﻿322 
  COLLECTIONS 
  FKOJl 
  MELANESIA. 
  

  

  have 
  the 
  articular 
  ridges 
  somewhat 
  reflexed. 
  Por 
  its 
  distribution 
  

   see 
  Darwin's 
  monograph 
  (p. 
  279), 
  by 
  whom 
  it 
  is 
  recorded 
  from 
  

   Moreton 
  Bay. 
  

  

  3. 
  Acasta 
  sulcata, 
  LamarcJc, 
  var. 
  

  

  A 
  single 
  specimen 
  in 
  the 
  collection 
  from 
  Albany 
  Island, 
  3-4 
  fms., 
  

   is 
  very 
  doubtfully 
  referred 
  to 
  this 
  species. 
  It 
  agrees 
  generally 
  in 
  

   its 
  external 
  characters 
  with 
  Mr. 
  Darvvin's 
  description, 
  and 
  also 
  in 
  

   the 
  broader 
  spur 
  of 
  the 
  tergum 
  of 
  the 
  operculum. 
  In 
  the 
  remarkable 
  

   reduction 
  of 
  the 
  width 
  of 
  the 
  parietes 
  of 
  the 
  carino-lateral 
  compart- 
  

   ments 
  it 
  altogether 
  resembles 
  a 
  specimen 
  from 
  Sydney 
  in 
  Mr. 
  

   Cuming's 
  collection 
  (now 
  in 
  the 
  British 
  Museum) 
  specially 
  referred 
  

   to 
  by 
  Mr. 
  Darwin 
  * 
  ; 
  but 
  it 
  differs 
  very 
  remarkably 
  in 
  the 
  external 
  

   armature 
  of 
  the 
  parietes 
  of 
  the 
  other 
  compartments, 
  which 
  are 
  

   armed 
  with 
  strong, 
  outwardly-projecting, 
  bluntly-triangulate 
  lobes 
  

   or 
  teeth, 
  one 
  such 
  tooth 
  being 
  situate 
  on 
  each 
  compartment, 
  not 
  

   very 
  far 
  below 
  the 
  apex, 
  except 
  on 
  the 
  carina, 
  where 
  there 
  are 
  two 
  

   teeth 
  ; 
  thus 
  there 
  are 
  five 
  in 
  all. 
  The 
  cup-shaped 
  basis 
  of 
  the 
  shell 
  

   is 
  pinkish 
  ; 
  the 
  epidermis, 
  which 
  remains 
  upon 
  the 
  basal 
  half 
  of 
  the 
  

   compartments, 
  bright 
  yellow. 
  

  

  Mr, 
  Darwin 
  (t.c. 
  p. 
  311) 
  mentions 
  some 
  remarkable 
  variations 
  in 
  

   the 
  external 
  armature 
  of 
  this 
  species, 
  but 
  none 
  which 
  at 
  all 
  resemble 
  

   the 
  specimen 
  now 
  described. 
  In 
  the 
  very 
  closely 
  allied 
  A. 
  spongites 
  

   the 
  calcareous 
  projections 
  of 
  the 
  shell 
  are 
  often 
  of 
  considerable 
  

   size, 
  yet 
  not 
  nearly 
  so 
  large 
  as 
  the 
  teeth 
  in 
  the 
  specimen 
  from 
  

   Albany 
  Island, 
  and 
  much 
  more 
  numerous 
  and 
  irregularly 
  distributed. 
  

   In 
  the 
  specimen 
  of 
  A. 
  sulcata 
  from 
  Sydney, 
  with 
  narrow-linear 
  

   carino-lateral 
  compartments, 
  the 
  walls 
  of 
  the 
  shell 
  are 
  externally 
  

   smooth. 
  

  

  * 
  Monograph 
  of 
  Cirripeclia, 
  Ealauidte, 
  p. 
  310 
  (1854). 
  

  

  