﻿470 
  COLLECTIONS 
  FROM 
  MELANESIA. 
  

  

  Internal 
  skeleton 
  formed 
  by 
  a 
  coarse 
  network 
  of 
  loose 
  spiculo-fibre, 
  

   the 
  subcortical 
  ends 
  of 
  the 
  fibres 
  rising 
  up 
  so 
  as 
  to 
  support 
  the 
  

   cortex. 
  A 
  strong 
  cortex 
  composed 
  of 
  a 
  zone 
  of 
  chiefly 
  subhorizontal 
  

   skeleton-spicules 
  united 
  by 
  sarcodic 
  substance, 
  and 
  about 
  -45 
  millim. 
  

   in 
  thickness. 
  

  

  Spicules 
  : 
  — 
  (1) 
  Skeleton 
  spinulate, 
  very 
  large, 
  decidedly 
  curved, 
  

   tapering 
  gradually 
  to 
  a 
  sharp 
  point 
  ; 
  head 
  oval, 
  shaft 
  tapering 
  

   slightly 
  towards 
  it, 
  forming 
  a 
  decided 
  but 
  slight 
  neck 
  ; 
  size 
  '8 
  

   by 
  "035 
  millim. 
  (2) 
  Spinispirular, 
  either 
  delicate, 
  long, 
  composed 
  

   of 
  about 
  three 
  bends, 
  which 
  are 
  gradual, 
  so 
  that 
  no 
  part 
  of 
  the 
  whole 
  

   spicule 
  lies 
  much 
  out 
  of 
  the 
  straight 
  line 
  ; 
  size 
  '05 
  to 
  -OoG 
  by 
  -0016 
  

   millim. 
  ; 
  or, 
  rather 
  stouter 
  and 
  shorter, 
  with 
  only 
  two 
  bends, 
  size 
  

   •032 
  by 
  "0022 
  millim.; 
  in 
  either 
  case 
  about 
  10 
  spines 
  to 
  a 
  bend; 
  

   spines 
  slender, 
  sharp-pointed, 
  '0022 
  to 
  -0032 
  millim. 
  long. 
  

  

  Hah. 
  Thursday 
  Island, 
  Torres 
  Straits, 
  4-5 
  fms. 
  

  

  The, 
  unfortunately, 
  single 
  and 
  dry 
  specimen 
  measures 
  35 
  millim. 
  

   (1;? 
  inch) 
  high 
  by 
  25 
  millim. 
  (1 
  inch) 
  in 
  extreme 
  breadth. 
  

  

  The 
  species 
  has 
  in 
  the 
  dry 
  state 
  the 
  colour 
  and 
  much 
  of 
  the 
  

   appearance 
  of 
  >S'. 
  var/abiinda 
  ; 
  both 
  forms 
  of 
  spicule, 
  however, 
  are 
  

   considerably 
  larger 
  than 
  in 
  that 
  form 
  and 
  the 
  angulation 
  of 
  the 
  

   flesh-spicule 
  is 
  less 
  abrupt. 
  It 
  is, 
  however, 
  undoubtedly 
  nearly 
  

   related 
  to 
  it. 
  

  

  100, 
  Spirastrella 
  decumbens. 
  (Plate 
  XLIII. 
  fig. 
  c.) 
  

  

  Incrusting, 
  thin 
  ('5 
  to 
  10 
  millim. 
  thick). 
  General 
  surface 
  level 
  

   (except 
  where 
  affected 
  by 
  the 
  inequalities 
  of 
  the 
  substance 
  to 
  which 
  

   it 
  is 
  attached), 
  glabrous. 
  Colour 
  in 
  sjnrit 
  grey, 
  slightly 
  tinged 
  

   with 
  pink. 
  Vents 
  not 
  made 
  out 
  with 
  certainty. 
  Texture 
  tough 
  

   and 
  leathery. 
  Internal 
  structure 
  very 
  compact 
  ; 
  no 
  large 
  spaces 
  

   seen, 
  as 
  a 
  rule, 
  in 
  vertical 
  sections. 
  Sarcode 
  dull 
  greenish, 
  sub- 
  

   transparent, 
  coloured 
  diffusely. 
  Skeleton 
  consisting 
  of 
  loose 
  spicular 
  

   tracts, 
  about 
  6 
  to 
  10 
  spicules 
  broad, 
  running 
  obliquely 
  or 
  at 
  right 
  

   angles 
  to 
  the 
  surface, 
  and 
  occasionally 
  forming 
  slight 
  prominences, 
  

   protected 
  by 
  the 
  cortex, 
  and 
  of 
  loose 
  skeleton-spicules 
  lying 
  in 
  all 
  

   directions 
  between 
  them. 
  Cortex 
  consisting 
  of 
  a 
  layer, 
  two 
  or 
  three 
  

   spicules 
  deep, 
  of 
  the 
  flesh-spicule, 
  lying 
  in 
  almost 
  colourless 
  sarcode. 
  

  

  Spicules 
  : 
  — 
  (1) 
  Skeleton 
  spinulate, 
  slender, 
  tapering 
  very 
  gradually 
  

   to 
  a 
  sharp 
  point, 
  and 
  very 
  gradually 
  also 
  to 
  the 
  head, 
  below 
  which 
  

   the 
  shaft 
  forms 
  a 
  decided 
  and 
  well-defined 
  neck 
  ; 
  head 
  oval, 
  rather 
  

   pointed 
  at 
  free 
  end, 
  of 
  about 
  the 
  same 
  diameter 
  as 
  the 
  middle 
  of 
  the 
  

   shaft, 
  viz. 
  '0095 
  millim. 
  ; 
  length 
  of 
  sincule 
  "35 
  millim. 
  (2) 
  Spini- 
  

   spirular, 
  moderately 
  stout 
  to 
  stout, 
  consisting 
  of 
  two 
  bends, 
  about 
  

   12 
  spines 
  to 
  a 
  bend 
  ; 
  spines 
  strong, 
  tapering 
  from 
  broad 
  bases 
  to 
  

   sharp 
  points, 
  length 
  about 
  '0045 
  millim. 
  ; 
  length 
  of 
  spicule 
  "025 
  

   millim., 
  thickness 
  (excluding 
  spines) 
  '0032 
  to 
  '0063 
  millim. 
  

  

  Hab. 
  Alert 
  Island, 
  Torres 
  Straits, 
  7 
  fms. 
  (growing 
  over 
  a 
  tubular 
  

   Retejjora). 
  

  

  This 
  species 
  appears 
  to 
  be 
  more 
  nearly 
  allied 
  in 
  its 
  spiculation 
  to 
  

   S. 
  {Alcyonium) 
  purpurea, 
  Lamarck, 
  than 
  to 
  any 
  other 
  Indo-Pacific 
  

   species, 
  but 
  it 
  differs 
  from 
  it 
  in 
  wanting 
  the 
  magnificent 
  crimson 
  colour 
  

  

  