﻿548 
  COLLECTIONS 
  FKOM 
  THE 
  WESTERN 
  IXDIAN' 
  OCEAX. 
  

  

  This 
  species 
  is 
  distiiig'uished 
  from 
  the 
  three 
  others 
  of 
  the 
  genus 
  

   b}^ 
  its 
  much 
  less 
  distinctly 
  trilobate 
  front. 
  P. 
  iridentata, 
  Miers, 
  

   which 
  is 
  its 
  nearest 
  ally 
  in 
  this 
  genus, 
  has 
  a 
  much 
  more 
  coarsely 
  

   punctulated 
  carapace, 
  and 
  differs 
  in 
  other 
  characters. 
  

  

  Three 
  small 
  male 
  specimens 
  of 
  a 
  species 
  of 
  Leucosia 
  from 
  the 
  

   Gulf 
  of 
  Suez 
  (R. 
  MacAndretv) 
  in 
  the 
  Museum 
  collection, 
  which 
  were 
  

   not 
  described 
  when 
  I 
  published 
  my 
  memoir 
  on 
  this 
  group 
  in 
  1877*, 
  

   because 
  I 
  doubted 
  if 
  they 
  presented 
  the 
  characters 
  of 
  the 
  fully 
  adult, 
  

   bear 
  a 
  curious 
  resemblance 
  to 
  this 
  species. 
  They 
  are 
  distinguished 
  

   not 
  only 
  by 
  possessing 
  a 
  distinct, 
  although 
  shallow 
  and 
  imperfectly 
  

   defined 
  thoracic 
  sinus, 
  but 
  also 
  by 
  the 
  absence 
  of 
  the 
  lines 
  of 
  

   granules 
  from 
  the 
  inferior 
  margin 
  of 
  the 
  palm 
  of 
  the 
  chelipedes 
  

   and 
  from 
  the 
  margins 
  of 
  the 
  outer 
  maxillipedes. 
  

  

  69. 
  Nursilia 
  dentata, 
  Bell. 
  

  

  A 
  male 
  was 
  obtained 
  at 
  the 
  Seychelles, 
  4-12 
  fms. 
  (j^o. 
  194). 
  

   The 
  wide 
  Oriental 
  distribution 
  of 
  this 
  species, 
  which 
  has 
  been 
  

   already 
  noticed 
  in 
  the 
  earlier 
  part 
  of 
  this 
  Report 
  (p. 
  253), 
  is 
  evidenced 
  

   by 
  the 
  acquisition 
  of 
  this 
  specimen. 
  

  

  70. 
  Arcania 
  undecimspinosa. 
  

  

  Arcania 
  uudecimspiuosa, 
  De 
  Haan, 
  Faun. 
  Japon, 
  Crust, 
  p. 
  135, 
  

   pi. 
  sxxiii. 
  fig. 
  8 
  (1841) 
  ; 
  Bell, 
  Trans. 
  Linn. 
  Soc. 
  xxi. 
  p. 
  309 
  (1855) 
  ; 
  

   Cat. 
  Leucos. 
  Brit. 
  Mus. 
  p. 
  21 
  (1855). 
  

  

  Arcania 
  granulosa, 
  Miers, 
  Trans. 
  Linn. 
  Soc. 
  ser. 
  2, 
  Zool. 
  p. 
  240, 
  

   pi. 
  xxxviii. 
  fig. 
  29 
  (1877) 
  ; 
  Proc. 
  Zool. 
  Soc. 
  p. 
  44 
  (1879). 
  

  

  Seychelles, 
  4-12 
  fms. 
  (N'o. 
  194) 
  ; 
  an 
  adult 
  male. 
  

  

  This 
  specimen 
  scarcely 
  differs 
  from 
  De 
  Haan's 
  figure 
  and 
  the 
  

   specim^en 
  from 
  Moreton 
  Bay 
  in 
  the 
  British-Museum 
  collection, 
  which 
  

   I 
  formerly 
  separated 
  on 
  insufficient 
  grounds 
  under 
  the 
  name 
  of 
  

   A. 
  (jranulosa, 
  except 
  in 
  its 
  somewhat 
  less 
  strongly 
  granulated 
  

   carapace 
  and 
  the 
  slightly 
  recurved 
  lateral 
  spines 
  of 
  the 
  third 
  pair. 
  

   Unfortunately 
  the 
  three 
  posterior 
  spines 
  of 
  the 
  carapace 
  were 
  (sub- 
  

   sequent 
  to 
  its 
  examination) 
  ac<iidentally 
  crushed 
  in 
  the 
  specimen 
  

   from 
  the 
  Seychelles. 
  

  

  There 
  is 
  in 
  the 
  collection 
  another 
  male 
  specimen 
  from 
  the 
  

   Seychelles 
  (4-12 
  fms.), 
  apparently 
  referable 
  to 
  this 
  genus, 
  but 
  

   which 
  I 
  hesitate 
  to 
  sepai-ate 
  as 
  a 
  distinct 
  species, 
  as, 
  on 
  account 
  of 
  

   its 
  very 
  small 
  size, 
  I 
  think 
  it 
  may 
  not 
  present 
  all 
  the 
  characters 
  of 
  

   the 
  fully-grown 
  animal. 
  The 
  carapace 
  is 
  nearly 
  circular 
  in 
  outline 
  

   and 
  is 
  covered 
  with 
  close-set 
  granules 
  ; 
  its 
  lateral 
  and 
  posterior 
  

   margins 
  are 
  armed 
  with 
  twelve 
  small 
  nearly 
  equidistant 
  and 
  equal 
  

   granulated 
  spines, 
  those 
  on 
  the 
  posterior 
  margin 
  being 
  smaller 
  and 
  

   tubcrculiform. 
  The 
  front 
  is 
  bilobate 
  and 
  slightly 
  concave 
  above 
  ; 
  

  

  * 
  Trans. 
  Linn. 
  Soc. 
  spr. 
  2, 
  Zool. 
  i. 
  p. 
  2o."i 
  (1877). 
  

  

  