﻿452 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  volxx 
  

  

  43. 
  TETRARHYNCHUS 
  ROBUSTUM 
  Linton. 
  

  

  Tetrarhynchus 
  rohiistmn 
  Linton, 
  U. 
  S. 
  Fish 
  Com. 
  Kept., 
  1887, 
  iip. 
  855-857, 
  pi. 
  

   xiY, 
  figs. 
  7-9. 
  

  

  No. 
  4821, 
  U.S.N.M.; 
  Woods 
  Holl, 
  Massachusetts, 
  August 
  14, 
  1889, 
  

   intestine 
  of 
  cow-nosed 
  ray 
  {Rhinoptera 
  honasus), 
  two 
  specimens. 
  

  

  The 
  dimensions 
  of 
  the 
  bothria 
  and 
  all 
  the 
  soft 
  parts 
  somewhat 
  less 
  

   than 
  those 
  given 
  of 
  2\ 
  robirstiim 
  in 
  original 
  descrii)tion 
  and 
  more 
  tluin 
  

   those 
  given 
  of 
  T. 
  tenue', 
  the 
  shape, 
  arrangement, 
  and 
  dimensions 
  of 
  the 
  

   hooks 
  agree 
  with 
  those 
  of 
  T. 
  robnstum. 
  Reprodnctive 
  apertures 
  aro 
  

   near 
  the 
  anterior 
  margin 
  of 
  the 
  proglottis. 
  

  

  This 
  species 
  was 
  originally 
  described 
  from 
  specimens 
  found 
  in 
  the 
  

   sting 
  ray 
  {Dasyatis 
  centrura). 
  

  

  44. 
  TETRARHYNCHUS 
  BISULCATUM 
  Linton. 
  

  

  Bhi/nchobothrium 
  hisitlcatuni 
  Linton, 
  U. 
  S. 
  Fish 
  Com. 
  Kept., 
  1886, 
  pp. 
  479-486, 
  

  

  pi. 
  IV, 
  figs. 
  9-23. 
  

   Tetrarhynclius 
  hiseiilatutn 
  Linton, 
  U. 
  S. 
  Fish 
  Com. 
  Kept 
  , 
  1887, 
  pj). 
  857-861, 
  pis. 
  

  

  XIV, 
  figs. 
  10-12; 
  XV, 
  fig. 
  1. 
  

  

  No. 
  4713, 
  U.S.N.M. 
  Label 
  reads: 
  "Spotted 
  shark, 
  No. 
  09." 
  

   Numerous 
  specimens 
  of 
  this 
  S])ecies 
  are 
  felted 
  together 
  into 
  a 
  mass 
  

   from 
  which 
  it 
  is 
  difticult 
  to 
  get 
  a 
  complete 
  specimen. 
  One 
  fragment 
  

   was 
  measured 
  and 
  found 
  to 
  be 
  over 
  150 
  mm. 
  in 
  length. 
  

  

  I 
  have 
  found 
  this 
  species 
  in 
  the 
  adult 
  condition, 
  thus 
  far, 
  only 
  in 
  the 
  

   dusky 
  shark 
  {GarcharinKs 
  ohseurus). 
  Tlie 
  luime 
  "spotted 
  shark" 
  is 
  not 
  

   distinctive. 
  The 
  host 
  in 
  this 
  case 
  was 
  without 
  much 
  doubt 
  Carchari- 
  

   nus 
  ohseurus. 
  

  

  45. 
  TETRARHYNCH-US 
  TENUE 
  Linton. 
  

  

  Tetrarhynclius 
  tenue 
  Linton, 
  U. 
  S. 
  Fish 
  Com. 
  Kept., 
  1887, 
  pp. 
  853-855, 
  ])1. 
  xiv, 
  

   figs. 
  5-6. 
  

  

  No. 
  4827, 
  U.S.N.M. 
  The 
  following 
  additional 
  find 
  of 
  this 
  species 
  is 
  

   here 
  noticed: 
  August 
  1(», 
  1889, 
  Woods 
  IIoll, 
  Massachusetts, 
  one 
  speci- 
  

   men 
  from 
  the 
  sting 
  ray 
  {Dasyatis 
  centrura) 
  stomach. 
  

  

  EXPLANATION 
  OF 
  PLATES. 
  

  

  The 
  following 
  letters 
  have 
  the 
  same 
  significance 
  in 
  all 
  figures: 
  

  

  a. 
  auxiliary 
  bothrium. 
  1m. 
  longitudinal 
  muscles. 
  

  

  h. 
  bothrium. 
  o. 
  ovary, 
  

  

  c. 
  cirrus. 
  t. 
  testes. 
  

  

  ch. 
  calcareous 
  bodies. 
  u. 
  uterus, 
  

  

  cm. 
  circular 
  muscles. 
  v. 
  vagina. 
  

  

  cj). 
  cirrus 
  pouch. 
  vd. 
  vas 
  deferens. 
  

  

  cii. 
  cuticle. 
  r 
  g. 
  vitelline 
  gland. 
  

  

  I'sp. 
  vaginal 
  sphincter. 
  

  

  Where 
  the 
  degree 
  of 
  enlargement 
  is 
  not 
  noted 
  on 
  the 
  figure, 
  the 
  symbols 
  used 
  in 
  

   these 
  explanations 
  refer 
  to 
  the 
  eyepieces 
  and 
  objectives 
  of 
  Zeiss, 
  stand 
  No. 
  VII. 
  

   The 
  degree 
  of 
  enlargement 
  with 
  the 
  eyepieces 
  and 
  objectives 
  Avhich 
  were 
  used 
  in 
  

  

  