
  birth. 
  It 
  is 
  probable 
  that 
  both 
  

   lips 
  take 
  part 
  in 
  this 
  stretching 
  but 
  it 
  also 
  seems 
  probable 
  that 
  the 
  

   posterior 
  (dorsal) 
  lip 
  has 
  the 
  principal 
  share 
  in 
  it. 
  The 
  muscles 
  

   which 
  join 
  the 
  dorsal 
  wall 
  of 
  the 
  vagina 
  and 
  the 
  posterior 
  lip 
  of 
  

   the 
  vulva 
  with 
  the 
  ridge-like 
  invagination 
  of 
  the 
  body-wall 
  (PL 
  II, 
  

   Fig. 
  3 
  p.B), 
  which 
  is 
  situated 
  just 
  dorsad 
  of 
  the 
  anus, 
  undoubtedly 
  

   have 
  for 
  their 
  function 
  the 
  raising 
  of 
  them 
  at 
  the 
  time 
  of 
  a 
  birth 
  

   and 
  thus 
  increasing 
  the 
  capacity 
  of 
  both 
  vagina 
  and 
  vulva, 
  as 
  will 
  

   be 
  further 
  explained 
  in 
  speaking 
  of 
  the 
  vagina. 
  

  

  The 
  vagina. 
  

  

  The 
  vulva 
  opens 
  into 
  the 
  vagina. 
  This 
  is 
  a 
  tube 
  of 
  the 
  same 
  

   width 
  as 
  the 
  vulva 
  which 
  extends 
  0,33 
  mm 
  for 
  ward 
  to 
  the 
  posterior 
  

   end 
  of 
  the 
  uterus 
  (PL 
  II, 
  Fig. 
  3 
  vag). 
  The 
  vagina 
  is 
  not 
  a 
  cylindrical 
  

   tube 
  but 
  varies 
  its 
  shape 
  between 
  its 
  anterior 
  and 
  posterior 
  ends. 
  

   At 
  its 
  posterior 
  end 
  it 
  is 
  a 
  dorso-ventrally 
  compressed 
  tube 
  with 
  

   three 
  shallow, 
  longitudinal 
  grooves 
  in 
  its 
  dorsal 
  wall, 
  one 
  in 
  the 
  

   median 
  line 
  and 
  the 
  other 
  two 
  at 
  the 
  extreme 
  right 
  and 
  left 
  sides. 
  

   These 
  three 
  grooves 
  increase 
  rapidly 
  in 
  depth 
  (height) 
  anteriad 
  as 
  

   far 
  as 
  the 
  beginning 
  of 
  the 
  uterus, 
  where 
  they 
  abruptly 
  terminate, 
  

   so 
  that 
  near 
  its 
  anterior 
  end 
  a 
  cross-section 
  of 
  the 
  vagina 
  presents 
  

   the 
  appearance 
  represented 
  by 
  PL 
  II, 
  Fig. 
  5. 
  The 
  median 
  groove 
  

  

  2* 
  

  

  