﻿EGGS 
  OF 
  A 
  NEW 
  SPECIES 
  OF 
  NEMATOID 
  WOKM 
  FROM 
  

  

  A 
  SHARK 
  

  

  By 
  G. 
  A. 
  MacCallum 
  

  

  Of 
  Baltimore, 
  Md. 
  

  

  On 
  July 
  6, 
  1924, 
  we 
  examined 
  at 
  the 
  United 
  States 
  Bureau 
  of 
  

   Fisheries 
  at 
  Woods 
  Hole, 
  a 
  large 
  shark, 
  Carcharhinus 
  commersoni, 
  

   and 
  I 
  found 
  on 
  the 
  white 
  under 
  surface 
  of 
  the 
  nose, 
  in 
  front 
  of 
  the 
  

   mouth, 
  a 
  curious 
  figure, 
  which 
  appeared 
  like 
  a 
  drawing 
  made 
  with 
  

   a 
  fine 
  pen 
  with 
  India 
  ink. 
  The 
  figure 
  was 
  formed 
  by 
  a 
  delicate 
  

   tracery 
  of 
  lines 
  extending 
  over 
  a 
  patch 
  about 
  2y 
  2 
  inches 
  by 
  iy 
  z 
  - 
  

   We 
  could 
  not 
  imagine 
  why 
  such 
  a 
  tracing 
  should 
  be 
  there, 
  and, 
  

   as 
  nothing 
  of 
  the 
  particulars 
  could 
  be 
  made 
  out 
  with 
  the 
  naked 
  

   eye, 
  I 
  sliced 
  off 
  portions 
  of 
  the 
  figure 
  and 
  placed 
  them 
  under 
  

   the 
  microscope 
  was 
  surprised 
  to 
  find 
  that 
  the 
  lines 
  were 
  made 
  

   up 
  of 
  black 
  eggs 
  laid 
  in 
  the 
  grooves 
  between 
  the 
  scales. 
  We 
  had 
  

   never 
  seen 
  anything 
  like 
  it 
  before 
  and 
  were 
  at 
  a 
  loss 
  to 
  know 
  what 
  

   form 
  could 
  have 
  laid 
  them 
  there, 
  how 
  it 
  was 
  done, 
  and 
  how 
  they 
  

   were 
  kept 
  in 
  place 
  and 
  not 
  swept 
  away 
  when 
  the 
  fish 
  made 
  its 
  way 
  

   through 
  the 
  water. 
  Careful 
  examination 
  has 
  failed 
  to 
  show 
  any 
  

   female 
  worm 
  which 
  could 
  have 
  laid 
  them. 
  

  

  Vertical 
  and 
  horizontal 
  sections 
  of 
  the 
  skin 
  were 
  made, 
  after 
  

   decalcifying 
  the 
  scales 
  with 
  hydrochloric 
  acid, 
  and 
  in 
  these 
  the 
  eggs 
  

   were 
  plainly 
  seen 
  to 
  be 
  those 
  of 
  some 
  small 
  worm, 
  and 
  attached 
  

   to 
  the 
  grooves 
  between 
  the 
  scales 
  by 
  some 
  transparent, 
  very 
  adhesive 
  

   glutinous 
  material 
  which 
  surrounds 
  them. 
  They 
  are 
  dark 
  brown, 
  

   almost 
  black, 
  where 
  the 
  shell 
  is 
  thickest, 
  and 
  are 
  of 
  an 
  elliptical 
  

   form, 
  measuring 
  0.10 
  mm. 
  in 
  length 
  by 
  0.005 
  mm. 
  in 
  width. 
  Ante- 
  

   riorly 
  each 
  has 
  a 
  closed 
  orifice 
  at 
  the 
  end 
  of 
  a 
  short 
  neck. 
  

  

  Dr. 
  N. 
  A. 
  Cobb, 
  Avho 
  was 
  kind 
  enough 
  to 
  examine 
  them, 
  thought 
  

   that 
  they 
  much 
  resembled 
  the 
  eggs 
  of 
  Trichocephalus 
  dispar 
  in 
  

   form, 
  and 
  later 
  it 
  was 
  decided 
  that 
  they 
  belong 
  in 
  all 
  probability 
  

   to 
  a 
  member 
  of 
  the 
  genus 
  Gapillaria. 
  Since 
  it 
  has 
  been 
  impossible 
  

   to 
  find 
  the 
  female 
  worm 
  that 
  laid 
  them, 
  the 
  question 
  arises 
  as 
  to 
  

   whether 
  it 
  may 
  be 
  that, 
  as 
  in 
  the 
  case 
  of 
  the 
  common 
  wild 
  rat 
  in 
  

   which 
  a 
  nematode 
  of 
  this 
  general 
  type 
  lays 
  eggs 
  in 
  fine 
  lines 
  over 
  

  

  No. 
  2588. 
  — 
  Proceedings 
  U. 
  S. 
  National 
  Museum, 
  Vol. 
  67, 
  Art. 
  16. 
  

  

  29109 
  — 
  25 
  1 
  

  

  