﻿SPONGHDA. 
  599 
  

  

  deration 
  of 
  the 
  large 
  size 
  of 
  a 
  specimen 
  from 
  Mauritius 
  (probably 
  

   from 
  deep 
  water) 
  in 
  the 
  National 
  collection 
  : 
  this 
  measures 
  170 
  by 
  

   100 
  millim. 
  in 
  greatest 
  length 
  and 
  breadth 
  ; 
  the 
  primary 
  fibres 
  

   project 
  strongly 
  from 
  the 
  paper-like 
  dermis, 
  and 
  the 
  conuli 
  are 
  5-10 
  

   millim. 
  apart 
  ; 
  the 
  fibre 
  shows 
  just 
  the 
  branching 
  arrangement 
  

   described 
  in 
  0. 
  colhctrix. 
  The 
  species 
  now 
  to 
  be 
  described 
  agrees 
  

   remarkably 
  in 
  general 
  characters 
  with 
  the 
  same 
  species, 
  and 
  is 
  also 
  

   sufficiently 
  large 
  to 
  be 
  called 
  adult. 
  

  

  14. 
  Oligoceras 
  conulosum. 
  

  

  Incrusting, 
  strongly 
  flattened 
  from 
  above 
  downwards, 
  forming 
  a 
  

   leathery 
  crust, 
  but 
  occasionally 
  throwing 
  out 
  flattened, 
  pointed, 
  free 
  

   lobes 
  from 
  lateral 
  margin 
  ; 
  strongly 
  hirsute 
  above 
  with 
  the 
  very 
  

   prominent, 
  slender, 
  and 
  pointed 
  conuli, 
  1-2 
  millim. 
  high, 
  2-4 
  millim. 
  

   apart 
  at 
  tips 
  ; 
  terminated 
  by 
  the 
  single 
  or 
  (more 
  rarely) 
  multiple 
  

   ends 
  of 
  primary 
  fibres, 
  which 
  stand 
  out 
  about 
  1 
  millim, 
  beyond 
  the 
  

   dermis. 
  Surface 
  between 
  ends 
  of 
  conuli 
  forming 
  a 
  series 
  of 
  slightly 
  

   concave 
  spaces 
  (in 
  spirit), 
  smooth, 
  glabrous, 
  of 
  leathery 
  appearance. 
  

   Colour 
  in 
  spirit 
  dull 
  putty-colour 
  to 
  pale 
  grey 
  ; 
  consistence 
  (when 
  

   occupied 
  by 
  Spongiojyhaga) 
  flexible, 
  tough. 
  Main 
  skeleton 
  — 
  pri- 
  

   mary 
  fibre 
  occasionally 
  branched 
  at 
  apex, 
  about 
  '17 
  to 
  "27 
  millim. 
  

   in 
  diameter 
  ; 
  axis 
  composed 
  of 
  closely 
  packed 
  foreign 
  bodies, 
  occupying 
  

   from 
  1^ 
  to 
  y^^ 
  of 
  the 
  entire 
  diameter 
  : 
  secondary 
  fibres 
  apparently 
  

   absent. 
  Dermal 
  skeleton 
  composed 
  of 
  irregularly 
  arranged 
  fibres, 
  

   chiefly 
  straight 
  and 
  parallel 
  to 
  each 
  other, 
  varying 
  in 
  composition 
  

   from 
  an 
  almost 
  entirely 
  horny 
  to 
  an 
  almost 
  entirely 
  sandy 
  state 
  ; 
  

   diameter 
  about 
  '14 
  to 
  '35 
  millim., 
  meshes 
  about 
  "35 
  millim. 
  wide 
  ; 
  a 
  

   small 
  quantity 
  of 
  free 
  foreign 
  bodies 
  is 
  to 
  be 
  found 
  interspersed 
  in 
  

   the 
  intervals 
  between 
  the 
  fibres. 
  Tissues 
  between 
  fibres 
  of 
  main 
  

   skeleton 
  also 
  containing 
  a 
  considerable 
  proportion 
  (about 
  one 
  fourth) 
  

   of 
  free, 
  small, 
  foreign 
  bodies. 
  Horny 
  matter 
  of 
  fibre 
  normally 
  pale 
  

   amber-yellow, 
  transparent. 
  Parenclayma 
  very 
  pale 
  brown, 
  trans- 
  

   parent. 
  

  

  ffab. 
  Glorioso 
  Islands, 
  7-10 
  fms. 
  ; 
  bottom, 
  sand 
  and 
  coral. 
  

  

  A 
  single 
  specimen 
  in 
  spirit, 
  60 
  millim. 
  in 
  extreme 
  diameter 
  at 
  

   base, 
  8 
  millim. 
  in 
  greatest 
  thickness 
  of 
  the 
  same 
  ; 
  the 
  lateral 
  lobe 
  

   (which 
  seems 
  to 
  have 
  been 
  decumbent) 
  is 
  30 
  millim. 
  high, 
  14 
  by 
  4 
  

   millim. 
  in 
  basal 
  diameter. 
  Tissues 
  infested 
  by 
  a 
  Sponglophaga 
  

   (Carter) 
  — 
  head 
  oval 
  or 
  subpyriform, 
  long 
  diameter 
  '095 
  to 
  '013 
  

   millim., 
  short 
  diameter 
  "006 
  to 
  -0095 
  millim. 
  ; 
  filament, 
  diameter 
  

   •004 
  to 
  "005 
  millim. 
  — 
  which 
  has 
  partly 
  destroyed 
  the 
  horny 
  matter 
  

   of 
  the 
  fibre, 
  and 
  forms 
  sheets 
  in 
  the 
  mesoderm. 
  

  

  The 
  apparent 
  total 
  absence 
  of 
  secondary 
  fibres 
  is 
  perhaps 
  due 
  to 
  

   youth 
  or 
  the 
  ravages 
  of 
  the 
  parasite 
  : 
  the 
  arrangement 
  of 
  the 
  skeleton 
  

   is 
  that 
  ascribed 
  by 
  F. 
  E. 
  Schulze 
  to 
  Oligoceras 
  colhctrix, 
  Schulze, 
  from 
  

  

  Oligoceras 
  to 
  possess 
  in 
  parts 
  the 
  ordinary 
  reticulate 
  arrangement 
  found 
  in 
  

   Cacospongia, 
  &c. 
  This 
  observation 
  seriously 
  militates 
  against 
  its 
  generic 
  

   distinctness. 
  

  

  