﻿126 
  COLLECTIONS 
  FROM 
  MELANESIA. 
  

  

  8. 
  Linckia 
  pauciforis. 
  

   Martens, 
  Arch.f. 
  Nat. 
  xxxii. 
  (1866), 
  p. 
  69. 
  

  

  In 
  only 
  one 
  example 
  is 
  one 
  of 
  the 
  arms 
  otherwise 
  than 
  perfect 
  ; 
  

   but 
  this 
  does 
  not 
  seem 
  to 
  have 
  been 
  budded 
  out 
  in 
  place 
  of 
  one 
  cast 
  

   off, 
  but 
  to 
  have 
  been 
  bitten 
  or 
  broken 
  off 
  not 
  far 
  from 
  its 
  tip. 
  

  

  Three 
  dry 
  specimens 
  from 
  Bird 
  Island, 
  N.E. 
  Australia; 
  coral- 
  

   reef. 
  

  

  9. 
  Linckia 
  megaloplax. 
  

  

  Arms 
  five. 
  R=67, 
  r=9, 
  or 
  Il=7'5 
  r 
  about. 
  Adambulacral 
  

   spines 
  flattened, 
  one 
  for 
  each 
  plate, 
  with 
  blunted 
  end 
  ; 
  externally 
  

   to 
  and 
  alternating 
  with 
  these 
  are 
  somewhat 
  shorter 
  papilliform 
  

   spines 
  ; 
  the 
  general 
  granulation 
  of 
  the 
  actinal 
  surface 
  of 
  the 
  disk 
  

   extends 
  between 
  these 
  latter; 
  externally 
  to 
  them 
  there 
  is 
  a 
  row 
  of 
  

   larger 
  spines, 
  the 
  distribution 
  of 
  which 
  is 
  extremely 
  irregular, 
  for 
  

   while 
  at 
  some 
  points 
  they 
  are 
  almost 
  as 
  closely 
  packed 
  as 
  those 
  of 
  

   the 
  more 
  internal 
  row, 
  they 
  are 
  at 
  others 
  separated 
  from 
  one 
  

   another 
  by 
  the 
  distance 
  of 
  three 
  or 
  four 
  of 
  the 
  inner 
  spines. 
  The 
  

   rest 
  of 
  the 
  abactinal 
  siirface 
  is 
  closely 
  covered 
  with 
  subequal 
  gra- 
  

   nules 
  of 
  some 
  size. 
  The 
  abactinal 
  surface 
  is 
  traversed 
  very 
  regu- 
  

   larly 
  by 
  six 
  rows 
  of 
  poriferous 
  spaces, 
  which 
  are 
  comparatively 
  

   large 
  and 
  markedly 
  rectangular 
  ; 
  the 
  smallest 
  spaces 
  are 
  found 
  in 
  

   the 
  lowest 
  row 
  on 
  either 
  side 
  ; 
  a 
  short 
  distance 
  from 
  the 
  tip 
  of 
  each 
  

   arm 
  the 
  spaces 
  completely 
  disappear, 
  and 
  the 
  granulation 
  becomes 
  

   a 
  little 
  more 
  prominent, 
  and 
  there 
  is 
  here, 
  as 
  in 
  some 
  allied 
  species, 
  

   a 
  large 
  specially 
  modified 
  plate 
  with 
  one 
  or 
  more 
  large 
  tubercles 
  

   upon 
  it. 
  The 
  disk 
  itself 
  is 
  covered 
  with 
  large 
  pore-areas, 
  and 
  the 
  

   only 
  noticeable 
  character 
  is 
  the 
  large 
  and 
  distinct, 
  though 
  not 
  pro- 
  

   jecting, 
  madrcporic 
  plate. 
  The 
  pore-areas 
  are 
  about 
  2 
  milhm. 
  wide, 
  

   and 
  the 
  length 
  of 
  the 
  madreporic 
  plate, 
  around 
  which 
  the 
  granules 
  

   are 
  very 
  distinct, 
  may 
  be 
  -1 
  millim. 
  The 
  colour 
  of 
  the 
  abactinal 
  sur- 
  

   face 
  is 
  deep 
  brown 
  or 
  black, 
  whilst 
  that 
  of 
  the 
  actinal 
  surface 
  is 
  

   lighter. 
  

  

  In 
  a 
  specimen 
  smaller 
  than 
  that 
  which 
  has 
  formed 
  the 
  chief 
  basis 
  

   of 
  this 
  description 
  the 
  two 
  surfaces 
  arc, 
  towards 
  the 
  free 
  end 
  of 
  the 
  

   arm, 
  distinguished 
  from 
  one 
  another 
  by 
  the 
  development 
  of 
  some 
  

   short 
  marginal 
  spines. 
  In 
  another, 
  dried, 
  specimen, 
  intermediate 
  

   in 
  size 
  between 
  these 
  two, 
  the 
  spines 
  at 
  the 
  upper 
  and 
  lower 
  mar- 
  

   gins 
  of 
  the 
  sides 
  of 
  the 
  arm, 
  though 
  insignificant, 
  are 
  both 
  larger 
  

   and 
  more 
  numerous. 
  

  

  The 
  idea 
  that 
  the 
  younger 
  forms 
  would 
  have 
  a 
  larger 
  supply 
  of 
  

   spines 
  is 
  opposed 
  by 
  the 
  fact 
  that 
  in 
  a 
  still 
  smaller 
  specimen 
  these 
  

   spines 
  are 
  altogether 
  absent 
  *, 
  while 
  the 
  skeletal 
  plates 
  are 
  stouter 
  

   than 
  in 
  the 
  specimens 
  which 
  bear 
  the 
  spines. 
  The 
  question 
  now 
  

   arises 
  as 
  to 
  whether 
  there 
  are 
  three 
  stages 
  — 
  («) 
  one 
  in 
  which 
  the 
  

   ossicles 
  are 
  so 
  stout 
  that 
  no 
  defensive 
  spines 
  are 
  needed 
  in 
  addition 
  ; 
  

   (h) 
  one 
  in 
  which 
  growth 
  has 
  proceeded 
  so 
  rapidly 
  that 
  the 
  bars 
  of 
  

  

  * 
  Cf. 
  Ann. 
  & 
  Mag. 
  N. 
  H. 
  (5) 
  viii. 
  p. 
  441. 
  

  

  