﻿604 
  COLLECTIONS 
  FROM 
  THE 
  WESTERN 
  INDIAN 
  OCEAN. 
  

  

  skeleton 
  — 
  primary 
  fibres 
  vertical 
  to 
  surface, 
  about 
  a 
  spicule's 
  length 
  

   apart, 
  containing 
  3 
  to 
  5 
  series 
  of 
  spicules 
  ; 
  secondaries 
  at 
  varioiis 
  

   angles 
  to 
  primaries, 
  spicules 
  1- 
  or 
  2-serial. 
  Sarcode 
  rich 
  brown, 
  

   subtransparent. 
  Spicules 
  acerate, 
  slightly 
  curved, 
  tapering 
  to 
  sharp 
  

   points 
  from 
  about 
  3 
  diameters 
  from 
  ends 
  ; 
  size 
  -17 
  by 
  '0085 
  millim. 
  

   It 
  branches 
  once 
  at 
  an 
  angle 
  of 
  about 
  35°, 
  its 
  total 
  length 
  is 
  50 
  

   millim. 
  (2 
  inches), 
  and 
  it 
  has 
  involved 
  a 
  mass 
  of 
  Polytrema, 
  Nulli- 
  

   pore, 
  cfec, 
  in 
  its 
  course 
  ; 
  the 
  Nullipore 
  bears 
  the 
  specimen 
  which 
  I 
  

   have 
  provisionally 
  assigned 
  to 
  Chondrilla 
  mixta, 
  Schulze. 
  

  

  In 
  the 
  character 
  of 
  the 
  skeleton 
  and 
  the 
  size 
  of 
  the 
  spicules 
  this 
  

   species 
  resembles 
  the 
  British 
  species 
  IsocUctya 
  simulans, 
  Bowcrbank, 
  

   and 
  Chcdina 
  montar/ui, 
  Johnston 
  ; 
  but 
  it 
  has 
  not 
  the 
  firm 
  texture 
  of 
  

   the 
  former, 
  nor 
  the 
  tubular 
  form 
  of 
  the 
  latter, 
  and 
  I 
  have 
  not 
  found 
  

   any 
  more 
  nearly 
  allied 
  species. 
  In 
  spite 
  of 
  its 
  repent 
  growth 
  I 
  have 
  

   assigned 
  it 
  to 
  Clialina 
  rather 
  than 
  to 
  CladochaUna, 
  the 
  proportions 
  

   of 
  the 
  spicules 
  and 
  the 
  character 
  of 
  the 
  fibre 
  agreeing 
  with 
  those 
  

   of 
  typical 
  Ghalince 
  (GhaUmda 
  of 
  Schmidt), 
  and 
  being 
  in 
  my 
  view 
  

   far 
  superior 
  as 
  diagnostic 
  characters 
  to 
  those 
  taken 
  only 
  from 
  the 
  

   external 
  habit. 
  

  

  Hab. 
  Marie 
  Louise 
  Island, 
  Amirante 
  group, 
  16-17 
  fms. 
  

  

  ACERVOCHALINA, 
  gen. 
  n. 
  

   See 
  Part 
  I., 
  p. 
  398, 
  of 
  this 
  Report. 
  

  

  21. 
  Acervochalina 
  finitima, 
  var. 
  

   Ohalina 
  finitima, 
  Schmidt, 
  Sponr/. 
  Atl. 
  Geb. 
  p. 
  33. 
  

  

  As 
  on 
  the 
  North- 
  Australian 
  margin 
  of 
  the 
  Indian 
  Ocean, 
  so 
  also 
  

   in 
  its 
  North-western 
  angle 
  this 
  otherwise 
  West-Indian* 
  species 
  

   seems 
  at 
  home. 
  Two 
  specimens 
  (the 
  one 
  25 
  millim., 
  the 
  other 
  40 
  

   millim. 
  in 
  extreme 
  diameter) 
  show 
  the 
  essential 
  characters 
  of 
  the 
  

   species 
  ; 
  the 
  vents, 
  however, 
  unlike 
  those 
  of 
  the 
  Australian 
  speci- 
  

   mens, 
  are 
  placed 
  on 
  the 
  margins 
  rather 
  than 
  the 
  upper 
  surface 
  of 
  

   the 
  sponge, 
  and 
  the 
  spicules 
  are 
  slightly 
  thicker 
  than 
  in 
  both 
  the 
  Aus- 
  

   tralian 
  and 
  W. 
  -Indian 
  forms, 
  viz. 
  '003 
  millim. 
  as 
  against 
  '0018 
  in 
  

   the 
  one 
  and 
  -0025 
  in 
  the 
  other. 
  

  

  Bed). 
  Seychelle 
  Islands, 
  4-12 
  fms. 
  

  

  Distributioti. 
  See 
  Part 
  I., 
  p. 
  399, 
  of 
  this 
  Report. 
  

  

  RENIERIDtE. 
  

  

  Besides 
  the 
  probably 
  almost 
  cosmopolitan 
  species 
  Tedania 
  digi- 
  

   tata, 
  I 
  find 
  that 
  several 
  of 
  the 
  representatives 
  of 
  this 
  generalized 
  

   Family 
  type 
  have 
  quite 
  a 
  European 
  fades, 
  and 
  I 
  have 
  identified 
  two 
  

   of 
  them 
  {Beniera 
  indistincta 
  and 
  rosea) 
  with 
  British 
  species 
  ; 
  but 
  

   two 
  members 
  of 
  the 
  same 
  genus, 
  now 
  described 
  for 
  the 
  first 
  time, 
  

   possess 
  external 
  characters 
  of 
  a 
  definiteness 
  and 
  singularity 
  unusual 
  

  

  * 
  Also 
  British, 
  if 
  Chalina 
  limhata, 
  Bowerbank, 
  is 
  identified 
  with 
  it. 
  

  

  