﻿N0.11S3. 
  TREMATODE 
  PARASITES 
  OF 
  FISHES— 
  LIXTOX. 
  517 
  

  

  of 
  the 
  uterus 
  crowded 
  witb 
  ova. 
  Folds 
  of 
  tbe 
  uterus 
  also 
  extend 
  for- 
  

   ward, 
  lying' 
  dorsal 
  to 
  the 
  ventral 
  sucker. 
  The 
  anterior 
  end 
  of 
  the 
  uterus 
  

   l)asses 
  above 
  the 
  ventral 
  sucker 
  aeconipauying- 
  the 
  vas 
  deferens, 
  but 
  

   lying 
  ventral 
  to 
  it, 
  along 
  the 
  dorsal 
  region 
  of 
  the 
  neck, 
  and 
  opens 
  with 
  

   the 
  vas 
  deferens 
  at 
  the 
  base 
  of 
  the 
  cirrus 
  behind 
  the 
  oral 
  sucker. 
  The 
  

   v;is 
  deferens 
  is 
  surrounded 
  by 
  a 
  prostate 
  gland 
  throughout 
  its 
  length 
  

   (Plate 
  XLIII, 
  fig. 
  4). 
  

  

  The 
  intestinal 
  crura 
  are 
  distinct, 
  with 
  rather 
  strong 
  walls. 
  They 
  

   extend 
  to 
  near 
  the 
  posterior 
  end 
  of 
  the 
  body, 
  although 
  not 
  as 
  far 
  as 
  the 
  

   very 
  short 
  retractile 
  portion. 
  

  

  The 
  excretory 
  vessel 
  was 
  seen 
  only 
  near 
  the 
  caudal 
  extremity, 
  where 
  

   it 
  communicates 
  as 
  a 
  simple 
  vessel 
  with 
  the 
  terminal 
  pore. 
  

  

  11. 
  DISTOMUM 
  LAEVE, 
  new 
  species. 
  

   (Plates 
  XLIII, 
  figs. 
  5-8; 
  XLIV, 
  fig. 
  1.) 
  

  

  From 
  Macronrus 
  hairdii, 
  United 
  States 
  Fish 
  Commission 
  Station 
  894. 
  

   Twelve 
  specimens 
  1.5 
  to 
  3.5 
  mm. 
  in 
  length. 
  

  

  Body 
  roundish, 
  elongated, 
  attenuate 
  both 
  anteriorily 
  and 
  posteriorly 
  

   from 
  near 
  middle 
  of 
  length, 
  somewhat 
  fusiform, 
  smooth, 
  with 
  an 
  atten- 
  

   uated 
  retractile 
  caudal 
  appendage. 
  Neck 
  short, 
  conical 
  ; 
  ventral 
  sucker 
  

   much 
  larger 
  than 
  oral, 
  aperture 
  nearly 
  circular; 
  month 
  subterminal, 
  

   aperture 
  longitudinal; 
  (esophagus, 
  none; 
  pharnyx, 
  ellii)soidal: 
  intes- 
  

   tinal 
  crura 
  capacious, 
  not 
  extending 
  into 
  tail; 
  cirrus 
  bulb 
  pyriform 
  

   in 
  front 
  of 
  ventral 
  sucker; 
  genital 
  aperture 
  near 
  posterior 
  end 
  of 
  

   pharynx. 
  Vitelline 
  glands 
  two, 
  dark-brown, 
  conspicuous, 
  subglobu- 
  

   lar, 
  situated 
  near 
  or 
  a 
  little 
  back 
  of 
  middle 
  of 
  post-acetabular 
  region; 
  

   ovary 
  placed 
  transversely 
  immediately 
  in 
  front 
  of 
  vitellaria, 
  and 
  touch- 
  

   ing 
  both. 
  Testes, 
  two, 
  subglobular, 
  lying 
  side 
  by 
  side 
  transversely 
  in 
  

   contact 
  with 
  posterior 
  wall 
  of 
  ventral 
  sucker. 
  Anterior 
  seminal 
  vessel 
  

   on 
  dorsal 
  side 
  of 
  ventral 
  sucker, 
  a 
  posterior 
  seminal 
  vessel 
  immediately 
  

   behind 
  vitellaria. 
  ITterus 
  long, 
  convoluted, 
  occupying 
  much 
  of 
  the 
  

   body 
  cavity 
  from 
  ventral 
  sm-ker 
  to 
  and 
  even 
  back 
  of 
  vitelline 
  glands, 
  

   filled 
  with 
  small 
  elliptical 
  ova, 
  0.026 
  and 
  0.012 
  mm. 
  in 
  the 
  two 
  principal 
  

   diameters. 
  Excretory 
  vessel 
  median, 
  from 
  posterior 
  end, 
  where 
  it 
  com- 
  

   municates 
  with 
  a 
  large 
  terminal 
  vessel, 
  to 
  ventral 
  sncker, 
  where 
  it 
  

   divides 
  into 
  two 
  branches, 
  which 
  pass 
  forward 
  and 
  unite 
  on 
  the 
  dorsal 
  

   side 
  of 
  the 
  pharynx. 
  The 
  excretory 
  vessel 
  is 
  filled 
  with 
  minute 
  gran- 
  

   nies, 
  which 
  appeared 
  white 
  in 
  a 
  specimen 
  cleared 
  up 
  in 
  oil 
  of 
  cloves 
  and 
  

   seen 
  under 
  reflected 
  light. 
  

  

  The 
  body 
  wall, 
  particularly 
  on 
  the 
  neck 
  where 
  iCast 
  obscured 
  by 
  the 
  

   internal 
  organs, 
  shows 
  beautiful 
  longitudinal 
  and 
  transverse 
  striae 
  

   when 
  highly 
  magnified. 
  These 
  stride 
  are 
  about 
  0.002 
  mm. 
  apart. 
  

  

  One 
  specimen 
  was 
  seen 
  which 
  was 
  irregularly 
  crossed 
  by 
  transverse 
  

   wrinkles 
  in 
  the 
  middle 
  region 
  of 
  the 
  body. 
  Others 
  were 
  entirely 
  smooth. 
  

  

  Dimensions 
  of 
  a 
  typical 
  specimen 
  follow: 
  Length, 
  3.5 
  mm.; 
  longitu- 
  

   dinal 
  diameter 
  of 
  oral 
  sucker, 
  0.13; 
  transverse 
  diameter 
  of 
  same, 
  0.11; 
  

  

  