﻿Eeproductive 
  organs 
  of 
  Taenia 
  pisiformis. 
  365 
  

  

  ciliate 
  columnar 
  epithelium, 
  but 
  toward 
  the 
  outer 
  end 
  the 
  nuclei 
  

   disappear 
  and 
  the 
  epithelium 
  becomes 
  continuous 
  with 
  the 
  cuticula. 
  

  

  These 
  differences 
  may 
  be 
  due 
  to 
  inaccuracies 
  of 
  various 
  in- 
  

   vestigators. 
  I 
  think 
  it 
  more 
  likely 
  however 
  that 
  an 
  epithelial 
  

   transformation 
  is 
  progressing 
  in 
  vas 
  deferens 
  and 
  vagina, 
  which 
  

   has 
  in 
  many 
  cases 
  already, 
  and 
  may 
  ultimately 
  in 
  all 
  result 
  in 
  the 
  

   formation 
  of 
  a 
  cuticula 
  from 
  an 
  epithelium.^ 
  ) 
  

  

  The 
  penis 
  sheath 
  develops 
  as 
  a 
  thin 
  sheath 
  of 
  obliquely 
  ^) 
  

   disposed 
  muscles 
  in 
  the 
  parenchyma 
  about 
  the 
  distal 
  part 
  of 
  the 
  

   vas 
  (Figs. 
  4, 
  5 
  and 
  11). 
  These 
  muscles 
  are 
  in 
  a 
  general 
  way 
  arranged 
  

   in 
  two 
  sets, 
  which 
  cross 
  one 
  another 
  at 
  right 
  angles 
  but 
  do 
  not 
  

   form 
  definite 
  layers. 
  Enclosed 
  by 
  this 
  sheath 
  is 
  a 
  mass 
  of 
  paren- 
  

   chyma 
  tissue 
  in 
  which 
  are 
  found 
  a 
  few 
  scattered 
  and 
  obliquely 
  

   disposed 
  muscles. 
  These 
  are 
  in 
  part 
  a 
  continuation 
  of 
  two 
  loose 
  

   bands 
  which 
  pass 
  outward 
  from 
  the 
  parenchyma 
  to 
  the 
  proximal 
  

   end 
  of 
  the 
  penis 
  sheath 
  into 
  which 
  they 
  are 
  inserted, 
  or, 
  passing 
  

   thru 
  it, 
  extend 
  to 
  the 
  wall 
  of 
  the 
  penis 
  itself 
  or 
  disappear 
  in 
  the 
  

   surrounding 
  tissue 
  (Fig. 
  5). 
  These 
  retractor 
  muscles 
  arise 
  near 
  the 
  

   transverse 
  muscles 
  of 
  the 
  proglottid, 
  but 
  a 
  definite 
  connection 
  between 
  

   them 
  is 
  difficult 
  to 
  trace. 
  Here 
  as 
  in 
  other 
  parts 
  of 
  the 
  vas 
  

   "prostate 
  cells" 
  are 
  apparently 
  lacking, 
  those 
  cells 
  within 
  the 
  penis 
  

   sheath 
  being 
  ordinary 
  parenchyma 
  cells 
  and 
  myoblasts. 
  The 
  muscles 
  

   here 
  as 
  elsewhere 
  arise 
  directly 
  from 
  parenchyma 
  strands. 
  

  

  According 
  to 
  the 
  hypothesis 
  of 
  Kahane 
  (1880) 
  the 
  genital 
  atrium 
  

   arises 
  as 
  an 
  invagination 
  of 
  the 
  body 
  wall, 
  from 
  the 
  bottom 
  of 
  which 
  

   the 
  penis 
  is 
  evaginated. 
  His 
  figure 
  (p. 
  222) 
  however 
  makes 
  it 
  clear 
  

   that 
  he 
  refers 
  to 
  the 
  evaginated 
  penis. 
  Since 
  the 
  evagination 
  of 
  

   this 
  organ 
  is 
  a 
  secondary 
  and 
  temporary 
  condition, 
  Kahane's 
  theory, 
  

   so 
  far 
  as 
  the 
  penis 
  is 
  concerned, 
  does 
  not 
  explain 
  its 
  origin. 
  

  

  The 
  number, 
  arrangement, 
  and 
  size 
  of 
  the 
  muscle 
  layers 
  forming 
  

   the 
  penis 
  sheath 
  show 
  marked 
  variations 
  according 
  to 
  the 
  accounts 
  

   of 
  different 
  authors. 
  In 
  general 
  they 
  are 
  two 
  in 
  number, 
  an 
  outer 
  

   longitudinal 
  and 
  inner 
  circular 
  layer, 
  but 
  the 
  reverse 
  arrangement 
  

   occurs 
  in 
  Calliobothrium 
  coronatum 
  according 
  to 
  Zschokke 
  (1888a) 
  

   and 
  Taenia 
  filicolUs 
  according 
  to 
  Kraemee 
  (1892), 
  while 
  Kiehm 
  (1881) 
  

   describes 
  three 
  layers 
  in 
  Dipylidiiim 
  latissimum. 
  Both 
  layers 
  may 
  

  

  1) 
  See 
  my 
  further 
  discussion 
  of 
  this 
  point 
  under 
  "The 
  Epithelial 
  

   Question", 
  page 
  403. 
  

  

  2) 
  With 
  reference 
  to 
  the 
  penis 
  axis. 
  

  

  