﻿CET7STACEA. 
  269 
  

  

  carpus 
  and 
  penultimate 
  joints 
  alternately 
  banded 
  with 
  yeUow 
  and 
  

   red. 
  

  

  The 
  type 
  of 
  Leach's 
  P. 
  lamarcl'ii 
  (from 
  Australia) 
  in 
  the 
  Museum 
  

   collection 
  has 
  lost 
  its 
  chelipedes; 
  hence 
  the 
  identification 
  is 
  not 
  

   certain 
  ; 
  but 
  the 
  carapace 
  in 
  all 
  respects 
  agrees 
  with 
  the 
  specimens 
  

   described 
  above, 
  and 
  there 
  exists 
  a 
  distinct 
  postocular 
  spine 
  on 
  the 
  

   lateral 
  margins. 
  

  

  The 
  type 
  specimens 
  of 
  P. 
  asiatims, 
  from 
  the 
  Mauritius, 
  are 
  of 
  

   larger 
  size, 
  but 
  scarcely 
  differ 
  except 
  in 
  having 
  the 
  anterior 
  margins 
  

   of 
  the 
  wrists 
  armed 
  with 
  more 
  distant, 
  but 
  relatively 
  smaller 
  teeth, 
  

   and 
  in 
  having 
  the 
  distal 
  ends 
  of 
  the 
  merus-joints 
  of 
  the 
  first 
  and 
  

   second 
  ambulatory 
  legs 
  more 
  distinctly 
  denticulated. 
  Specimens 
  

   apparently 
  belonging 
  to 
  this 
  form 
  are 
  in 
  the 
  Miiseum 
  collection 
  

   from 
  various 
  islands 
  of 
  the 
  Pacific 
  and 
  Malaysian 
  seas 
  ; 
  and 
  I 
  think 
  

   it 
  very 
  probable 
  that 
  it 
  should 
  be 
  united 
  with 
  P. 
  lamarclii. 
  I 
  

   may 
  note 
  here 
  that 
  the 
  specimen 
  recently 
  figured 
  by 
  Eichters* 
  as 
  

   P. 
  asiatims. 
  Leach 
  (and 
  by 
  him 
  retained 
  in 
  the 
  genus 
  Porcellana), 
  

   has 
  a 
  more 
  distinctly 
  truncated 
  median 
  frontal 
  lobe, 
  and 
  only 
  two 
  

   teeth 
  on 
  the 
  posterior 
  margin 
  of 
  the 
  arm 
  of 
  the 
  chelipede, 
  and 
  may 
  

   perhaps 
  belong 
  to 
  a 
  distinct 
  species. 
  

  

  V3. 
  Petrolisthes 
  liaswelli. 
  (Plate 
  XXIX. 
  fig. 
  A.) 
  

  

  Carapace 
  flattened, 
  longer 
  than 
  broad, 
  and 
  marked 
  with 
  faint 
  

   transverse 
  strife, 
  which 
  are 
  bordered 
  with 
  short 
  hairs 
  ; 
  the 
  lateral 
  

   margins 
  are 
  cristated, 
  the 
  carinee 
  extending 
  from 
  the 
  outer 
  orbital 
  

   angles 
  to 
  about 
  the 
  middle 
  of 
  the 
  branchial 
  regions 
  ; 
  the 
  front 
  is 
  

   subtriangulate, 
  with 
  the 
  apex 
  rounded 
  and 
  concave 
  above, 
  the 
  

   margins 
  somewhat 
  sinuated 
  : 
  the 
  outer 
  orbital 
  angle 
  is 
  not 
  very 
  

   prominent, 
  behind 
  it 
  there 
  is 
  a 
  spine 
  on 
  the 
  hepatic 
  region 
  ; 
  the 
  upper 
  

   orbital 
  margins 
  are 
  entire. 
  The 
  eyes 
  are 
  short 
  and 
  thick. 
  There 
  

   is 
  a 
  prominent 
  tooth 
  or 
  lobe 
  i;pon 
  the 
  antepenultimate 
  joint 
  of 
  the 
  

   peduncle 
  of 
  the 
  antenna}, 
  whose 
  flagella 
  are 
  very 
  long 
  and 
  naked. 
  

   The 
  chelipedes 
  are 
  moderately 
  robust, 
  the 
  merus 
  or 
  arm 
  very 
  short, 
  

   with 
  a 
  prominent 
  lobe 
  at 
  the 
  distal 
  end 
  of 
  its 
  inner 
  margin 
  : 
  the 
  

   carpus 
  is 
  flattened 
  above, 
  its 
  upper 
  surface 
  tuberculated, 
  the 
  tubercles, 
  

   which 
  in 
  the 
  middle 
  line 
  are 
  generally 
  larger, 
  are 
  flattened 
  and 
  

   bordered 
  with 
  short 
  hairs 
  ; 
  its 
  anterior 
  margin 
  armed 
  with 
  four 
  or 
  

   five 
  unequal 
  teeth, 
  whose 
  margins 
  are 
  themselves 
  generally 
  denticu- 
  

   lated 
  ; 
  the 
  posterior 
  margin 
  armed 
  with 
  three 
  spines 
  at 
  its 
  distal 
  

   end 
  ; 
  palm 
  and 
  fingers 
  closely 
  tuberculated 
  on 
  their 
  outer 
  surface, 
  

   the 
  tiibercles 
  bordered 
  with 
  short 
  hairs, 
  and 
  merging 
  toward 
  the 
  

   upper 
  margin 
  into 
  longitudinal 
  striae 
  ; 
  the 
  lower 
  margin 
  of 
  the 
  

   palm 
  is 
  straight 
  and 
  subcristated 
  ; 
  fingers 
  shorter 
  than 
  the 
  palm, 
  

   meeting 
  along 
  their 
  inner 
  edges, 
  and 
  incurved 
  at 
  the 
  tips. 
  Ambu- 
  

   latory 
  legs 
  slightly 
  hairy, 
  with 
  the 
  merus-joint 
  moderately 
  dilated 
  

   and 
  compressed, 
  without 
  spinules 
  or 
  teeth, 
  except 
  one 
  or 
  two 
  small 
  

   denticles 
  at 
  the 
  distal 
  end 
  of 
  the 
  lower 
  margin 
  ; 
  the 
  following 
  joints 
  

  

  * 
  In 
  Mobius, 
  Beitr. 
  ziir 
  Meeresfauna 
  der 
  Insel 
  Mauritius 
  &c., 
  Decapoda, 
  

   p. 
  159. 
  pi. 
  xvii. 
  fig. 
  13 
  (1880). 
  

  

  