﻿466 
  COLLECTIONS 
  PROM 
  MELANESIA. 
  

  

  spirit-specimen 
  in 
  the 
  present 
  collection 
  is 
  in 
  reality 
  entirely 
  in- 
  

   crusting, 
  though 
  apparently 
  in 
  part 
  erect 
  and 
  cylindrical, 
  owing 
  to 
  its 
  

   growing 
  along 
  the 
  stem 
  of 
  a 
  Tubularian 
  Hydroid, 
  which 
  is 
  planted 
  

   on 
  the 
  back 
  of 
  the 
  crab 
  on 
  which 
  the 
  sponge-growth 
  commenced. 
  

   In 
  the 
  thicker 
  parts 
  of 
  the 
  sponge 
  the 
  s])icules 
  form 
  long 
  tracts, 
  

   about 
  6 
  spicules 
  in 
  breadth, 
  connected 
  by 
  interdigitation, 
  or 
  by 
  

   loose, 
  irregularly 
  crossing 
  spicular 
  tracts. 
  The 
  sarcode 
  is 
  subtrans- 
  

   parent, 
  somewhat 
  granular, 
  diffusely 
  stained 
  of 
  a 
  reddish-brown 
  

   colour. 
  The 
  spicules 
  in 
  both 
  the 
  type 
  and 
  the 
  present 
  specimen 
  

   measure 
  about 
  '25 
  milhm. 
  in 
  length 
  by 
  "0063 
  millim. 
  in 
  the 
  

   diameter 
  of 
  the 
  shaft. 
  

  

  Hah. 
  Port 
  Curtis, 
  Queensland, 
  7 
  fms. 
  

  

  Distrihution. 
  " 
  Probably 
  the 
  seas 
  of 
  America 
  " 
  (LamarcJc). 
  

  

  HYMENIACIDON. 
  

  

  Botverbank, 
  Mon. 
  Brit. 
  Spong. 
  i. 
  p. 
  191. 
  

  

  It 
  appears 
  to 
  me 
  that 
  Bowerbank's 
  genus 
  should 
  be 
  retained 
  for 
  

   those 
  sponges 
  with 
  spiculo-fibrous 
  skeleton 
  without 
  horny 
  matter, 
  

   but 
  in 
  which 
  primary 
  lines 
  are 
  distinguishable, 
  breaking 
  up 
  at 
  the 
  

   surface 
  and 
  more 
  or 
  less 
  within 
  the 
  sponge 
  into 
  tufts 
  (thus 
  forming 
  

   tracts 
  which 
  represent 
  the 
  secondary 
  fibres 
  of 
  llenieridiB), 
  and 
  in 
  

   which 
  there 
  is 
  but 
  one 
  form 
  of 
  spicule, 
  a 
  slender 
  skeleton 
  acuate 
  

   with 
  or 
  without 
  indications 
  of 
  incipient 
  spinulation. 
  Such 
  are 
  the 
  

   characters 
  derived 
  from 
  H. 
  canincida, 
  Bowerbank, 
  the 
  species 
  

   which 
  that 
  author 
  (I. 
  c.) 
  has 
  named 
  as 
  the 
  type 
  of 
  his 
  genus. 
  It 
  

   differs 
  from 
  Suberites 
  in 
  the 
  absence 
  of 
  distinct 
  spinulation 
  of 
  the 
  

   skeleton-spicule. 
  Schmidt 
  refers 
  this 
  sponge 
  to 
  Amorphina 
  (Spong. 
  

   Atl. 
  Geb. 
  p. 
  76), 
  although 
  he 
  assigns 
  in 
  his 
  diagnosis 
  {op. 
  cit. 
  

   p. 
  40) 
  acerate 
  spicules 
  to 
  that 
  genus, 
  which 
  belongs 
  to 
  the 
  family 
  

   Renicridfe, 
  whereas 
  Hymeniacidon 
  s. 
  str. 
  is 
  decidedly 
  a 
  Suberitid, 
  

   closely 
  allied 
  to 
  Stiberites. 
  

  

  05. 
  Hymeniacidon 
  caruncula, 
  Bowerhanl-. 
  

  

  A 
  broad, 
  horizontally 
  extended 
  specimen 
  from 
  a 
  crab's 
  back 
  ; 
  it 
  

   presents 
  a 
  few 
  short 
  mamillfe 
  on 
  its 
  free 
  surface. 
  The 
  form 
  of 
  the 
  

   spicules 
  and 
  arrangement 
  of 
  the 
  skeleton 
  are 
  fully 
  in 
  accordance 
  

   with 
  the 
  type 
  specimens 
  of 
  this 
  British 
  species. 
  The 
  spicules 
  mea- 
  

   sure 
  -23 
  to 
  -29 
  by 
  -0063 
  to 
  -OOS 
  millim. 
  ; 
  those 
  of 
  the 
  type 
  specimen 
  

   from 
  Tenby, 
  -19 
  to 
  -32 
  by 
  -0063 
  to 
  -008 
  millim. 
  

  

  Ifah. 
  Port 
  Jackson, 
  5-7 
  fms. 
  

  

  Distribidion. 
  British 
  seas 
  (Bowerhanl-). 
  

  

  96. 
  Hymeniacidon 
  agminata. 
  

   (Plate 
  XLI. 
  fig. 
  E 
  ; 
  Plate 
  XLIII. 
  figs. 
  /, 
  /.) 
  

  

  Aggregations 
  of 
  erect, 
  flexuous, 
  more 
  or 
  less 
  compressed 
  stems, 
  

   8 
  to 
  10 
  millim. 
  in 
  longest 
  diameter, 
  anastomosing; 
  subdividing 
  in 
  a 
  

  

  