﻿242 
  COLLECTIONS 
  FKOM 
  MELANESIA. 
  

  

  86. 
  PseudorhomMa 
  sulcatifrons 
  (Stimiyson), 
  var. 
  australiensis. 
  

   (Plate 
  XXIV. 
  fig. 
  C.) 
  

  

  As 
  this 
  variety 
  may 
  prove 
  to 
  be 
  specifically 
  distinct, 
  I 
  subjoin 
  the 
  

   following 
  description 
  : 
  — 
  

  

  As 
  in 
  Heteroplax 
  dentata, 
  Stimpson, 
  the 
  carapace 
  is 
  slightly 
  trans- 
  

   verse, 
  anteriorly 
  somewhat 
  deflexed, 
  posteriorly 
  plane 
  ; 
  it 
  attains 
  its 
  

   greatest 
  width 
  at 
  the 
  third 
  lateral 
  tooth. 
  The 
  front 
  is 
  about 
  half 
  

   the 
  width 
  of 
  the 
  carapace 
  ; 
  its 
  anterior 
  margin 
  is 
  faintly 
  transversely 
  

   sulcated, 
  without 
  any 
  median 
  fissure, 
  and 
  is 
  straight 
  ; 
  there 
  is, 
  how- 
  

   ever, 
  a 
  small 
  notch 
  on 
  each 
  side 
  close 
  to 
  the 
  lateral 
  angles, 
  which 
  

   thus 
  are 
  separated 
  as 
  small 
  teeth. 
  The 
  antero-lateral 
  margins 
  of 
  

   the 
  carapace 
  are 
  much 
  shorter 
  than 
  the 
  postero-lateral 
  and 
  armed 
  

   with 
  four 
  teeth 
  (the 
  outer 
  orbital 
  angle 
  included) 
  ; 
  the 
  third 
  tooth 
  

   is 
  larger 
  and 
  more 
  prominent 
  than 
  the 
  others, 
  the 
  fourth 
  the. 
  

   smallest 
  ; 
  there 
  is 
  a 
  small 
  median 
  notch 
  in 
  the 
  middle 
  of 
  the 
  upper 
  

   orbital 
  margin 
  ; 
  slight 
  transverse 
  inequalities 
  are 
  apparent 
  on 
  the 
  

   front 
  of 
  the 
  gastric 
  region 
  and 
  on 
  the 
  sides 
  of 
  the 
  carapace 
  near 
  the 
  

   lateral 
  teeth. 
  The 
  postabdomen 
  is 
  triangulate, 
  with 
  the 
  segments 
  

   distinct, 
  the 
  penultimate 
  and 
  the 
  last 
  being 
  the 
  longest 
  ; 
  the 
  second 
  

   segment 
  covers 
  the 
  whole 
  width 
  of 
  the 
  sternum 
  and 
  reaches 
  to 
  the 
  

   bases 
  of 
  the 
  fifth 
  legs. 
  The 
  eyes 
  are 
  placed 
  upon 
  rather 
  short 
  thick 
  

   pedicels. 
  The 
  antennules 
  are 
  rather 
  long 
  and 
  transversely 
  folded. 
  

   The 
  basal 
  antennal 
  joint 
  is 
  slender, 
  and 
  although 
  longer 
  than 
  either 
  

   of 
  the 
  following 
  joints, 
  does 
  not 
  reach 
  to 
  the 
  frontal 
  margin 
  ; 
  the 
  

   flagellum 
  is 
  elongated. 
  Scarcely 
  any 
  traces 
  are 
  visible 
  of 
  palatal 
  

   ridges. 
  The 
  merus-joint 
  of 
  the 
  maxillipedes 
  is 
  quadrate, 
  and 
  much 
  

   shorter 
  than 
  the 
  preceding 
  ; 
  the 
  next 
  joint 
  is 
  articulated 
  wdth 
  it 
  at 
  

   its 
  antero-internal 
  angle. 
  The 
  chelipedes 
  are 
  of 
  nearly 
  equal 
  size 
  ; 
  

   merus 
  trigonous, 
  short, 
  with 
  a 
  tooth 
  near 
  the 
  distal 
  end 
  of 
  its 
  upper 
  

   margin 
  ; 
  carpus 
  smooth 
  externally, 
  with 
  a 
  spiniform 
  tooth 
  on 
  its 
  

   inner 
  margin 
  ; 
  palm 
  smooth 
  externally, 
  moderately 
  convex 
  ; 
  fingers 
  

   about 
  as 
  long 
  as 
  the 
  palm, 
  denticulated 
  on 
  their 
  inner 
  margins 
  and 
  

   having 
  between 
  them 
  scarcely 
  any 
  interspace 
  when 
  closed. 
  Ambu- 
  

   latory 
  legs 
  rather 
  long, 
  with 
  the 
  joints 
  very 
  slender, 
  unarmed 
  ; 
  the 
  

   last 
  three 
  with 
  their 
  margins 
  somewhat 
  scantily 
  pubescent. 
  Length 
  

   of 
  carapace 
  nearly 
  3 
  lines 
  (6 
  millim.), 
  breadth 
  nearly 
  4 
  lines 
  

   (8 
  millim.) 
  ; 
  length 
  of 
  ambulatory 
  leg 
  of 
  third 
  pair 
  about 
  6| 
  lines 
  

   (14 
  millim.). 
  

  

  The 
  single 
  specimen 
  was 
  obtained 
  at 
  Port 
  Molle, 
  14 
  fms. 
  (No. 
  93), 
  

   and 
  is 
  apparently 
  a 
  female, 
  although 
  possessing 
  an 
  unusually, 
  nar- 
  

   row 
  postabdomen. 
  It 
  difters 
  from 
  Heteroplcuv 
  dentata 
  and 
  H. 
  trans- 
  

   versa, 
  Stimpson*, 
  in 
  having 
  the 
  second 
  tooth 
  of 
  the 
  antero-lateral 
  

   margins 
  as 
  long 
  as 
  the 
  preceding, 
  and 
  also, 
  it 
  would 
  appear, 
  the 
  

   shorter 
  thicker 
  eye-peduncles, 
  and 
  from 
  the 
  latter 
  also 
  in 
  the 
  

   narrower 
  carapace. 
  Prom 
  the 
  typical 
  P. 
  sulcatifrons 
  (Stimpson), 
  

   from 
  Hong-Kong, 
  it 
  is 
  distinguished 
  only 
  by 
  the 
  non-emarginate 
  

  

  * 
  Proc. 
  Acad. 
  Nat. 
  Sci. 
  Philad. 
  p. 
  94 
  (1858). 
  

  

  