﻿SPONGIIDA. 
  621 
  

  

  long, 
  from 
  those 
  of 
  the 
  latter 
  in 
  the 
  greater 
  relative 
  stoutness 
  of 
  

   the 
  basal 
  end 
  and 
  in 
  their 
  superior 
  length 
  (about 
  twice 
  that 
  of 
  

   fenestratus). 
  

  

  43. 
  Leucophlceus 
  fenestratus, 
  var. 
  (Plate 
  LIII. 
  fig. 
  A.) 
  

  

  See 
  Part 
  I., 
  p. 
  464, 
  of 
  this 
  Report. 
  

  

  A 
  spirit-specimen 
  and 
  some 
  fragments, 
  combining 
  the 
  external 
  

   characters 
  (viz. 
  erect, 
  laminate, 
  with 
  the 
  upper 
  portion 
  echinated 
  

   by 
  fine 
  upwardly 
  directed 
  processes, 
  and 
  with 
  smooth, 
  thick 
  basal 
  

   portion) 
  of 
  Leucophlceus 
  proteus, 
  mihi, 
  with 
  a 
  spiculatiou 
  of 
  the 
  

   character 
  of 
  L. 
  fenestratus. 
  The 
  outward 
  form 
  of 
  these 
  two 
  species 
  

   is, 
  however, 
  essentially 
  the 
  same, 
  and 
  the 
  differences 
  observed 
  in 
  

   this 
  point 
  are 
  mainly 
  individual. 
  The 
  present 
  specimen, 
  linking 
  

   the 
  Australian 
  to 
  the 
  more, 
  western 
  form, 
  has 
  decided 
  a 
  doubt 
  which 
  

   I 
  had 
  as 
  to 
  the 
  rightful 
  position 
  of 
  the 
  former 
  species 
  in 
  the 
  genus. 
  

   The 
  specimen 
  is 
  young, 
  measuring 
  5U 
  millim. 
  (2 
  inches) 
  in 
  height 
  by 
  

   (including 
  a 
  fragment 
  which 
  appears 
  to 
  belong 
  to 
  it) 
  35 
  millim. 
  in 
  

   greatest 
  diameter 
  (that 
  of 
  the 
  base). 
  It 
  consists 
  of 
  a 
  massive 
  basal 
  

   portion, 
  enclosing 
  a 
  large 
  quantity 
  of 
  calcareous 
  matter 
  (Nullipore, 
  

   &c.), 
  and 
  of 
  a 
  slender 
  flattened 
  expansion, 
  20 
  millim. 
  high, 
  10 
  millim. 
  

   broad, 
  4 
  millim. 
  thick, 
  arising 
  from 
  it 
  ; 
  the 
  base 
  is 
  glabrous, 
  the 
  sur- 
  

   face 
  being 
  formed 
  by 
  a 
  thin, 
  transparent 
  membrane, 
  loosely 
  attached. 
  

   Main 
  skeleton 
  consisting 
  of 
  compact 
  spiculo-fibres 
  about 
  10 
  spicules 
  

   broad, 
  and 
  of 
  broad 
  expansions 
  containing 
  a 
  large 
  number 
  of 
  spicules 
  

   loosely 
  aggregated. 
  There 
  is 
  no 
  sign 
  of 
  horny 
  uniting 
  substance. 
  

   Spicules 
  tapering 
  gradually 
  from 
  near 
  the 
  centre, 
  or 
  about 
  mid- 
  

   way 
  between 
  the 
  centre 
  and 
  base, 
  to 
  a 
  smaller 
  rounded 
  basal 
  ex- 
  

   tremity, 
  which 
  is 
  about 
  one 
  half 
  the 
  maximum 
  diameter 
  of 
  the 
  

   spicule 
  ; 
  spicule 
  tapering 
  rapidly 
  to 
  moderately 
  sharp 
  point 
  from 
  two 
  

   or 
  three 
  diameters 
  from 
  apex; 
  size 
  of 
  spicule 
  -8 
  to 
  1-1 
  millim. 
  bv 
  

   •02 
  to 
  -032 
  millim. 
  (a 
  considerable 
  range 
  for 
  only 
  two 
  or 
  three 
  speci- 
  

   mens). 
  The 
  spicule 
  has 
  thus 
  practically 
  the 
  same 
  form 
  as 
  in 
  both 
  

   the 
  Australian 
  varieties, 
  and 
  in 
  its 
  range 
  ot 
  dimensions 
  connects 
  the 
  

   two. 
  The 
  colour, 
  which 
  is 
  purple, 
  as 
  in 
  L. 
  proteus, 
  but 
  pale, 
  is 
  

   possibly 
  derived 
  from 
  some 
  purple 
  sponges 
  which 
  had 
  been 
  kept 
  in 
  

   the 
  same 
  vessel. 
  

  

  Hab. 
  Providence 
  Keef, 
  Mascarene 
  group, 
  24 
  fms. 
  

  

  SUBERITID^. 
  

  

  The 
  few 
  species 
  received 
  illustrate 
  well 
  the 
  wide 
  affinities 
  of 
  

   Sponges 
  from 
  this 
  district. 
  Tethya, 
  s. 
  str., 
  which 
  was 
  not 
  found 
  on 
  

   the 
  northern 
  and 
  eastern 
  coasts 
  of 
  Austraha, 
  but 
  which 
  is 
  recorded 
  

   by 
  Bowerbank 
  from 
  the 
  west 
  coa^t, 
  appears 
  here 
  also, 
  in 
  the 
  shape 
  

   of 
  a 
  species 
  described 
  by 
  Bowerbank 
  from 
  Freemantle. 
  Of 
  the 
  two 
  

   new 
  species 
  of 
  S/nrasirella, 
  IS. 
  transitoria 
  appears 
  to 
  throw 
  fresh 
  

   light 
  on 
  the 
  homologies 
  of 
  the 
  spinispirular 
  spicule. 
  The 
  Vioa 
  

   is 
  identical 
  with 
  a 
  Mediterranean 
  species. 
  

  

  