﻿584 
  COLLECTIONS 
  FROM 
  THE 
  WESTERN 
  INDIAN 
  OCEAN. 
  

  

  Indian 
  Oceau 
  sliallow-water 
  faunas, 
  wo 
  find 
  16 
  out 
  of 
  the 
  56 
  spe- 
  

   cies 
  obtained 
  in 
  the 
  latter 
  region 
  to 
  be 
  identical 
  with 
  Australian 
  

   species, 
  a 
  proportion 
  to 
  the 
  whole 
  of 
  2 
  : 
  7, 
  or 
  28 
  per. 
  cent. 
  It 
  is 
  

   still 
  more 
  remarkable 
  to 
  find 
  that 
  of 
  these, 
  three 
  (viz. 
  Carterispongia 
  

   otahitica, 
  lotrocJiota 
  purpurea^ 
  Clathria 
  frondifera) 
  occur 
  abun- 
  

   dantly 
  in 
  both 
  places. 
  Had 
  Dr. 
  Coppinger's 
  researches 
  enabled 
  me 
  

   to 
  add 
  more 
  species 
  to 
  the 
  list, 
  I 
  have 
  little 
  doubt 
  that 
  still 
  greater 
  

   proofs 
  would 
  have 
  been 
  forthcoming 
  of 
  a 
  former 
  communication 
  

   between 
  these 
  two 
  widely 
  remote 
  districts. 
  As 
  might 
  almost 
  have 
  

   been 
  expected, 
  14 
  of 
  these 
  identical 
  species 
  occur 
  in 
  tropical 
  waters 
  

   in 
  Australia 
  also 
  (chiefiy 
  from 
  Torres 
  Straits 
  or 
  N. 
  Queeusland, 
  but 
  

   one 
  third 
  of 
  the 
  number 
  from 
  Port 
  Darwin). 
  

  

  Of 
  the 
  mutual 
  relations 
  of 
  the 
  different 
  localities 
  in 
  the 
  district 
  at 
  

   present 
  under 
  notice 
  I 
  have 
  little 
  to 
  say, 
  as 
  the 
  investigation 
  of 
  them 
  

   must 
  be 
  admitted 
  not 
  to 
  be 
  sufficient 
  for 
  a 
  satisfactory 
  comparison. 
  

   In 
  spite 
  of 
  its 
  much 
  more 
  westerly 
  longitude 
  and 
  of 
  its 
  separation 
  

   from 
  the 
  other 
  localities 
  by 
  much 
  open 
  sea 
  and 
  in 
  part 
  by 
  that 
  great 
  

   body 
  of 
  land, 
  the 
  island 
  of 
  Madagascar, 
  we 
  find 
  no 
  decided 
  difli'er- 
  

   ences 
  between 
  the 
  fauna 
  of 
  Mozambique 
  and 
  that 
  of 
  the 
  rest 
  of 
  the 
  

   district 
  ; 
  perhaps 
  the 
  Mozambique 
  current 
  partly 
  accounts 
  for 
  this. 
  

   On 
  the 
  other 
  hand, 
  we 
  find 
  that 
  7 
  out 
  of 
  the 
  13 
  species 
  recorded 
  

   from 
  the 
  Seychelles 
  were 
  not 
  found 
  in 
  the 
  other 
  localities: 
  probably 
  

   this 
  is 
  partly 
  duo 
  to 
  the 
  fact 
  that 
  here 
  alone 
  was 
  dredging 
  regularly 
  

   carried 
  out. 
  The 
  Amirante 
  Islands 
  have 
  the 
  greatest 
  number 
  of 
  

   species 
  (26). 
  

  

  Taxonowy. 
  — 
  Of 
  the 
  strictly 
  taxonomical 
  aspects 
  of 
  this 
  part 
  of 
  

   the 
  collection 
  little 
  has 
  to 
  be 
  said 
  which 
  has 
  not 
  been 
  already 
  said 
  in 
  

   the 
  Melanesian 
  portion 
  of 
  this 
  Ileport. 
  I 
  therefore 
  refer 
  those 
  in- 
  

   terested 
  in 
  the 
  subject 
  to 
  that 
  part 
  of 
  the 
  Ileport 
  for 
  most 
  questions 
  

   relating 
  to 
  the 
  general 
  zoology 
  of 
  the 
  Group 
  and 
  to 
  the 
  bearing 
  of 
  

   these 
  collections 
  on 
  classification 
  and 
  morphology. 
  The 
  full 
  descrip- 
  

   tions 
  of 
  new 
  species 
  and 
  genera 
  which 
  are 
  represented 
  also 
  in 
  the 
  

   Melanesian 
  collection 
  will 
  be 
  found 
  in 
  the 
  Ileport 
  on 
  that 
  collection 
  ; 
  

   they 
  are 
  not 
  noticed 
  at 
  length 
  in 
  this 
  place. 
  This 
  collection 
  from 
  

   the 
  Western 
  Indian 
  Ocean 
  is 
  remarkable 
  for 
  the 
  large 
  proportion 
  

   (31 
  per 
  cent, 
  of 
  the 
  whole) 
  which 
  the 
  Ceratose 
  sponges 
  bear 
  to 
  the 
  

   remaining 
  groups 
  : 
  this 
  is 
  no 
  doubt 
  largely 
  due 
  to 
  the 
  number 
  of 
  

   " 
  beach 
  specimens 
  " 
  included 
  in 
  the 
  collection, 
  representing, 
  as 
  such 
  

   specimens 
  naturally 
  would, 
  most 
  chiefiy 
  this 
  less 
  perishable 
  order. 
  

   This 
  proportion 
  probably 
  more 
  closely 
  resembles 
  that 
  which 
  would 
  

   be 
  obtained 
  in 
  the 
  South-west 
  of 
  Australia 
  than 
  that 
  found 
  by 
  the 
  

   ' 
  Alert 
  ' 
  in 
  the 
  Eastern 
  and 
  Northern 
  parts 
  of 
  that 
  continent 
  (which 
  

   was 
  about 
  18 
  per 
  cent.) 
  ; 
  but 
  the 
  species 
  are 
  smaller 
  than 
  the 
  gene- 
  

   rality 
  of 
  those 
  which 
  contribute 
  so 
  largely 
  to 
  the 
  shore 
  gatherings 
  

   at 
  Freeman 
  tie, 
  West 
  Australia. 
  

  

  No 
  species 
  of 
  the 
  order 
  Ceratosa 
  call 
  for 
  special 
  notice 
  here. 
  

   Of 
  the 
  MonactinelUd 
  SUicea 
  none 
  of 
  the 
  Families 
  are 
  strongly 
  re- 
  

   presented, 
  the 
  RenieridDS, 
  with 
  7 
  species, 
  being 
  the 
  most 
  abundant, 
  

   and 
  yet 
  maintaining 
  only 
  about 
  the 
  same 
  proportion 
  (15 
  per 
  cent.) 
  to 
  

   the 
  remainder 
  of 
  the 
  Sponges 
  as 
  in 
  the 
  Melanesian 
  collection. 
  

  

  