﻿SOME 
  NEW 
  SPECIES 
  OP 
  THE 
  GENUS 
  PHREODRILUS. 
  297 
  

  

  smaller 
  size, 
  aud 
  the 
  orifice 
  is 
  terminal 
  (it 
  is 
  represented 
  too 
  large 
  in 
  the 
  

   figure). 
  

  

  [N.B. 
  — 
  Pigs. 
  18 
  — 
  28, 
  representing 
  transverse 
  sections 
  of 
  the 
  efferent 
  

   apparatus, 
  are 
  drawn, 
  under 
  Leitz, 
  oil 
  immersion, 
  yL, 
  as 
  carefully 
  as 
  possible; 
  

   they 
  are 
  not 
  camera 
  drawings, 
  and 
  consequently 
  they 
  are 
  not 
  all 
  quite 
  of 
  the 
  

   same 
  relative 
  size.] 
  

  

  Ftg. 
  18. 
  — 
  Cuts 
  through 
  the 
  spermiducal 
  gland 
  at 
  its 
  entrance 
  into 
  the 
  atrial 
  

   sac 
  ; 
  note 
  the 
  circular 
  muscle 
  at 
  one 
  end 
  of 
  the 
  figure. 
  

  

  Fig. 
  19. 
  — 
  The 
  section 
  immediately 
  following 
  the 
  preceding. 
  It 
  cuts 
  the 
  

   gland 
  twice; 
  one 
  section 
  {gl.) 
  is 
  outside 
  the 
  atrial 
  sac, 
  the 
  other 
  {71.) 
  is 
  now 
  

   within 
  the 
  sac. 
  There 
  is 
  a 
  marked 
  difference 
  in 
  the 
  character 
  of 
  the 
  cytoplasm 
  

   in 
  the 
  two 
  cases 
  and 
  the 
  size 
  of 
  the 
  lumen. 
  

  

  Pig. 
  20. 
  — 
  Transverse 
  sections 
  of 
  the 
  sperm-duct. 
  

  

  Pig. 
  21. 
  — 
  Section 
  involving 
  the 
  entrance 
  of 
  the 
  sperm-duct 
  {s.d.) 
  into 
  the 
  

   neck 
  («.) 
  of 
  the 
  spermiducal 
  gland 
  within 
  the 
  atrial 
  sac 
  {cits.). 
  The 
  section 
  

   is 
  the 
  third 
  below 
  that 
  shown 
  at 
  fig. 
  19. 
  The 
  epithelium 
  of 
  the 
  neck 
  is 
  

   formed 
  of 
  low 
  cells, 
  deeply 
  staining, 
  aud 
  apparently 
  ciliated. 
  

  

  Pig. 
  22. 
  — 
  A 
  transverse 
  section 
  through 
  the 
  upper 
  part 
  of 
  the 
  atrial 
  sac 
  (the 
  

   sixth 
  section 
  below 
  fig. 
  21) 
  at 
  nearly 
  its 
  widest 
  region 
  ; 
  it 
  shows 
  the 
  atrium 
  

   {al.) 
  cut 
  through 
  thrice, 
  owing 
  to 
  its 
  coiling. 
  The 
  epithelium 
  closely 
  resembles 
  

   that 
  of 
  the 
  sperm-duct, 
  and, 
  like 
  it, 
  is 
  ciliated, 
  m. 
  c. 
  Muscle-cells 
  attached 
  to 
  

   the 
  iuner 
  surface 
  of 
  the 
  wall 
  of 
  the 
  sac, 
  and 
  produced 
  into 
  radiating 
  muscle- 
  

   fibres 
  (r. 
  7«.) 
  passing 
  to 
  the 
  atrium, 
  which 
  they 
  enwrap 
  in 
  a 
  spiral 
  direction, 
  

   so 
  that 
  the 
  fibres 
  in 
  places 
  are 
  cut 
  transversely 
  (as 
  at 
  r. 
  »/.). 
  The 
  wall 
  of 
  the 
  

   sac 
  is 
  formed 
  of 
  circular 
  muscles 
  (<?. 
  m.), 
  which 
  appear 
  to 
  be 
  connected 
  with 
  

   the 
  muscles 
  {mw.) 
  from 
  the 
  body-wall. 
  

  

  Pig. 
  23. 
  — 
  A 
  section 
  through 
  the 
  atrial 
  sac 
  some 
  distance 
  lower 
  down. 
  The 
  

   diameter 
  of 
  the 
  sac 
  has 
  diminished. 
  The 
  epithelium 
  of 
  the 
  atrium 
  has 
  altered 
  

   its 
  character 
  ; 
  it 
  no 
  longer 
  bears 
  cilia, 
  and 
  is 
  covered 
  internally 
  by 
  a 
  striated 
  

   cuticle. 
  The 
  radiating 
  muscle-fibres 
  are 
  cut 
  obliquely 
  on 
  tiie 
  right, 
  presenting 
  

   the 
  appearance 
  of 
  short 
  filaments 
  and 
  refringent 
  dots. 
  The 
  parent 
  muscle- 
  

   cells 
  (»/. 
  c.) 
  form 
  almost 
  a 
  complete 
  lining 
  to 
  the 
  sac. 
  

  

  Pig. 
  24. 
  — 
  Tlie 
  twenty-eighth 
  section 
  below 
  that 
  figured 
  at 
  fig. 
  22. 
  It 
  

   cuts 
  the 
  atrium 
  longitudinally 
  at 
  a 
  bend 
  near 
  its 
  lower 
  extremity, 
  just 
  before 
  

   it 
  passes 
  into 
  the 
  penial 
  sac 
  (cf. 
  fig. 
  17). 
  On 
  the 
  right 
  (y.) 
  the 
  epithelium 
  is 
  

   infolded. 
  The 
  circular 
  muscles 
  of 
  the 
  atrial 
  sac 
  are 
  now 
  seen 
  cut 
  across. 
  

  

  Pig. 
  25.— 
  The 
  fourth 
  section 
  from 
  fig. 
  2i. 
  The 
  epithelium 
  is 
  seen 
  to 
  be 
  

   much 
  folded 
  (y.). 
  

  

  Pig. 
  26.— 
  The 
  section 
  following 
  that 
  drawn 
  at 
  fig. 
  25 
  passes 
  obliquely 
  

   through 
  the 
  tip 
  of 
  the 
  penis, 
  the 
  aperture 
  of 
  which 
  (0/).) 
  is 
  seen 
  to 
  occupy 
  the 
  

  

  