﻿362 
  R- 
  T. 
  Young, 
  

  

  A 
  layer 
  of 
  delicate 
  scattered 
  muscles 
  develops 
  just 
  external 
  to 
  

   the 
  basement 
  membrane. 
  These 
  muscles 
  run 
  parallel 
  to 
  the 
  vagina 
  

   thru 
  most 
  of 
  its 
  extent 
  (Fig. 
  25), 
  but 
  near 
  the 
  seminal 
  receptacle 
  they 
  

   are 
  circular 
  in 
  direction 
  forming 
  a 
  loose 
  sphincter. 
  That 
  these 
  

   muscle 
  fibres 
  develop 
  directly 
  from 
  préexistent 
  parenchyma 
  fibres 
  

   is 
  shown 
  by 
  their 
  continuity 
  with 
  the 
  latter 
  during 
  development. 
  

   Further, 
  as 
  I 
  showed 
  in 
  my 
  study 
  of 
  Cysticercus 
  pisiformis 
  (Young, 
  

   1908). 
  there 
  is 
  no 
  definite 
  relation 
  between 
  fibres 
  and 
  cells, 
  the 
  

   former 
  being 
  laid 
  down 
  in 
  the 
  parenchyma 
  syncitium 
  unrelated 
  to 
  

   any 
  special 
  cell. 
  

  

  The 
  outer 
  w^all 
  of 
  the 
  vagina 
  soon 
  loses 
  the 
  more 
  or 
  less 
  definite 
  

   arrangement 
  of 
  its 
  cells, 
  wliich 
  become 
  irregularl}' 
  scattered 
  around 
  

   the 
  duct.^) 
  It 
  thus 
  merges 
  directly 
  with 
  the 
  surrounding 
  parenchyma, 
  

   but 
  remains 
  distinguished 
  therefrom 
  by 
  its 
  denser 
  structure 
  (Fig. 
  11). 
  

  

  The 
  further 
  consideration 
  of 
  these 
  and 
  the 
  following 
  observations 
  

   in 
  relation 
  to 
  the 
  epithelial 
  question 
  may 
  be 
  postponed 
  to 
  a 
  later 
  

   part 
  of 
  this 
  paper. 
  

  

  A 
  muscular 
  vaginal 
  sack, 
  resembling 
  the 
  penis 
  sheath 
  which 
  

   has 
  been 
  described 
  by 
  various 
  authors 
  — 
  Eiehm 
  (1881) 
  in 
  Bipylidium 
  

   pectinatum, 
  Zschokke 
  (1888a) 
  in 
  Idiogenes 
  otidis, 
  CaMobotlirium 
  

   leuckarti 
  and 
  Onchohotlirium 
  uncinatmn 
  , 
  Keaemer 
  (1892) 
  in 
  Cijaiho- 
  

   cepJialus 
  truncatiis, 
  etc., 
  or 
  a 
  specialized 
  vaginal 
  sphincter 
  described 
  

   by 
  Keaemer 
  (1892) 
  in 
  Taenia 
  fdicoUis, 
  Stiles 
  & 
  Hassall 
  (1893) 
  in 
  

   Moniema 
  planissima, 
  etc. 
  — 
  does 
  not 
  occur 
  in 
  Taenia 
  insiformis. 
  Nor 
  is 
  

   any 
  valvular 
  apparatus, 
  such 
  as 
  has 
  been 
  described 
  by 
  von 
  Linstow 
  

   (1875) 
  for 
  Taenia 
  depressa, 
  Sommer 
  (1874) 
  for 
  Taenia 
  saginata 
  and 
  

   solium 
  and 
  Eiehm 
  (1881) 
  for 
  Dipylidium 
  latissimum, 
  here 
  present. 
  

  

  According 
  to 
  Zschokke 
  (1888a) 
  in 
  several 
  species 
  of 
  Taenia-), 
  

   Keaemee 
  (1892) 
  in 
  Taenia 
  filicoUis 
  and 
  tondosa, 
  Roboz 
  (1882) 
  in 
  

   SolenopJiorus 
  megalocephalus 
  , 
  etc. 
  an 
  epithelium 
  is 
  present 
  in 
  the 
  

  

  1) 
  These 
  cells 
  are 
  probably 
  the 
  same 
  as 
  those 
  described 
  as 
  gland 
  

   cells 
  by 
  various 
  authors, 
  Keaemee 
  (1892) 
  in 
  Taenia 
  filicollis 
  and 
  longi- 
  

   collis, 
  Zschokke 
  (1888a) 
  in 
  Galhobothrium 
  vertirAllalum, 
  AnihobotJirinm 
  

   auriculahmi 
  etc., 
  and 
  which 
  Beaun 
  (1894 
  — 
  1900) 
  surmises 
  may 
  be 
  myo- 
  

   blasts. 
  See 
  further 
  in 
  this 
  connection 
  my 
  discussion 
  of 
  the 
  so-called 
  

   "prostate 
  cells" 
  of 
  the 
  vas 
  deferens, 
  page 
  364. 
  

  

  2) 
  In 
  CalUohothrium 
  verticillatum 
  Zschokke 
  describes 
  the 
  wall 
  of 
  the 
  

   vagina 
  as 
  "au 
  début 
  cellulaire, 
  plus 
  tard 
  hyaline" 
  (1. 
  c, 
  p. 
  225). 
  This 
  

   agrees 
  with 
  my 
  account. 
  In 
  several 
  other 
  sjDecies 
  the 
  wall 
  of 
  the 
  vagina 
  

   is 
  described 
  as 
  either 
  hyaline 
  or 
  its 
  specific 
  structure 
  is 
  not 
  stated. 
  

  

  