﻿NO. 
  lis;!. 
  TBEMATODE 
  PARASITES 
  OF 
  FISHES— 
  LINTOX. 
  539 
  

  

  A 
  single 
  specimen 
  belougiug 
  to 
  the 
  United 
  States 
  jSTational 
  Museum 
  

   collectiou 
  (No. 
  4:801, 
  U.S.X.M.), 
  from 
  tbe 
  intestine 
  of 
  tlie 
  cod 
  [Oadus 
  

   caUaria.s), 
  is 
  referred 
  provisionally 
  to 
  tbe 
  species 
  above 
  named. 
  

  

  30. 
  DISTOMUM 
  CLAVATUM 
  Rudolphi. 
  

  

  (Plate 
  LIII, 
  figs. 
  8-11.) 
  

  

  Dislo 
  itum 
  clavatum 
  Die.sinu, 
  Syst. 
  Helm., 
  I, 
  p. 
  366; 
  Nachtr. 
  znr 
  Revis. 
  d. 
  Myz- 
  

   helm., 
  p. 
  431. 
  — 
  Wa(;ener, 
  Troschel's 
  Archiv., 
  XXVI, 
  I, 
  p. 
  182, 
  pi. 
  viii, 
  figs. 
  

   11, 
  12. 
  — 
  COBBOLD, 
  Jour. 
  Liun. 
  Soc, 
  IX, 
  pp. 
  200-20.5. 
  — 
  Joikdax, 
  Revue 
  sc. 
  

   Natur. 
  Montpelliev, 
  1881, 
  II, 
  pp. 
  438-44i), 
  pis. 
  vii, 
  viii[Vou 
  Linstow, 
  Coiu- 
  

   peuil. 
  <1. 
  Heltuiutb. 
  aud 
  Nachtiag 
  to 
  Compend.]. 
  — 
  Cauus, 
  Prodr. 
  Faiiu;i' 
  

   Mediterr., 
  I, 
  p. 
  131. 
  — 
  Stossich, 
  Dist. 
  d. 
  Peso.. 
  ]i. 
  46. 
  

  

  I 
  refer 
  a 
  lot 
  of 
  distoma, 
  ten 
  in 
  number, 
  from 
  the 
  stouiacb 
  of 
  tbe 
  sword 
  

   fish 
  {XqjJiias 
  (jiadiiis), 
  United 
  States 
  National 
  3Iuseuin 
  (No. 
  4846), 
  to 
  

   this 
  species. 
  The 
  host 
  was 
  taken 
  by 
  tbe 
  Ignited 
  States 
  Fish 
  Commis- 
  

   sion 
  (1883) 
  trawl 
  lines, 
  station 
  2001, 
  steamer 
  Alhaiross. 
  

  

  Tbe 
  specimens 
  are 
  all 
  nearly 
  of 
  tbe 
  same 
  size. 
  Tbe 
  largest 
  specimen 
  

   (alcoholic) 
  presented 
  tbe 
  following 
  dimensions: 
  Length, 
  18 
  mm.; 
  diani 
  

   eter 
  of 
  head, 
  1.75; 
  diameter 
  of 
  body 
  at 
  ventral 
  sucker, 
  4.5; 
  diameter 
  of 
  

   body 
  behind 
  ventral 
  sucker, 
  4.2; 
  diameter 
  of 
  mouth, 
  1.75. 
  Ventral 
  

   sucker, 
  5.5 
  long 
  and 
  4.5 
  broad 
  ; 
  aperture 
  of 
  ventral 
  sucker, 
  2.5 
  long 
  and 
  

   1.8 
  broad; 
  breadth 
  of 
  neck, 
  0.25. 
  

  

  The 
  color 
  is 
  dark 
  brown, 
  approacbiug 
  dark 
  olivaceous 
  in 
  posterior 
  

   half 
  of 
  body 
  proper. 
  Body 
  and 
  neck 
  for 
  most 
  part 
  transversely 
  wrin 
  

   kled, 
  in 
  some 
  simply 
  roughened, 
  irregularly 
  rugose 
  in 
  posterior 
  region. 
  

   Neck 
  nmeh 
  more 
  slender 
  than 
  body, 
  not 
  (|uite 
  half 
  the 
  length 
  of 
  tbe 
  

   body, 
  strongly 
  arched, 
  cylindrical, 
  more 
  or 
  less 
  flattened 
  or 
  even 
  con- 
  

   cave 
  on 
  under 
  side. 
  Mouth 
  circular 
  with 
  wrinkled 
  or 
  puckered 
  mar- 
  

   gin, 
  oi)ening 
  ventrally. 
  Ventral 
  sucker 
  sessile, 
  much 
  larger 
  than 
  oral, 
  

   irregularly 
  corrugated, 
  with 
  deep 
  cavity 
  and 
  oblong-elliptical 
  aperture, 
  

   its 
  longer 
  axis 
  coinciding 
  with 
  tbe 
  longitudinal 
  axis 
  of 
  tbe 
  bodj\ 
  Gen- 
  

   ital 
  aperture 
  about 
  midway 
  between 
  oral 
  and 
  ventral 
  sucker. 
  Body 
  

   proper 
  nearly 
  cylintlrical 
  or 
  only 
  slightly 
  appressed, 
  slightly 
  arcuate, 
  

   enlarging 
  near 
  its 
  posterior 
  third 
  and 
  ending 
  in 
  a 
  blunt 
  point 
  in 
  which 
  

   there 
  is 
  a 
  minute 
  terminal 
  i)ore, 
  usually 
  profoundly 
  wrinkled 
  trans- 
  

   versely. 
  

  

  Tbe 
  mouth 
  cavity 
  is 
  deep 
  and 
  communicates 
  almost 
  immediately 
  with 
  

   the 
  pharynx. 
  Testes 
  two, 
  lying 
  close 
  together 
  aud 
  in 
  specimen 
  exam- 
  

   ined 
  both 
  touching 
  posterior 
  edge 
  of 
  ventral 
  sucker, 
  aud 
  together 
  fill- 
  

   ing 
  body 
  cavity 
  from 
  dorsal 
  to 
  ventral 
  wall. 
  Behind 
  the 
  testes 
  lie 
  tbe 
  

   folds 
  of 
  tbe 
  uterus 
  filled 
  with 
  minute 
  golden-brown 
  ova, 
  which 
  are 
  0.034 
  

   and 
  0.024 
  mm. 
  in 
  tbe 
  two 
  principal 
  diameters. 
  Several 
  ova 
  were 
  noticed 
  

   with 
  a 
  cap 
  or 
  oi)ercle 
  at 
  one 
  end. 
  (Fig. 
  11.) 
  In 
  longitudinal 
  median 
  

   vertical 
  section 
  this 
  organ 
  looks 
  like 
  a 
  sacculated 
  lumen 
  filled 
  with 
  dark 
  

   granular 
  material. 
  In 
  posterior 
  transverse 
  section 
  tbe 
  two 
  lumens 
  of 
  

   the 
  intestinal 
  crura 
  a[)pear 
  in 
  tbe 
  midst 
  of 
  tbe 
  vitellaria, 
  laterally 
  

  

  