﻿221 
  

  

  THE 
  GENITALIA 
  OF 
  ACANTHINULA 
  ACULEATA. 
  

  

  By 
  Dr. 
  A. 
  E. 
  Boycott, 
  F.B.S. 
  

  

  Bead 
  9th 
  March, 
  1917. 
  

  

  The 
  following 
  account 
  of 
  the 
  genital 
  apparatus 
  of 
  A. 
  aculeata 
  is 
  based 
  

   on 
  the 
  examination 
  of 
  twenty 
  adult 
  specimens 
  from 
  six 
  localities, 
  

   displayed 
  by 
  complete 
  series 
  of 
  microscopical 
  sections. 
  The 
  figure 
  has 
  

   been 
  reconstructed 
  from 
  one 
  such 
  specimen, 
  the 
  parts 
  being 
  separated 
  

   in 
  the 
  drawing 
  so 
  that 
  they 
  may 
  be 
  shown 
  on 
  conventional 
  lines 
  for 
  

   easy 
  comparison 
  with 
  other 
  species. 
  The 
  male 
  and 
  female 
  ducts 
  

   diverge 
  not 
  far 
  from 
  the 
  genital 
  orifice 
  {GO), 
  and 
  through 
  the 
  intervaj^ 
  

   between 
  tliem 
  passes 
  the 
  right 
  ocular 
  retractor. 
  The 
  penis 
  (P) 
  in 
  its 
  

   lower 
  part 
  is 
  generally 
  similar 
  in 
  structure 
  to 
  the 
  lower 
  part 
  of 
  the 
  

   oviduct 
  without 
  any 
  particular 
  abundance 
  of 
  muscular 
  tissue 
  ; 
  for 
  

   a 
  distance 
  of 
  about 
  0*1 
  mm. 
  or 
  rather 
  less 
  above 
  the 
  origin 
  of 
  the 
  

   appendix 
  {A) 
  there 
  is, 
  however, 
  a 
  well-developed 
  muscular 
  sheath 
  

   loosely 
  embracing 
  the 
  organ. 
  At 
  its 
  upper 
  end 
  the 
  penis 
  divides 
  into 
  

   three 
  ; 
  on 
  either 
  side 
  is 
  a 
  curious 
  liorn, 
  the 
  minute 
  structure 
  of 
  

   which 
  does 
  not 
  appear 
  to 
  differ 
  materially 
  from 
  that 
  of 
  the 
  upper 
  

   part 
  of 
  the 
  body 
  of 
  the 
  penis 
  and 
  suggests 
  no 
  special 
  function 
  ; 
  the 
  

   main 
  channel 
  of 
  the 
  penis 
  continues 
  upwards 
  a 
  little 
  way 
  beyond 
  the 
  

   origin 
  of 
  the 
  horns 
  and 
  then 
  curves 
  over 
  to 
  join 
  the 
  vas 
  deferens, 
  which 
  

   is 
  embedded 
  in 
  the 
  wall 
  of 
  the 
  penis 
  for 
  some 
  little 
  distance 
  below 
  the 
  

   actual 
  junction. 
  The 
  vasdeferens 
  ( 
  VOand 
  VD) 
  loops 
  round 
  below 
  in 
  the 
  

   customary 
  fashion 
  and 
  is 
  divided 
  into 
  two 
  distinct 
  parts, 
  an 
  ascending 
  

   limit 
  not 
  much 
  less 
  bulky 
  than 
  the 
  penis 
  itself 
  and 
  a 
  long 
  (about 
  

   1'2 
  mm.), 
  tliin, 
  descending 
  limb 
  lying 
  in 
  close 
  relation 
  with 
  the 
  

   oviduct 
  into 
  which 
  it 
  eventually 
  opens 
  above. 
  The 
  appendix 
  to 
  the 
  

   penis 
  [A) 
  has 
  a 
  duct 
  wide 
  below 
  and 
  narrow 
  above, 
  and 
  finally 
  ends 
  

   in 
  a 
  bulbous 
  swelling, 
  the 
  terminal 
  expansion 
  being 
  due 
  as 
  much 
  to 
  

   an 
  increase 
  in 
  the 
  substance 
  of 
  the 
  wall 
  as 
  to 
  a 
  larger 
  lumen. 
  This 
  

   appendi.x 
  naturally 
  lies 
  folded 
  up 
  in 
  a 
  more 
  or 
  less 
  complicated 
  way, 
  

   most 
  commonly 
  in 
  a 
  double 
  M 
  loop 
  with 
  the 
  terminal 
  bulb 
  close 
  to 
  

   the 
  upper 
  end 
  of 
  the 
  penis. 
  Its 
  minute 
  structure 
  is 
  not 
  suggestive 
  

   of 
  its 
  function 
  ; 
  I 
  found 
  no 
  definite 
  contents 
  in 
  the 
  bulb. 
  The 
  

   oviduct 
  {OV) 
  may 
  as 
  usual 
  be 
  divided 
  into 
  three 
  parts. 
  Below 
  is 
  

   a 
  simple 
  conducting 
  tube 
  constituting 
  the 
  free 
  oviduct 
  ( 
  OVC). 
  This 
  

   expands 
  above 
  into 
  the 
  ^/(T?j^m/«/' 
  oi;/V/«c^ 
  {OVB), 
  a 
  wider 
  tube 
  with 
  

   voluminous 
  walls 
  of 
  mucinous 
  cells, 
  the 
  lumen 
  still 
  remaining 
  

   relatively 
  simple 
  : 
  one 
  small 
  section 
  of 
  the 
  wall 
  forms 
  a 
  little 
  recess 
  

   lined 
  with 
  cubical, 
  ciliated 
  epithelium 
  and 
  lies 
  in 
  close 
  relation 
  to 
  the 
  

   upper 
  end 
  of 
  the 
  descending 
  limb 
  of 
  the 
  vas 
  deferens, 
  which 
  eventually 
  

   opens 
  into 
  it. 
  Above 
  the 
  origin' 
  of 
  the 
  vas 
  deferens 
  the 
  oviduct 
  

   expands 
  still 
  further 
  and 
  forms 
  the 
  complex 
  folded 
  spermoviduct 
  

   {OTA) 
  with 
  massive 
  mucinous 
  walls. 
  In 
  the 
  upper 
  part 
  there 
  is 
  

  

  ' 
  The 
  figure 
  indicates 
  the 
  actual, 
  not 
  the 
  superficial, 
  origin 
  of 
  the 
  vas. 
  

  

  