﻿590 
  COILECTIOKS 
  FROM 
  THE 
  "WESTERN 
  INDIAN 
  OCEAN. 
  

  

  CERATOSA. 
  

  

  This 
  Order 
  is 
  well 
  represented, 
  viz. 
  by 
  17 
  species 
  (or 
  31 
  per 
  cent.), 
  

   as 
  the 
  tropical 
  position 
  of 
  the 
  localities 
  would 
  load 
  one 
  to 
  expect. 
  

   Carterisjjongia 
  is 
  the 
  dominant 
  type, 
  and 
  probably 
  more 
  abundant 
  

   here 
  in 
  species, 
  and 
  not 
  less 
  so 
  in 
  individuals, 
  than 
  in 
  any 
  other 
  part 
  

   of 
  the 
  world 
  ; 
  the 
  two 
  aberrant 
  Hippospongice 
  described 
  are 
  also 
  

   wonderfully 
  abundant. 
  A 
  Mediterranean 
  type, 
  Oligoceras, 
  is 
  for 
  

   the 
  first 
  time 
  recorded 
  from 
  the 
  Indo-Pacific 
  area. 
  

  

  SPONGIIDJE. 
  

   1. 
  Cacospongia 
  cavernosa. 
  

  

  Schmidt, 
  Sjiong. 
  Adr. 
  Meer. 
  p. 
  28 
  ; 
  F. 
  E. 
  Schulze, 
  Zeitsch. 
  wiss. 
  Zool. 
  

   xxxii. 
  p. 
  653, 
  pis. 
  xxxiv. 
  fig. 
  11, 
  pi. 
  xxxv. 
  fig. 
  17, 
  pi. 
  xxxvii. 
  figs. 
  7, 
  13. 
  

  

  In 
  spite 
  of 
  the 
  remarkable 
  geographical 
  distribution 
  which 
  is 
  

   involved 
  by 
  identifying 
  the 
  present 
  specimens 
  with 
  a 
  Mediter- 
  

   ranean 
  species, 
  the 
  identity 
  seems 
  to 
  me 
  fairly 
  certain. 
  The 
  cha- 
  

   racters 
  agree 
  well 
  with 
  those 
  given 
  by 
  Schmidt 
  and 
  with 
  Schulze's 
  

   figures. 
  The 
  conuli 
  are 
  2-4 
  millim. 
  high 
  and 
  about 
  5 
  millim. 
  

   apart, 
  in 
  spirit 
  ; 
  the 
  colour 
  in 
  spirit 
  is 
  dark 
  grey 
  ; 
  the 
  primary 
  

   fibres 
  measure 
  •18-*24 
  millim. 
  in 
  diameter. 
  Vents 
  numerous, 
  2-3 
  

   millim. 
  in 
  diameter, 
  grouped 
  at 
  summits 
  of 
  the 
  lobes 
  formed 
  by 
  the 
  

   sponge. 
  Eepresented 
  here 
  by 
  semi-repent 
  masses 
  growing 
  between 
  

   and 
  over 
  stones 
  or 
  rocks, 
  and 
  sending 
  up 
  cylindrical 
  lobes 
  18-25 
  

   millim. 
  in 
  diameter, 
  which 
  tend 
  to 
  divide 
  above 
  and 
  to 
  attach 
  foreign 
  

   bodies 
  to 
  themselves. 
  The 
  skeleton 
  shows 
  an 
  irregularly 
  rectangular 
  

   arrangement 
  of 
  the 
  fibres 
  similar 
  to 
  that 
  figured 
  by 
  Schulze. 
  

  

  Hab. 
  Seychelles 
  Islands, 
  4-12 
  fms. 
  

  

  Distribution. 
  Adriatic 
  (Schmidt 
  and 
  Schulze) 
  ; 
  Algiers 
  {Schmidt). 
  

  

  2. 
  Hippospongia 
  intestinalis, 
  var. 
  (Plate 
  LIII. 
  fig. 
  D.) 
  

  

  Spongia 
  intestiiiafis, 
  Lnmarclc, 
  Ann. 
  Mus. 
  Hist. 
  Nat. 
  xx. 
  p. 
  434. 
  

   Spongelia 
  velata, 
  Hyatt, 
  Mem. 
  Bost. 
  Soc. 
  ii. 
  p. 
  634, 
  pi. 
  xvii. 
  fig. 
  8. 
  

  

  The 
  tortuous 
  perforated 
  tubes 
  are 
  sometimes 
  single, 
  but 
  sometimes 
  

   form 
  confused 
  reticulate 
  masses 
  (see 
  fig. 
  D, 
  Plate 
  LIII.), 
  which, 
  when 
  

   the 
  soft 
  tissues 
  are 
  dried 
  on 
  them, 
  have 
  a 
  very 
  different 
  appearance, 
  

   and 
  as 
  such 
  have 
  been 
  described 
  under 
  the 
  above 
  separate 
  name 
  by 
  

   Hyatt, 
  whose 
  figure 
  well 
  represents 
  this 
  state 
  ; 
  their 
  diameter 
  varies 
  

   from 
  about 
  5 
  to 
  20 
  millim. 
  The 
  surface 
  is 
  covered 
  in 
  fresh 
  specimens 
  

   by 
  a 
  delicate 
  diteliform 
  network, 
  as 
  stated 
  by 
  Hyatt, 
  and 
  as 
  found 
  

   in 
  our 
  specimens 
  ; 
  the 
  sarcodo 
  in 
  spirit 
  is 
  opaque 
  pale 
  brownish 
  

   yellow. 
  The 
  species 
  must 
  be 
  nearly 
  related 
  to 
  Hircinia 
  clathrata. 
  

   Carter 
  ; 
  but 
  that 
  species 
  would 
  seem 
  to 
  assume 
  a 
  decidedly 
  vertical 
  

   growth, 
  whereas 
  this 
  has 
  the 
  appearance 
  of 
  being 
  subrepent. 
  

   Mr. 
  Carter's 
  description 
  of 
  that 
  form 
  speaks 
  of 
  sand-cored 
  fibre 
  as 
  

   only 
  occurring 
  here 
  and 
  there, 
  esjiecially 
  near 
  the 
  surface, 
  whereas 
  

   in 
  H. 
  intestinalis 
  long 
  straight 
  primary 
  fibres 
  cored 
  with 
  foreign 
  

  

  