﻿NO. 
  1950. 
  CRUSTACEAN 
  PARASITES 
  OF 
  FISH 
  AND 
  CRABS— 
  WILSON. 
  231 
  

  

  shaped 
  like 
  an 
  ovate 
  acute 
  leaf, 
  each 
  actually 
  wider 
  than 
  the 
  fifth 
  

   segment 
  and 
  reaching 
  well 
  beyond 
  the 
  posterior 
  margin 
  of 
  the 
  dorsal 
  

   plate 
  of 
  the 
  fourth 
  segment. 
  Fourth 
  legs 
  biramose, 
  each 
  ramus 
  

   broad 
  and 
  leaf-hke 
  at 
  the 
  base 
  and 
  tapering 
  into 
  a 
  long 
  and 
  acuminate 
  

   tip, 
  which 
  shows 
  for 
  nearly 
  its 
  entire 
  length 
  beyond 
  the 
  posterior 
  

   margin 
  of 
  the 
  dorsal 
  plate 
  of 
  the 
  fourth 
  segment. 
  

  

  Total 
  length, 
  without 
  legs, 
  8 
  mm.; 
  with 
  fourth 
  legs, 
  11.5 
  mm. 
  

   Cephalothorax, 
  3 
  mm. 
  long, 
  1.9 
  mm. 
  wide. 
  Dorsal 
  plate 
  on 
  fourth 
  

   segment, 
  3.2 
  mm. 
  wide, 
  2,5 
  mm. 
  long, 
  

  

  2Iale. 
  — 
  General 
  body 
  form 
  oblong, 
  the 
  same 
  width 
  throughout, 
  

   three 
  times 
  as 
  long 
  as 
  wide. 
  Cephalothorax 
  ovate, 
  tliree-sevenths 
  of 
  

   the 
  entire 
  length; 
  antennal 
  area 
  distinctly 
  separated 
  and 
  much 
  nar- 
  

   rower 
  than 
  the 
  remainder 
  of 
  the 
  cephalothorax. 
  Free 
  thorax, 
  genital 
  

   segment, 
  and 
  abdomen 
  well 
  fused, 
  without 
  trajisverse 
  grooves, 
  but 
  

   with 
  marginal 
  invaginations 
  indicating 
  the 
  segmentation. 
  Genital 
  

   segment 
  considerably 
  narrower 
  than 
  the 
  free 
  thorax; 
  anal 
  lamina? 
  

   elongate 
  and 
  flattened, 
  but 
  not 
  as 
  foliaceous 
  as 
  in 
  the 
  female. 
  

   Appendages 
  similar 
  to 
  those 
  of 
  the 
  female, 
  the 
  terminal 
  claws 
  of 
  the 
  

   second 
  maxillas 
  and 
  maxilHpeds 
  longer 
  and 
  sharper. 
  Thijrd 
  and 
  

   fourth 
  legs 
  biramose, 
  slender, 
  and 
  thread-like; 
  endopod 
  of 
  third 
  pair 
  

   rudhnentary 
  and 
  very 
  short; 
  endopod 
  of 
  fourth 
  pair 
  much 
  shorter 
  

   than 
  the 
  exopod, 
  which 
  latter 
  is 
  nearly 
  as 
  long 
  as 
  the 
  entire 
  body; 
  

   fifth 
  legs 
  wanting. 
  

  

  Color 
  of 
  both 
  sexes 
  a 
  creamy 
  yellow, 
  without 
  pigment 
  markings. 
  

  

  Total 
  length, 
  without 
  fourth 
  legs, 
  3.5 
  mm.; 
  with 
  fourth 
  legs, 
  5.5 
  

   mm. 
  Cephalothorax, 
  1.5 
  mm. 
  long, 
  1 
  mm. 
  wide. 
  Posterior 
  body, 
  

   2 
  mm. 
  long, 
  0.9 
  mm. 
  wide. 
  

  

  (frondeus, 
  covered 
  with 
  leaves, 
  in 
  allusion 
  to 
  the 
  shape 
  of 
  the 
  third, 
  

   fourth, 
  and 
  fifth 
  legs 
  and 
  the 
  anal 
  laminae 
  in 
  the 
  female.) 
  

  

  NauiMus 
  larva. 
  — 
  Body 
  shield-sliaped, 
  with 
  square 
  anterior 
  corners 
  

   and 
  a 
  pointed 
  posterior 
  margin. 
  Eye 
  very 
  far 
  forward, 
  just 
  behind 
  

   the 
  anterior 
  margin. 
  Appendages 
  of 
  the 
  usual 
  pattern, 
  the 
  three 
  

   pairs 
  of 
  about 
  the 
  same 
  length. 
  Balancers 
  far 
  back 
  on 
  either 
  side 
  of 
  

   the 
  posterior 
  point, 
  cm'ved 
  outward 
  and 
  forward, 
  rather 
  short 
  and 
  

   stout. 
  Center 
  of 
  the 
  body 
  filled 
  with 
  a 
  dark 
  mass 
  of 
  cinnamon- 
  

   brown 
  pigment, 
  leaving 
  only 
  a 
  narrow 
  margin 
  clear. 
  This 
  mass 
  of 
  

   pigment 
  makes 
  the 
  egg-strings 
  of 
  the 
  adult 
  female 
  very 
  dark 
  brown 
  

   just 
  before 
  they 
  are 
  ready 
  to 
  hatch. 
  

  

  This 
  species 
  can 
  be 
  readily 
  distinguished 
  by 
  the 
  broad 
  and 
  foHaceous 
  

   logs 
  and 
  anal 
  laminae 
  of 
  the 
  female, 
  and 
  by 
  the 
  fact 
  that 
  the 
  cephalo- 
  

   thorax 
  and 
  free 
  segments 
  of 
  both 
  sexes 
  are 
  about 
  the 
  same 
  width. 
  

   The 
  two 
  pairs 
  of 
  antennae 
  are 
  also 
  peculiarly 
  prominent 
  in 
  dorsal 
  

   view. 
  It 
  is 
  one 
  of 
  the 
  larger 
  species, 
  and 
  gives 
  an 
  excellent 
  typical 
  

   idea 
  of 
  the 
  genus 
  which 
  it 
  represents. 
  

  

  