﻿NO. 
  1950. 
  CRUSTACEAN 
  PARASITES 
  OF 
  FISH 
  AND 
  CRABS— 
  WILSON. 
  249 
  

  

  the 
  others, 
  the 
  fifth 
  segment 
  forming 
  a 
  wide 
  lobe 
  on 
  either 
  side 
  of 
  the 
  

   genital 
  segment 
  and 
  abdomen, 
  and 
  extending 
  a 
  little 
  beyond 
  the 
  

   posterior 
  margm 
  of 
  the 
  latter. 
  Fused 
  genital 
  segment 
  and 
  abdomen 
  

   semielliptical, 
  one-sixth 
  of 
  the 
  width 
  of 
  the 
  third 
  segment, 
  one-half 
  

   wider 
  than 
  long, 
  with 
  a 
  nearly 
  straight 
  posterior 
  margin; 
  anal 
  

   laminaB 
  elliptical, 
  a 
  little 
  longer 
  than 
  wide, 
  each 
  tipped 
  with 
  three 
  

   setae 
  of 
  equal 
  length. 
  

  

  Egg-strings 
  five-ninths 
  of 
  the 
  body 
  length, 
  one-fourth 
  as 
  wide 
  as 
  

   long, 
  each 
  containing 
  eight 
  or 
  nine 
  large 
  eggs. 
  

  

  First 
  antennae 
  five-jointed, 
  the 
  joints 
  diminishing 
  regularly 
  in 
  size 
  

   outwards 
  and 
  well 
  armed 
  with 
  setae 
  and 
  spines. 
  Terminal 
  claw 
  of 
  

   the 
  second 
  pair 
  fully 
  as 
  long 
  as 
  the 
  basal 
  joint, 
  bent 
  at 
  a 
  right 
  angle 
  

   near 
  the 
  tip 
  and 
  with 
  a 
  swelling 
  on 
  the 
  inner 
  margin 
  near 
  the 
  base. 
  

   Mouth 
  tube 
  conical, 
  widest 
  near 
  the 
  base 
  and 
  tapering 
  to 
  a 
  rather 
  

   sharp 
  tip; 
  maxillae 
  simple 
  pimples 
  without 
  setge 
  or 
  spines; 
  maxilli- 
  

   peds 
  of 
  the 
  usual 
  pattern, 
  the 
  two 
  terminal 
  joints 
  about 
  the 
  same 
  

   length 
  as 
  the 
  much 
  stouter 
  basal 
  joint. 
  Exopods 
  of 
  the 
  swimming 
  

   legs 
  two-jointed, 
  endopods 
  one-jointed, 
  a 
  slender 
  spine 
  outside 
  the 
  

   base 
  of 
  the 
  exopods, 
  the 
  other 
  spines 
  as 
  shown 
  in 
  the 
  drawings. 
  

  

  Cement 
  glands 
  close 
  to 
  the 
  median 
  line, 
  the 
  glandular 
  portion 
  

   about 
  half 
  the 
  entire 
  length 
  and 
  showing 
  no 
  trace 
  of 
  segmentation. 
  

   Semen 
  receptacle 
  a 
  long 
  median 
  bag 
  lying 
  between 
  the 
  ducts 
  of 
  the 
  

   cement 
  glands, 
  divided 
  posteriorly, 
  with 
  a 
  duct 
  extending 
  nearly 
  at 
  

   right 
  angles 
  to 
  the 
  long 
  axis 
  of 
  the 
  bag 
  and 
  opening 
  close 
  to 
  the 
  exter- 
  

   nal 
  orifice 
  of 
  each 
  oviduct. 
  In 
  figure 
  255 
  a 
  spermatophore 
  may 
  be 
  

   seen 
  with 
  its 
  long 
  duct 
  attached 
  to 
  this 
  opening. 
  Evidently 
  the 
  

   ducts 
  of 
  these 
  spermatophores 
  are 
  not 
  crossed 
  as 
  in 
  some 
  of 
  the 
  other 
  

   copepods. 
  

  

  Color 
  a 
  translucent 
  orange-yellow, 
  deeper 
  on 
  the 
  appendages 
  and 
  

   along 
  the 
  midfine; 
  oviducts 
  dark 
  cinnamon-brown; 
  eggs 
  in 
  the 
  

   external 
  cases 
  also 
  dark 
  brown, 
  increasing 
  in 
  intensity 
  with 
  devel- 
  

   opment. 
  

  

  Total 
  length, 
  2.75 
  mm. 
  Carapace, 
  1.33 
  mm. 
  wide, 
  1 
  mm. 
  long. 
  

   Fused 
  thorax, 
  2 
  mm. 
  long, 
  1.28 
  mm. 
  wide. 
  Egg-strings, 
  1.75 
  mm. 
  

   long, 
  0.33 
  mm. 
  wide. 
  

  

  Male. 
  — 
  Body 
  proportionally 
  longer 
  and 
  narrower 
  than 
  that 
  of 
  the 
  

   female; 
  carapace 
  nearly 
  circular 
  in 
  general 
  outline, 
  but 
  projecting 
  a 
  

   little 
  anteriorly 
  on 
  the 
  midline 
  and 
  reentrant 
  posteriorly 
  leaving 
  a 
  

   well-defined 
  lateral 
  lobe 
  on 
  either 
  side. 
  Near 
  the 
  center 
  of 
  the 
  cara- 
  

   pace 
  a 
  small 
  eye 
  can 
  be 
  seen 
  on 
  either 
  side 
  of 
  the 
  midline 
  with 
  a 
  

   central 
  mass 
  fusing 
  them 
  together. 
  

  

  Fused 
  thorax 
  nearly 
  three 
  times 
  as 
  long 
  as 
  wide, 
  with 
  the 
  segmen- 
  

   tation 
  clearly 
  indicated 
  along 
  the 
  lateral 
  margins, 
  even 
  the 
  first 
  and 
  

   second 
  segments 
  being 
  separated 
  by 
  a 
  deep 
  marginal 
  indentation. 
  

  

  