﻿222 
  COLLECTIONS 
  FROM 
  MELANESIA. 
  

  

  57. 
  Pilumnus 
  semilanatus. 
  (Plate 
  XXII. 
  fig. 
  B.) 
  

  

  The 
  carapace 
  is 
  not 
  very 
  convex 
  ; 
  a 
  few 
  granules 
  exist 
  near 
  the 
  

   antero-lateral 
  teeth 
  ; 
  its 
  anterior 
  part 
  (i. 
  e. 
  the 
  frontal 
  and 
  post- 
  

   frontal 
  regions 
  and 
  parts 
  adjacent 
  to 
  the 
  antero-lateral 
  margins) 
  is 
  

   clothed 
  with 
  longish 
  hairs, 
  which 
  are 
  altogether 
  absent 
  from 
  the 
  

   gastric, 
  cardiac, 
  and 
  branchial 
  regions, 
  which 
  are 
  nearly 
  plain 
  and 
  

   smooth 
  ; 
  the 
  cervical 
  suture 
  only 
  is 
  distinct 
  in 
  some 
  specimens 
  ; 
  

   the 
  frontal 
  lobes 
  are 
  scarcely 
  defined 
  by 
  a 
  median 
  notch, 
  and 
  are 
  

   very 
  little 
  prominent 
  ; 
  the 
  antero-lateral 
  margins 
  much 
  shorter 
  

   than 
  the 
  postero-lateral, 
  and 
  armed 
  with 
  three 
  teeth, 
  the 
  first 
  of 
  

   which 
  is 
  blunt 
  and 
  is 
  itself 
  crenulated, 
  the 
  second 
  dentiform, 
  and 
  

   the 
  third 
  very 
  small 
  ; 
  no 
  tooth 
  exists 
  at 
  the 
  exterior 
  angle 
  of 
  the 
  

   orbit, 
  but 
  immediately 
  behind 
  it 
  are 
  sometimes 
  one 
  or 
  two 
  small 
  

   granules 
  ; 
  the 
  orbital 
  margins 
  are 
  rather 
  obscurely 
  denticulated 
  ; 
  

   the 
  pterygostomian 
  regions 
  nearly 
  smooth 
  ; 
  all 
  the 
  postabdominal 
  

   segments 
  are 
  distinct 
  ; 
  the 
  basal 
  antennal 
  joint 
  barely 
  reaches 
  to 
  

   the 
  subfrontal 
  process 
  ; 
  the 
  merus-joint 
  of 
  the 
  outer 
  maxiliipedes 
  is 
  

   nearly 
  quadrate. 
  The 
  chelipedes 
  are 
  of 
  moderate 
  size 
  ; 
  arm 
  with 
  a 
  

   small 
  spine 
  near 
  the 
  distal 
  end 
  of 
  its 
  upper 
  margin; 
  wrist 
  granu- 
  

   lated 
  externally, 
  the 
  granules 
  inconspicuous, 
  and 
  with 
  a 
  small 
  spine 
  

   on 
  its 
  inner 
  margin 
  ; 
  palm 
  also 
  granulated 
  above 
  and 
  externally, 
  the 
  

   granules 
  large 
  and 
  showing 
  a 
  tendency 
  to 
  disposition 
  in 
  longitudinal 
  

   series, 
  and 
  becoming 
  more 
  crowded 
  toward 
  the 
  lower 
  margin 
  ; 
  fingers 
  

   brownish, 
  the 
  coloration 
  not 
  extending 
  over 
  the 
  palm 
  : 
  legs 
  slender 
  

   and 
  proportionately 
  rather 
  long. 
  Length 
  of 
  the 
  largest 
  perfect 
  

   specimen 
  rather 
  over 
  4 
  lines 
  (9 
  millim.), 
  breadth 
  5 
  lines 
  (nearly 
  

   11 
  millim.). 
  

  

  Three 
  small 
  specimens 
  (a 
  male 
  and 
  two 
  females) 
  are 
  in 
  the 
  

   first 
  collection, 
  but 
  unfortunately 
  without 
  definite 
  locality 
  ; 
  the 
  label 
  

   with 
  particulars 
  respecting 
  habitat 
  (if 
  there 
  existed 
  any) 
  was 
  lost 
  

   when 
  the 
  bottle 
  (No. 
  123) 
  came 
  into 
  my 
  hands. 
  In 
  the 
  second 
  

   collection 
  two 
  males 
  from 
  Prince 
  of 
  Wales 
  Channel, 
  7-9 
  fms. 
  

  

  Either 
  the 
  left 
  or 
  the 
  right 
  hand 
  may 
  be 
  the 
  larger. 
  

  

  There 
  are 
  in 
  the 
  collection 
  of 
  the 
  British 
  Museum 
  a 
  male 
  and 
  a 
  

   female 
  specimen 
  preserved 
  dry, 
  and 
  collected 
  by 
  Mr. 
  J, 
  Macgillivrav 
  

   (H.M.S. 
  ' 
  Rattlesnake 
  ') 
  off" 
  Cape 
  Capricorn, 
  in 
  15 
  fathoms, 
  on 
  a 
  muddy, 
  

   sandy, 
  and 
  shelly 
  bottom, 
  that 
  I 
  refer 
  to 
  this 
  species 
  ; 
  also 
  an 
  adult 
  

   male 
  from 
  Moreton 
  Bay 
  (piirchased). 
  The 
  coloration 
  of 
  Dr. 
  Cop- 
  

   pinger's 
  spirit-specimens 
  is 
  ])urplish, 
  that 
  of 
  the 
  dry 
  examples 
  reddish 
  

   brown. 
  

  

  This 
  species 
  bears 
  some 
  slight 
  resemblance 
  to 
  P. 
  monilifera, 
  Has- 
  

   well, 
  from 
  Tasmania 
  (vide 
  Cat. 
  p. 
  65, 
  pi. 
  i. 
  fig. 
  3), 
  which, 
  however, 
  

   has 
  the 
  carapace 
  and 
  limbs 
  covered 
  with 
  a 
  short 
  close 
  pubescence, 
  

   and 
  the 
  front 
  much 
  more 
  deeply 
  incised, 
  the 
  carapace 
  more 
  granu- 
  

   lated. 
  

  

  58. 
  Pilumnus 
  semimidus. 
  (Plate 
  XXI. 
  fig. 
  C.) 
  

  

  This 
  species 
  resembles 
  the 
  foregoing 
  in 
  having 
  the 
  gastric, 
  cardiac, 
  

   and 
  branchial 
  regions 
  of 
  the 
  carapace 
  smooth 
  and 
  naked 
  ; 
  but 
  it 
  may 
  

  

  