﻿SPONGIIUA. 
  437 
  

  

  70. 
  Esperia 
  pellucida. 
  

   (Plate 
  XL. 
  fig. 
  K 
  ; 
  Plate 
  XLII. 
  fig. 
  h.) 
  

  

  Growth 
  horizontal, 
  spreading 
  over 
  and 
  between 
  stones 
  &c., 
  rising 
  

   at 
  certain 
  points 
  into 
  slender 
  lobes. 
  Surface 
  even, 
  glabrous. 
  Con- 
  

   sistence 
  rather 
  firm 
  and 
  brittle. 
  Vents? 
  Colour 
  in 
  spirit 
  pale 
  

   pink 
  or 
  dirty 
  white, 
  subtransparent. 
  Dermal 
  membrane 
  gela- 
  

   tinous, 
  transparent, 
  subelastic, 
  firm 
  ; 
  internal 
  structures 
  soft. 
  Main 
  

   skeleton 
  formed 
  of 
  delicate, 
  widely 
  inosculating 
  fibres 
  4 
  to 
  6 
  spi- 
  

   cules 
  broad, 
  soft, 
  branching 
  at 
  obtuse 
  angles. 
  Dermal 
  skeleton 
  

   consisting 
  of 
  angular 
  meshes 
  formed 
  by 
  distinct 
  straight 
  tracts 
  of 
  

   spicules, 
  2 
  to 
  4 
  spicules 
  broad. 
  

  

  SjHCules 
  : 
  — 
  (1) 
  Skeleton 
  subspinulate 
  ; 
  straight 
  or 
  slightly 
  curved 
  ; 
  

   head 
  marked 
  by 
  a 
  slight 
  and 
  gradual 
  enlargement 
  a 
  little 
  below 
  

   base 
  ; 
  head 
  round 
  and 
  blunt, 
  diameter 
  less 
  than 
  maximum 
  diameter 
  

   of 
  shaft 
  : 
  shaft 
  tapering 
  gradually 
  to 
  sharp 
  point 
  from 
  within 
  about 
  

   2 
  to 
  6 
  diameters 
  of 
  apex 
  ; 
  size 
  -42 
  by 
  -0095 
  millim. 
  (2) 
  Large 
  

   inequianchorate 
  ; 
  shaft 
  strong, 
  slightly 
  bent, 
  of 
  same 
  diameter 
  

   throughout 
  except 
  near 
  the 
  two 
  ends. 
  Large 
  end 
  forming 
  about 
  

   one 
  third 
  of 
  total 
  length 
  of 
  spicule, 
  diameter 
  about 
  the 
  same 
  as 
  its 
  

   length. 
  Lateral 
  palms, 
  as 
  seen 
  from 
  front, 
  broad, 
  truncate 
  below, 
  

   inferior 
  angle 
  projecting 
  slightly 
  ; 
  outer 
  margin 
  slightly 
  reverted 
  

   throughout 
  ; 
  median 
  ])a!m 
  oval, 
  small 
  ; 
  tubercle 
  distinct, 
  small, 
  

   pear-shaped 
  ; 
  small 
  end 
  almost 
  truncate 
  above 
  as 
  seen 
  from 
  front, 
  

   but 
  with 
  the 
  supero-lateral 
  angles 
  sharp, 
  slightly 
  produced 
  upwards, 
  

   outer 
  margins 
  reverted 
  throughout 
  ; 
  tubercle 
  relatively 
  large, 
  anvil- 
  

   shaped 
  ; 
  the 
  small 
  end 
  of 
  the 
  s]iicule 
  is 
  truncate 
  below 
  and 
  about 
  

   half 
  the 
  diameter 
  of 
  the 
  large 
  end 
  ; 
  length 
  of 
  spicule 
  '1 
  millim, 
  

   (3) 
  Small 
  inequianchorate 
  ; 
  shaft 
  slender, 
  gradually 
  curved 
  ; 
  large 
  

   end 
  forming 
  about 
  two 
  fifths 
  of 
  total 
  length 
  of 
  spicule 
  ; 
  lateral 
  palms 
  

   with 
  sharp 
  inferior 
  angles, 
  being 
  excavated 
  on 
  inner 
  side, 
  outer 
  

   margin 
  reverted 
  throughout; 
  tubercle 
  narrow, 
  elongate; 
  smaller 
  end 
  

   about 
  half 
  the 
  length 
  of 
  upper 
  (larger) 
  end 
  ; 
  outer 
  margin 
  reverted 
  

   throughout 
  ; 
  tviberele 
  subterminal, 
  s(|uarish 
  ; 
  end 
  truncate 
  below 
  : 
  

   length 
  of 
  spicule 
  -032 
  millim. 
  (4) 
  Bihamate, 
  contort, 
  slender, 
  with 
  

   wide 
  curve 
  , 
  size 
  'Go? 
  by 
  '0032 
  millim. 
  (5) 
  Trichites, 
  in 
  bundles 
  

   of 
  from 
  20 
  to 
  30, 
  with 
  tine 
  points 
  ; 
  size 
  of 
  individual 
  spicules 
  -06 
  

   by 
  -0015 
  minim. 
  

  

  Hah. 
  Alert 
  Island, 
  Torres 
  Straits, 
  7 
  fms. 
  ; 
  bottom 
  sand. 
  

   The 
  anchorate 
  of 
  this 
  spicule 
  belongs 
  to 
  the 
  more 
  common 
  of 
  the 
  

   types 
  occurring 
  in 
  Atlantic 
  and 
  Mediterranean 
  Esperia' 
  ; 
  it 
  is, 
  how- 
  

   ever, 
  larger 
  than 
  most, 
  if 
  not 
  all, 
  and 
  the 
  presence 
  of 
  a 
  second 
  form 
  

   of 
  inequianchorate 
  is 
  another 
  unusual 
  point. 
  The 
  single 
  specimen 
  

   is 
  in 
  spirit 
  and 
  runs 
  over 
  and 
  between 
  a 
  number 
  of 
  lor 
  so 
  and 
  

   attached 
  calcareous 
  fragments, 
  i. 
  e. 
  shells 
  &c. 
  The 
  upright 
  lobes 
  are 
  

   about 
  16 
  millim. 
  long 
  and 
  somewhat 
  flattened. 
  

  

  