﻿512 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  

  

  wliicli 
  make 
  the 
  outer 
  boundaries 
  of 
  the 
  two 
  outer 
  sectors 
  of 
  the 
  plec 
  

   tauum, 
  there 
  are 
  four, 
  each 
  of 
  the 
  outer 
  quarter 
  circles 
  being 
  interrupted 
  

   iu 
  the 
  middle, 
  so 
  that 
  the 
  chitinous 
  circumference 
  is 
  divided 
  into 
  six 
  

   instead 
  of 
  four 
  parts. 
  Outside 
  of 
  the 
  su])porting 
  ring 
  there 
  is 
  a 
  thin, 
  

   transparent 
  membrane 
  which 
  projects 
  a 
  little 
  waj^ 
  iu 
  front 
  and 
  is 
  entire 
  

   in 
  outline. 
  The 
  fine, 
  parallel 
  costie 
  which 
  cover 
  the 
  surface 
  of 
  the 
  two 
  

   outer 
  sectors 
  (Plates 
  XL, 
  tig, 
  11 
  ; 
  XLI, 
  fig. 
  2) 
  are 
  of 
  two 
  kinds, 
  long 
  and 
  

   short. 
  The 
  former 
  cover 
  the 
  greater 
  part 
  of 
  the 
  surface 
  and 
  extend 
  

   from 
  the 
  rib 
  which 
  separates 
  the 
  pair 
  of 
  outer 
  sectors, 
  while 
  the 
  short 
  

   costie 
  extend 
  from 
  the 
  ribs 
  which 
  separate 
  the 
  outer 
  pair 
  from 
  the 
  

   inner 
  pair 
  of 
  sectors. 
  

  

  A 
  large 
  specimen 
  had 
  in 
  life 
  the 
  following 
  dimensions: 
  Length, 
  

   28 
  mm. 
  in 
  repose, 
  shortening 
  to 
  20, 
  lengthening 
  proportionally; 
  greatest 
  

   breadth, 
  3.5; 
  diameter 
  of 
  slender 
  portion, 
  O.S; 
  length 
  of 
  slender 
  portion, 
  

   7; 
  diameter 
  of 
  rosette, 
  3.5; 
  length 
  of 
  pedicels, 
  L4; 
  diameter 
  of 
  pedicels, 
  

   O.G; 
  diameter 
  of 
  mouth, 
  0.19; 
  diameter 
  of 
  anterior 
  suckers, 
  0.15. 
  The 
  

   slender 
  portion 
  was 
  tubular, 
  slightly 
  appressed, 
  and 
  transversely 
  wrin- 
  

   kled. 
  It 
  was 
  not 
  observed 
  to 
  change 
  much 
  iu 
  shape 
  in 
  any 
  of 
  the 
  speci- 
  

   mens 
  except 
  the 
  smallest. 
  A 
  large 
  specimen 
  was 
  observed 
  to 
  vary 
  iu 
  

   length 
  from 
  G 
  to 
  11 
  mm. 
  The 
  reproductive 
  aperture 
  as 
  seen 
  in 
  a 
  large 
  

   living 
  specimen 
  was 
  about 
  the 
  middle 
  of 
  the 
  flat 
  dilatable 
  portion 
  of 
  the 
  

   body 
  and 
  was 
  apparently 
  oblique. 
  

  

  In 
  one 
  specimen 
  the 
  digestive 
  system 
  was 
  filled 
  with 
  the 
  blood 
  of 
  its 
  

   host. 
  This 
  was 
  driven 
  backward 
  and 
  forward 
  by 
  alternate 
  contrac- 
  

   tions 
  and 
  dilations, 
  making 
  a 
  kind 
  of 
  peristaltic 
  motion. 
  In 
  the 
  narrow 
  

   middle 
  portion 
  the 
  digestive 
  system 
  is 
  reduced 
  to 
  two 
  longitudinal 
  

   channels 
  which 
  divide 
  on 
  the 
  upper 
  side 
  of 
  the 
  rosette 
  into 
  a 
  number 
  of 
  

   small 
  branches, 
  which 
  supply 
  the 
  eight 
  bothria. 
  Under 
  high 
  power 
  

   branches 
  of 
  uterus 
  seen 
  filliug 
  dilated 
  part 
  of 
  body 
  and 
  filled 
  with 
  ova. 
  

   Circulation 
  observed 
  in 
  two 
  large 
  much-branching 
  longitudinal 
  channels 
  

   and 
  along 
  each 
  side, 
  at 
  least 
  along 
  dilated 
  i)ortion. 
  

  

  Mr. 
  Tarr 
  makes 
  the 
  following 
  color 
  note 
  on 
  one 
  of 
  his 
  specimens: 
  

   "The 
  flat 
  portion 
  is 
  minutely 
  dotted 
  with 
  light 
  reddish-brown 
  dots, 
  

   while 
  the 
  narrow 
  part 
  is 
  white 
  and 
  the 
  suckers 
  flesh-colored." 
  

  

  The 
  hooks 
  seen 
  in 
  the 
  genital 
  aperture 
  are 
  arranged 
  in 
  a 
  circle 
  and 
  

   at 
  first 
  were 
  thought 
  to 
  be 
  arranged 
  in 
  pairs. 
  Subsequent 
  study 
  of 
  

   them 
  resulted 
  in 
  demonstrating 
  the 
  su])posed 
  pairs 
  of 
  hooks 
  to 
  be 
  iu 
  

   reality 
  single 
  bifurcate 
  hooks 
  (Plate 
  XL, 
  fig. 
  12); 
  of 
  these 
  there 
  

   appear 
  to 
  be 
  about 
  fifteen. 
  The 
  ova 
  are 
  fusiform, 
  with 
  very 
  long 
  atten- 
  

   uated 
  ends. 
  The 
  specimens 
  which 
  were 
  sectioned 
  did 
  not 
  have 
  mature 
  

   ova, 
  but 
  in 
  those 
  convolutions 
  of 
  the 
  oviduct 
  which 
  were 
  most 
  remote 
  

   from 
  the 
  germarium 
  the 
  characteristic 
  shape 
  of 
  the 
  mature 
  ova 
  was 
  

   faintly 
  foreshadowed 
  iu 
  the 
  developing 
  ova. 
  

  

  The 
  species 
  is 
  near 
  0. 
  palmatum 
  Leuckart, 
  iu 
  general 
  appearance 
  

   also 
  resembles 
  0. 
  lanceolatum 
  Leuckart, 
  the 
  hooks 
  of 
  the 
  latter 
  as 
  fig- 
  

   ured 
  by 
  Dujardin 
  bear 
  a 
  close 
  superficial 
  resemblance 
  to 
  those 
  of 
  0. 
  

   affine. 
  The 
  fusiform 
  ova 
  resemble 
  those 
  of 
  0. 
  denticulatum 
  Olsson. 
  

  

  