﻿spoNGnDA. 
  397 
  

  

  Eah. 
  Thursday 
  Island, 
  Torres 
  Straits. 
  

  

  The 
  abrupt 
  termination 
  of 
  the 
  spicules 
  and 
  the 
  stouter 
  fibre 
  dis- 
  

   tinguish 
  this 
  form 
  of 
  C. 
  nuda. 
  A 
  single 
  dry 
  specimen, 
  X05 
  millim. 
  

   (44- 
  inches) 
  long. 
  

  

  25. 
  Cladochalina 
  subarmigera. 
  

   (Plate 
  XXXIX. 
  fig. 
  H 
  ; 
  Plate 
  XLI. 
  figs. 
  Z, 
  I'.) 
  

  

  Repent, 
  tortuous, 
  solid, 
  subcylindrical 
  ; 
  stems 
  4 
  to 
  8 
  millim. 
  in 
  

   diameter 
  (2 
  to 
  4 
  in 
  a 
  dwarf 
  form), 
  branching 
  dichotomously 
  at 
  

   rather 
  long 
  intervals, 
  somewhat 
  fiattened 
  above. 
  Branches 
  of 
  same 
  

   general 
  character 
  as 
  stems, 
  often 
  increasing 
  somewhat 
  in 
  diameter 
  

   towards 
  apices, 
  maximum 
  length 
  about 
  45 
  millim., 
  attached 
  at 
  

   various 
  points 
  of 
  lower 
  surface. 
  A 
  few 
  sharp 
  points 
  1 
  to 
  2 
  millim. 
  

   long 
  project 
  from 
  sides 
  of 
  stem 
  and 
  branches 
  here 
  and 
  there, 
  espe- 
  

   cially 
  in 
  the 
  neighbourhood 
  of 
  the 
  larger 
  vents 
  ; 
  absent 
  in 
  some 
  

   specimens 
  ; 
  surface 
  otherwise 
  even. 
  Vents 
  numerous, 
  in 
  a 
  single 
  

   series, 
  2 
  to 
  6 
  millim. 
  apart, 
  along 
  upper 
  surfaces 
  of 
  stem 
  and 
  

   branches, 
  circular, 
  1 
  to 
  2 
  millim. 
  deep, 
  1 
  to 
  2*5 
  millim. 
  in 
  diameter 
  ; 
  

   lumen 
  cylindrical 
  ; 
  margins 
  level 
  with 
  the 
  flattened 
  upper 
  surface 
  

   of 
  the 
  sponge. 
  Texture 
  in 
  spirit 
  compressible, 
  elastic, 
  tough 
  ; 
  

   surface 
  somewhat 
  harsh 
  to 
  the 
  touch 
  ; 
  colour 
  umber-brown. 
  

  

  Main 
  skeleton 
  strictly 
  rectangular 
  in 
  arrangement, 
  rather 
  vari- 
  

   able 
  in 
  siz.e 
  of 
  meshes 
  and 
  diameter 
  of 
  fibres 
  in 
  diiferent 
  specimens 
  ; 
  

   thus 
  the 
  distance 
  between 
  primaries 
  is 
  '28 
  to 
  '77 
  millim., 
  between 
  

   secondaries 
  "042 
  to 
  -28 
  millim. 
  ; 
  diameter 
  of 
  primaries 
  -053 
  to 
  '09 
  

   millim., 
  of 
  secondaries 
  "035 
  to 
  -053 
  millim. 
  (in 
  dwarf 
  form, 
  pri- 
  

   maries 
  -035 
  to 
  -053, 
  secondaries 
  '023 
  to 
  -035 
  millim.) 
  ; 
  fibre 
  almost 
  

   entirely 
  spicular, 
  a 
  very 
  narrow 
  horny 
  margin 
  alone 
  being 
  usually 
  

   discernible 
  (rarely 
  in 
  the 
  dwarf 
  specimen) 
  ; 
  spicules 
  6- 
  to 
  poly- 
  

   serial 
  in 
  primaries, 
  3- 
  to 
  5-serial 
  in 
  secondaries 
  (in 
  the 
  dwarf 
  form, 
  

   4- 
  to 
  8-serial 
  in 
  the 
  former, 
  2- 
  to 
  4- 
  in 
  the 
  latter). 
  Dermal 
  skeleton 
  

   of 
  irregular 
  wide 
  meshes, 
  composed 
  of 
  fibres 
  of 
  the 
  same 
  structure 
  

   as 
  those 
  of 
  the 
  main 
  skeleton 
  ; 
  between 
  these 
  a 
  close 
  angular 
  net- 
  

   work 
  of 
  fine 
  unisijiciilar 
  fibre, 
  meshes 
  -053 
  to 
  '08 
  millim. 
  in 
  diameter. 
  

   Horny 
  matter 
  of 
  fibres 
  amber-yellow. 
  Sarcode 
  rich 
  yellowish 
  brown, 
  

   finely 
  granular. 
  Spicules 
  smooth 
  acerate, 
  slender, 
  almost 
  cylindrical 
  

   to 
  within 
  three 
  diameters 
  of 
  ends, 
  whence 
  they 
  taper 
  to 
  sharp 
  points 
  ; 
  

   size 
  -08 
  by 
  -0032 
  millim., 
  '09 
  by 
  -0032, 
  -095 
  by 
  -002, 
  to 
  -12 
  by 
  

   •002 
  (in 
  difl^erent 
  specimens). 
  

  

  Hah. 
  Warrior 
  Ilecf, 
  Alert 
  Island, 
  Thursday 
  Island, 
  Prince 
  of 
  

   Wales 
  Channel, 
  Torres 
  Straits, 
  4-7 
  fms., 
  &c. 
  ; 
  bottom 
  pearl-shells 
  

   or 
  sand, 
  &c. 
  Albany 
  Island, 
  X. 
  coast 
  of 
  Australia, 
  3-4 
  fms. 
  ; 
  bot- 
  

   tom 
  mud 
  (dwarf 
  form). 
  

  

  A 
  few 
  spirit-specimens 
  represent 
  the 
  larger 
  form 
  of 
  the 
  species, 
  

   one 
  of 
  them 
  is 
  105 
  millim, 
  (4| 
  inches) 
  in 
  maximum 
  extent. 
  A 
  small 
  

   specimen, 
  25 
  millim. 
  long, 
  is 
  the 
  dwarf 
  form 
  above 
  mentioned. 
  

  

  The 
  species 
  is 
  perhaps 
  most 
  closely 
  allied 
  to 
  Cladochalina 
  armiqera, 
  

   Duch. 
  & 
  Mich., 
  of 
  described 
  species 
  ; 
  the 
  surface-spines, 
  however, 
  

   which 
  are 
  the 
  most 
  striking 
  external 
  feature 
  of 
  C. 
  anjn(/era, 
  are 
  

  

  