﻿NO. 
  1125. 
  CESTODE 
  PARASITES 
  OF 
  FISHES— 
  LINTON. 
  433 
  

  

  each 
  a 
  single 
  ripe 
  proglottis 
  and 
  one 
  bore 
  two 
  rii)e 
  proglottides. 
  (Figs. 
  

   9, 
  10.) 
  The 
  ripe 
  proglottides 
  were 
  attached 
  by 
  a 
  slender 
  pedicel, 
  so 
  

   that 
  if 
  there 
  were 
  a 
  number 
  of 
  tliein 
  they 
  would 
  make 
  a 
  decidedly 
  

   moniliform 
  chaiu. 
  AVhen 
  viewed 
  on 
  the 
  flat 
  surface 
  they 
  are 
  irregu- 
  

   larly 
  circular 
  in 
  outline, 
  in 
  some 
  cases 
  longer 
  than 
  broad, 
  in 
  others 
  

   broader 
  than 
  long. 
  They 
  are 
  loosely 
  attached. 
  In 
  each 
  case 
  they 
  

   begin 
  abruptly. 
  These 
  strobiles 
  were 
  from 
  40 
  to 
  50 
  mm. 
  in 
  length. 
  

   Dimensions 
  of 
  one: 
  Length, 
  45 
  mm.; 
  length 
  of 
  head, 
  1.85; 
  breadth 
  of 
  

   head 
  at 
  base, 
  1.7; 
  tbickness 
  of 
  head 
  at 
  base, 
  1.3; 
  breadth 
  of 
  neck 
  

   behind 
  head, 
  1; 
  thickness 
  of 
  neck, 
  0.4; 
  length 
  of 
  median 
  segments, 
  

   0.35; 
  breadth 
  of 
  median 
  segments, 
  2.5; 
  length 
  of 
  segments 
  near 
  pos- 
  

   terior 
  end, 
  0.55; 
  breadth 
  of 
  segments 
  near 
  posterior 
  end, 
  2.7; 
  length 
  

   ol 
  ripe 
  proglottis, 
  1.4; 
  breadth 
  of 
  ripe 
  proglottis, 
  1.7. 
  

  

  The 
  genital 
  apertures 
  are 
  about 
  the 
  middle 
  of 
  the 
  lateral 
  margins, 
  

   irregularly 
  alternate, 
  usually 
  two 
  or 
  three 
  on 
  same 
  lateral 
  margin 
  of 
  

   successive 
  segments; 
  anemargination 
  at 
  lateral 
  margin 
  indicates 
  posi- 
  

   tion 
  of 
  aperture. 
  The 
  genital 
  aperture 
  is 
  cup-shaped, 
  0.07 
  mm. 
  deep 
  

   and 
  O.OG 
  in 
  diameter. 
  The 
  cirrus-pouch 
  in 
  the 
  specimens 
  examined 
  

   measured 
  0.22mm. 
  in 
  length 
  and 
  0.14 
  in 
  diameter. 
  Xo 
  sections 
  were 
  

   made. 
  In 
  a 
  specimen 
  cleared 
  up 
  in 
  oil 
  of 
  cloves 
  there 
  appeared 
  in 
  some 
  

   of 
  the 
  segments 
  a 
  slender, 
  somewhat 
  sinuous 
  tube 
  lying 
  beside 
  the 
  cir- 
  

   rus, 
  which 
  I 
  take 
  to 
  be 
  the 
  vagina. 
  If 
  this 
  is 
  correct, 
  then 
  the 
  pores 
  on 
  

   the 
  flat 
  surface 
  of 
  the 
  segments 
  are 
  for 
  the 
  escape 
  of 
  ova. 
  The 
  poste- 
  

   rior 
  segments 
  are 
  filled 
  with 
  ova, 
  especially 
  the 
  round 
  terminal, 
  loosely 
  

   attached 
  segments. 
  The 
  ova 
  are 
  nearly 
  spherical, 
  with 
  thin 
  shells. 
  

   They 
  are 
  about 
  0.04 
  mm. 
  in 
  the 
  greatest 
  diameter. 
  The 
  segments 
  con- 
  

   tain 
  numerous 
  calcareous 
  bodies, 
  which 
  exhibit 
  a 
  concentric 
  structure. 
  

  

  12. 
  DIBOTHRIUM 
  species. 
  

  

  Fragment 
  No. 
  1473, 
  U.S.X.M, 
  From 
  intestine 
  of 
  dogfish 
  {Miistelus 
  

   cants); 
  Woods 
  IIoll, 
  Massachusetts, 
  July 
  21, 
  1887, 
  

  

  A 
  chain 
  of 
  proglottides, 
  11mm. 
  in 
  length 
  and 
  consisting 
  of 
  nine 
  

   proglottides, 
  breadth 
  5.5; 
  ova 
  escaijiug 
  from 
  median 
  pores 
  near 
  ante- 
  

   rior 
  ends 
  of 
  segments; 
  reproductive 
  aperture 
  on 
  lateral 
  margin 
  about 
  

   middle 
  of 
  length; 
  all 
  on 
  same 
  side 
  of 
  chain, 
  the 
  aperture 
  a 
  prominent 
  

   cloaca; 
  dimensions 
  of 
  ova, 
  0.053 
  and 
  0.035 
  mm. 
  in 
  two 
  principal 
  diameters. 
  

  

  Careful 
  search 
  was 
  made 
  for 
  other 
  fragments, 
  so 
  that 
  if 
  any 
  had 
  

   been 
  present 
  they 
  certainly 
  would 
  have 
  been 
  found. 
  These 
  segments, 
  

   without 
  much 
  doubt,' 
  had 
  been 
  introduced 
  in 
  their 
  present 
  state 
  of 
  

   development 
  along 
  with 
  food. 
  

  

  13. 
  DIBOTHRIUM 
  CORDICEPS 
  Leidy. 
  

  

  Diholhrium 
  cordieepa 
  Leidy, 
  Hayden'.s 
  Prelim. 
  Kept. 
  U. 
  S. 
  Geolog. 
  Survey^ 
  1871, 
  

   pp. 
  381-382.— 
  LiNTOX, 
  Bull. 
  U. 
  S. 
  Fish 
  Com., 
  IX, 
  1889, 
  pp. 
  72-76, 
  pis. 
  xxv- 
  

   xxvii; 
  pp. 
  337-358, 
  pis. 
  cvii-cxix: 
  1889-1891, 
  p. 
  517. 
  

  

  No. 
  4730, 
  U.S.N.M. 
  Neither 
  host 
  nor 
  locality 
  are 
  given; 
  numerous 
  

   Proc. 
  N. 
  M. 
  vol. 
  XX 
  28 
  

  

  