﻿STUDIES 
  ON 
  THE 
  LARVAE 
  OF 
  CRABS 
  OF 
  THE 
  FAMILY 
  

  

  XANTIIIDAE 
  * 
  

  

  By 
  O. 
  W. 
  Hyman 
  

  

  Of 
  the 
  College 
  of 
  Medicine, 
  University 
  of 
  Tennessee 
  

  

  The 
  larval 
  stages 
  of 
  the 
  Xanthidae 
  are 
  better 
  known 
  than 
  those 
  

   of 
  any 
  other 
  family 
  of 
  the 
  Brachyura. 
  This 
  doubtless 
  is 
  due 
  to 
  the 
  

   fact 
  that 
  the 
  adults 
  habitually 
  are 
  found 
  in 
  shallow 
  water 
  near 
  

   the 
  shore 
  and 
  usually 
  are 
  very 
  abundant. 
  Ovigerous 
  females 
  may 
  

   be 
  taken 
  without 
  trouble, 
  and 
  thus 
  the 
  early 
  zoeal 
  stages 
  may 
  be 
  

   known 
  with 
  certainty. 
  

  

  The 
  family 
  is 
  well 
  represented 
  at 
  Beaufort, 
  N. 
  C., 
  and 
  the 
  writer 
  

   is 
  able 
  to 
  incorporate 
  in 
  these 
  pages 
  descriptions 
  of 
  the 
  larvae 
  of 
  

   five 
  genera 
  based 
  upon 
  material 
  collected 
  there. 
  Most 
  of 
  the 
  known 
  

   Xanthid 
  larvae 
  hatch 
  with 
  the 
  prezoeal 
  cuticle 
  still 
  intact. 
  This 
  

   is 
  shed, 
  however, 
  within 
  a 
  few 
  minutes. 
  The 
  first 
  zoeal 
  stage 
  is 
  

   characterized 
  by 
  the 
  presence 
  of 
  dorsal, 
  lateral, 
  and 
  rostral 
  spines 
  

   on 
  the 
  carapace 
  and 
  usually 
  long 
  and 
  robust 
  antennae. 
  

  

  The 
  known 
  zoeas 
  of 
  the 
  family 
  are 
  separable 
  into 
  two 
  groups. 
  

   Those 
  of 
  Panopeus 
  and 
  X 
  ant 
  ho 
  have 
  extremely 
  minute 
  exopoclites 
  

   on 
  the 
  antennae. 
  Those 
  of 
  the 
  remaining 
  genera 
  so 
  far 
  known 
  have 
  

   a 
  well-developed 
  exopodite. 
  When 
  arranged 
  in 
  a 
  series, 
  the 
  zoea 
  

   of 
  Panopeus 
  is 
  found 
  to 
  be 
  most 
  highly 
  specialized, 
  while 
  that 
  of 
  

   Pilumnus 
  is 
  least 
  so. 
  

  

  The 
  author 
  is 
  greatly 
  indebted 
  to 
  Drs. 
  Mary 
  J. 
  Rathbun 
  and 
  

   Waldo 
  L. 
  Schmitt 
  of 
  the 
  United 
  States 
  National 
  Museum 
  for 
  their 
  

   generous 
  aid 
  in 
  preparing 
  the 
  material 
  of 
  this 
  paper 
  for 
  the 
  press. 
  

   The 
  indebtedness 
  of 
  the 
  author 
  is 
  also 
  acknowledged 
  to 
  the 
  United 
  

   States 
  Bureau 
  of 
  Fisheries 
  for 
  the 
  use 
  of 
  the 
  facilities 
  of 
  its 
  Beau- 
  

   fort, 
  N. 
  C, 
  station. 
  The 
  director, 
  Mr. 
  Charles 
  Hatsel, 
  has 
  been 
  of 
  

   great 
  assistance 
  in 
  collecting 
  the 
  material 
  presented 
  here. 
  

  

  1 
  This 
  is 
  the 
  third 
  of 
  a 
  series 
  of 
  studies 
  on 
  the 
  larval 
  stages 
  of 
  crabs. 
  The 
  first. 
  

   Studies 
  on 
  larvae 
  of 
  crabs 
  of 
  the 
  Family 
  Pinnotheridae 
  was 
  published 
  in 
  the 
  Proceedings 
  

   of 
  the 
  U. 
  S. 
  National 
  Museum 
  (vol. 
  64, 
  art. 
  7, 
  pp. 
  1-9, 
  pis. 
  1-6), 
  and 
  the 
  second, 
  Studies 
  

   upon 
  larvae 
  of 
  crabs 
  of 
  the 
  Family 
  Grapsidae, 
  in 
  the 
  same 
  serial, 
  vol. 
  Go, 
  art. 
  10, 
  pp. 
  1-8, 
  

   pis. 
  1—2. 
  A 
  further 
  study 
  on 
  the 
  Development 
  of 
  Gelasimus 
  [Uca] 
  after 
  hatching, 
  Is 
  

   cited 
  in 
  the 
  accompanying 
  bibliography. 
  

  

  No. 
  2575. 
  — 
  Proceedings 
  U. 
  S. 
  National 
  Museum, 
  Vol. 
  67, 
  Art. 
  3 
  

  

  22246—25 
  1 
  1 
  

  

  