﻿size. 
  

  

  A 
  MONOGRAPH 
  OF 
  THE 
  VICTOEIAN 
  SPONGES. 
  73 
  

  

  PLATE 
  III. 
  

  

  Figure 
  1. 
  — 
  Leucosolenia 
  protogenes. 
  Part 
  of 
  a 
  large 
  specimen 
  ; 
  natural 
  size. 
  

  

  Figure 
  2. 
  — 
  Leucosolenia 
  pelliciilata. 
  A 
  good-sized 
  specimen 
  ; 
  x 
  2. 
  

  

  Figure 
  3. 
  — 
  Leucosolenia 
  ventricosa, 
  var. 
  solida. 
  Part 
  of 
  a 
  large 
  colony 
  ; 
  natural 
  

  

  Figure 
  4. 
  — 
  Leucosolenia 
  depressa. 
  Upper 
  surface 
  of 
  the 
  specimen 
  ; 
  natural 
  size. 
  

   Figure 
  4ii.~~Leucosolenia 
  depressa. 
  Lower 
  surface 
  of 
  the 
  specimen 
  ; 
  natural 
  size. 
  

  

  PLATE 
  IV. 
  

  

  Figure 
  1. 
  — 
  Leucosolenia 
  lucasi. 
  The 
  upper 
  portion 
  of 
  a 
  single 
  Ascon-person, 
  

   highly 
  magnified. 
  At 
  the 
  summit 
  of 
  the 
  tube 
  is 
  shown 
  the 
  wide 
  osculum 
  (o.) 
  and 
  

   in 
  the 
  right 
  hand 
  upper 
  portion 
  of 
  the 
  figure 
  a 
  piece 
  of 
  the 
  thin 
  wall 
  of 
  the 
  tube 
  is 
  

   supposed 
  to 
  be 
  cut 
  away 
  so 
  as 
  to 
  show 
  the 
  gastral 
  cavity. 
  The 
  collared 
  cells 
  are 
  

   coloured 
  red 
  and 
  the 
  spicules 
  blue. 
  

  

  a. 
  r. 
  Apical 
  ray 
  of 
  quadriradiate 
  spicule 
  projecting 
  into 
  the 
  gastral 
  

   cavity. 
  

  

  0. 
  Osculum. 
  

  

  ox. 
  Oxeote 
  spicule 
  projecting 
  from 
  the 
  outer 
  surface 
  of 
  the 
  tube 
  

   wall. 
  

  

  pr. 
  Prosopyle. 
  

  

  ra, 
  Triradiate 
  and 
  quadriradiate 
  spicules 
  lying 
  in 
  the 
  thickness 
  of 
  

   the 
  mesoderm. 
  

  

  Figure 
  2. 
  — 
  Leucosolenia 
  stipitata. 
  Vertical 
  section, 
  passing 
  through 
  the 
  

   osculum, 
  of 
  the 
  specimen 
  represented 
  in 
  Figure 
  6, 
  Plate 
  I.; 
  showing 
  the 
  arrangement 
  

   of 
  the 
  canal 
  system. 
  For 
  the 
  sake 
  of 
  clearness 
  the 
  thickness 
  of 
  the 
  walls 
  of 
  the 
  

   Ascon-tubes 
  is 
  slightly 
  exaggerated. 
  The 
  endoderm 
  is 
  coloured 
  red. 
  (Zeiss 
  ag, 
  Oc. 
  2, 
  

   Camera.) 
  

  

  g.c. 
  Gastral 
  cavity. 
  

  

  int. 
  Interspace 
  between 
  Ascon-tubes 
  

  

  0. 
  Osculum. 
  

  

  p. 
  Pseudopore. 
  

  

  pd. 
  Pseudoderm. 
  

  

  Figure 
  3. 
  — 
  Leucosolenia 
  pulchevrinia. 
  Vertical 
  section, 
  jiiisslng 
  through 
  an 
  

   osculum, 
  of 
  the 
  specimen 
  represented 
  in 
  Figure 
  7, 
  Plat(^I.; 
  showing 
  the 
  arraugenu^nt 
  

   of 
  the 
  canal 
  system. 
  The 
  endoderm 
  is 
  coloured 
  red. 
  (Zeiss 
  a^, 
  Oc. 
  2, 
  Camera.) 
  

  

  st. 
  Stalk. 
  

  

  Other 
  lettering 
  as 
  in 
  Figure 
  2. 
  

  

  