﻿8P0NG1IDA. 
  455 
  

  

  •11 
  by 
  -0095 
  millim. 
  ; 
  and 
  thus 
  gives 
  a 
  wider 
  range 
  to 
  the 
  possible 
  

   variation 
  in 
  the 
  sizes 
  of 
  spicules 
  within 
  the 
  limits 
  of 
  a 
  species. 
  

  

  The 
  only 
  locality 
  hitherto 
  known 
  with 
  certainty 
  was 
  N.W. 
  

   Australia. 
  

  

  Ilah. 
  Port 
  Curtis, 
  Queensland 
  (apparently 
  from 
  beach). 
  

  

  Distribution. 
  N.W. 
  Australia 
  (liidleij). 
  

  

  Obs. 
  This 
  specimen 
  most 
  forcibly 
  illustrates 
  some 
  remarks 
  which 
  

   I 
  published 
  in 
  the 
  ' 
  Journal 
  of 
  the 
  Linnean 
  Society 
  ' 
  (Zool. 
  xv. 
  

   p. 
  149), 
  on 
  the 
  possible 
  intrusion 
  of 
  extraneous 
  spicules 
  into 
  sponges. 
  

   The 
  dermis 
  contains, 
  in 
  fascicles 
  and 
  scattered, 
  large 
  numbers 
  of 
  a 
  

   slender 
  acuate 
  form, 
  which 
  is 
  wholly 
  alien 
  to 
  the 
  sponge, 
  but 
  whose 
  

   appearance 
  and 
  position 
  are 
  so 
  natural 
  that 
  I 
  found 
  it 
  difficult 
  to 
  

   estabhsh 
  this 
  fact. 
  Ee-examination 
  of 
  the 
  slide 
  referred 
  to 
  by 
  me 
  

   (I.e. 
  supra, 
  p. 
  495) 
  as 
  representing 
  a 
  specimen 
  of 
  this 
  species, 
  pro- 
  

   bably 
  from 
  Freemantle, 
  !S.W. 
  Australia, 
  has 
  satisfied 
  me 
  that 
  it 
  is 
  

   not 
  referable 
  to 
  the 
  species, 
  but 
  to 
  one 
  of 
  those 
  Ecliinodictya 
  which 
  

   possess 
  fine 
  acuate 
  spicules 
  in 
  addition 
  to 
  the 
  skeleton 
  acerate 
  (see 
  

   above) 
  ; 
  the 
  fine 
  acuates 
  M'ere 
  at 
  first 
  regarded 
  by 
  me 
  as 
  adventitious. 
  

  

  84. 
  Echinodictyum 
  costiferum. 
  (Platb 
  XLII. 
  fig. 
  r.) 
  

   ? 
  Spongia 
  costifera, 
  Lamarck, 
  Ann. 
  Mtis. 
  Hist, 
  Nat. 
  xx. 
  p. 
  432. 
  

  

  Normally 
  probably 
  turbinate, 
  forming 
  an 
  open 
  cup 
  ; 
  wall 
  about 
  3 
  

   to 
  8 
  millim, 
  thick, 
  undulating. 
  Inner 
  surface 
  uneven, 
  beset 
  at 
  in- 
  

   tervals 
  of 
  about 
  5 
  millim. 
  with 
  pointed 
  monticular 
  eminences, 
  about 
  

   3 
  millim. 
  high 
  ; 
  outer 
  surface 
  proliferating 
  into 
  subdivided 
  ridge- 
  

   like 
  or 
  monticular 
  eminences, 
  each 
  beset 
  with 
  several 
  sharp 
  points 
  ; 
  

   these 
  eminences 
  are 
  about 
  5 
  to 
  8 
  millim. 
  high. 
  Surface 
  between 
  

   eminences 
  on 
  both 
  sides 
  cancellated 
  and 
  more 
  or 
  less 
  cavernous 
  in 
  

   dry 
  state. 
  Texture 
  in 
  dry 
  state 
  very 
  harsh 
  to 
  touch, 
  hard, 
  brittle 
  ; 
  

   colour 
  pale 
  buff'-yellow. 
  Main 
  skeleton 
  : 
  — 
  spiculo-fibre 
  compact, 
  

   no 
  horny 
  matter 
  apparent, 
  but 
  surrounded 
  by 
  yellow 
  sarcode 
  ; 
  all 
  

   fibres 
  echinated 
  by 
  the 
  spined 
  spicules 
  ; 
  consists 
  of 
  (i.) 
  a 
  longitudinal 
  

   series 
  of 
  stout 
  branching 
  fibres, 
  -032 
  to 
  -095 
  millim. 
  thick, 
  running 
  

   towards 
  the 
  free 
  edge 
  of 
  the 
  sponge, 
  and 
  outwards 
  into 
  its 
  surface- 
  

   eminences, 
  where 
  they 
  form 
  the 
  sharp 
  points 
  referred 
  to 
  above, 
  and 
  

   (ii.) 
  an 
  intermediate 
  network 
  composed 
  of 
  meshes 
  varying 
  in 
  shape 
  

   from 
  subrectangular 
  (square 
  or 
  oblong) 
  to 
  oval 
  and 
  round, 
  the 
  angles 
  

   always 
  more 
  or 
  less 
  rounded 
  off, 
  greatest 
  diameter 
  from 
  •00 
  to 
  

   •15 
  millim. 
  ; 
  the 
  deeper 
  fibres 
  bear 
  the 
  slender 
  acuate 
  spicule 
  

   (No. 
  2) 
  laid 
  along 
  the 
  surface 
  or 
  projecting 
  at 
  very 
  acute 
  angles 
  

   from 
  it, 
  sparingly. 
  Dermal 
  skeleton 
  as 
  main 
  skeleton, 
  but 
  spicule 
  

   No. 
  2 
  apparently 
  absent. 
  

  

  Spicules 
  : 
  — 
  (1) 
  Smooth 
  acerate, 
  slightly 
  bent, 
  tapering 
  to 
  more 
  or 
  

   less 
  sharp 
  points 
  from 
  about 
  3 
  to 
  5 
  diameters 
  from 
  ends 
  ; 
  size 
  "22 
  to 
  ^28 
  

   by 
  -0079 
  to.-0095 
  millim. 
  : 
  forms 
  the 
  skeleton- 
  fibre. 
  (2) 
  Smooth 
  

   acuate, 
  with 
  weU-rounded 
  base, 
  tapering 
  gradually 
  to 
  fine 
  point 
  ; 
  

   size 
  ^44 
  by 
  •005 
  millim, 
  : 
  on 
  surface 
  of 
  deeper 
  skeleton-fibres. 
  

   (3) 
  Spined 
  cylindrical, 
  tapering 
  gradually 
  from 
  rounded 
  base 
  to 
  the 
  

   rather 
  coarsely 
  spined 
  free 
  end 
  ; 
  spines 
  distributed 
  all 
  over 
  spicule, 
  

  

  