﻿194 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol. 
  44. 
  

  

  In 
  this 
  they 
  are 
  peculiar, 
  since 
  in 
  other'specics 
  the 
  tip 
  of 
  the 
  palp 
  

   does 
  not 
  project 
  beyond 
  the 
  end 
  of 
  the 
  basal 
  joint. 
  First 
  maxilla 
  a 
  

   large 
  knob, 
  armed 
  with 
  two 
  equal 
  setae; 
  second 
  maxilla 
  with 
  a 
  large 
  

   and 
  stout 
  basal 
  joint 
  and 
  a 
  short 
  terminal 
  blade, 
  which 
  does 
  not 
  

   reach 
  the 
  midline; 
  terminal 
  tuft 
  of 
  setae 
  short 
  and 
  dense. 
  

  

  Rami 
  of 
  swimming 
  legs 
  three-jointed, 
  except 
  the 
  exopod 
  of 
  the 
  

   fourth 
  pair, 
  which 
  has 
  but 
  two 
  joints; 
  arrangement 
  of 
  spines 
  and 
  

   setae 
  as 
  follows 
  : 
  First 
  exopod, 
  I 
  — 
  0, 
  — 
  1, 
  — 
  6; 
  endopod, 
  — 
  1,0 
  — 
  2, 
  

   1—4. 
  Second 
  exopod, 
  I— 
  0, 
  I— 
  1, 
  0—6; 
  endopod, 
  0—1, 
  0—2, 
  1—5. 
  

   Third 
  exopod, 
  0—0, 
  0—1, 
  0—6; 
  endopod, 
  0—1, 
  0—1, 
  0—5. 
  Fourth 
  

   exopod, 
  I— 
  0, 
  0—5; 
  endopod, 
  0—0, 
  0—2, 
  0—4. 
  Fifth 
  legs 
  wholly 
  

   lacking. 
  

  

  Color 
  a 
  uniform 
  cartilage 
  gray, 
  without 
  pigment 
  markings 
  of 
  any 
  

   sort, 
  quickly 
  becoming 
  light 
  brown 
  in 
  preservatives. 
  

  

  Total 
  length, 
  1.20 
  mm. 
  Cephalothorax, 
  0.75 
  mm. 
  long, 
  0.6 
  mm. 
  

   wide. 
  Genital 
  segment, 
  0.1 
  mm. 
  long 
  and 
  the 
  same 
  width. 
  Egg 
  

   strings, 
  0.76 
  mm. 
  long, 
  0.20 
  mm. 
  wide. 
  

  

  (longus, 
  long, 
  and 
  palpus, 
  a 
  palp, 
  alluding 
  to 
  the 
  exceptional 
  length 
  

   of 
  the 
  mandibular 
  palps.) 
  

  

  This 
  species 
  is 
  difficult 
  to 
  distinguish 
  except 
  by 
  the 
  mouth 
  parts, 
  

   where 
  the 
  projection 
  of 
  the 
  long 
  and 
  narrow 
  palps 
  beyond 
  the 
  tips 
  

   of 
  the 
  basal 
  mandibular 
  joints, 
  and 
  the 
  short 
  terminal 
  joints 
  of 
  the 
  

   second 
  maxillae 
  are 
  very 
  noticeable. 
  * 
  

  

  ERGASILUS 
  MYCTAROTHES, 
  new 
  species. 
  

   Plate 
  18, 
  figs. 
  7-12. 
  

  

  Host 
  and 
  record 
  of 
  specimens. 
  — 
  Seven 
  females 
  of 
  this 
  species, 
  four 
  of 
  

   which 
  carried 
  egg 
  strings, 
  were 
  taken 
  from 
  the 
  mucus 
  in 
  the 
  nasal 
  

   tubes 
  of 
  a 
  hammer-head 
  shark, 
  Sphyrna 
  zygsena. 
  

  

  Type-specimen. 
  — 
  Cat. 
  No. 
  43597, 
  U.S.N.M. 
  Paratypes, 
  Cat. 
  No. 
  

   42255, 
  U.S.N.M. 
  

  

  Female. 
  — 
  General 
  body 
  form 
  elongate 
  and 
  narrow; 
  carapace 
  ellip- 
  

   tical, 
  nearly 
  twice 
  as 
  long 
  as 
  wide, 
  narrowed 
  about 
  equally 
  anteriorly 
  

   and 
  posteriorly, 
  with 
  shallow, 
  but 
  distinct, 
  notches 
  in 
  the 
  lateral 
  mar- 
  

   gins 
  two-fifths 
  of 
  the 
  length 
  from 
  the 
  posterior 
  end, 
  which 
  indicate 
  the 
  

   point 
  of 
  union 
  of 
  the 
  head 
  with 
  the 
  first 
  thorax 
  segment. 
  Free 
  

   thorax 
  and 
  abdomen 
  only 
  two-fifths 
  as 
  long 
  as 
  the 
  carapace 
  and 
  

   tapering 
  rapidly 
  posteriorly; 
  second, 
  third,, 
  and 
  fourth 
  segments 
  the 
  

   same 
  length, 
  but 
  diminishing 
  regularly 
  in 
  width; 
  fifth 
  segment 
  so 
  

   completely 
  fused 
  with 
  the 
  genital 
  segment 
  that 
  there 
  is 
  no 
  indication 
  

   of 
  the 
  union 
  either 
  in 
  a 
  groove 
  or 
  in 
  a 
  pair 
  of 
  rudimentary 
  fifth 
  legs. 
  

   Genital 
  segment 
  barrel-shaped, 
  a 
  little 
  wider 
  than 
  long, 
  with 
  convex 
  

   lateral 
  margins 
  and 
  a 
  pair 
  of 
  short, 
  broadly 
  rounded 
  posterior 
  lobes. 
  

  

  Abdomen 
  three-jointed, 
  joints 
  diminishing 
  regularly 
  in 
  length 
  and 
  

   width; 
  terminal 
  joint 
  with 
  a 
  deep 
  anal 
  incision; 
  anal 
  laminae 
  con- 
  

  

  