﻿the 
  Gulf 
  of 
  Manaar. 
  91 
  

  

  Dr. 
  Norman 
  was 
  misled 
  by 
  Bowerbank's 
  account 
  ; 
  and 
  while 
  

   he 
  shows 
  that 
  the 
  species 
  cannot 
  be 
  assigned 
  to 
  the 
  genus 
  

   Haltpht/sema, 
  he 
  proposes 
  for 
  it 
  the 
  new 
  generic 
  name 
  Aulo- 
  

   spongus 
  *. 
  It 
  is 
  unnecessary, 
  however, 
  to 
  erect 
  a 
  new 
  genus 
  

   for 
  the 
  reception 
  of 
  this 
  sponge, 
  which 
  falls 
  very 
  well 
  under 
  

   Axinella. 
  

  

  We 
  have 
  here 
  one 
  of 
  the 
  most 
  remarkable 
  cases 
  of 
  com- 
  

   mensalism 
  known 
  amongst 
  sponges. 
  

  

  Ciocalypta 
  Tyleri, 
  Bowerbank, 
  var. 
  manaarensis, 
  nov. 
  

  

  1873. 
  Ciocalypta 
  Tyleri, 
  Bowerbank, 
  Proc. 
  Zool. 
  Soc. 
  Lond. 
  p. 
  21, 
  

   pi. 
  iv. 
  figs. 
  9-12. 
  

  

  Of 
  this 
  variety 
  there 
  are 
  in 
  the 
  collection 
  two 
  good 
  dry 
  

   specimens 
  and 
  one 
  of 
  the 
  digitate 
  processes 
  preserved 
  in 
  

   spirit. 
  The 
  external 
  form 
  of 
  the 
  specimens 
  closely 
  resembles 
  

   Dr. 
  Bowerbank's 
  figure. 
  The 
  surface 
  of 
  the 
  digitate 
  pro- 
  

   cesses 
  is 
  much 
  corrugated. 
  The 
  colour 
  in 
  the 
  living 
  state 
  

   was 
  white, 
  and 
  it 
  is 
  also 
  dirty 
  yellowish 
  white 
  in 
  the 
  dry 
  state 
  

   and 
  in 
  spirit. 
  The 
  taller 
  of 
  the 
  two 
  specimens 
  is 
  55 
  millim. 
  

   high 
  and 
  47 
  millim. 
  in 
  diameter 
  at 
  the 
  base, 
  which 
  is 
  approxi- 
  

   mately 
  circular 
  ; 
  it 
  bears 
  about 
  a 
  dozen 
  digitate 
  processes, 
  

   springing 
  from 
  the 
  cushion-shaped 
  base, 
  and 
  sometimes 
  

   anastomosing, 
  but 
  never 
  branching. 
  The 
  digitate 
  processes 
  

   are 
  about 
  8 
  millim. 
  in 
  diameter 
  at 
  the 
  base. 
  

  

  The 
  skeleton 
  is 
  arranged 
  as 
  usual 
  in 
  the 
  genus, 
  with 
  a 
  

   dense 
  central 
  axis, 
  from 
  which 
  arise 
  short 
  columns 
  supporting 
  

   the 
  dermal 
  membrane 
  at 
  their 
  outer 
  ends. 
  

  

  Spicules. 
  — 
  Slightly 
  curved 
  and 
  very 
  gradually 
  and 
  sharply 
  

   pointed 
  oxea, 
  resembling 
  those 
  of 
  Halichondria 
  panicea 
  ; 
  

   occasionally 
  an 
  odd 
  stylote 
  form 
  may 
  be 
  observed 
  amongst 
  

   the 
  larger 
  ones. 
  They 
  vary 
  very 
  greatly 
  in 
  size 
  ; 
  in 
  the 
  

   dermal 
  membrane 
  they 
  are 
  small 
  and 
  slender, 
  measuring 
  as 
  a 
  

   rule 
  about 
  0*3 
  by 
  - 
  007 
  millim., 
  but 
  with 
  a 
  wide 
  range 
  of 
  

   variation, 
  though 
  never 
  attaining 
  to 
  nearly 
  the 
  dimensions 
  of 
  

   those 
  in 
  the 
  central 
  axis 
  ; 
  in 
  the 
  axis 
  also 
  they 
  vary 
  greatly, 
  

   measuring 
  up 
  to 
  about 
  1*25 
  by 
  0*024 
  millim., 
  though 
  this 
  

   extreme 
  size 
  appears 
  to 
  be 
  reached 
  only 
  rarely, 
  the 
  average 
  

   size 
  of 
  the 
  full-grown 
  spicule 
  being 
  about 
  0'8 
  by 
  0*011 
  

   millim. 
  

  

  This 
  variety 
  differs 
  from 
  the 
  types 
  of 
  the 
  species 
  in 
  the 
  

   presence 
  of 
  the 
  very 
  large 
  oxea 
  in 
  the 
  central 
  axis. 
  

  

  The 
  species 
  has 
  hitherto 
  been 
  obtained 
  from 
  Port 
  Eliza- 
  

  

  * 
  hoc. 
  cit. 
  

  

  7* 
  

  

  