﻿NO. 
  1950. 
  CRVSTACEAS' 
  PARASITES 
  OF 
  FISH 
  AND 
  CRABS— 
  WILSON. 
  239 
  

  

  Color 
  similar 
  to 
  that 
  of 
  tlio. 
  female. 
  

  

  Total 
  length, 
  1.70 
  mm. 
  Carapace, 
  0.66 
  mm. 
  long, 
  0.25 
  mm. 
  

   wide. 
  Fourth 
  thorax 
  segment, 
  0.5 
  mm. 
  long, 
  0.3 
  mm. 
  wide. 
  

  

  (versicolor, 
  variegated 
  in 
  color.) 
  

  

  This 
  West 
  Indian 
  species 
  is 
  quite 
  different 
  from 
  the 
  one 
  found 
  

   upon 
  the 
  sharp-nosed 
  shark, 
  Scoliodon 
  terrse-novx, 
  farther 
  north, 
  off 
  

   the 
  coast 
  of 
  Georgia 
  and 
  the 
  Carolinas. 
  

  

  If 
  we 
  contrast 
  the 
  females 
  we 
  notice 
  first 
  that 
  the 
  cephalothorax 
  

   is 
  relatively 
  larger 
  in 
  the 
  northern 
  form, 
  and 
  has 
  evenly 
  curved 
  

   margins, 
  without 
  any 
  projections. 
  But 
  there 
  is 
  a 
  tooth 
  on 
  each 
  

   lateral 
  margin 
  of 
  the 
  second 
  segment, 
  a 
  shallow 
  sinus 
  in 
  each 
  lateral 
  

   margin 
  of 
  the 
  fourth 
  segment, 
  and 
  the 
  dorsal 
  plate 
  of 
  the 
  fifth 
  seg- 
  

   ment 
  is 
  three-lobed 
  posteriorly, 
  none 
  of 
  which 
  conditions 
  are 
  found 
  

   in 
  the 
  southern 
  species. 
  The 
  filth 
  and 
  genital 
  segments 
  and 
  the 
  

   abdomen 
  are 
  also 
  relatively 
  much 
  larger 
  in 
  the 
  northern 
  form; 
  

   there 
  are 
  minor 
  differences 
  in 
  the 
  antennae, 
  mouth 
  parts, 
  and 
  swim- 
  

   ming 
  legs. 
  

  

  When 
  we 
  compare 
  the 
  males 
  we 
  find 
  far 
  greater 
  distinctions. 
  In 
  

   the 
  northern 
  form 
  the 
  body 
  is 
  about 
  the 
  same 
  width 
  throughout; 
  

   the 
  carapace 
  is 
  a 
  regular 
  ellipse, 
  one-third 
  of 
  the 
  entire 
  length, 
  and 
  

   ^^^der 
  than 
  any 
  of 
  the 
  following 
  segments; 
  the 
  second, 
  third, 
  and 
  

   fourth 
  segments 
  diminish 
  regularly 
  in 
  width 
  and 
  length; 
  the 
  m.axil- 
  

   lipeds 
  have 
  simple 
  and 
  regular 
  claws. 
  In 
  the 
  West 
  Indian 
  species, 
  

   on 
  the 
  contrary, 
  the 
  carapace 
  is 
  oblong, 
  with 
  nearly 
  straight 
  sides, 
  

   is 
  less 
  than 
  one-fifth 
  the 
  entire 
  length, 
  and 
  is 
  considerably 
  narrower 
  

   than 
  the 
  fourth 
  segment; 
  the 
  second, 
  third, 
  and 
  fourth 
  segments 
  

   increase 
  considerably 
  in 
  length 
  and 
  width; 
  the 
  maxillipeds 
  form 
  a 
  

   well 
  defined 
  chela 
  instead 
  of 
  a 
  simple 
  claw. 
  

  

  HATSCHEKIA 
  ALBIRUBRA, 
  new 
  species. 
  

   Plate 
  41, 
  figs. 
  209-215. 
  

  

  Host 
  and 
  record 
  of 
  specimens. 
  — 
  Four 
  females 
  of 
  this 
  new 
  form, 
  all 
  

   without 
  the 
  egg 
  strings, 
  were 
  taken 
  from 
  the 
  gills 
  of 
  the 
  lane 
  snapper, 
  

   Neomsenis 
  synagris, 
  July 
  16, 
  1910. 
  They 
  are 
  made 
  paratypes 
  and 
  have 
  

   been 
  given 
  Cat. 
  No. 
  42288, 
  U.S.N.M. 
  

  

  Another 
  lot, 
  also 
  of 
  four 
  females 
  without 
  egg 
  strings, 
  was 
  obtained 
  

   from 
  the 
  giQs 
  of 
  the 
  yellowtaU, 
  Ocyurus 
  chrysurus, 
  on 
  August 
  4. 
  

  

  Type-specimen. 
  — 
  Cat. 
  No. 
  43591, 
  U.S.N.M. 
  Paratypes 
  Cat. 
  No. 
  

   42309, 
  U.S.N.M., 
  both 
  from 
  the 
  yellow-tail. 
  

  

  Female. 
  — 
  General 
  body 
  form 
  elongate, 
  three 
  and 
  one-half 
  times 
  as 
  

   long 
  as 
  wide; 
  carapace 
  small, 
  only 
  one-eighth 
  the 
  entire 
  length 
  and 
  

   much 
  narrower 
  than 
  the 
  thorax, 
  transversely 
  elliptical, 
  one-third 
  

   wider 
  than 
  long, 
  with 
  an 
  evenly 
  curved 
  outline. 
  

  

  Fused 
  frontal 
  plates 
  projecting 
  from 
  the 
  frontal 
  margin; 
  dorsal 
  

   median 
  carina 
  weU 
  defined 
  and 
  divided 
  into 
  a 
  Y 
  anteriorly. 
  Fused 
  

  

  