﻿A 
  MONOGKAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  71 
  

  

  " 
  Quadriradiate, 
  triradiate 
  and 
  acerate 
  spicules. 
  The 
  radial 
  tubes 
  in 
  regular 
  strobiloid 
  circles 
  around 
  the 
  cylindrical 
  

   Gastral 
  cavity 
  wliich 
  is 
  clothed 
  up 
  to 
  the 
  margin 
  of 
  the 
  Osculum 
  with 
  frilled 
  flagellate 
  cells. 
  Gastral 
  quadriradiates, 
  

   eentripetal 
  radial 
  ray 
  002 
  — 
  004 
  x 
  00024 
  conic, 
  pointed 
  and 
  straight 
  ; 
  lateral 
  tangental 
  ray 
  slightly 
  curved, 
  convex 
  outside 
  

   0'0.5 
  X 
  00038 
  ; 
  longitudinal, 
  aboral 
  tangental 
  ray 
  0'04 
  x 
  0-0038. 
  Parenchymal 
  triradiates 
  ; 
  internal 
  triradiates 
  with 
  unequal 
  

   rays, 
  radial 
  centrifugal 
  ray 
  0048 
  x 
  0032 
  conic, 
  sometimes 
  protruding 
  into 
  the 
  Gastral 
  cavity. 
  Tangental 
  basal 
  rays 
  

   curved 
  0'0074— 
  0011 
  x 
  0-0048, 
  convex 
  towards 
  the 
  outer 
  side 
  often 
  equatorially 
  situated. 
  

  

  " 
  Median 
  triradiates 
  regular, 
  rays 
  conic 
  0'048 
  x 
  0-003. 
  Dermal 
  rays 
  similar 
  in 
  size 
  and 
  shape 
  to 
  the 
  former 
  on 
  

   the 
  summits 
  of 
  the 
  radial 
  tubes 
  some 
  triradiates 
  are 
  situated, 
  the 
  outer 
  rays 
  of 
  which 
  protrude 
  beyond 
  the 
  surface. 
  

   Dermal 
  acerates 
  protruding 
  and 
  leaning 
  towards 
  the 
  Osculum 
  under 
  an 
  angle 
  of 
  45° 
  0-71 
  x 
  0-0071 
  mm., 
  cylindrical, 
  

   pointed, 
  the 
  centrifugal 
  end 
  abruptly 
  pointed 
  to 
  a 
  sharp 
  point. 
  Situated 
  in 
  groups 
  of 
  10 
  to 
  12 
  on 
  the 
  summits 
  of 
  the 
  

   radial 
  tubes. 
  Oscular 
  acerates 
  a 
  longitudinal 
  cylinder 
  forming 
  a 
  kind 
  of 
  Oesophagus 
  with 
  a 
  frill 
  of 
  horizontal 
  acerates. 
  

   The 
  former 
  slightly 
  curved, 
  convex 
  on 
  the 
  inner 
  side 
  0-57 
  x 
  0-0016, 
  the 
  latter 
  0-21 
  x 
  0-003 
  slightly 
  concave 
  to 
  the 
  front. 
  

  

  " 
  Persons 
  attaining 
  a 
  height 
  of 
  14 
  mm., 
  and 
  a 
  breadth 
  of 
  5 
  mm. 
  

  

  " 
  Homoderma 
  Sycandra 
  is 
  connected 
  with 
  the 
  Asconidfe 
  by 
  forms 
  such 
  as 
  Ascaltis 
  canariensis,* 
  and 
  Ascaltis 
  

   Gegenbauri.f 
  

  

  " 
  Locality 
  : 
  East 
  coast 
  of 
  Australia, 
  Port 
  Jackson, 
  south 
  coast 
  of 
  Australia, 
  Port 
  Phillip, 
  Von 
  Lendenfeld." 
  

  

  In 
  view 
  of 
  the 
  meagreness 
  of 
  the 
  above 
  description 
  and 
  especially 
  of 
  the 
  entire 
  

   absence 
  of 
  histological 
  details, 
  and 
  in 
  spite 
  of 
  the 
  elaborately 
  diagrammatic 
  figm'es 
  

   which 
  accompany 
  it, 
  I 
  fear 
  we 
  must 
  at 
  present 
  place 
  Homoderina 
  sycandra 
  amongst 
  

   the 
  doubtful 
  species. 
  It 
  remains 
  to 
  be 
  proved 
  that 
  the 
  collared 
  cells 
  really 
  do 
  extend 
  

   beyond 
  the 
  limits 
  of 
  the 
  radial 
  tubes, 
  if 
  they 
  do 
  not 
  then 
  the 
  sponge 
  is 
  an 
  ordinary 
  

   Sycon. 
  It 
  will 
  be 
  observed 
  that 
  the 
  sponge, 
  whatever 
  it 
  may 
  be, 
  differs 
  widely 
  

   in 
  strnctm'e 
  from 
  Leticosoleuia 
  tripodifera. 
  

  

  * 
  Hreckel. 
  "Die 
  Kalkschwiimme," 
  Vol. 
  II., 
  p. 
  52; 
  Vol. 
  III., 
  PI. 
  IX., 
  Fig. 
  1-3, 
  PI. 
  X., 
  Figs, 
  la— 
  Ic. 
  

   t 
  Loc. 
  cit. 
  Vol. 
  II., 
  p. 
  62 
  ; 
  Vol. 
  III., 
  PI. 
  IX. 
  Figs. 
  6—8 
  ; 
  PI. 
  X., 
  Figs. 
  5a— 
  M. 
  

  

  