﻿8 
  PEOCEEDINGS 
  OF 
  THE 
  NATIONAL. 
  MUSEUM 
  vol. 
  67 
  

  

  two. 
  The 
  endopodite 
  is 
  composed 
  of 
  five 
  segments 
  and 
  is 
  greatly 
  

   enlarged. 
  

  

  At 
  the 
  change 
  to 
  the 
  megalops, 
  the 
  pereiopods 
  acquire 
  what 
  is 
  

   practically 
  the 
  adult 
  condtion. 
  Each 
  appendage, 
  however, 
  is 
  rela- 
  

   tive 
  longer 
  and 
  more 
  slender 
  than 
  in 
  the 
  adult. 
  There 
  is 
  "no 
  differ- 
  

   ence 
  between 
  the 
  right 
  and 
  left 
  chelae. 
  

  

  Abdomen. 
  — 
  The 
  whole 
  abdomen 
  becomes 
  depressed. 
  The 
  telson 
  

   is 
  greatly 
  changed. 
  Its 
  long 
  cornua 
  are 
  lost 
  and 
  it 
  becomes 
  a 
  simple 
  

   plate 
  with 
  a 
  rounded 
  posterior 
  border. 
  The 
  abdominal 
  appendages 
  

   (figs. 
  103 
  and 
  104) 
  now 
  become 
  the 
  chief 
  organs 
  of 
  locomotion. 
  In 
  

   each 
  the 
  exopodite 
  becomes 
  flattened 
  and 
  carries 
  long 
  swimming 
  

   hairs 
  along 
  its 
  distal 
  border. 
  There 
  are 
  18 
  such 
  hairs 
  on 
  the 
  append- 
  

   age 
  of 
  the 
  second 
  segment 
  and 
  6 
  on 
  that 
  of 
  the 
  sixth. 
  The 
  endopo- 
  

   dite 
  in 
  each 
  case 
  is 
  a 
  small 
  simple 
  bud. 
  

  

  first 
  crab 
  (flgs. 
  7S 
  and 
  70) 
  

  

  After 
  at 
  least 
  four 
  molts, 
  the 
  megalops 
  assumes 
  the 
  form 
  of 
  the 
  

   first 
  crab 
  stage. 
  The 
  structural 
  changes 
  are 
  not 
  great. 
  The 
  animal 
  

   now 
  loses 
  the 
  power 
  of 
  swimming 
  and 
  crawls 
  about 
  near 
  the 
  tide 
  

   line. 
  

  

  Cephalathorax. 
  — 
  The 
  carapace 
  is 
  somewhat 
  broadened. 
  The 
  last 
  

   trace 
  of 
  the 
  rostral 
  spine 
  is 
  lost 
  and 
  the 
  frontal 
  margin 
  of 
  the 
  cara- 
  

   pace 
  very 
  closely 
  resembles 
  that 
  of 
  the 
  adult. 
  The 
  eye 
  is 
  still 
  a 
  

   single 
  segment 
  and 
  can 
  not 
  be 
  erected. 
  

  

  Cephalic 
  appendages. 
  — 
  The 
  antennule 
  assumes 
  the 
  adult 
  condi- 
  

   tion. 
  The 
  external 
  flagellum 
  disappears 
  and 
  the 
  internal 
  becomes 
  

   divided 
  into 
  six 
  segments. 
  The 
  other 
  cephalic 
  appendages 
  undergo 
  

   very 
  slight 
  modifications. 
  

  

  Thar-acic 
  appendages. 
  — 
  The 
  maxillipeds 
  are 
  very 
  slightly 
  changed. 
  

   The 
  most 
  noticeable 
  change 
  is 
  in 
  the 
  endopodite 
  of 
  the 
  third. 
  Its 
  

   proximal 
  two 
  segments 
  become 
  enlarged 
  to 
  form 
  an 
  operculum 
  for 
  

   the 
  mouthparts 
  and 
  the 
  distal 
  three 
  segments 
  appear 
  as 
  a 
  palp. 
  

  

  Abdomen. 
  — 
  With 
  the 
  assumption 
  of 
  the 
  crab 
  form 
  the 
  abdomen 
  

   undergoes 
  a 
  considerable 
  change. 
  It 
  is 
  further 
  flattened 
  and 
  is 
  

   permanently 
  flexed 
  under 
  the 
  sternum. 
  Birge 
  does 
  not 
  describe 
  the 
  

   abdominal 
  appendages 
  of 
  the 
  juvenile 
  crab 
  stages. 
  Possibly 
  the 
  

   larval 
  appendages 
  of 
  the 
  megalops 
  atrophy 
  and 
  are 
  replaced 
  by 
  the 
  

   permanent 
  organs 
  as 
  in 
  Una 
  (G 
  'elaslmus) 
  . 
  2 
  

  

  EURYPANOPEUS 
  DEPRESSUS 
  (Smith) 
  

  

  Plate 
  1, 
  figs. 
  2, 
  4, 
  8, 
  14, 
  18 
  ; 
  plate 
  2, 
  figs. 
  24, 
  28, 
  32 
  ; 
  plate 
  9 
  

  

  This 
  species 
  is 
  not 
  uncommon 
  at 
  Beaufort, 
  but 
  it 
  is 
  not 
  so 
  abund- 
  

   ant 
  as 
  Neopanope. 
  Its 
  zoeas 
  are 
  frequently 
  found 
  in 
  the 
  tow 
  and 
  

  

  -' 
  Hyman. 
  1920, 
  p. 
  409; 
  1922, 
  pp. 
  457,. 
  458. 
  

  

  