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  COLLECTIONS 
  PEOM 
  MELANESIA. 
  

  

  and 
  the 
  fibre 
  appears 
  to 
  agree 
  with 
  Ehlers's 
  account 
  of 
  the 
  species, 
  

   but 
  I 
  do 
  not 
  find 
  the 
  acuate 
  spicules 
  mentioned 
  by 
  hira 
  as 
  occurriug 
  

   less 
  abundantly 
  than 
  the 
  acerates 
  ; 
  the 
  size 
  of 
  the 
  latter 
  in 
  the 
  pre- 
  

   sent 
  specimens 
  is 
  -15 
  to 
  '16 
  by 
  "0055 
  to 
  "007 
  millim. 
  (Ehlers 
  gives 
  

   •17 
  millim. 
  for 
  the 
  length) 
  ; 
  and 
  I 
  find 
  (what 
  Ehlers 
  does 
  not 
  mention) 
  

   fine 
  bihamates 
  measuring 
  -02 
  by 
  •001 
  to 
  -0016 
  millim. 
  But 
  a 
  more 
  

   extraordinary 
  fact 
  connected 
  with 
  the 
  species 
  is 
  that 
  the 
  sponge- 
  

   tissue 
  is 
  almost 
  entirely 
  replaced 
  (this 
  seems 
  to 
  bo 
  the 
  true 
  expla- 
  

   nation 
  of 
  the 
  facts) 
  by 
  a 
  ramifying 
  and 
  anastomosing 
  algal 
  fibre, 
  

   •1 
  to 
  •IS 
  millim 
  in 
  diameter, 
  of 
  a 
  semitransparent 
  appearance 
  and 
  

   tough 
  elastic 
  texture 
  in 
  the 
  dry 
  state, 
  like 
  that 
  of 
  dry 
  isinglass 
  : 
  the 
  

   component 
  cells 
  are 
  about 
  ^007 
  millim. 
  in 
  their 
  smallest 
  diameter. 
  

   It 
  appears 
  to 
  be 
  the 
  same 
  species 
  as 
  that 
  which 
  forms 
  the 
  sub- 
  

   stratum 
  of 
  the 
  mass 
  described 
  by 
  Bowerbank 
  (P. 
  Z. 
  S. 
  1876, 
  p. 
  771, 
  

   pi. 
  Ixxx.) 
  as 
  Oplditaspongia 
  facoich's, 
  which 
  is 
  nothing 
  more 
  than 
  

   a 
  coating 
  Suberitid 
  Sponge 
  running 
  over 
  the 
  fibrous 
  filaments 
  of 
  

   this 
  same 
  alga, 
  which 
  Bowerbank 
  has 
  taken, 
  though 
  not 
  without 
  

   hesitation 
  (see 
  p. 
  772, 
  I. 
  c.) 
  for 
  the 
  horny 
  fibre 
  of 
  an 
  OpJditi- 
  

   spongia, 
  although 
  ho 
  has 
  identified 
  isolated 
  portions 
  as 
  alga. 
  In 
  

   this 
  case 
  also 
  it 
  is 
  not 
  until 
  examined 
  with 
  the 
  microscope 
  that 
  the 
  

   algal 
  nature 
  of 
  most 
  of 
  the 
  structure 
  is 
  identified 
  with 
  certainty. 
  

   This 
  form 
  of 
  s>/mhiosis 
  has 
  been 
  lately 
  noticed 
  by 
  Prof. 
  K. 
  Semper 
  

   in 
  ' 
  Die 
  natiirlichen 
  Existenz-Bedingungen 
  ' 
  ('Animal 
  Life,' 
  Inter- 
  

   national 
  Scientific 
  Series), 
  where 
  Spongia 
  carfilaginen, 
  Esper, 
  is 
  used 
  

   in 
  illustration 
  ; 
  it 
  is 
  probably 
  of 
  not 
  uncommon 
  occurrence 
  in 
  the 
  

   Spongida. 
  A 
  Formosa 
  specimen 
  agrees 
  closely 
  in 
  the 
  characters 
  

   both 
  of 
  the 
  sponge 
  and 
  alga 
  with 
  those 
  from 
  Australia. 
  Mr. 
  Carter 
  

   (Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  1878, 
  ii. 
  p. 
  163) 
  descril)es 
  exactly 
  the 
  same 
  

   circumstance 
  in 
  an 
  allied 
  species 
  from 
  Hong 
  Kong, 
  and 
  adds 
  other 
  

   similar 
  instances. 
  Several 
  specimens, 
  dry 
  and 
  in 
  spirit. 
  

  

  Hub. 
  Thursday 
  Island, 
  Prince 
  of 
  Wales 
  Channel, 
  Torres 
  Straits, 
  

   7-9 
  fms. 
  ; 
  Port 
  Molle, 
  Queensland, 
  coral-reef. 
  

  

  Distribution. 
  Ceylon 
  (Esper) 
  ; 
  Formosa 
  (coll. 
  Brit. 
  Mas.). 
  

  

  This 
  species 
  has 
  a 
  similar 
  habit 
  to 
  G. 
  varius, 
  if 
  the 
  form 
  may 
  be 
  

   regarded 
  as 
  that 
  of 
  the 
  sponge 
  and 
  not 
  of 
  the 
  alga 
  ; 
  but 
  its 
  acerate 
  

   spicules 
  are 
  not 
  so 
  long 
  and 
  scarcely 
  half 
  as 
  thick 
  as 
  those 
  of 
  that 
  

   species. 
  

  

  GELLIODES, 
  g. 
  n. 
  

  

  Desmacidinidoe 
  of 
  erect 
  habit 
  and 
  well-defined 
  form, 
  fibre 
  distinct 
  

   and 
  compact 
  ; 
  outer 
  surface 
  of 
  sponge 
  beset 
  with 
  pointed 
  eminences. 
  

   Spicules 
  smooth 
  skeleton 
  acerate 
  and 
  bihamate. 
  

  

  This 
  genus 
  unites 
  the 
  habit 
  of 
  Echinonemata 
  with 
  the 
  fibre 
  of 
  

   Desmacidinidfe 
  and 
  the 
  spiculation 
  of 
  OcUius 
  {Desmacodcs). 
  Mr. 
  

   Carter 
  (Ann. 
  & 
  Mag. 
  N. 
  H. 
  1882, 
  ix. 
  p. 
  288) 
  has 
  referred 
  his 
  spe- 
  

   cies 
  jLros 
  Jibnlata 
  to 
  the 
  genus 
  Phorbas, 
  Duch. 
  and 
  Mich., 
  together 
  

   with 
  his 
  Axos 
  ancliorata, 
  which 
  can 
  hardly 
  be 
  generically 
  identical 
  

   with 
  it, 
  as 
  its 
  spiculation 
  is 
  an 
  acerate 
  and 
  an 
  anchorate, 
  while 
  

   Phorbas 
  nmftrrinthus, 
  the 
  second 
  species 
  of 
  the 
  genus, 
  has 
  oidy 
  an 
  

  

  