﻿98 
  On 
  Sponges 
  from 
  the 
  Guff 
  of 
  Manaar. 
  

  

  the 
  fact 
  that 
  flagellated 
  chambers 
  occur 
  scattered 
  between 
  the 
  

   individual 
  fibres 
  in 
  a 
  compound 
  fibre. 
  

  

  The 
  compound 
  fibres 
  are 
  very 
  stout 
  and 
  very 
  widely 
  sepa- 
  

   rated 
  from 
  one 
  another, 
  terminating 
  in 
  the 
  surface 
  conuli. 
  

   Each 
  compound 
  fibre 
  may 
  be 
  as 
  much 
  as 
  2 
  millim. 
  in 
  dia- 
  

   meter 
  in 
  the 
  dry 
  condition. 
  

  

  Mr. 
  Carter's 
  first 
  description 
  of 
  this 
  species 
  was 
  very 
  

   imperfect 
  ; 
  the 
  specimen 
  upon 
  which 
  it 
  was 
  founded 
  came 
  

   from 
  the 
  Gulf 
  of 
  Manaar. 
  His 
  second 
  description, 
  founded 
  on 
  

   a 
  specimen 
  from 
  Ceylon 
  and 
  one 
  from 
  Australia, 
  leaves 
  no 
  

   doubt 
  in 
  my 
  mind 
  as 
  to 
  the 
  correctness 
  of 
  my 
  identification 
  ; 
  

   but 
  I 
  think 
  it 
  very 
  probable 
  that 
  the 
  Australian 
  specimen 
  

   described 
  by 
  Mr. 
  Carter 
  belongs 
  to 
  a 
  different 
  species. 
  

  

  Aplysina 
  fusca 
  : 
  Carter. 
  

  

  1880. 
  Aplysina 
  fusca, 
  Carter, 
  Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  ser. 
  5, 
  

   vol. 
  vi. 
  p. 
  36 
  (vide 
  also 
  ser. 
  5, 
  vol. 
  viii. 
  p. 
  107). 
  

  

  I 
  refer 
  three 
  dry 
  specimens 
  present 
  in 
  the 
  collection 
  to 
  this 
  

   species. 
  They 
  are 
  necessarily 
  lobate 
  or 
  digitate, 
  and 
  the 
  sur- 
  

   face 
  is 
  beset 
  with 
  abundant 
  small, 
  sharp, 
  conical 
  eminences, 
  

   between 
  which 
  the 
  dermal 
  membrane 
  is 
  shrunk 
  clown. 
  The 
  

   surface 
  is 
  glabrous 
  or 
  subglabrous, 
  and 
  the 
  texture 
  in 
  the 
  dry 
  

   state 
  is 
  very 
  hard 
  and 
  incompressible, 
  membranous. 
  Colour 
  

   in 
  the 
  dry 
  state 
  dark 
  brown. 
  The 
  largest 
  specimen 
  is 
  195 
  

   millim. 
  high 
  by 
  about 
  160 
  millim. 
  in 
  greatest 
  breadth. 
  Two 
  

   of 
  the 
  specimens 
  are 
  cavernous 
  internally, 
  while 
  the 
  third 
  

   appears 
  to 
  be 
  much 
  more 
  solid 
  ; 
  I 
  do 
  not 
  think, 
  however, 
  

   that 
  there 
  is 
  any 
  specific 
  difference 
  between 
  them. 
  

  

  I 
  have 
  very 
  little 
  doubt 
  that 
  this 
  is 
  Mr. 
  Carter's 
  Aplysina 
  

   fusca 
  (especially 
  as 
  the 
  type 
  of 
  the 
  species 
  came 
  from 
  the 
  Gulf 
  

   of 
  Manaar), 
  although 
  I 
  have 
  not 
  had 
  the 
  opportunity 
  of 
  

   studying 
  the 
  type, 
  and 
  the 
  original 
  description 
  is 
  too 
  short 
  to 
  

   make 
  an 
  identification 
  as 
  reliable 
  as 
  might 
  be 
  desired. 
  In 
  

   Mr. 
  Carter's 
  second 
  account 
  of 
  the 
  species* 
  very 
  little 
  is 
  added 
  

   to 
  the 
  first. 
  

  

  EXPLANATION 
  OF 
  THE 
  PLATES. 
  

   Plate 
  III. 
  

  

  Fig. 
  1. 
  Petrosia 
  testudinaria, 
  from 
  the 
  neighbourhood 
  of 
  the 
  Tuticorin 
  

  

  Pearl 
  Banks. 
  Collected 
  by 
  Mr. 
  Thurston. 
  

   Fig. 
  2. 
  Petrosia 
  testudinaria, 
  from 
  Padau 
  Bay, 
  Mergui 
  Islands. 
  Collected 
  

  

  by 
  Dr. 
  Anderson. 
  

  

  * 
  Loc. 
  cit. 
  

  

  