﻿364 
  I^- 
  T. 
  Young, 
  

  

  parenchyma 
  strands. 
  The 
  fate 
  of 
  the 
  epithelium 
  is 
  différent 
  iir 
  

   different 
  parts 
  of 
  the 
  duct. 
  In 
  the 
  penis 
  it 
  is 
  modified 
  as 
  in 
  the 
  

   vagina 
  to 
  form 
  a 
  ciliate 
  ^) 
  cuticula, 
  the 
  process 
  of 
  development 
  

   being- 
  the 
  same 
  here 
  as 
  there 
  (Figs. 
  11 
  and 
  13). 
  In 
  the 
  rest 
  of 
  the 
  

   vas 
  however 
  the 
  epithelium 
  persists, 
  but 
  only 
  as 
  a 
  few 
  scattered 
  

   and 
  flattened 
  cells, 
  whose 
  distribution 
  and 
  form 
  appear 
  to 
  be 
  due 
  

   to 
  a 
  great 
  distension 
  of 
  the 
  original 
  layer 
  consequent 
  upon 
  the 
  

   enlargement 
  of 
  the 
  vas, 
  as 
  there 
  is 
  but 
  little 
  evidence 
  of 
  a 
  loss 
  of 
  

   cells 
  by 
  scaling 
  or 
  degeneration 
  (Fig. 
  15). 
  In 
  the 
  outer 
  laj^er 
  of 
  the 
  

   duct 
  wall 
  the 
  cells 
  gradually 
  separate 
  from 
  each 
  other 
  during 
  the 
  

   growth 
  of 
  the 
  duct, 
  ultimately 
  forming 
  a 
  layer 
  of 
  scattered 
  cells 
  which 
  

   have 
  been 
  described 
  by 
  various 
  authors 
  — 
  Zschokke 
  (1888a 
  and 
  b) 
  

   in 
  several 
  forms, 
  Fuhrmann 
  (1895) 
  in 
  Taeyiia 
  depressa, 
  etc. 
  — 
  as 
  

   '•prostate 
  cells", 
  but 
  which 
  appear 
  to 
  me 
  in 
  no 
  way 
  different 
  from 
  

   those 
  of 
  the 
  parenchyma 
  (Fig. 
  15). 
  Regarding 
  these 
  cells 
  Beaun 
  

   (1894—1900, 
  p. 
  1407) 
  says 
  "Ein 
  sicherer 
  Beweis, 
  dass 
  diese 
  so 
  häufig 
  

   beobachteten 
  Zellen 
  Drüsenzellen 
  sind, 
  ist 
  jedoch 
  nicht 
  erbracht, 
  

   da 
  — 
  so 
  viel 
  ich 
  sehe 
  — 
  keiner 
  der 
  genannten 
  Autoren 
  Ausmündungs- 
  

   stellen 
  in 
  der 
  Membran 
  des 
  Vas 
  deferens 
  gesehen 
  hat, 
  keiner 
  solche 
  

   auch 
  abbildet. 
  Es 
  ist 
  mir 
  deshalb 
  . 
  . 
  . 
  wahrscheinlich, 
  dass 
  wir 
  es 
  

   hier 
  — 
  wie 
  übrigens 
  z. 
  B. 
  auch 
  bei 
  der 
  Vagina 
  — 
  ebenfalls 
  mit 
  

   Matrixzellen 
  der 
  die 
  Wand 
  des 
  Vas 
  deferens 
  bildenden 
  Cuticula 
  zu 
  

   thun 
  haben, 
  die 
  wie 
  die 
  peripheren 
  Subcuticularzellen 
  durch 
  Ein- 
  

   senken 
  in 
  das 
  Parenchym 
  ihre 
  epitheliale 
  Anordnung 
  aufgegeben 
  

   haben." 
  Apparently 
  similar 
  cells 
  have 
  been 
  described 
  by 
  Diamare 
  

   (1893) 
  surrounding 
  the 
  penis 
  sheath 
  in 
  the 
  Dipylidinae 
  and 
  by 
  

   various 
  authors 
  around 
  the 
  vagina.^) 
  

  

  The 
  lining 
  of 
  the 
  vas 
  is 
  variously 
  described 
  by 
  different 
  authors. 
  

   Some 
  ^) 
  describe 
  it 
  as 
  a 
  thin 
  homogeneous 
  membrane, 
  while 
  according 
  

   to 
  others 
  *) 
  an 
  epithelium 
  is 
  present. 
  As 
  regards 
  the 
  penis 
  the 
  same 
  

   different 
  accounts 
  are 
  given. 
  According 
  to 
  Lönnberg 
  (1892) 
  in 
  

   Diplogonoporus 
  halaenopterae 
  the 
  penis 
  is 
  lined 
  in 
  part 
  by 
  a 
  high 
  

  

  1) 
  See 
  foot 
  note, 
  page 
  361. 
  

  

  2) 
  See 
  footnote, 
  page 
  362. 
  

  

  3) 
  Leuckart 
  (1886), 
  Zschokke 
  (1888a) 
  in 
  most 
  but 
  not 
  all 
  of 
  the- 
  

   forms 
  studied 
  by 
  him, 
  LuNGWiTZ 
  (1895) 
  in 
  Taenia 
  ovilla, 
  etc. 
  

  

  4) 
  Kraemer 
  (1881) 
  in 
  Taenia 
  torulosa, 
  ROBOZ 
  (1882) 
  in 
  Solenophorus^ 
  

   megalocephalus, 
  Lönnberg 
  (1891) 
  in 
  Bothriocephalas 
  pundatus, 
  Piycho^ 
  

   hothrium 
  helones, 
  Abothrlum 
  rugosum 
  and 
  TetrarhyncJius 
  tetrabothrius. 
  

  

  