﻿310 
  

  

  W. 
  BLAXLAND 
  BENHAM. 
  

  

  worm 
  from 
  New 
  Zealand 
  (P. 
  violaceus), 
  in 
  which 
  the 
  sperm- 
  

   ducts 
  present 
  the 
  peculiarity 
  of 
  both 
  opening 
  independently, 
  

   but 
  in 
  the 
  same 
  segment. 
  Since 
  this 
  genus 
  is 
  provided 
  with 
  

   only 
  a 
  single 
  pair 
  of 
  ovaries, 
  I 
  have 
  kept 
  in 
  view 
  the 
  possi- 
  

   bility 
  of 
  this 
  being 
  the 
  case 
  in 
  the 
  new 
  worm, 
  but 
  although 
  I 
  

   did 
  not 
  succeed 
  in 
  tracing 
  the 
  second 
  pair 
  of 
  male 
  ducts 
  to 
  the 
  

   body- 
  wall, 
  yet 
  there 
  is 
  nothing 
  in 
  the 
  direction 
  of 
  the 
  ducts 
  to 
  

   indicate 
  that 
  tlie 
  first 
  pair 
  passes 
  through 
  an 
  entire 
  segment. 
  

   Moreover, 
  a 
  second 
  species 
  of 
  this 
  genus, 
  P. 
  ignatovi, 
  has 
  

   recently 
  been 
  described 
  by 
  Dr. 
  Michaelsen 
  (6), 
  in 
  which 
  the 
  

   arrangement 
  of 
  the 
  sperm-ducts 
  is 
  similar 
  to 
  that 
  in 
  Haplo- 
  

   taxis, 
  so 
  that 
  the 
  general 
  arrangement 
  of 
  the 
  genital 
  ducts 
  

   and 
  pores 
  in 
  this 
  species 
  agrees 
  pretty 
  well 
  with 
  that 
  

   described 
  in 
  H. 
  heterogyne. 
  But 
  the 
  agreement 
  ceases 
  

   here, 
  for 
  in 
  all 
  those 
  anatomical 
  characters 
  by 
  which 
  

   Pelodrilus 
  is 
  distinguished 
  from 
  Haplotaxis 
  the 
  new 
  

   species 
  now 
  under 
  discussion 
  agrees 
  precisely 
  with 
  the 
  latter. 
  

   It 
  forms, 
  in 
  fact, 
  with 
  P. 
  ignatovi, 
  a 
  link 
  between 
  the 
  

   genera 
  Pelodrilus 
  and 
  Haplotaxis 
  as 
  originally 
  charac- 
  

   terised. 
  This 
  is 
  seen 
  in 
  the 
  following 
  tabular 
  summary 
  of 
  

   the 
  characters 
  under 
  discussion, 
  though 
  there 
  are 
  several 
  

   other 
  differences 
  between 
  the 
  two 
  genera 
  : 
  

  

  