﻿ON 
  A 
  NEW 
  SPECIES 
  OF 
  THE 
  GENUS 
  HAPLOTAXIS. 
  299 
  

  

  On 
  a 
  New 
  Species 
  of 
  the 
  Genus 
  Haplotaxis 
  ; 
  with 
  

   some 
  Remarks 
  on 
  the 
  Genital 
  Ducts 
  in 
  the 
  

   Oligochaeta. 
  

  

  By 
  

  

  W. 
  Blaxland 
  Benhani, 
  D.Sc.(Loiid.), 
  M.A.(Oxoii.), 
  F.Z.S. 
  

   (Professor 
  of 
  Biology 
  in 
  tlie 
  Uniyersity 
  of 
  Otago, 
  New 
  Zaalaud.) 
  

  

  With 
  Plates 
  16—18. 
  

  

  Amongst 
  the 
  material 
  collected 
  by 
  Mr. 
  Keith 
  Lucas 
  during 
  

   his 
  biological 
  survey 
  of 
  the 
  New 
  Zealand 
  lakes 
  I 
  find 
  two 
  

   small 
  worms 
  belonging 
  to 
  the 
  genus 
  Haplotaxis, 
  of 
  

   Hoffmeister 
  (= 
  Phreoryctes, 
  auctorum), 
  which 
  differ 
  from 
  

   the 
  two 
  species 
  already 
  known 
  — 
  H. 
  gordioides, 
  from 
  Europe 
  

   and 
  America^ 
  and 
  H. 
  smith 
  i, 
  from 
  New 
  Zealand 
  — 
  in 
  being 
  

   provided 
  with 
  only 
  a 
  single 
  pair 
  of 
  ovaries 
  and 
  oviducts. 
  For 
  

   this 
  new 
  species, 
  therefore, 
  I 
  propose 
  the 
  name 
  Haplotaxis 
  

   heterogyne. 
  Justification 
  for 
  placing 
  the 
  worms 
  in 
  this 
  

   genus, 
  hitherto 
  characterised 
  by 
  the 
  possession 
  of 
  two 
  pairs 
  

   of 
  female 
  organs, 
  will 
  be 
  found 
  below. 
  

  

  The 
  worm 
  is 
  further 
  remarkable 
  and 
  of 
  general 
  morpho- 
  

   logical 
  interest 
  on 
  account 
  of 
  the 
  very 
  close 
  structural 
  

   resemblance, 
  I 
  may 
  almost 
  say 
  identity, 
  of 
  the 
  sperm-ducts 
  

   with 
  the 
  nephridia. 
  This 
  matter 
  also 
  is 
  resei'ved 
  for 
  dis- 
  

   cussion 
  till 
  the 
  characters 
  of 
  the 
  new 
  species 
  have 
  been 
  

   described. 
  

  

  Haplotaxis 
  heterogyne, 
  n. 
  sp. 
  

  

  . 
  Of 
  the 
  two 
  individuals 
  one 
  is 
  sexually 
  mature, 
  the 
  other 
  has 
  

   only 
  the 
  rudiments 
  of 
  the 
  genital 
  organs. 
  The 
  former 
  was 
  

  

  