﻿14 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  67 
  

  

  THIRD 
  (SECOND?) 
  ZOEA 
  (fig. 
  153) 
  

  

  It 
  is 
  difficult 
  to 
  decide 
  from 
  Cano's 
  description 
  and 
  figures 
  whether 
  

   his 
  second 
  zoeal 
  stage 
  should 
  arise 
  directly 
  from 
  his 
  1 
  first 
  or 
  whether 
  

   he 
  has 
  overlooked 
  a 
  stage 
  between 
  the 
  two. 
  Figure 
  153 
  seems 
  to 
  

   be 
  that 
  of 
  a 
  second 
  zoea. 
  There 
  are 
  only 
  five 
  abdominal 
  segments. 
  

   The 
  pleopods 
  are 
  not 
  protruding 
  as 
  is 
  typically 
  the 
  case 
  in 
  the 
  third 
  

   zoea. 
  The 
  swimming 
  hairs 
  number 
  six. 
  On 
  the 
  other 
  hand 
  the 
  an- 
  

   tenna 
  (fig. 
  156) 
  shows 
  the 
  bud 
  of 
  the 
  endopodite, 
  a 
  characteristic 
  

   of 
  the 
  third 
  zoeal 
  stage, 
  and 
  the 
  telson 
  (fig. 
  160) 
  shows 
  four 
  pairs 
  

   of 
  medial 
  spines 
  that 
  also 
  characterize 
  the 
  third 
  zoea. 
  

  

  It 
  may 
  be 
  that 
  Eriphia 
  has 
  only 
  three 
  zoeal 
  stages 
  or 
  it 
  may 
  be 
  

   that 
  Cano 
  has 
  failed 
  to 
  distinguish 
  the 
  second 
  stage 
  from 
  the 
  third 
  

   and 
  thus 
  has 
  described 
  the 
  appendages 
  of 
  the 
  third 
  stage 
  as 
  belonging 
  

   to 
  the 
  second. 
  

  

  FOURTH 
  ZOEA 
  (fig. 
  154) 
  

  

  The 
  last 
  zoeal 
  stage 
  described 
  by 
  Cano 
  agrees 
  very 
  closely 
  with 
  

   the 
  fourth 
  zoeal 
  stage 
  of 
  Panopeus 
  and 
  Xantho. 
  The 
  swimming 
  

   hairs 
  number 
  12 
  to 
  14. 
  The 
  endopodite 
  of 
  the 
  antenna 
  is 
  elongated 
  

   and 
  the 
  pleopods 
  are 
  elongated 
  and 
  biramous. 
  

  

  Cephalic 
  appendages. 
  — 
  The 
  antennule 
  (fig. 
  157) 
  shows 
  a 
  proximal 
  

   portion 
  composed 
  of 
  three 
  enlarged 
  segments. 
  The 
  first 
  of 
  these 
  

   contains 
  the 
  developing 
  statocyst. 
  Distally 
  the 
  inner 
  ramus 
  of 
  the 
  

   antennule 
  shows 
  evidence 
  of 
  two 
  or 
  three 
  joints, 
  while 
  the 
  outer 
  

   is 
  a 
  simple 
  bud. 
  

  

  The 
  endopodite 
  of 
  the 
  antenna 
  (fig. 
  157) 
  is 
  almost 
  as 
  long 
  as 
  the 
  

   spine 
  and 
  shows 
  the 
  outlines 
  of 
  its 
  future 
  joints. 
  

  

  Thoracic 
  appendages. 
  — 
  The 
  pereiopods 
  are 
  all 
  well 
  formed 
  and 
  

   their 
  gill 
  buds 
  are 
  prominent, 
  The 
  first 
  and 
  second 
  maxillipeds 
  are 
  

   the 
  only 
  thoracic 
  appendages 
  that 
  are 
  functional 
  as 
  yet 
  however. 
  

  

  Abdomen. 
  — 
  The 
  telson 
  is 
  now 
  separated 
  from 
  the 
  sixth 
  abdominal 
  

   segment 
  by 
  a 
  joint. 
  The 
  pleopods 
  are 
  elongated 
  and 
  biramous, 
  

   although 
  none 
  of 
  them 
  bear 
  hairs 
  as 
  yet. 
  The 
  telson 
  (fig. 
  161) 
  has 
  

   four 
  pairs 
  of 
  median 
  spines. 
  

  

  MENIPPE 
  MERCENARIA 
  (Say) 
  

  

  Plate 
  13 
  

  

  Menippe 
  mercenaria 
  is 
  quite 
  abundant 
  at 
  Beaufort 
  and 
  its 
  zoeas 
  

   are 
  frequently 
  taken 
  in 
  towing. 
  However, 
  only 
  the 
  prezoeal 
  and 
  first 
  

   zoeal 
  stages 
  are 
  known. 
  Menippe 
  differs 
  from 
  many 
  other 
  

   Brachyura 
  in 
  that 
  its 
  eggs 
  do 
  not 
  always 
  hatch 
  at 
  dusk 
  or 
  at 
  night. 
  

   They 
  seem 
  to 
  hatch 
  at 
  any 
  hour 
  of 
  day 
  or 
  night. 
  

  

  riiEzoEA 
  (fig. 
  163) 
  

  

  The 
  prezoea 
  sheds 
  its 
  cuticle 
  in 
  a 
  few 
  minutes 
  after 
  leaving 
  the 
  

   egg. 
  It 
  differs 
  from 
  that 
  of 
  Panopeus 
  in 
  details 
  only. 
  The 
  cuticle 
  

  

  