﻿518 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.xx. 
  

  

  longitudinal 
  diameter 
  of 
  ventral 
  sucker, 
  0.31; 
  transverse 
  diameter 
  of 
  

   same, 
  0.27; 
  length 
  of 
  (esophagus, 
  0.09; 
  diameter 
  of 
  oesophagus, 
  O.OS; 
  

   distance 
  between 
  suckers, 
  0.3; 
  length 
  of 
  cirrus 
  bulb, 
  0,19; 
  diameter 
  of 
  

   cirrus 
  bulb, 
  0.14; 
  genital 
  aperture, 
  0.1(3 
  in 
  front 
  of 
  ventral 
  sucker. 
  

  

  This 
  species 
  is 
  near 
  1). 
  appendlcuhiiu)n 
  . 
  

  

  Tiipe.—^o. 
  4852, 
  U.S.KM. 
  

  

  12. 
  DISTOMUM 
  MONTICELLII, 
  new 
  species. 
  

   (Plate 
  XLIV, 
  figs. 
  2-8.) 
  

  

  Body 
  slender, 
  cylindrical, 
  attenuate 
  both 
  posteriorly 
  and 
  anteriorly, 
  

   but 
  most 
  in 
  front, 
  from 
  region 
  of 
  ventral 
  .sucker; 
  uimrmed, 
  often 
  with 
  

   fine 
  transverse 
  rugie; 
  tail 
  retractile. 
  Neck 
  very 
  versatile 
  in 
  life, 
  some- 
  

   times 
  elongated, 
  linear, 
  at 
  others 
  contracted 
  until 
  the 
  two 
  sucliers 
  are 
  

   close 
  together, 
  trequeutly 
  in 
  alcoholic 
  specimens 
  sharply 
  curved 
  ven- 
  

   trally 
  in 
  form 
  of 
  a 
  hook. 
  Vitelline 
  glaiuls, 
  a 
  tubular-lobed 
  body 
  situated 
  

   behind 
  the 
  ovary 
  \vell 
  toward 
  the 
  posterior 
  end. 
  Ovary 
  globular, 
  con- 
  

   tiguous 
  with 
  vitelline 
  gland. 
  Testes, 
  two, 
  globular, 
  placed 
  close 
  together 
  

   obliquely 
  about 
  halfway 
  between 
  ventral 
  sucker 
  and 
  ovary. 
  Uterus 
  

   long, 
  its 
  folds 
  lying 
  both 
  dorsally 
  and 
  ventrally 
  between 
  testes 
  and 
  

   vitelline 
  glands 
  and 
  extending 
  forward 
  dorsally 
  to 
  the 
  genital 
  aperture 
  

   a 
  short 
  distance 
  in 
  front 
  of 
  ventral 
  sucker, 
  and 
  posteriori}'- 
  to 
  or 
  eveu 
  

   behind 
  vitelline 
  gland 
  filled 
  with 
  ova. 
  Cirrus 
  bulb 
  and 
  seminal 
  recep- 
  

   tacle 
  at 
  base 
  of 
  neck, 
  dorsally 
  placed, 
  whence 
  by 
  contraction 
  or 
  com- 
  

   pression 
  they 
  may 
  be 
  forced 
  either 
  to 
  the 
  right 
  or 
  the 
  left 
  of 
  the 
  ventral 
  

   sucker. 
  Crura 
  of 
  intestine 
  long. 
  Ventral 
  sucker 
  very 
  prominent, 
  much 
  

   larger 
  than 
  oral 
  sucker, 
  aperture 
  circular, 
  with 
  perforate 
  contractile 
  

   velum. 
  Aperture 
  of 
  oral 
  sucker 
  oval, 
  transverse 
  in 
  life, 
  longitudinal 
  

   in 
  death. 
  Oral 
  sucker 
  contiguous 
  with 
  pharynx, 
  i. 
  e., 
  tesophagus 
  

   practically 
  none. 
  Excretory 
  vessel 
  proceeding 
  from 
  the 
  vicinity 
  of 
  the 
  

   (esophagus 
  in 
  two 
  branches 
  which 
  pass 
  on 
  either 
  side 
  of 
  the 
  ventral 
  

   sucker, 
  uniting 
  behind 
  that 
  organ 
  about 
  halfway 
  between 
  it 
  and 
  the 
  

   anterior 
  testes, 
  thence 
  proceeding 
  to 
  the 
  posterior 
  end 
  of 
  tlie 
  body. 
  

   Length, 
  5.5 
  mm. 
  

  

  Tijpea.—^o^. 
  4855, 
  4856, 
  U.S.N.M. 
  

  

  1 
  have 
  found 
  this 
  parasite 
  in 
  the 
  stomach 
  of 
  the 
  sucker 
  [Remora 
  

   reinora) 
  at 
  four 
  different 
  times, 
  namely, 
  August 
  1, 
  0, 
  10, 
  1887, 
  and 
  

   July 
  22, 
  1889, 
  Woods 
  lloll, 
  Massachusetts. 
  One 
  fish 
  was 
  examined 
  

   each 
  time 
  except 
  the 
  last, 
  when 
  two 
  Avere 
  examined. 
  Numerous 
  speci- 
  

   mens 
  of 
  tliis 
  worm 
  were 
  found 
  in 
  each 
  fish, 
  with 
  one 
  exception. 
  One 
  

   of 
  the 
  two 
  examined 
  in 
  1889 
  had 
  no 
  i)arasites. 
  

  

  The 
  anatomy 
  of 
  this 
  species 
  bears 
  a 
  very 
  close 
  resemblance 
  to 
  ^Monti- 
  

   celli's' 
  Apohlona 
  stosfiichii, 
  about 
  the 
  only 
  material 
  difierence 
  being 
  the 
  

   position 
  of 
  the 
  cirrus 
  bulb 
  and 
  seminal 
  vescicle, 
  which 
  in 
  A. 
  fitossichii 
  

   is 
  behind 
  the 
  ventral 
  sucker. 
  The 
  caudal 
  appendage 
  in 
  A. 
  stossichii 
  

  

  'Atti 
  (lella 
  R. 
  Accailemia 
  delle 
  Scien/.e 
  ilc 
  Toriuo, 
  XXVI. 
  

  

  