﻿384 
  COLLECTIONS 
  FROM 
  MELANESIA. 
  

  

  fibres, 
  was 
  also 
  obtained. 
  So 
  far 
  as 
  the 
  vents 
  can 
  be 
  made 
  out, 
  

   they 
  are 
  numerous, 
  and 
  occur 
  in 
  a 
  zone 
  just 
  inside 
  the 
  margin 
  of 
  the 
  

   cup. 
  The 
  primary 
  fibres 
  are 
  very 
  stout 
  at 
  the 
  margin 
  of 
  cup, 
  viz. 
  

   about 
  '5 
  to 
  '7 
  millim. 
  in 
  diameter, 
  exclusive 
  of 
  their 
  sandy 
  coating. 
  

  

  Hah. 
  Port 
  Molle, 
  Uuecnsland, 
  between 
  tide-marks 
  ; 
  Arafura 
  Sea, 
  

   off 
  north 
  coast 
  of 
  Australia, 
  32-36 
  fms. 
  (the 
  larger 
  specimen). 
  

  

  The 
  external 
  position 
  of 
  the 
  sand 
  on 
  the 
  fibres 
  recalls 
  Manricea, 
  

   Carter 
  (xinn. 
  & 
  Mag. 
  N. 
  H. 
  (4) 
  xx. 
  p. 
  174), 
  for 
  which 
  see 
  below 
  

   (Carterisponr/ia). 
  In 
  this 
  point, 
  and 
  in 
  the 
  arrangement, 
  propor- 
  

   tions, 
  and 
  other 
  characters 
  of 
  the 
  skeleton-fibres, 
  the 
  species 
  strongly 
  

   resembles 
  Bowerhank's 
  PolyJihro.<i2)Oiic/iaJlnbenif 
  era 
  (Proc. 
  Zool. 
  Soc. 
  

   1877, 
  p. 
  459), 
  from 
  the 
  north 
  of 
  Xew 
  Guinea: 
  but 
  the 
  shape 
  of 
  

   that 
  species 
  is 
  entirely 
  different, 
  being 
  fan-shaped 
  and 
  quite 
  thin, 
  

   aud 
  the 
  vents 
  are 
  described 
  as 
  inconspicuous. 
  

  

  7. 
  Stelospongus 
  implexus. 
  (Plate 
  XXXIX. 
  fig. 
  B.) 
  

  

  Stipitate, 
  with 
  short, 
  usually 
  flattened 
  or 
  compound 
  pedicel 
  ; 
  sub- 
  

   turbinate, 
  the 
  wall 
  usually 
  proliferating 
  inwards, 
  and 
  then 
  anasto- 
  

   mosing, 
  forming 
  a 
  chambered 
  cuj), 
  with 
  thin 
  walls 
  (2 
  to 
  4 
  millim. 
  

   thick). 
  Outer 
  and 
  inner 
  surfaces 
  even, 
  tlie 
  outer 
  marked 
  strongly, 
  

   in 
  the 
  dry 
  state, 
  by 
  longitudinal 
  projecting 
  skeleton-ridges, 
  the 
  inner 
  

   slightly 
  so 
  by 
  the 
  subrectangular 
  superficial 
  skeleton-network. 
  Vents? 
  

   Texture 
  in 
  dry 
  state 
  harsh, 
  but 
  yielding 
  and 
  rather 
  brittle. 
  Colour 
  

   pale 
  greyish 
  brown. 
  

  

  Main 
  skeleton 
  at 
  some 
  distance 
  below 
  surface 
  consisting 
  of 
  stout 
  

   fascicles 
  of 
  primary 
  fibres, 
  vertical 
  to 
  the 
  surface, 
  about 
  -17 
  millim. 
  in 
  

   diameter 
  (the 
  individual 
  fibrils 
  about 
  -025 
  millim.), 
  densely 
  coated 
  

   by 
  a 
  mosaic 
  of 
  small 
  sand-grains, 
  connected 
  towards 
  the 
  surface 
  by 
  

   secondary 
  lines 
  of 
  similar 
  structure, 
  about 
  -07 
  millim. 
  in 
  diameter 
  ; 
  

   the 
  primaries, 
  when 
  near 
  the 
  surface, 
  become 
  cored 
  with 
  foreign 
  

   bodies, 
  and 
  become 
  more 
  condensed, 
  sometimes 
  forming 
  but 
  a 
  single 
  

   fibre, 
  "1 
  millim. 
  thick. 
  Dermal 
  skeleton 
  on 
  exterior 
  of 
  cup 
  consist- 
  

   ing 
  of 
  parallel 
  single 
  fibres 
  -1 
  to 
  '17 
  millim. 
  in 
  diameter, 
  coated, 
  

   and 
  to 
  some 
  extent 
  cored, 
  by 
  small 
  foreign 
  bodies 
  : 
  intermediate 
  mem- 
  

   brane 
  sparsely 
  strewn 
  with 
  similar 
  foreign 
  bodies. 
  Sarcode 
  pale 
  

   amber-yellow, 
  transparent. 
  Skeleton-fibre 
  very 
  pale 
  yellow 
  in 
  the 
  

   small, 
  deep 
  amber 
  in 
  the 
  large 
  fibres. 
  

  

  Hah. 
  Port 
  Molle, 
  Queensland, 
  coral-reef. 
  

  

  This 
  species 
  differs 
  in 
  external 
  form 
  from 
  all 
  those 
  described 
  by 
  

   Hyatt 
  (Mem. 
  Post. 
  Soc. 
  ii.). 
  In 
  the 
  only 
  cup-shaped 
  form 
  alluded 
  

   to 
  by 
  Schmidt 
  (Atl. 
  Geb. 
  p. 
  29) 
  the 
  walls 
  would 
  appear 
  to 
  be 
  rela- 
  

   tively 
  much 
  thicker, 
  as 
  is 
  the 
  case 
  in 
  S. 
  excavatus, 
  mihi 
  (stqird). 
  

   This 
  form 
  approaches 
  that 
  species 
  closely, 
  the 
  skeleton- 
  and 
  surface- 
  

   structure 
  being 
  almost 
  identical 
  in 
  the 
  two 
  cases 
  ; 
  but 
  the 
  well- 
  

   marked 
  tendency 
  to 
  proliferation 
  and 
  formation 
  of 
  secondary 
  cavities 
  

   in 
  the 
  cup 
  and 
  the 
  shortness 
  of 
  the 
  pedicel 
  further 
  distinguish 
  /S'. 
  im- 
  

   plexus. 
  This 
  is 
  a 
  small 
  species 
  : 
  all 
  four 
  specimens 
  obtained 
  (which 
  

   were 
  dry) 
  were 
  in 
  their 
  natural 
  state 
  between 
  40 
  and 
  60 
  millim. 
  

   high, 
  and 
  between 
  40 
  and 
  60 
  millim. 
  in 
  greatest 
  diameter 
  at 
  the 
  

   top. 
  

  

  