﻿rilEMATODE 
  PARASITES 
  OF 
  FISHES— 
  LINTOX. 
  511 
  

  

  6. 
  OCTOPLECTANUM 
  AFFINE, 
  new 
  species. 
  

   (Plates 
  XL, 
  iigs. 
  10-18; 
  XLI, 
  figs. 
  1-5.) 
  

  

  Body 
  variable- 
  spatiil 
  ate 
  in 
  outliue, 
  consisting 
  of 
  tbree 
  ])ortions, 
  an 
  

   anterior 
  broad 
  aj^pressed 
  i)ortion 
  whicb 
  may 
  be 
  round 
  or 
  long, 
  oval, 
  lan- 
  

   ceolate, 
  or 
  even 
  linear 
  in 
  ontline, 
  according 
  to 
  state 
  of 
  contraction; 
  a 
  

   median 
  slender 
  cylindrical 
  portion 
  of 
  variable 
  relative 
  length, 
  and 
  a 
  

   posterior 
  palmate 
  or 
  rosette-like 
  portion 
  consisting 
  of 
  an 
  elongated 
  

   tubular 
  enlargement 
  of 
  the 
  posterior 
  end 
  of 
  the 
  slender 
  middle 
  portion, 
  

   bearing 
  eight 
  digitate 
  appendages, 
  each 
  consisting 
  of 
  a 
  tiexible 
  pedicel 
  

   surmounted 
  by 
  a 
  Hat, 
  cup-shaped 
  disk 
  which 
  is 
  divided 
  into 
  four 
  loculi 
  

   and 
  armed 
  with 
  a 
  complicated 
  set 
  of 
  chitinons 
  bodies. 
  The 
  outer 
  pair 
  

   of 
  locnli 
  with 
  fine 
  parallel 
  costa?; 
  one 
  of 
  the 
  others 
  with 
  an 
  elevated, 
  

   circular, 
  muscular 
  border. 
  Anterior 
  end 
  broadly 
  rounded, 
  with 
  two 
  

   transversely 
  elliptical 
  suckers 
  placed 
  on 
  either 
  side 
  of 
  month 
  and 
  a 
  lit- 
  

   tle 
  posterior 
  to 
  the 
  mouth. 
  The 
  mouth 
  is 
  also 
  transversely 
  elliptical 
  

   (in 
  alcoholic 
  specimens) 
  and 
  is, 
  in 
  life, 
  subterminal 
  and 
  circular; 
  repro- 
  

   ductive 
  aperture 
  on 
  median 
  line 
  a 
  short 
  distance 
  back 
  of 
  month; 
  cirrus 
  

   armed 
  with 
  a 
  circle 
  of 
  bifurcate 
  hooks, 
  fifteen 
  in 
  number. 
  Ground 
  color 
  

   liale, 
  very 
  faintly 
  tinged 
  with 
  yellowish-green, 
  densely 
  leticnlated, 
  with 
  

   brown 
  pigment 
  spots; 
  bothria 
  transparent, 
  bluish 
  in 
  reflected 
  light, 
  

   greenish-yellow 
  in 
  transmitted 
  light; 
  rosette 
  and 
  slender 
  portion 
  a 
  

   dirty 
  yellowish 
  green. 
  Length 
  of 
  longest 
  living 
  s]>ecimen 
  observed 
  

   28 
  mm. 
  One 
  alcoholic 
  specimen 
  with 
  exceedingly 
  long 
  attenuated 
  

   middle 
  jwrtion 
  measured 
  about 
  40 
  mm. 
  in 
  length. 
  

  

  Type.—^u. 
  487G, 
  U.S.jS".M. 
  Six 
  S])e(;imens 
  from 
  mouth 
  of 
  common 
  

   flounder 
  {Paralichthi/s 
  dottatxs); 
  Woods 
  Holl, 
  Massachusetts, 
  Septem- 
  

   ber 
  2, 
  1887. 
  Also 
  two 
  lots 
  in 
  United 
  States 
  National 
  Museum 
  col- 
  

   lection 
  (No. 
  4875), 
  August 
  8, 
  1883; 
  two 
  perfect 
  specimens 
  and 
  one 
  

   fragment 
  (No. 
  4875), 
  one 
  perfect 
  specimen 
  and 
  one 
  fragment; 
  both 
  

   lots 
  from 
  counnon 
  flounder; 
  Woods 
  Holl, 
  Massachusetts 
  (Vineyard 
  

   Sound), 
  United 
  States 
  Fish 
  Commission 
  ; 
  E. 
  S. 
  Tarr, 
  collector. 
  This 
  

   worm 
  is 
  very 
  variable 
  in 
  life, 
  but 
  the 
  alcoholic 
  specimens 
  are 
  of 
  rather 
  

   uniform 
  shape. 
  Following 
  are 
  dimensious 
  of 
  a 
  specimen 
  i)reserved 
  in 
  

   glycerin: 
  Length, 
  12 
  mm.; 
  breadth 
  (transverse 
  diameter) 
  of 
  one 
  of 
  

   anterior 
  suckers, 
  0.134; 
  length 
  of 
  pharynx, 
  0.216; 
  diameter 
  of 
  pharynx, 
  

   0.125; 
  diameter 
  of 
  mouth, 
  0.080; 
  diameter 
  of 
  circle 
  of 
  hooks 
  of 
  repro- 
  

   ductive 
  apparatus, 
  0.576; 
  length 
  of 
  one 
  of 
  these 
  hooks, 
  0.024. 
  

  

  Following 
  is 
  an 
  abstract 
  of 
  notes 
  made 
  at 
  time 
  of 
  collecting: 
  

  

  The 
  pedicels 
  are 
  very 
  changeable, 
  becoming 
  short, 
  conical, 
  and 
  trans- 
  

   versely 
  wrinkled 
  when 
  contracted 
  or, 
  when 
  elongated, 
  slender 
  and 
  

   smooth, 
  and 
  capitate, 
  the 
  terminal 
  organ 
  (plectanum) 
  not 
  appearing 
  to 
  

   be 
  susceptible 
  of 
  much 
  diversity 
  of 
  form. 
  My 
  notes 
  on 
  the 
  plectana 
  of 
  

   living 
  specimens 
  mention 
  a 
  character 
  which 
  does 
  not 
  appear 
  in 
  the 
  one 
  

   studied 
  as 
  an 
  alcoholic 
  specimen 
  which 
  is 
  shown 
  in 
  Plate 
  XLI, 
  fig. 
  2. 
  

   The 
  difference 
  is 
  that 
  instead 
  of 
  the 
  two 
  crescentic 
  chitinons 
  bodies, 
  

  

  