﻿NO. 
  1950. 
  CRUSTACEAN 
  PARASITES 
  OF 
  FISH 
  AND 
  CRABS— 
  WILSON. 
  219 
  

  

  legs; 
  in 
  the 
  arrangement 
  of 
  the 
  endopod 
  and 
  exopod 
  of 
  the 
  second 
  

   legs 
  ; 
  in 
  the 
  fusion 
  of 
  the 
  endopod 
  of 
  the 
  third 
  legs 
  to 
  the 
  basal 
  plate 
  ; 
  

   in 
  the 
  practical 
  disappearance 
  of 
  the 
  abdomen 
  in 
  the 
  female; 
  and 
  in 
  

   the 
  peculiar 
  size 
  and 
  shape 
  of 
  the 
  egg-strings. 
  

  

  Taken 
  separately, 
  none 
  of 
  these 
  modifications 
  possesses 
  very 
  much 
  

   systematic 
  value, 
  but 
  collectively 
  they 
  serve 
  to 
  distinguish 
  the 
  new 
  

   species 
  from 
  all 
  that 
  have 
  previously 
  been 
  described. 
  

  

  In 
  its 
  general 
  make-up 
  and 
  in 
  its 
  habits 
  it 
  is 
  a 
  typical 
  Caligus, 
  

   and 
  although 
  the 
  species 
  is 
  so 
  small 
  the 
  enlargement 
  of 
  the 
  eggs 
  

   indicates 
  that 
  the 
  nauplii 
  on 
  hatching 
  are 
  fully 
  the 
  size 
  of 
  those 
  from 
  

   larger 
  species. 
  This 
  increase 
  in 
  size 
  and 
  consequent 
  ability 
  must 
  

   compensate 
  in 
  some 
  way 
  for 
  the 
  paucity 
  in 
  the 
  number 
  of 
  eggs. 
  

  

  CALIGUS 
  SUFFUSCUS. 
  new 
  species. 
  

   Plate 
  30, 
  figs. 
  107-115. 
  

  

  Host 
  and 
  record 
  of 
  specimens. 
  — 
  A 
  couple 
  of 
  females 
  were 
  taken 
  

   from 
  the 
  mouth 
  of 
  the 
  blue 
  parrot 
  fish, 
  Scarus 
  cceruleus, 
  June 
  30, 
  

   1910. 
  

  

  Type-specimen.— 
  C&t. 
  No. 
  42267, 
  U.S.N.M. 
  

  

  Female. 
  — 
  General 
  body 
  form 
  short 
  and 
  plump; 
  carapace 
  defi- 
  

   nitely 
  more 
  than 
  half 
  the 
  entire 
  length, 
  one-fourth 
  longer 
  than 
  wide. 
  

   Frontal 
  plates 
  not 
  prominent; 
  anterior 
  margin 
  nearly 
  straight, 
  with 
  

   an 
  incision 
  at 
  the 
  center; 
  lunules 
  of 
  medium 
  size 
  and 
  widely 
  sepa- 
  

   rated, 
  just 
  reaching 
  the 
  anterior 
  margin. 
  Eye 
  relatively 
  large 
  and 
  

   situated 
  far 
  forward; 
  crossbar 
  of 
  the 
  H 
  about 
  in 
  the 
  center 
  of 
  the 
  

   carapace; 
  lateral 
  areas 
  very 
  narrow, 
  less 
  than 
  one-fourth 
  the 
  width 
  

   of 
  the 
  thoracic 
  area; 
  lateral 
  lobes 
  obliquely 
  truncated 
  posteriorly; 
  

   posterior 
  sinuses 
  shallow; 
  median 
  lobe 
  considerably 
  more 
  than 
  half 
  

   the 
  entire 
  width 
  and 
  projecting 
  far 
  behind 
  the 
  lateral 
  lobes. 
  Free 
  

   segment 
  one-third 
  the 
  width 
  of 
  the 
  carapace, 
  short 
  and 
  strongly 
  con- 
  

   tracted 
  anteriorly 
  and 
  posteriorl3^ 
  Genital 
  segment 
  one-third 
  the 
  

   entire 
  length, 
  ovate 
  in 
  outline, 
  squarely 
  truncated 
  posteriorly; 
  cor- 
  

   ners 
  smoothly 
  rounded 
  and 
  without 
  lobes; 
  fifth 
  legs 
  visible. 
  

  

  Abdomen 
  mirute, 
  elliptical, 
  about 
  one-fourth 
  the 
  width 
  and 
  length 
  

   of 
  the 
  genital 
  segment; 
  anal 
  laminae 
  widely 
  separated 
  and 
  divergent, 
  

   each 
  tipped 
  with 
  three 
  long 
  setae 
  and 
  three 
  short 
  spines 
  on 
  the 
  outer 
  

   margin. 
  Egg-tubes 
  unknown. 
  

  

  First 
  antennae 
  short 
  and 
  plump, 
  not 
  reaching 
  the 
  level 
  of 
  the 
  

   lateral 
  margin; 
  second 
  pair 
  fairly 
  stout, 
  the 
  terminal 
  claw 
  strongly 
  

   cui-ved, 
  the 
  basal 
  joint 
  reinforced 
  by 
  a 
  long 
  and 
  sharp 
  spine 
  just 
  

   behind 
  its 
  insertion. 
  Mouth 
  tube 
  short 
  and 
  stout, 
  first 
  maxilla 
  long 
  

   and 
  slender, 
  reaching 
  well 
  beyond 
  the 
  tip 
  of 
  the 
  mouth 
  tube. 
  Maxil- 
  

   liped 
  with 
  a 
  swoUen 
  basal 
  joint 
  and 
  a 
  stout 
  terminal 
  claw, 
  three- 
  

   quarters 
  as 
  long 
  as 
  the 
  basal 
  joint 
  and 
  strongly 
  curved, 
  with 
  an 
  

   accessory 
  spine 
  on 
  its 
  inner 
  margin 
  near 
  the 
  center. 
  Furca 
  large 
  

  

  