﻿NO. 
  1950. 
  CRUSTACEAN 
  PARASITES 
  OF 
  FISH 
  AND 
  CRABS— 
  WILSON. 
  207 
  

  

  of 
  about 
  the 
  same 
  length. 
  Second 
  maxilla 
  tipped 
  with 
  two 
  spines, 
  

   the 
  posterior 
  one 
  twice 
  the 
  size 
  of 
  the 
  anterior. 
  MaxiUipeds 
  -wdth 
  the 
  

   terminal 
  joint 
  bent 
  back 
  against 
  the 
  basal 
  and 
  tipped 
  with 
  two 
  spines, 
  

   the 
  outer 
  (posterior) 
  of 
  which 
  is 
  twice 
  the 
  size 
  of 
  the 
  inner. 
  Behind 
  

   the 
  bases 
  of 
  the 
  maxillipeds, 
  on 
  either 
  side 
  of 
  the 
  midline 
  and 
  close 
  

   to 
  it, 
  is 
  a 
  short 
  accessory 
  spine. 
  

  

  Each 
  ramus 
  of 
  the 
  first 
  legs 
  is 
  two-jointed, 
  those 
  of 
  the 
  second, 
  

   third, 
  and 
  fourth 
  legs 
  three-jointed, 
  with 
  the 
  arrangement 
  of 
  the 
  

   spines 
  and 
  setae 
  as 
  follows: 
  Second 
  exopod, 
  I 
  — 
  0, 
  I 
  — 
  1, 
  II 
  — 
  7 
  

   endopod, 
  0—1, 
  0—2, 
  II— 
  4. 
  Third 
  exopod, 
  I— 
  0, 
  I— 
  1, 
  II— 
  6 
  

   endopod, 
  0—1, 
  1—2, 
  II— 
  3. 
  Fourth 
  exopod, 
  I— 
  0, 
  I— 
  1, 
  1—6 
  

   endopod, 
  — 
  1, 
  I 
  — 
  2, 
  II 
  — 
  3. 
  Fifth 
  legs 
  two-jointed, 
  the 
  terminal 
  

   joint 
  enlarged 
  and 
  tipped 
  with 
  four 
  spines. 
  

  

  Ovaries 
  in 
  the 
  lateral 
  portions 
  of 
  the 
  cephalothorax 
  ; 
  oviducts 
  

   extending 
  back 
  along 
  the 
  lateral 
  margins 
  of 
  the 
  free 
  thorax 
  segments, 
  

   sending 
  out 
  short 
  and 
  stout 
  uterine 
  processes 
  into 
  each 
  segment. 
  

  

  Color 
  a 
  clear 
  cartilage 
  gray, 
  the 
  ovaries 
  and 
  processes 
  white. 
  

  

  Total 
  length, 
  3 
  mm. 
  Cephalothorax, 
  0.70 
  mm. 
  long, 
  0.98 
  mm. 
  

   wide. 
  Free 
  thorax, 
  1 
  mm. 
  long. 
  Egg-cases, 
  1.5 
  mm. 
  long. 
  

  

  {fiagellans, 
  flagellating 
  or 
  lashing, 
  in 
  allusion 
  to 
  the 
  lashing 
  motions 
  

   when 
  disturbed.) 
  

  

  This 
  genus 
  was 
  established 
  by 
  Sumpf 
  (1871) 
  upon 
  some 
  specimens 
  

   obtained 
  from 
  the 
  gills 
  of 
  Oarcharias 
  {Oarcharhinus) 
  lamia. 
  A 
  new 
  

   species 
  was 
  added 
  by 
  the 
  present 
  author 
  in 
  1910 
  obtained 
  from 
  the 
  

   vent 
  of 
  the 
  bonnet-head 
  shark, 
  Spliyrna 
  tihuro. 
  The 
  present 
  is 
  a 
  

   third 
  species 
  from 
  the 
  giUs 
  of 
  the 
  hammer-head, 
  and 
  having 
  been 
  

   studied 
  alive 
  some 
  notes 
  can 
  be 
  added 
  on 
  the 
  habits 
  of 
  the 
  genus. 
  

   All 
  the 
  specimens 
  were 
  found 
  attached 
  to 
  the 
  skin 
  of 
  the 
  gill 
  partitions 
  

   just 
  outside 
  of 
  the 
  filaments. 
  When 
  detached 
  and 
  placed 
  in 
  an 
  

   aquarium 
  they 
  swim 
  about 
  as 
  freely 
  as 
  pelagic 
  forms 
  and 
  may 
  be 
  

   kept 
  alive 
  for 
  several 
  days. 
  The 
  ventral 
  disk 
  protrudes 
  like 
  a 
  

   sucker's 
  mouth 
  and 
  is 
  the 
  chief 
  organ 
  of 
  attachment, 
  thus 
  emphasizing 
  

   one 
  of 
  the 
  chief 
  differences 
  between 
  the 
  subfamilies 
  of 
  the 
  Ergasilidse. 
  

   In 
  the 
  Ergasilinae 
  there 
  is 
  no 
  ventral 
  disk 
  and 
  attachment 
  is 
  entirely 
  

   by 
  means 
  of 
  the 
  second 
  antennae; 
  in 
  the 
  Bomolocliinae 
  there 
  is 
  such 
  

   a 
  disk, 
  but 
  the 
  stout 
  claws 
  on 
  the 
  maxillipeds 
  show 
  that 
  they 
  play 
  

   an 
  important 
  part 
  in 
  attachment; 
  here 
  in 
  the 
  Tseniacanthinse 
  the 
  

   ventral 
  disk 
  is 
  fully 
  developed, 
  and 
  is 
  the 
  only 
  organ 
  of 
  attachment, 
  

   the 
  antennae 
  and 
  maxilhpeds 
  having 
  degenerated 
  beyond 
  practical 
  use. 
  

   The 
  parasites 
  catch 
  on 
  and 
  let 
  go 
  with 
  great 
  ease 
  and 
  celerity 
  and 
  

   adhere 
  to 
  glass 
  as 
  readily 
  as 
  to 
  the 
  fish's 
  giUs. 
  When 
  thus 
  attached 
  

   the 
  long 
  thorax 
  and 
  abdomen 
  are 
  lashed 
  about 
  actively, 
  especially 
  

   upon 
  irritation, 
  and 
  this 
  peculiar 
  habit 
  is 
  sure 
  to 
  attract 
  attention 
  

   to 
  the 
  copepod. 
  When 
  the 
  giQs 
  are 
  placed 
  in 
  water 
  the 
  parasites 
  

   leave 
  them 
  quickly 
  and 
  swim 
  about, 
  usually 
  without 
  returning 
  to 
  

   them 
  again. 
  

  

  