﻿8P0NGIIDA. 
  4G9 
  

  

  lufcernal 
  structure 
  rendered 
  cavernous 
  by 
  the 
  wide 
  canals 
  of 
  the 
  

   excretory 
  system 
  ; 
  texture 
  of 
  internal 
  structures 
  moderately 
  tough, 
  

   luternal 
  skeleton 
  formed 
  of 
  trabeculas 
  and 
  sheet-like 
  expansions 
  

   some 
  larger 
  trabecular 
  formed 
  of 
  crossed 
  skeleton-spicules 
  strength- 
  

   ened 
  by 
  dense 
  sarcode 
  proceed 
  from 
  the 
  interior 
  and 
  support 
  the 
  

   cortex 
  ; 
  they 
  are 
  from 
  --1 
  to 
  -S 
  millim. 
  in 
  diameter. 
  A 
  strong 
  cortex, 
  

   about 
  -8 
  millim. 
  thick, 
  tough, 
  formed 
  chiefly 
  by 
  the 
  skeleton-spicules 
  

   much 
  intercrossed, 
  and 
  united 
  by 
  a 
  somewhat 
  dense, 
  brownish, 
  sub- 
  

   transparent 
  sarcode 
  (becoming 
  less 
  visible 
  when 
  the 
  specimen 
  is 
  

   dried). 
  Spicules: 
  — 
  (1) 
  Skeleton 
  spinulate, 
  strong, 
  slightly 
  curved 
  ; 
  

   head 
  oblong, 
  almost 
  oval 
  ; 
  shaft 
  gradually 
  diminishing 
  to 
  about 
  two 
  

   thirds 
  of 
  its 
  full 
  diameter 
  towards 
  head, 
  and 
  tapering 
  gradually 
  to 
  

   sharp 
  distal 
  point 
  ; 
  average 
  maximum 
  size 
  -6 
  by 
  "02 
  millim. 
  (2) 
  

   Spiuispirular, 
  delicate, 
  composed 
  of 
  about 
  three 
  rather 
  sharp 
  bends, 
  

   with 
  about 
  4 
  to 
  8 
  rather 
  blunt 
  spines, 
  -0021 
  millim. 
  long, 
  to 
  each 
  

   bend 
  ; 
  shaft 
  of 
  equal 
  diameter 
  in 
  all 
  parts 
  ; 
  average 
  maximum 
  size 
  

   •032 
  by 
  -0016 
  millim. 
  (exclusive 
  of 
  spines). 
  

  

  Hnb. 
  Thursday 
  and 
  West 
  Islands, 
  Torres 
  Straits, 
  4-7 
  fms. 
  ; 
  

   bottom 
  sand 
  or 
  coral. 
  

  

  Distribution. 
  Trincomalee 
  (Carter); 
  Galle 
  coast, 
  Ceylon 
  (coll. 
  

   Mus. 
  Brit., 
  ex 
  coll. 
  Dr. 
  Oiidaatje). 
  

  

  The 
  external 
  appearance 
  of 
  this 
  fine 
  species 
  is 
  more 
  characteristic 
  

   and 
  constant 
  than 
  is 
  usual 
  in 
  the 
  Suberitidae. 
  Mr. 
  Carter 
  has 
  

   shortly 
  described 
  it, 
  but 
  without 
  name. 
  The 
  largest 
  specimen 
  

   known 
  to 
  me 
  is 
  one 
  brought 
  by 
  Dr. 
  Ondaatje, 
  Colonial 
  Surgeon, 
  

   from 
  Ceylon, 
  which 
  measures 
  225 
  millim. 
  by 
  13(J 
  millim. 
  (9 
  by 
  5 
  

   inches), 
  by 
  GO 
  millim. 
  (2| 
  inches) 
  in 
  greatest 
  thickness 
  ; 
  it 
  was 
  

   obtained 
  at 
  or 
  near 
  low-water 
  mark. 
  

  

  The 
  species 
  is 
  nearly 
  allied 
  to 
  Hymeniacidon 
  angulata 
  of 
  Bower- 
  

   bank 
  (Madeira), 
  but 
  has 
  a 
  skeleton-spicule 
  of 
  twice 
  the 
  diameter 
  of 
  

   the 
  spinulate 
  found 
  in 
  that 
  species. 
  

  

  The 
  spicules 
  show 
  no 
  striking 
  variation 
  in 
  size 
  ; 
  the 
  length 
  of 
  the 
  

   spinulate 
  varies 
  from 
  -55 
  to 
  '63 
  millim. 
  in 
  different 
  specimens 
  ; 
  its 
  

   breadth 
  and 
  the 
  size 
  of 
  the 
  flesh-spicule 
  are 
  almost 
  constant. 
  

  

  Colour. 
  This 
  is 
  produced 
  by 
  a 
  number 
  of 
  globular 
  or 
  suboval 
  cells 
  

   of 
  olive-green 
  colour 
  throughout, 
  provided 
  with 
  a 
  large 
  nucleus 
  of 
  a 
  

   darker 
  colour 
  ; 
  they 
  measure 
  about 
  -0095 
  millim. 
  in 
  diameter, 
  and 
  

   have 
  a 
  well-defined 
  outline 
  ; 
  they 
  appear 
  to 
  be 
  confined 
  to 
  tho 
  

   mesoderm. 
  

  

  99. 
  Spirastrella 
  congenera. 
  (Plate 
  XLIII. 
  figs, 
  d, 
  d'.) 
  

  

  Massive, 
  attached 
  by 
  broad 
  base, 
  tending 
  to 
  rise 
  into 
  pyramidal 
  or 
  

   cylindrical 
  lobes, 
  each 
  terminated 
  by 
  the 
  vent. 
  General 
  surface 
  

   even, 
  smooth 
  (in 
  dry 
  state). 
  Colour 
  (in 
  dry 
  state) 
  pale 
  fawn. 
  Vent 
  

   (in 
  the 
  single 
  dry 
  specimen) 
  oval, 
  8 
  millim. 
  in 
  greatest 
  diameter, 
  

   leading 
  deeply 
  into 
  the 
  body 
  of 
  the 
  sponge, 
  the 
  margin 
  level 
  with 
  

   the 
  general 
  surface 
  (in 
  the 
  single 
  specimen 
  a 
  tongue-like 
  process, 
  

   8 
  millim. 
  high, 
  stands 
  at 
  one 
  side 
  of 
  it). 
  Internal 
  structure 
  cavernous, 
  

   with 
  wide 
  spaces 
  ; 
  texture 
  of 
  internal 
  structures 
  moderately 
  touo'h. 
  

  

  