﻿380 
  COLLECTIONS 
  FROM 
  MELANESIA. 
  

  

  millim. 
  respectively 
  ; 
  the 
  vertical 
  height, 
  viz. 
  to 
  base 
  of 
  uppermost 
  

   tube, 
  is 
  30 
  millim. 
  The 
  surface 
  is 
  darkish 
  umber-brown 
  iu 
  colour, 
  

   that 
  of 
  the 
  body 
  has 
  a 
  slightly 
  irregularly 
  wrinkled 
  parchment-like 
  

   appearance, 
  that 
  of 
  the 
  tubes 
  is 
  somewhat 
  wrinkled 
  in 
  the 
  direction 
  

   of 
  their 
  length, 
  and 
  one 
  of 
  them 
  presents 
  further 
  a 
  somewhat 
  

   shagreen-like 
  surface, 
  as 
  if 
  beset 
  with 
  very 
  short 
  conuli 
  (scarcely 
  1 
  

   millim. 
  high). 
  On 
  dissection 
  it 
  is 
  found 
  that 
  whereas 
  the 
  tubes 
  are 
  

   chiefly 
  (in 
  the 
  dry 
  state) 
  composed 
  of 
  a 
  horny 
  skeleton, 
  1-2 
  millim. 
  

   thick, 
  the 
  bodj^ 
  is 
  a 
  very 
  cavernous 
  mass 
  whose 
  bulk 
  is 
  largely 
  

   occupied 
  by 
  large 
  canals 
  or 
  chambers, 
  7-10 
  millim. 
  wide, 
  opening 
  

   directly 
  into 
  the 
  bases 
  of 
  the 
  similarly 
  wide 
  tubes, 
  the 
  skeleton 
  of 
  

   the 
  body 
  thus 
  consisting 
  of 
  trabecuhe 
  with 
  smooth, 
  rounded 
  surfaces 
  ; 
  

   the 
  subglobular 
  appearance 
  of 
  the 
  body 
  is 
  produced 
  by 
  the 
  bridging 
  

   over 
  of 
  the 
  spaces 
  between 
  these 
  trabeculse 
  by 
  a 
  brown 
  paper-like 
  

   membrane, 
  which 
  is 
  found 
  on 
  microscopic 
  examination 
  to 
  contain 
  

   no 
  horny 
  elements, 
  but 
  may 
  or 
  may 
  not 
  enclose 
  a 
  certain 
  quantity 
  

   of 
  minute 
  foreign 
  bodies 
  (sponge-spicules, 
  &c. 
  ). 
  

  

  Examining 
  the 
  skeleton 
  of 
  the 
  body 
  with 
  the 
  microscope, 
  I 
  find 
  

   from 
  vertical 
  sections 
  that 
  it 
  consists 
  of 
  a 
  close 
  reticulation 
  of 
  solid 
  

   cylindrical 
  horny 
  fibres, 
  distinguishable 
  as 
  : 
  — 
  (1) 
  primary, 
  stouter, 
  

   approximately 
  straight 
  and 
  parallel 
  to 
  each 
  other, 
  about 
  •07-'04 
  

   millim. 
  apart, 
  more 
  or 
  less 
  vertical 
  to 
  the 
  surface, 
  according 
  to 
  

   position, 
  thickness 
  about 
  •03-"04 
  millim. 
  ; 
  and 
  (2) 
  secondary, 
  similar 
  

   to 
  primary, 
  and 
  more 
  or 
  less 
  vertical 
  to 
  them, 
  but 
  often 
  very 
  ob- 
  

   liquely 
  placed, 
  thickness 
  about 
  -OlS-'OS 
  millim.; 
  distance 
  apart 
  very 
  

   variable, 
  from 
  -14 
  millim. 
  upwards. 
  Colour 
  of 
  fibre, 
  pale 
  to 
  medium 
  

   amber-colour. 
  Although 
  single 
  primary 
  fibres 
  do 
  not 
  appear 
  to 
  

   project 
  in 
  the 
  u 
  ay 
  strikingly 
  exhibited 
  in 
  the 
  more 
  typical 
  forms 
  of 
  

   Easpongia 
  officinalis, 
  where 
  they 
  project 
  well 
  above 
  the 
  general 
  sur- 
  

   face, 
  and 
  where 
  distinct 
  " 
  conuli 
  " 
  are 
  formed 
  by 
  the 
  dermis 
  around 
  

   their 
  bases, 
  yet 
  the 
  sections 
  show 
  an 
  aggregation 
  and 
  projection 
  of 
  

   the 
  general 
  skeleton 
  at 
  certain 
  points, 
  apparently 
  representing 
  conuli, 
  

   but 
  not 
  (in 
  the 
  present 
  state 
  of 
  the 
  sponge) 
  finding 
  expression 
  on 
  

   the 
  outer 
  surface 
  in 
  the 
  conical 
  eminences 
  which 
  usually 
  occur 
  here 
  

   in 
  Easpongia. 
  On 
  the 
  tubes 
  the 
  dermis 
  (immediately 
  below 
  a 
  mem- 
  

   branous 
  substance 
  containing 
  a 
  few 
  foreign 
  bodies) 
  is 
  formed 
  by 
  

   a 
  very 
  close 
  and 
  regular 
  horny 
  network, 
  composed 
  of 
  primary 
  

   and 
  secondary 
  fibres, 
  like 
  the 
  main 
  skeleton, 
  but 
  arranged 
  parallel, 
  

   instead 
  of 
  vertically, 
  to 
  the 
  surface. 
  The 
  proportions 
  of 
  the 
  fibres 
  

   are 
  about 
  the 
  same, 
  respectively, 
  as 
  those 
  of 
  the 
  main 
  skeleton, 
  but 
  

   the 
  primaries 
  are 
  only 
  -OS-'l 
  millim. 
  apart. 
  All 
  the 
  skeleton- 
  

   fibres 
  are 
  devoid 
  of 
  sand-core, 
  but 
  are 
  coated 
  (in 
  parts 
  strongly) 
  by 
  

   the 
  minute 
  strongly 
  refractive 
  brown 
  globules 
  which 
  Prof. 
  F. 
  E. 
  

   Schulze 
  has 
  considered 
  to 
  be 
  probably 
  of 
  Cryptogamous 
  affinities. 
  

  

  In 
  two 
  points 
  is 
  this 
  sponge 
  of 
  especial 
  interest, 
  viz. 
  (1) 
  in 
  the 
  

   almost 
  complete 
  subordination 
  of 
  the 
  general 
  arrangement 
  of 
  the 
  

   skeletal 
  framework 
  to 
  the 
  largely 
  developed 
  excretory 
  canals 
  ; 
  (2) 
  

   in 
  the 
  almost 
  total 
  suppression 
  of 
  the 
  "conuli." 
  A 
  further 
  point 
  

   is 
  the 
  absence 
  of 
  sand-cored 
  fibres. 
  I 
  was 
  at 
  first 
  inclined 
  to 
  sepa- 
  

   rate 
  it 
  generically 
  from 
  Euspongia, 
  as 
  having 
  the 
  large 
  maeandrine 
  

  

  