﻿600 
  COLLECTIONS 
  FROM 
  THE 
  -WESTERN 
  INDIAN 
  OCEAN, 
  

  

  the 
  Adriatic. 
  The 
  conuli 
  are 
  more 
  prominent 
  and 
  distant 
  than 
  in 
  

   that 
  species, 
  and 
  the 
  proportion 
  of 
  horny 
  matter 
  in 
  the 
  fibre 
  is 
  

   considerably 
  greater. 
  

  

  APLYSINID^. 
  

  

  Althongh 
  Pallas 
  and 
  Lamarck 
  cite 
  lantJiella 
  JIabelliformts 
  as 
  from 
  

   the 
  Indian 
  Ocean, 
  I 
  am 
  not 
  aware 
  that 
  the 
  genus 
  has 
  been 
  hitherto 
  

   shown 
  to 
  occur 
  on 
  the 
  western 
  side 
  of 
  that 
  ocean. 
  

  

  15. 
  Aplysina 
  fusca. 
  

  

  Carter, 
  Ann. 
  ^ 
  Mag. 
  N. 
  H. 
  1880, 
  vi. 
  p. 
  36. 
  

  

  A 
  spirit-specimen, 
  agreeing 
  in 
  its 
  more 
  slender 
  fibre 
  (maximum 
  

   diameter 
  about 
  -7 
  millim.), 
  especially 
  near 
  the 
  surface, 
  and 
  in 
  its 
  

   smaller 
  interconular 
  spaces 
  with 
  the 
  Ceylon 
  specimen 
  rather 
  than 
  

   with 
  that 
  from 
  S.W. 
  Australia, 
  subsequently 
  assigned 
  to 
  the 
  same 
  

   species 
  by 
  Carter 
  (Ann, 
  &Mag. 
  N. 
  H. 
  1881, 
  viii. 
  p. 
  107), 
  which 
  I 
  have 
  

   seen. 
  In 
  this 
  spirit-specimen 
  the 
  cells 
  which 
  are 
  so 
  numerously 
  

   congregated 
  in 
  the 
  surface-membrane 
  are 
  not 
  colourless, 
  as 
  in 
  the 
  

   dry 
  specimen 
  from 
  Australia, 
  but 
  are 
  very 
  granular 
  and 
  of 
  brownish 
  

   colour; 
  they 
  measure 
  '008 
  millim. 
  in 
  average 
  diameter, 
  whereas 
  those 
  

   of 
  the 
  Australian 
  specimen 
  measure 
  about 
  '013 
  millim. 
  Having 
  re- 
  

   gard 
  to 
  these 
  diiferenees, 
  it 
  seems 
  to 
  me 
  not 
  unlikely 
  that 
  the 
  latter 
  

   specimen 
  is 
  specifically 
  distinct. 
  If 
  the 
  expression 
  " 
  hollow 
  " 
  of 
  Mr, 
  

   Carter's 
  original 
  description 
  denotes 
  fistulose, 
  the 
  present 
  specimen 
  

   differs 
  from 
  the 
  Ceylon 
  form 
  in 
  being 
  solid 
  (with 
  the 
  exception 
  of 
  

   the 
  usual 
  spaces 
  between 
  the 
  fibres). 
  

  

  Hah. 
  Seychelle 
  Islands, 
  12 
  fms. 
  

  

  Distribution. 
  Ceylon, 
  S.W. 
  Australia? 
  {Carter). 
  

  

  16. 
  Aplysina 
  pallasi. 
  

  

  ? 
  Spongia 
  membranosa, 
  pars, 
  Pallas, 
  Elcnch. 
  Zoojih. 
  p. 
  398. 
  

  

  Columnar 
  masses, 
  generally 
  less 
  than 
  an 
  inch 
  in 
  diameter 
  at 
  their 
  

   broadest 
  part, 
  and 
  tending 
  to 
  bifurcate 
  early 
  and 
  at 
  acute 
  angles 
  

   into 
  secondary 
  lobes 
  of 
  a 
  diameter 
  inferior 
  to 
  that 
  of 
  the 
  main 
  body 
  

   of 
  the 
  sponge 
  ; 
  the 
  ends 
  of 
  the 
  conuli 
  are 
  only 
  about 
  5 
  millim. 
  apart, 
  

   except 
  near 
  the 
  ends 
  of 
  the 
  lobes, 
  where 
  they 
  approach 
  each 
  other 
  

   more 
  closely 
  ; 
  a 
  single 
  or 
  bifurcate 
  purple-black 
  fibre 
  projects 
  about 
  

   1 
  millim. 
  from 
  the 
  end 
  of 
  almost 
  every 
  conulus, 
  replacing 
  the 
  blunt 
  

   compound 
  fibrillated 
  mass 
  which 
  is 
  characteristic 
  of 
  this 
  part 
  in 
  

   A. 
  membranosa 
  (see 
  Carter, 
  also 
  Part 
  I. 
  of 
  this 
  Report). 
  Vents 
  

   oval, 
  2-4 
  millim. 
  in 
  diameter, 
  few, 
  at 
  sides 
  of 
  terminal 
  lobes. 
  Con- 
  

   sistence 
  elastic, 
  very 
  compressible. 
  

  

  The 
  skeleton-fibre 
  is 
  much 
  branched 
  and 
  anastomoses 
  frequently, 
  

   and 
  ranges 
  in 
  diameter 
  from 
  about 
  "9 
  miUim, 
  in 
  main 
  fibres 
  to 
  as 
  

   little 
  as 
  "1 
  millim. 
  in 
  some 
  subdermal 
  twigs 
  ; 
  those 
  which 
  terminate 
  

   the 
  conuli 
  are 
  about 
  -3 
  millim. 
  in 
  average 
  diameter 
  ; 
  the 
  main 
  

   direction 
  is 
  upwards 
  and 
  outwards 
  ; 
  the 
  fibre 
  is 
  firm, 
  compact, 
  tough 
  ; 
  

  

  