﻿52 
  A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  

  

  [b.) 
  Arrangement 
  of 
  the 
  Skeleton. 
  — 
  The 
  skeleton 
  consists 
  of 
  triradiate 
  spicules 
  

   only, 
  arranged 
  in 
  a 
  single 
  layer 
  in 
  the 
  mesoderm. 
  In 
  the 
  outer 
  slmi 
  (pseudoderm) 
  

   the 
  spicules 
  are 
  arranged 
  fairly 
  regularly, 
  in 
  a 
  single 
  layer, 
  with 
  all 
  the 
  basal 
  rays 
  

   pointing 
  towards 
  the 
  stem. 
  In 
  the 
  stem 
  the 
  spicules 
  are 
  very 
  densely 
  and 
  rather 
  

   irregularly 
  arranged, 
  hut 
  still 
  with 
  a 
  large 
  proportion 
  of 
  the 
  basal 
  rays 
  pointing 
  

   downwards. 
  

  

  (c.) 
  The 
  Spicules 
  (PI. 
  IX., 
  Fig. 
  5). 
  — 
  As 
  already 
  stated 
  these 
  are 
  all 
  triradiate; 
  

   they 
  are 
  more 
  or 
  less 
  sagittal, 
  and 
  the 
  rays 
  are 
  all 
  straight, 
  conical 
  or 
  suhfusiform, 
  

   and 
  gradually 
  sharp-pointed. 
  In 
  the 
  spicules 
  of 
  the 
  pseudoderm 
  the 
  basal 
  ray 
  

   measures 
  up 
  to 
  O'l 
  by 
  0-01 
  mm., 
  and 
  the 
  lateral 
  rays 
  about 
  0-07 
  by 
  0-0085 
  mm. 
  

   The 
  spicules 
  of 
  the 
  deeper 
  parts 
  of 
  the 
  body 
  are 
  more 
  nearly 
  regular 
  and 
  somewhat 
  

   slenderer 
  than 
  those 
  at 
  the 
  surface. 
  The 
  rays 
  of 
  the 
  dermal 
  spicules 
  are 
  slightly 
  

   curved, 
  in 
  such 
  a 
  manner 
  that 
  the 
  centre 
  of 
  the 
  spicule 
  is 
  uplifted 
  above 
  the 
  plane 
  

   in 
  which 
  the 
  apices 
  of 
  the 
  three 
  rays 
  lie. 
  

  

  (ct.) 
  Affinities. 
  — 
  This 
  species 
  very 
  closely 
  resembles 
  von 
  Lendenfeld's 
  Ascetta 
  

   macleayi* 
  in 
  external 
  form 
  and 
  spiculation 
  ; 
  indeed 
  for 
  a 
  long 
  time 
  I 
  regarded 
  

   the 
  two 
  as 
  identical, 
  but 
  if 
  von 
  Lendenfeld's 
  description 
  of 
  the 
  canal 
  svstem 
  in 
  

   Leucosolenia 
  ninclcnyi 
  be 
  correct 
  the 
  two 
  species 
  differ 
  very 
  markedly 
  in 
  this 
  respect. 
  

   According 
  to 
  von 
  Jje\\(\Q\\ie\t\ 
  Ascetta 
  mnclcayi 
  is 
  one 
  of 
  Hfeckel's 
  "Auloplegma" 
  

   forms, 
  with 
  a 
  pseudogaster 
  and 
  pseudosculum, 
  while 
  in 
  Leucosolenia 
  stipitata 
  there 
  is 
  

   no 
  pseudogaster 
  and 
  the 
  osculum 
  is 
  a 
  true 
  osculum. 
  It 
  appears 
  to 
  me 
  very 
  desirable 
  

   to 
  distinguish 
  by 
  different 
  names 
  forms 
  which 
  differ 
  so 
  widely 
  in 
  anatomical 
  

   characters, 
  but 
  this 
  question 
  has 
  been 
  already 
  discussed 
  in 
  the 
  section 
  of 
  the 
  

   present 
  work 
  dealing 
  with 
  classification. 
  

  

  The 
  species 
  closely 
  resembles 
  one 
  form 
  of 
  Miklucho-Macleay's 
  Guancha 
  hlanca,\ 
  

   but 
  considering 
  the 
  great 
  variety 
  of 
  forms 
  included 
  under 
  that 
  name 
  and 
  the 
  fact 
  that 
  

   the 
  spicules 
  appear 
  to 
  be 
  much 
  stouter 
  and 
  more 
  sharply 
  pointed 
  in 
  Leucosolenia 
  

   stipitata 
  it 
  seems 
  best 
  to 
  give 
  a 
  distinct 
  name 
  to 
  the 
  latter. 
  

  

  {e.) 
  Locality.— 
  Nesiv 
  Port 
  Phillip 
  Heads. 
  (Coll. 
  J. 
  B. 
  Wilson.) 
  

  

  6. 
  Leucosolenia 
  pulcherrima, 
  n. 
  sp. 
  

  

  (PI. 
  I., 
  Fig. 
  7 
  ; 
  PI. 
  IV., 
  Fig. 
  3 
  ; 
  PI. 
  X., 
  Fig.3.) 
  

  

  {a.) 
  General 
  Appearance 
  and 
  Canal 
  System.— 
  Hhe 
  sponge 
  consists 
  of 
  a 
  relatively 
  

   large 
  body 
  perched 
  on 
  the 
  end 
  of 
  a 
  short 
  stalk. 
  Figure 
  7, 
  Plate 
  I., 
  represents 
  a 
  

   typical 
  example 
  multiplied 
  seven 
  diameters. 
  The 
  body 
  is 
  irregularly 
  ovoid 
  in 
  shape, 
  

  

  ' 
  Proceedings 
  of 
  the 
  Linnean 
  Society 
  of 
  New 
  South 
  Wales, 
  Vol. 
  IX., 
  Part 
  4, 
  p. 
  1086. 
  

   t 
  Jenaisclie 
  Zeitschriff, 
  Band 
  IV., 
  18C8. 
  

  

  