﻿NO. 
  1133. 
  TEEMATODE 
  PARASITES 
  OE 
  FISHES— 
  LIXTOX. 
  523 
  

  

  compared 
  with 
  similar 
  series 
  of 
  D. 
  nigrojiavum 
  and 
  D. 
  foUatum. 
  The 
  

   vitellaria 
  were 
  fouud 
  to 
  be 
  most 
  strongly 
  developed 
  above 
  and 
  in 
  front 
  

   of 
  the 
  ventral 
  sucker, 
  extending 
  through 
  the 
  neck 
  dorsally 
  and 
  axially 
  

   nearly 
  as 
  far 
  as 
  the 
  oral 
  sucker, 
  sparsely 
  scattered 
  through 
  the 
  body 
  as 
  

   far 
  back 
  as 
  the 
  ovary. 
  Doubtless 
  in 
  younger 
  specimens 
  the 
  vitellaria 
  

   are 
  more 
  conspicuous 
  organs 
  tlum 
  in 
  the 
  sectioned 
  individuals, 
  the 
  

   larger 
  part 
  of 
  whose 
  bodies 
  was 
  tilled 
  with 
  ripe 
  ova. 
  The 
  testes 
  lie 
  

   close 
  together, 
  one 
  immediately 
  following 
  the 
  other, 
  the 
  anterior 
  one 
  a 
  

   little 
  toward 
  the 
  left, 
  the 
  posterior 
  one 
  a 
  little 
  toward 
  the 
  right 
  side 
  of 
  

   the 
  body, 
  and 
  the 
  former 
  close 
  behind 
  the 
  ventral 
  sucker. 
  They 
  are 
  

   ventrally 
  placed 
  and 
  oval 
  in 
  sha]>e. 
  The 
  anterior 
  1.07 
  and 
  the 
  posterior 
  

   1.04 
  mm. 
  in 
  length. 
  The 
  seminal 
  receptacle 
  lies 
  in 
  voluminous 
  folds 
  

   above 
  and 
  in 
  front 
  of 
  the 
  ventral 
  sucker. 
  The 
  vas 
  deferens 
  traverses 
  

   a 
  large 
  prostate 
  gland 
  and 
  ends 
  in 
  a 
  relatively 
  small 
  cirrus 
  immediately 
  

   behind 
  the 
  oral 
  sucker. 
  At 
  the 
  base 
  of 
  the 
  cirrus 
  the 
  vas 
  deferens 
  is 
  

   joined 
  by 
  the 
  uterus, 
  winch 
  traverses 
  the 
  ventral 
  region 
  of 
  the 
  neck. 
  

   The 
  ovary 
  is 
  subglobular 
  in 
  sha])e, 
  about 
  0.84 
  mm. 
  in 
  diameter, 
  lies 
  

   about 
  the 
  middle 
  of 
  the 
  post 
  acetabular 
  region; 
  on 
  its 
  anterior 
  border, 
  

   and 
  lying 
  toward 
  the 
  right 
  side 
  of 
  the 
  body 
  is 
  the 
  shell 
  gland 
  (0.37 
  mm. 
  

   in 
  diameter), 
  not 
  shown 
  in 
  tig. 
  9, 
  which 
  was 
  made 
  from 
  the 
  left 
  side. 
  

   The 
  posterior 
  part 
  of 
  the 
  body 
  m 
  the 
  sections 
  is 
  filled 
  with 
  the 
  volumi- 
  

   nous 
  folds 
  of 
  the 
  uterus, 
  which 
  are 
  crowded 
  with 
  ova. 
  The 
  chaiacter- 
  

   istic 
  rami 
  of 
  the 
  longitudinal 
  vessels 
  of 
  the 
  body 
  proper, 
  as 
  well 
  as 
  

   those 
  of 
  the 
  neck, 
  are 
  shown 
  in 
  Plates 
  XLV, 
  fig. 
  10 
  ^ 
  XLVI, 
  fig. 
  1. 
  

  

  The 
  vessels 
  are 
  peculiar 
  in 
  being 
  variously 
  branched. 
  They 
  are 
  

   tilled 
  with 
  finely 
  granular 
  materal, 
  as 
  is 
  the 
  case 
  in 
  1>. 
  ni<iroHarum 
  and 
  

   h.follaium. 
  A 
  few 
  minute 
  tetragonal 
  crystals 
  were 
  observed 
  in 
  the 
  

   contents 
  of 
  these 
  vessels. 
  The 
  branching 
  vessels 
  of 
  the 
  posterior 
  j^art 
  

   of 
  the 
  body 
  appear 
  to 
  communicate 
  with 
  a 
  common 
  i>osterior 
  sinus 
  

   which 
  opens 
  to 
  the 
  exterior 
  by 
  a 
  terminal 
  pore. 
  I 
  was 
  unable 
  in 
  my 
  

   sections 
  to 
  demonstrate 
  any 
  communication 
  between 
  these 
  vessels 
  and 
  

   the 
  pharynx. 
  They 
  certainly 
  liave 
  their 
  origin 
  in 
  front 
  of 
  that 
  organ. 
  

   They 
  agree 
  in 
  stiucture 
  with 
  intestinal 
  crura, 
  but 
  otherwise 
  resemble 
  

   excretory 
  vessels. 
  « 
  

  

  17. 
  DISTOMUM 
  GRACILE 
  Diesing. 
  

   (Plate 
  XLVI, 
  figs. 
  6-8.) 
  

  

  Crniostomum 
  gracile 
  Lkidy, 
  Proc. 
  Acad. 
  Phil., 
  VIII 
  (1856), 
  p. 
  45. 
  

   DisioniHM 
  firacUe 
  DiESixi;, 
  Kevis. 
  d. 
  Myzbehii, 
  p. 
  336. 
  — 
  Wiught, 
  Coiitril). 
  to 
  

   Amer. 
  Helm., 
  pp.9, 
  10. 
  

  

  Body 
  oblong-elliptical, 
  in 
  dorsal 
  or 
  ventral 
  view, 
  with 
  slight 
  constric- 
  

   tion 
  opposite 
  ventral 
  sucker, 
  compressed; 
  neck 
  short, 
  convex 
  above, 
  

   concave 
  below. 
  Head 
  obliquely 
  truncate, 
  oral 
  sucker 
  situated 
  at 
  the 
  

   bottom 
  of 
  a 
  shallow 
  dei)ression 
  and 
  surrounded 
  in 
  iiont 
  by 
  a 
  prominent 
  

   border, 
  from 
  which 
  a 
  lip-like 
  projection 
  extends 
  back 
  over 
  the 
  anterior 
  

   edge 
  of 
  the 
  sucker; 
  aperture 
  of 
  oral 
  sucker 
  circular; 
  cesophagus 
  none, 
  

   pharynx 
  oval. 
  Ventral 
  sucker 
  globular, 
  much 
  larger 
  than 
  oral 
  sucker, 
  

  

  