﻿286 
  W. 
  BLAXLAND 
  BENHAM. 
  

  

  sac, 
  such 
  as 
  is 
  seen 
  in 
  Beddard's 
  fig. 
  1 
  , 
  in 
  which 
  the 
  wider 
  and 
  

   shaded 
  ^^oi'tion 
  there 
  shown 
  seems 
  to 
  correspond 
  with 
  the 
  

   "uniform 
  tube/' 
  or 
  atrium, 
  just 
  described. 
  The 
  atrium, 
  how- 
  

   ever, 
  in 
  the 
  present 
  species 
  is 
  not 
  absolutely 
  uniform 
  either 
  

   in 
  diameter 
  or 
  in 
  structure, 
  for 
  at 
  the 
  point 
  where 
  it 
  receives 
  

   the 
  sperm- 
  duct 
  and 
  the 
  gland 
  it 
  is 
  for 
  a 
  very 
  short 
  distance 
  

   somewhat 
  narrower 
  than 
  it 
  becomes 
  lower 
  down, 
  and 
  also 
  

   varies 
  somewhat 
  in 
  diameter 
  along 
  its 
  course. 
  Moreover, 
  the 
  

   upper 
  coiled 
  portion 
  has 
  the 
  same 
  structure 
  as 
  the 
  sperm-duct; 
  

   the 
  lower 
  differs 
  in 
  structure. 
  The 
  absence 
  of 
  a 
  distinct 
  penis 
  

   in 
  P. 
  subterraneus 
  may 
  possibly 
  be 
  accounted 
  for 
  by 
  the 
  

   fact 
  that 
  the 
  individuals 
  which 
  formed 
  the 
  material 
  for 
  

   Beddard's 
  memoir 
  were 
  immature 
  ; 
  but, 
  as 
  I 
  shall 
  point 
  out 
  

   below, 
  there 
  appears 
  to 
  be 
  a 
  small 
  indication 
  of 
  this 
  organ. 
  

  

  The 
  histological 
  structure 
  of 
  the 
  male 
  efferent 
  apparatus 
  

   of 
  the 
  present 
  species 
  agrees 
  in 
  general 
  with 
  the 
  account 
  

   given 
  by 
  Beddard. 
  

  

  The 
  spermiducal 
  funnel 
  is 
  a 
  flat, 
  circular 
  disc, 
  perforated 
  

   centrally 
  for 
  the 
  exit 
  to 
  the 
  vas 
  deferens. 
  The 
  cells 
  form- 
  

   ing 
  this 
  disc 
  are 
  cubical, 
  and 
  bear 
  quite 
  short 
  cilia 
  ; 
  this 
  fact, 
  

   again, 
  is 
  clear 
  enough 
  in 
  the 
  dissected 
  and 
  isolated 
  apparatus, 
  

   but 
  in 
  sections 
  it 
  is 
  not 
  quite 
  easy 
  to 
  distinguish 
  between 
  the 
  

   cilia 
  and 
  the 
  spermatozoa 
  accumulated 
  around 
  the 
  funnel. 
  The 
  

   spermiducal 
  gland, 
  i.e. 
  Beddard's 
  diverticulum 
  or 
  "appendix 
  

   of 
  the 
  sperm-duct," 
  consists 
  (fig. 
  19, 
  gl.) 
  of 
  an 
  epithelium 
  

   surrounding 
  a 
  fairly 
  large 
  lumen, 
  and 
  covered 
  externally 
  by 
  

   peritoneum. 
  Between 
  the 
  two 
  layers 
  of 
  cells 
  is 
  a 
  thin 
  coat 
  of 
  

   circularly 
  disposed 
  muscle-fibres, 
  which 
  are 
  readily 
  seen 
  in 
  

   the 
  glycerine 
  preparation, 
  but 
  are 
  more 
  difficult 
  to 
  recognise 
  

   in 
  sections 
  owing 
  to 
  the 
  thinness 
  of 
  the 
  layer. 
  The 
  epi- 
  

   thelial 
  cells 
  are 
  tall, 
  granular, 
  with 
  a 
  vacuolated 
  cytoplasm, 
  — 
  

   the 
  minute 
  granules 
  being 
  arranged 
  in 
  a 
  network, 
  — 
  and 
  

   possess 
  large 
  circular 
  nuclei 
  near 
  their 
  bases. 
  

  

  The 
  spermiducal 
  gland 
  enters 
  the 
  atrial 
  sac 
  at 
  its 
  apex 
  

   (figs. 
  16, 
  18). 
  Close 
  to 
  this 
  point 
  the 
  circular 
  muscular 
  coat 
  

   becomes 
  thicker. 
  The 
  gland 
  then 
  diminishes 
  in 
  diameter, 
  

   (fig. 
  19, 
  11.), 
  the 
  cells 
  become 
  more 
  distinctly 
  columnar, 
  

  

  