﻿368 
  R- 
  T. 
  Young. 
  

  

  the 
  basement 
  membrane 
  (Fig. 
  20). 
  The 
  latter 
  forms 
  the 
  outer 
  part 
  

   of 
  the 
  duct 
  wall, 
  separating 
  it 
  from 
  the 
  parenchj^ma. 
  In 
  the 
  ampulla 
  

   which 
  forms 
  the 
  slightly 
  enlarged 
  proximal 
  end 
  of 
  the 
  oviduct 
  

   proper 
  however 
  the 
  basement 
  membrane 
  develops 
  in 
  the 
  syncytial 
  

   cord, 
  dividing 
  the 
  latter 
  into 
  two 
  layers 
  of 
  cells. 
  In 
  the 
  mem- 
  

   brane 
  at 
  this 
  point 
  muscle 
  fibres 
  whose 
  general 
  course 
  is 
  circular 
  

   to 
  the 
  duct 
  are 
  formed 
  as 
  elsewhere 
  by 
  a 
  direct 
  modification 
  of 
  

   fibrillae; 
  and 
  here 
  the 
  outer 
  layer 
  of 
  the 
  wall 
  is 
  continuous 
  with 
  

   that 
  of 
  the 
  main 
  duct, 
  whose 
  development 
  has 
  just 
  been 
  described 
  

   (Fig. 
  22). 
  During 
  the 
  early 
  development 
  of 
  the 
  ovary 
  the 
  distal 
  ends 
  

   of 
  the 
  branches 
  of 
  the 
  oviduct 
  retain 
  their 
  original 
  structure 
  of 
  

   solid 
  cords, 
  whose 
  cells 
  however 
  are 
  not 
  intimately 
  united, 
  but 
  form 
  a 
  

   loose 
  syncytium 
  thru 
  which 
  the 
  ripe 
  ova 
  are 
  easily 
  extruded 
  (Fig. 
  26). 
  

   Gradually 
  however 
  the 
  lumen 
  of 
  the 
  ducts 
  extends 
  to 
  the 
  follicles. 
  

   The 
  development 
  of 
  the 
  parenchyma 
  membrane 
  surrounding 
  the 
  

   follicles 
  will 
  be 
  discussed 
  below. 
  It 
  is 
  continuous 
  with 
  the 
  basement 
  

   membrane 
  of 
  the 
  oviduct 
  branches. 
  

  

  LÖNNBERG 
  (1891) 
  in 
  Amphiptijclies 
  urna 
  and 
  Bothriocephahis 
  

   pundatus, 
  Keaemer 
  (1892) 
  in 
  Taenia 
  torulosa, 
  Lungwitz 
  (1895) 
  in 
  

   Taenia 
  ovilla 
  etc. 
  describe 
  the 
  oviduct 
  as 
  lined 
  by 
  epithelium, 
  while 
  

   ZscHOKKE 
  (1888a) 
  in 
  most 
  of 
  the 
  forms 
  he 
  studied 
  \), 
  Balss 
  (1908) 
  

   in 
  Anoplocephala 
  magna, 
  and 
  Gough 
  (1911) 
  in 
  Avitellina 
  centripunctata 
  

   describe 
  it 
  otherwise. 
  Here 
  again 
  the 
  difference 
  may 
  be 
  due 
  to 
  

   inaccuracy 
  of 
  observation, 
  or 
  imperfection 
  of 
  technique 
  of 
  some 
  

   workers; 
  but 
  the 
  explanation 
  given 
  above-), 
  relative 
  to 
  similar 
  

   differences 
  in 
  statements 
  regarding 
  vas 
  deferens 
  and 
  vagina, 
  appears 
  

   to 
  me 
  more 
  reasonable. 
  In 
  Taenia 
  pisiformis 
  there 
  is 
  no 
  essential 
  

   difference 
  between 
  the 
  epithelium 
  of 
  the 
  oviduct 
  branches 
  and 
  that 
  

   of 
  the 
  other 
  ducts. 
  In 
  all 
  cases 
  solid 
  cords 
  of 
  cells 
  are 
  first 
  formed 
  

   out 
  of 
  which 
  the 
  epithelium 
  is 
  developed. 
  In 
  the 
  oviduct 
  branches 
  

   the 
  original 
  cell 
  cord 
  is 
  much 
  looser 
  and 
  the 
  differentiation 
  of 
  an 
  

   epithelium 
  occurs 
  later 
  than 
  in 
  the 
  other 
  ducts 
  ^), 
  but 
  in 
  all 
  cases 
  

   an 
  epithelium 
  is 
  present 
  sooner 
  or 
  later 
  during 
  development 
  becoming 
  

  

  1) 
  But 
  in 
  Calliohothrium 
  veriicillaturn 
  he 
  says 
  (1. 
  c, 
  p. 
  226 
  — 
  227) 
  

   "Les 
  parois 
  du 
  germiducte 
  sont 
  entourées 
  d'une 
  simple 
  couche 
  de 
  grandes 
  

   cellules 
  polygonales 
  . 
  . 
  . 
  La 
  partie 
  initiale 
  de 
  l'oviducte 
  ... 
  a 
  des 
  parois 
  

   fournies 
  de 
  cellules 
  polygonales 
  . 
  . 
  ." 
  

  

  2) 
  Page 
  365. 
  

  

  3) 
  Excepting 
  those 
  of 
  the 
  yolk 
  gland 
  to 
  be 
  described 
  shortly. 
  

  

  