﻿spoNGiroA. 
  617 
  

  

  39. 
  Echinonema 
  gracilis. 
  (Plate 
  LIV. 
  figs. 
  I, 
  V 
  .) 
  

  

  Erect, 
  very 
  slender, 
  brandling 
  dichotomoiisly 
  and 
  seldom 
  ; 
  branches 
  

   given 
  off 
  at 
  angles 
  of 
  from 
  aboiit 
  60° 
  to 
  90°, 
  cylindrical 
  or 
  irregular, 
  

   sometimes 
  somewhat 
  flattened, 
  diameter 
  2 
  to 
  5 
  millim. 
  Surface 
  

   smooth. 
  Vents 
  not 
  apparent. 
  Consistence 
  in 
  spirit 
  soft, 
  elastic, 
  

   very 
  compressible, 
  rather 
  tough 
  ; 
  colour 
  very 
  dark 
  purplish 
  brown. 
  

  

  Main 
  skeleton 
  subrectangular 
  in 
  arrangement 
  ; 
  primary 
  fibres 
  "05 
  

   to 
  '07 
  millim. 
  in 
  diameter, 
  pale 
  yellow, 
  almost 
  filled 
  with 
  the 
  skeleton- 
  

   spicule 
  ; 
  secondaries 
  -035 
  to 
  -05 
  millim. 
  in 
  diameter, 
  containing 
  one 
  

   or 
  two 
  series 
  of 
  spicules. 
  Dermal 
  skeleton 
  consisting 
  of 
  radiating 
  

   tufts 
  of 
  subspinulate 
  spicules, 
  the 
  bases 
  of 
  the 
  tufts 
  about 
  "25 
  millim. 
  

   apart, 
  the 
  points 
  of 
  adjacent 
  tufts 
  crossing 
  each 
  other. 
  Sarcode 
  of 
  

   interior 
  dark 
  yellow, 
  granular 
  ; 
  that 
  of 
  dermis 
  transparent, 
  very 
  pale 
  

   purple. 
  Spicules 
  : 
  — 
  (1) 
  Subspinulate 
  of 
  skeleton 
  and 
  dermis, 
  straight, 
  

   shaft 
  smooth, 
  head 
  provided 
  with 
  a 
  few 
  terminal 
  very 
  fine 
  spines 
  ; 
  

   head 
  oval, 
  of 
  about 
  same 
  diameter 
  as 
  middle 
  of 
  shaft, 
  neck 
  slight 
  ; 
  

   spicule 
  tapering 
  gradually 
  to 
  sharp 
  point 
  ; 
  size 
  -34 
  by 
  -012 
  millim. 
  

  

  (2) 
  Acuate, 
  minutely 
  spined 
  on 
  base, 
  straight, 
  tapering 
  gradually 
  to 
  

   sharp 
  point; 
  size 
  -25 
  by 
  '014 
  millim. 
  (in 
  centre 
  of 
  primary 
  fibre). 
  

  

  (3) 
  Echinating 
  spined 
  subspinulate, 
  tapering 
  to 
  sharp 
  point 
  from 
  two 
  

   or 
  three 
  diameters 
  from 
  end, 
  well 
  spined 
  over 
  head 
  and 
  distal 
  two 
  

   thirds 
  ; 
  the 
  spines 
  sharp 
  and 
  strong, 
  those 
  on 
  shaft 
  recurvate 
  towards 
  

   head 
  ; 
  size 
  of 
  spicule 
  -082 
  by 
  -013 
  millim. 
  (4) 
  Trieurvate 
  acerate 
  

   of 
  sarcode, 
  smooth, 
  middle 
  curve 
  bold 
  ; 
  size 
  '057 
  by 
  -001 
  millim. 
  

   (5) 
  Equianchorate, 
  navicular, 
  shaft 
  slightly 
  curved 
  ; 
  length 
  of 
  spicule 
  

   •02 
  millim. 
  

  

  Hah. 
  Providence 
  Eeef, 
  Mascarene 
  Islands, 
  24 
  fms. 
  ; 
  bottom, 
  sand 
  

   and 
  dead 
  coral. 
  

  

  Several 
  small 
  and 
  more 
  or 
  less 
  imperfect 
  specimens 
  in 
  spirit; 
  the 
  

   largest 
  measures 
  75 
  millim. 
  (3 
  inches) 
  in 
  length. 
  In 
  the 
  slender 
  

   proportions 
  of 
  the 
  sponge 
  (which 
  gives 
  it 
  the 
  appearance 
  of 
  a 
  

   Raspailia) 
  and 
  in 
  the 
  weak 
  development 
  of 
  the 
  horny 
  fibre 
  this 
  

   species 
  stands 
  quite 
  apart 
  from 
  the 
  Australian 
  species 
  as 
  well 
  as 
  

   from 
  the 
  foregoing 
  form. 
  

  

  AXINELLID^. 
  

  

  Of 
  the 
  four 
  species 
  to 
  be 
  enumerated, 
  one 
  is 
  found 
  also 
  on 
  the 
  

   southern 
  and 
  one 
  on 
  the 
  west 
  northern 
  coasts 
  of 
  Australia. 
  The 
  

   very 
  variable 
  character 
  of 
  the 
  surface 
  of 
  Leucophlcieus 
  proteus 
  is 
  a 
  

   somewhat 
  unusual 
  manifestation 
  of 
  the 
  polymorphism 
  of 
  Sponges. 
  

  

  40. 
  Azinella 
  spiculifera. 
  (Plate 
  LIV. 
  fig. 
  b.) 
  

  

  Spongia 
  spiculifera, 
  Lamarch, 
  Ann. 
  Mus, 
  Hist. 
  Nat. 
  xx. 
  p. 
  449. 
  

  

  A 
  specimen 
  in 
  spirit, 
  agreeing 
  well 
  with 
  the 
  fragment 
  in 
  the 
  

   Museum 
  which 
  represents 
  Lamarck's 
  species. 
  It 
  consists 
  of 
  two 
  

  

  