﻿210 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.44. 
  

  

  the 
  genital 
  segment 
  and 
  indistinctl}^ 
  two-jointed, 
  the 
  basal 
  joint 
  

   much 
  the 
  shorter; 
  anal 
  laminje 
  small 
  and 
  circular, 
  each 
  tipped 
  with 
  

   three 
  long 
  setae 
  and 
  a 
  shorter 
  one 
  on 
  the 
  lateral 
  margin. 
  

  

  Terminal 
  joints 
  of 
  the 
  first 
  antennae 
  even 
  longer 
  and 
  more 
  slender 
  

   than 
  in 
  the 
  female. 
  

  

  Second 
  antennae 
  with 
  a 
  much 
  longer 
  second 
  joint 
  and 
  a 
  shorter 
  

   terminal 
  claw, 
  curved 
  into 
  a 
  horseshoe 
  shape. 
  Maxillary 
  hooks 
  

   longer 
  and 
  more 
  slender 
  but 
  straight; 
  other 
  appendages 
  like 
  those 
  

   of 
  the 
  female 
  except 
  that 
  both 
  the 
  fifth 
  and 
  sixth 
  legs 
  are 
  present 
  on 
  

   the 
  genital 
  segment, 
  the 
  former 
  on 
  the 
  lateral 
  margins 
  opposite 
  the 
  

   sperm 
  receptacles, 
  the 
  latter 
  forming 
  the 
  posterior 
  lobes. 
  

  

  Color 
  as 
  in 
  the 
  female. 
  

  

  Total 
  length, 
  2.85 
  mm. 
  Carapace, 
  1.6 
  mm. 
  long, 
  1.7 
  mm. 
  wide. 
  

   Genital 
  segment, 
  0.65 
  mm. 
  long, 
  0.45 
  mm. 
  wide. 
  

  

  Heller's 
  description 
  of 
  the 
  female 
  of 
  this 
  species 
  was 
  good 
  and 
  such 
  

   figures 
  as 
  he 
  presented 
  were 
  excellent, 
  but 
  both 
  were 
  made 
  from 
  

   preserved 
  material 
  alone 
  and 
  lacked 
  many 
  details. 
  Bassett-Smith's 
  

   description 
  of 
  the 
  male 
  is 
  far 
  from 
  satisfactory 
  and 
  his 
  single 
  figure 
  

   gives 
  no 
  details 
  whatever. 
  

  

  The 
  present 
  specimens 
  having 
  been 
  obtained 
  ahve 
  and 
  kept 
  for 
  

   several 
  days, 
  an 
  attempt 
  has 
  been 
  made 
  to 
  give 
  a 
  complete 
  descrip- 
  

   tion 
  from 
  them, 
  particularly 
  with 
  regard 
  to 
  color 
  and 
  proportions. 
  

   Among 
  these 
  specimens 
  were 
  two 
  chalimus 
  larvae; 
  in 
  the 
  smaller 
  

   one 
  only 
  the 
  first 
  thorax 
  segment 
  was 
  fused 
  with 
  the 
  carapace 
  and 
  

   the 
  endopod 
  of 
  the 
  first 
  legs 
  was 
  as 
  large 
  as 
  the 
  exopod. 
  In 
  the 
  

   larger 
  one 
  the 
  first 
  two 
  thorax 
  segments 
  were 
  fused 
  with 
  the 
  carapace 
  

   and 
  the 
  first 
  endopod 
  had 
  become 
  very 
  rudimentary. 
  Both 
  sexes 
  

   swim 
  about 
  in 
  an 
  aquarium 
  almost 
  constantly 
  and 
  are 
  fully 
  as 
  lively 
  

   as 
  C. 
  rapax. 
  The 
  species 
  is 
  not 
  a 
  common 
  one, 
  for 
  among 
  the 
  large 
  

   number 
  of 
  jacks 
  examined 
  during 
  the 
  season 
  only 
  two 
  were 
  found 
  

   infested 
  with 
  this 
  parasite. 
  One 
  of 
  these, 
  however, 
  yielded 
  a 
  dozen 
  

   specimens, 
  which 
  was 
  an 
  exceptionally 
  large 
  number. 
  

  

  CALIGUS 
  IRRITANS 
  Heller. 
  

   Plate 
  25, 
  fig. 
  62; 
  plate 
  27. 
  

   Caligus 
  irritans 
  Heller, 
  1865, 
  p. 
  177, 
  pi. 
  15, 
  figs. 
  7 
  and 
  8. 
  

  

  Host 
  and 
  record 
  of 
  specimens. 
  — 
  A 
  male 
  and 
  female 
  of 
  this 
  species 
  

   were 
  obtained 
  from 
  the 
  gills 
  of 
  a 
  large 
  (12 
  pounds) 
  red 
  snapper, 
  

   Neomsenis 
  aya, 
  on 
  July 
  22, 
  1910. 
  They 
  have 
  been 
  given 
  Cat. 
  No. 
  

   42262, 
  U.S.N.M. 
  

  

  Female. 
  — 
  General 
  body 
  form 
  long 
  and 
  stout; 
  carapace 
  ovate, 
  

   longer 
  than 
  wide 
  and 
  one-fourth 
  shorter 
  than 
  the 
  rest 
  of 
  the 
  body; 
  

   frontal 
  plates 
  prominent, 
  lunules 
  enormous 
  and 
  circular, 
  separated 
  

   by 
  a 
  distance 
  equal 
  to 
  their 
  own 
  diameter; 
  lateral 
  areas 
  narrow, 
  

   lateral 
  lobes 
  curved 
  inward 
  at 
  their 
  tips 
  and 
  bluntly 
  rounded; 
  

  

  