﻿78 
  A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  

  

  Figure 
  5. 
  — 
  Small 
  portion 
  of 
  a 
  thin 
  section 
  of 
  an 
  Ascon-tube, 
  showing 
  how 
  the 
  

   collared 
  cells 
  spread 
  in 
  from 
  the 
  "wall 
  of 
  the 
  tube 
  over 
  the 
  mesodermal 
  ingrowths, 
  

   thus 
  forming 
  with 
  the 
  latter 
  the 
  eudogastric 
  septa. 
  (Zeiss 
  F, 
  Oc. 
  2.) 
  

  

  c. 
  c. 
  Collared 
  cells. 
  

  

  incs. 
  Mesoderm 
  of 
  the 
  tube-wall. 
  

  

  Dies'. 
  Ingrowth 
  of 
  mesoderm 
  into 
  the 
  gastral 
  cavitj'. 
  

  

  PLATE 
  VIII. 
  

  

  Figure 
  1. 
  — 
  Leucosolcnia 
  proxima. 
  Vertical 
  section 
  of 
  the 
  specimen 
  represented 
  

   in 
  Figure 
  1, 
  Plate 
  11. 
  ; 
  showing 
  the 
  arrangement 
  of 
  the 
  canal 
  sj^stem. 
  The 
  

   endoderm 
  is 
  coloured 
  red. 
  (Zeiss 
  as, 
  Oc. 
  2, 
  Camera.) 
  

  

  g. 
  c. 
  Gastral 
  cavity 
  of 
  Ascon-tube. 
  

  

  /;//. 
  Interspace 
  between 
  Ascon-tubes. 
  

  

  0. 
  Osculum. 
  

  

  p, 
  Pseudopore. 
  

  

  pd. 
  Pseudoderm. 
  

  

  r. 
  Eoot-like 
  attaching 
  process. 
  

  

  St. 
  c. 
  Stellate 
  mesoderm 
  cells 
  forming 
  a 
  network 
  in 
  the 
  gastral 
  

   cavity. 
  

  

  Figure 
  2. 
  — 
  Lencosolenia 
  proxima. 
  A 
  small 
  portion 
  of 
  a 
  section 
  more 
  highly 
  

   magnified 
  (Zeiss 
  F, 
  Oc. 
  2) 
  ; 
  showing 
  part 
  of 
  the 
  wall 
  of 
  an 
  Ascon-tube 
  and 
  part 
  

   of 
  the 
  network 
  of 
  stellate 
  mesodermal 
  cells 
  in 
  the 
  gastral 
  cavity. 
  

  

  c. 
  c. 
  Collared 
  cells 
  (collars 
  and 
  fiagella 
  completely 
  retracted). 
  

  

  ect. 
  Ectoderm. 
  

  

  mes. 
  Mesodermal 
  ground-substance. 
  

  

  nu. 
  Nucleus 
  of 
  stellate 
  cell. 
  

  

  sp. 
  Spicule. 
  

  

  St. 
  c. 
  Network 
  of 
  stellate 
  cells 
  in 
  the 
  gastral 
  cavity. 
  

  

  Figures 
  3, 
  4..—Leucosolema 
  proxima. 
  Group 
  of 
  three 
  collared 
  cells 
  and 
  isolated 
  

   collared 
  cell. 
  The 
  collars 
  are 
  still 
  extended 
  but 
  the 
  fiagella 
  are 
  withdrawn 
  (Zeiss 
  

   F, 
  Oc. 
  4.) 
  • 
  * 
  ^ 
  

  

  col. 
  Collar. 
  

  

  nu. 
  Nucleus. 
  

  

  