﻿NO. 
  1133. 
  TREMATODE 
  I'AIUSITES 
  OF 
  FISHES— 
  LIXTOX. 
  535 
  

  

  length 
  of 
  testis, 
  0.C5; 
  length 
  of 
  cirrus 
  pouch, 
  0.57; 
  diameter 
  of 
  cirrus 
  

   pouch, 
  0.2(3, 
  

  

  The 
  thiu-walled 
  iutestiual 
  tracts 
  exteud 
  to 
  within 
  about 
  1 
  mm. 
  of 
  the 
  

   posterior 
  end 
  of 
  a 
  specimen 
  5 
  mm. 
  in 
  leugth. 
  

  

  26. 
  DISTOMUM 
  TENUE, 
  new 
  species. 
  

   (I'late 
  LII. 
  tigs. 
  2-8.) 
  

  

  Head 
  disciform, 
  surrounded 
  by 
  a 
  double 
  row 
  of 
  spiues; 
  mouth 
  ter- 
  

   miual, 
  triangular, 
  at 
  times 
  appearing 
  circular 
  from 
  invagination 
  of 
  its 
  

   border; 
  neck 
  cylindrical 
  attenuate 
  in 
  front 
  of 
  pharynx; 
  neck 
  and 
  ante- 
  

   rior 
  part 
  of 
  body 
  closely 
  beset 
  with 
  short 
  triangular 
  spines, 
  becoming- 
  

   sparse 
  or 
  even 
  entirely 
  wanting 
  toward 
  posterior 
  end 
  of 
  body. 
  

  

  Body 
  rather 
  slender, 
  linear-lanceolate, 
  slightly 
  depressed. 
  Ventral 
  

   sucker 
  prominent, 
  sessile 
  at 
  base 
  of 
  neck, 
  mucli 
  larger 
  than 
  oral 
  sucker, 
  

   with 
  circular 
  aperture. 
  I'harynx 
  large, 
  remote 
  from 
  head, 
  (esophagus 
  

   of 
  good 
  leugth, 
  rather 
  slender, 
  tubular, 
  branches 
  of 
  intestine 
  capacious. 
  

   Genital 
  ai»erture 
  in 
  front 
  of 
  ventral 
  sucker. 
  Testes 
  situated 
  toward 
  

   posterior 
  end 
  of 
  body. 
  Folds 
  of 
  uterus 
  mainly 
  near 
  center 
  of 
  body; 
  

   ova 
  rather 
  large, 
  elliptical. 
  

  

  The 
  foregoing 
  is 
  a 
  description 
  of 
  a 
  species 
  of 
  IHstomtim 
  found 
  at 
  two 
  

   diti'erent 
  times 
  in 
  the 
  striped 
  bass 
  [Rocciis 
  llneatus). 
  This 
  species, 
  it 
  

   will 
  be 
  observed, 
  possesses 
  nmny 
  characters 
  common 
  to 
  D. 
  cesficillus 
  

   Molin, 
  but 
  is 
  very 
  much 
  smaller 
  than 
  that 
  species 
  besides 
  occurring 
  in 
  

   a 
  very 
  different 
  host. 
  

  

  There 
  appear 
  to 
  be 
  twenty-one 
  spines 
  in 
  each 
  row 
  surrounding 
  the 
  

   mouth, 
  the 
  spines 
  of 
  one 
  row 
  alternating 
  with 
  those 
  of 
  the 
  other. 
  

   These 
  are 
  conical 
  and 
  slightly 
  recurved. 
  In 
  some 
  specimens, 
  kept 
  in 
  

   water 
  over 
  night, 
  the 
  part 
  bearing 
  these 
  two 
  rows 
  of 
  spines 
  became 
  

   invaginated 
  so 
  as 
  to 
  conceal 
  them. 
  The 
  mouth 
  in 
  fresh 
  specimens 
  had 
  

   three 
  toothlike 
  folds 
  within 
  the 
  sucker. 
  The 
  spines 
  on 
  the 
  body 
  are 
  

   short, 
  triangular, 
  appressed. 
  Immediately 
  back 
  of 
  the 
  oral 
  armature 
  

   there 
  is 
  a 
  brief 
  interval 
  which 
  is 
  without 
  spines. 
  The 
  spines 
  on 
  the 
  

   neck 
  are 
  arranged 
  symmetrically 
  in 
  transverse 
  rows. 
  They 
  become 
  

   snuiUer 
  in 
  the 
  vicinity 
  of 
  the 
  ventral 
  sucker, 
  back 
  of 
  it 
  they 
  are 
  still 
  

   smaller, 
  while 
  the 
  povsterior 
  part 
  of 
  the 
  body 
  is 
  smooth, 
  or 
  very 
  sparsely 
  

   covered 
  with 
  minute 
  spines. 
  

  

  Types.— 
  ^os. 
  48G6, 
  48()7, 
  U.S.N.M. 
  

  

  Length 
  of 
  oral 
  spines, 
  0.051; 
  breadth 
  at 
  base, 
  0.018 
  mm.; 
  length 
  of 
  

   spines 
  on 
  neck, 
  0.025; 
  breadth 
  at 
  base, 
  0.014; 
  length 
  of 
  spines 
  near 
  

   posterior 
  end, 
  0.007; 
  breadth, 
  0.002. 
  The 
  tirst 
  five 
  or 
  six 
  transverse 
  

   rows 
  of 
  spines 
  on 
  the 
  neck 
  are 
  broken 
  for 
  a 
  short 
  interval 
  on 
  the 
  ven- 
  

   tral 
  side. 
  (Fig. 
  3.) 
  

  

  The 
  cesophagus 
  is 
  ])yriforin, 
  its 
  larger 
  end 
  lying 
  near 
  the 
  anterior 
  

   margin 
  of 
  the 
  ventral 
  sucker; 
  in 
  one 
  specimen, 
  living, 
  somewhat 
  dis- 
  

   torted 
  by 
  compression; 
  the 
  length 
  of 
  the 
  oesophagus 
  was 
  0.44, 
  its 
  max- 
  

   imum 
  diameter 
  0.34 
  mm. 
  

  

  