﻿NO. 
  1950. 
  CRUSTACEAN 
  PARASITES 
  OF 
  FISU 
  AND 
  CRABS— 
  WILSON. 
  255 
  

  

  head 
  was 
  buried 
  close 
  to 
  the 
  ventral 
  aorta, 
  while 
  the 
  body 
  trailed 
  

   back 
  along 
  the 
  gill 
  arches, 
  The 
  better 
  specimen 
  of 
  the 
  two 
  has 
  been 
  

   made 
  the 
  type. 
  

  

  Type-specimen.— 
  Cat. 
  No. 
  42320, 
  U.S.N.M. 
  

  

  Female. 
  — 
  General 
  body 
  form 
  slightly 
  curved 
  and 
  slender; 
  diameter 
  

   almost 
  uniform 
  throughout, 
  only 
  slightly 
  enlarged 
  posteriorly. 
  Horns 
  

   long 
  and 
  slender 
  and 
  profusely 
  branched; 
  posterior 
  processes 
  all 
  

   pointed 
  backward, 
  crowded 
  together, 
  and 
  unbranched. 
  

  

  The 
  dividing 
  line 
  between 
  the 
  fifth 
  and 
  sixth 
  (genital) 
  segments 
  is 
  

   clearly 
  indicated 
  by 
  a 
  transverse 
  groove 
  and 
  also 
  by 
  a 
  marked 
  change 
  

   in 
  color. 
  This 
  groove 
  is 
  situated 
  at 
  the 
  beginning 
  of 
  the 
  posterior 
  

   enlargement 
  of 
  the 
  bod}', 
  and 
  the 
  color 
  changes 
  from 
  wine-red 
  to 
  a 
  

   dull 
  white. 
  Head 
  flattened 
  more 
  than 
  in 
  recurvus 
  and 
  projecting 
  

   much 
  farther 
  in 
  front 
  of 
  the 
  base 
  of 
  the 
  horns. 
  Lateral 
  horns 
  four 
  

   times 
  compounded; 
  posterior 
  horn 
  not 
  at 
  right 
  angles 
  to 
  the 
  body 
  

   axis, 
  but 
  pointing 
  diagonally 
  backward, 
  almost 
  parallel 
  with 
  the 
  

   thorax, 
  and 
  three 
  times 
  compounded. 
  Sides 
  of 
  the 
  head 
  fluted 
  or 
  

   wrinkled, 
  the 
  wrinkles 
  extending 
  around 
  to 
  the 
  bases 
  of 
  the 
  second 
  

   antennae 
  and 
  mouth 
  parts 
  on 
  the 
  front 
  of 
  the 
  head. 
  First 
  antennae 
  

   practically 
  wanting, 
  only 
  the 
  merest 
  vestiges 
  of 
  knobs 
  being 
  left; 
  

   second 
  antennae 
  and 
  mouth 
  parts 
  similar 
  to 
  those 
  of 
  recurvus, 
  but 
  

   with 
  these 
  differences. 
  The 
  knobs 
  representing 
  all 
  the 
  appendages 
  

   are 
  relatively 
  larger 
  ; 
  the 
  maxillipeds 
  are 
  much 
  more 
  irregular 
  and 
  are 
  

   fully 
  twice 
  the 
  size 
  of 
  the 
  second 
  antennae, 
  and 
  there 
  is 
  much 
  less 
  space 
  

   between 
  the 
  two 
  at 
  the 
  sides 
  of 
  the 
  head. 
  The 
  mouth 
  depression 
  is 
  

   shallower, 
  but 
  the 
  form, 
  size, 
  and 
  arrangement 
  of 
  the 
  three 
  small 
  

   knobs 
  is 
  almost 
  exactly 
  the 
  same. 
  • 
  

  

  The 
  swimming 
  legs 
  are 
  smaller 
  than 
  in 
  recurvus, 
  not 
  as 
  distinctly 
  

   triangular, 
  and 
  they 
  have 
  no 
  spines; 
  they 
  are 
  also 
  farther 
  apart 
  so 
  

   that 
  they 
  do 
  not 
  even 
  touch 
  one 
  another. 
  The 
  genital 
  segment 
  is 
  

   not 
  recurved, 
  but 
  is 
  bent 
  only 
  slightly 
  out 
  of 
  a 
  straight 
  line. 
  The 
  

   egg-tubes 
  are 
  coiled 
  into 
  tight 
  bundles, 
  entirely 
  concealed 
  by 
  the 
  

   posterior 
  processes; 
  each, 
  if 
  straightened 
  out, 
  would 
  be 
  about 
  one 
  

   and 
  a 
  half 
  times 
  the 
  length 
  of 
  the 
  body. 
  

  

  Total 
  length, 
  27 
  mm. 
  Length 
  of 
  horns, 
  7.5 
  mm.; 
  of 
  posterior 
  pro- 
  

   cesses, 
  6.5 
  mm. 
  Diameter 
  of 
  head, 
  2.7 
  mm.; 
  of 
  neck, 
  1.6 
  mm.; 
  of 
  

   genital 
  segment, 
  2.6 
  mm. 
  

  

  Color 
  of 
  the 
  anterior 
  body 
  and 
  horns 
  a 
  pale 
  wine-red, 
  of 
  the 
  genital 
  

   segment 
  a 
  dull 
  white, 
  of 
  the 
  appendages 
  a 
  pale 
  yellow. 
  

  

  {striaius, 
  fluted 
  or 
  grooved, 
  alluding 
  to 
  the 
  sides 
  of 
  the 
  head.) 
  

  

  This 
  species 
  is 
  readily 
  distinguished 
  by 
  the 
  fluted 
  head, 
  large 
  second 
  

   antennae 
  and 
  mouth 
  parts, 
  straight 
  body, 
  and 
  posteriorly 
  pointing 
  

   and 
  unbranched 
  processes. 
  

  

  