﻿NO. 
  1950. 
  CRUSTACEA 
  X 
  PARASITES 
  OF 
  FISH 
  AND 
  CRABS— 
  WILSON. 
  217 
  

  

  on 
  the 
  fourth 
  legs 
  instead 
  of 
  four; 
  from 
  the 
  latter 
  it 
  may 
  be 
  distin- 
  

   guished 
  at 
  once 
  by 
  the 
  relative 
  size 
  and 
  shape 
  of 
  the 
  carapace 
  and 
  

   abdomen. 
  

  

  CALIGUS 
  ENORMIS, 
  new 
  species. 
  

   Plate 
  31. 
  

  

  Host 
  and 
  record 
  of 
  specimens. 
  — 
  A 
  dozen 
  specimens, 
  including 
  both 
  

   sexes, 
  were 
  found 
  clinging 
  to 
  the 
  inside 
  of 
  the 
  gill 
  filaments 
  of 
  the 
  

   same 
  8-pound 
  green 
  parrot 
  fish, 
  Sparisoma 
  viride, 
  that 
  served 
  as 
  the 
  

   host 
  of 
  the 
  preceding 
  species. 
  

  

  Type-siJecimen. 
  — 
  A 
  female, 
  Cat. 
  No. 
  43593, 
  U.S.N.M. 
  Paratypes, 
  

   Cat. 
  No, 
  42263, 
  U.S.N.M. 
  

  

  Female. 
  — 
  General 
  body 
  form 
  elongate 
  and 
  narrow; 
  carapace 
  and 
  

   genital 
  segment 
  approximately 
  the 
  same 
  size, 
  each 
  of 
  them 
  being 
  

   constricted 
  where 
  it 
  joins 
  the 
  fourth 
  (free) 
  segment, 
  thus 
  giving 
  the 
  

   body 
  somewhat 
  the 
  shape 
  of 
  a 
  dumb-bell. 
  Carapace 
  only 
  three- 
  

   sevenths 
  of 
  the 
  entire 
  length, 
  elliptical, 
  one-third 
  longer 
  than 
  wide; 
  

   frontal 
  plates 
  narrow 
  and 
  prominent; 
  lunules 
  reduced 
  to 
  narrow 
  lines 
  

   with 
  scarcely 
  any 
  curve, 
  close 
  together, 
  with 
  no 
  incision 
  in 
  the 
  short 
  

   frontal 
  margin 
  between 
  them. 
  Eye 
  large 
  and 
  placed 
  well 
  forward. 
  

   Lateral 
  areas 
  wide, 
  the 
  posterior 
  lobes 
  turned 
  slightly 
  outward; 
  

   median 
  lobe 
  twice 
  the 
  width 
  of 
  the 
  lateral 
  lobes 
  and 
  reaching 
  more 
  

   than 
  half 
  its 
  length 
  behind 
  them; 
  posterior 
  sinuses 
  broad 
  and 
  shallow. 
  

  

  Free 
  segment 
  one-third 
  the 
  width 
  of 
  the 
  carapace, 
  with 
  convex 
  

   lateral 
  margins. 
  Genital 
  segment 
  elliptical, 
  the 
  same 
  length 
  as 
  the 
  

   carapace 
  but 
  a 
  little 
  narrower, 
  with 
  rounded 
  corners 
  and 
  nearly 
  

   straight 
  sides. 
  

  

  Abdomen 
  reduced 
  to 
  a 
  comparatively 
  minute 
  protuberance 
  at 
  the 
  

   posterior 
  end 
  of 
  the 
  genital 
  segment, 
  triangular 
  and 
  one-jointed; 
  

   each 
  anal 
  lamina 
  as 
  large 
  as 
  its 
  half 
  of 
  the 
  abdomen 
  and 
  tipped 
  with 
  

   three 
  short 
  setae 
  and 
  a 
  fourth 
  one 
  on 
  the 
  outer 
  margin. 
  

  

  Egg-strings 
  exceptionally 
  short 
  and 
  wide, 
  similar 
  to 
  those 
  found 
  in 
  

   many 
  Dichelestiids, 
  each 
  half 
  the 
  width 
  of 
  the 
  genital 
  segment 
  and 
  

   not 
  quite 
  equaling 
  it 
  in 
  length; 
  only 
  six 
  or 
  seven 
  eggs 
  in 
  each 
  string. 
  

  

  First 
  antennae 
  short 
  and 
  stout, 
  not 
  reaching 
  more 
  than 
  halfway 
  to 
  

   he 
  lateral 
  margins, 
  the 
  two 
  joints 
  about 
  the 
  same 
  length 
  and 
  well 
  

   armed. 
  Second 
  pair 
  with 
  a 
  slender 
  terminal 
  claw, 
  slightly 
  bent 
  near 
  

   the 
  tip. 
  Maxillary 
  hooks 
  and 
  first 
  rnaxillEe 
  reduced 
  to 
  tiny 
  spines 
  

   that 
  can 
  hardly 
  be 
  detected 
  ; 
  second 
  maxillae 
  exceptionally 
  large 
  and 
  

   stout, 
  the 
  two 
  joints 
  about 
  the 
  same 
  size, 
  the 
  terminal 
  claws 
  short 
  and 
  

   stout. 
  Maxillipeds 
  with 
  a 
  swollen 
  basal 
  joint 
  and 
  a 
  strong 
  terminal 
  

   claw 
  carrying 
  an 
  accessory 
  spine 
  on 
  its 
  inner 
  margin 
  toward 
  the 
  tip. 
  

   Furca 
  entirely 
  lacking. 
  First 
  swimming 
  legs 
  rudimentaiy, 
  made 
  up 
  

   of 
  three 
  short 
  and 
  wide 
  joints 
  of 
  about 
  the 
  same 
  size, 
  the 
  terminal 
  one 
  

   with 
  four 
  claws 
  at 
  the 
  tip 
  but 
  no 
  setae 
  on 
  the 
  posterior 
  margin. 
  Exo- 
  

   pods 
  of 
  second 
  pair 
  extending 
  outward 
  in 
  line 
  with 
  the 
  basal 
  joint 
  

  

  