﻿66 
  A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  

  

  {b.) 
  Arrangement 
  of 
  the 
  Skeleton. 
  — 
  The 
  skeleton 
  consists 
  of 
  triradiate 
  and 
  

   qiiadriradiate 
  spicules 
  arranged 
  irregularly 
  in 
  one 
  or 
  more 
  layers 
  in 
  the 
  thickness 
  of 
  

   the 
  mesoderm. 
  

  

  (f.) 
  The 
  Spindes 
  (PL 
  XL, 
  Fig. 
  4). 
  

  

  (1) 
  Triradiates. 
  — 
  Eegular. 
  Dermal. 
  Large 
  and 
  stout; 
  rays 
  conical 
  or 
  

   slightly 
  fusiform, 
  gradually 
  sharp-pointed, 
  measuring 
  about 
  0-2 
  by 
  0-028 
  

   mm. 
  Deep. 
  Kays 
  long 
  and 
  rather 
  slender, 
  fairly 
  gradually 
  and 
  sharply 
  

   pointed, 
  measuring 
  about 
  0'14 
  by 
  0*008 
  mm. 
  

  

  (2) 
  Onadriradiates. 
  — 
  These 
  spicules 
  are 
  abundant, 
  they 
  resemble 
  the 
  deep 
  

  

  triradiates 
  but 
  have 
  a 
  feebly 
  developed 
  apical 
  ray. 
  

  

  iyd.) 
  Affinities. 
  — 
  I 
  at 
  first 
  regarded 
  this 
  sponge 
  as 
  a 
  variety 
  of 
  Leitcosolenia 
  

   wilsoni, 
  which 
  it 
  closely 
  resembles 
  in 
  external 
  appearance 
  and 
  in 
  canal 
  system, 
  but 
  

   considering 
  the 
  differences 
  in 
  spiculation 
  it 
  is 
  perhaps 
  better 
  for 
  the 
  present 
  to 
  regard 
  

   it 
  as 
  a 
  distinct 
  species. 
  The 
  specimen 
  contains 
  numerous 
  unsegmented 
  ova*, 
  in 
  the 
  

   same 
  position 
  as 
  the 
  embryos 
  in 
  L. 
  wilsoni, 
  but 
  there 
  is 
  no 
  special 
  epithelial 
  capsule 
  

   visible 
  around 
  them, 
  perhaps 
  this 
  is 
  developed 
  only 
  after 
  segmentation. 
  

  

  {e.) 
  Locality.~^eM 
  Port 
  Phillip 
  Heads. 
  (Coll. 
  J. 
  B. 
  Wilson.) 
  

  

  Section 
  3. 
  Radiata. 
  

  

  The 
  sponge 
  consists 
  of 
  a 
  single 
  central 
  Ascon-tube 
  from 
  which 
  smaller 
  tubes 
  

   are 
  budded 
  off 
  radially. 
  

  

  14. 
  Leucosolenia 
  tripodifera, 
  Carter, 
  sp. 
  

  

  (PL 
  IL, 
  Figs. 
  5, 
  6; 
  PL 
  V., 
  Figs. 
  3, 
  4; 
  PL 
  YIIL, 
  Figs. 
  5, 
  6 
  ; 
  PL 
  XL, 
  Fig. 
  5.) 
  

  

  Leucetta 
  clathrata, 
  Carter, 
  Annals 
  and 
  Magazine 
  of 
  Natural 
  History, 
  1883 
  

   Vol. 
  XL, 
  p. 
  33. 
  

  

  Clathrina 
  tripodifera. 
  Carter, 
  Annals 
  and 
  Magazine 
  of 
  Natural 
  History, 
  June, 
  

   1886, 
  p. 
  505. 
  

  

  Clathrina 
  tripodifera 
  ^2,y. 
  gravida, 
  Carter, 
  lac. 
  eit., 
  p. 
  507. 
  

  

  {a.) 
  General 
  Appearance 
  and 
  Canal 
  System}?.— 
  k^ 
  I 
  have 
  already 
  given 
  a 
  full 
  

  

  * 
  Described 
  on 
  pp. 
  17, 
  18. 
  

  

  