﻿A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  77 
  

  

  PLATE 
  YII. 
  

  

  Anatomy 
  and 
  histology 
  of 
  Leucosoleuia 
  wilsoni. 
  (Eed=endoderm 
  ; 
  blne= 
  

   spicules). 
  

  

  Figure 
  1. 
  — 
  Part 
  of 
  a 
  vertical 
  transverse 
  section 
  of 
  the 
  specimen 
  represented 
  in 
  

   Figure 
  3, 
  Plate 
  II.; 
  showing 
  the 
  arrangement 
  of 
  the 
  canal 
  sj'stem. 
  (Zeiss 
  ag, 
  Oc. 
  2, 
  

   Camera.) 
  

  

  em. 
  Embryo. 
  

  

  g. 
  c. 
  Gastral 
  cavities 
  of 
  Ascon-tubes, 
  more 
  or 
  less 
  subdivided 
  by 
  

   endogastric 
  septa. 
  

  

  mt. 
  Interspaces 
  between 
  Ascon-tubes. 
  

  

  0. 
  Osculum. 
  

  

  p. 
  Pseudopore. 
  

  

  pd, 
  Pseudoderm. 
  

  

  r. 
  Pvoot-like 
  process 
  which 
  attaches 
  the 
  sponge 
  to 
  the 
  substratum. 
  

  

  Figure 
  2, 
  — 
  Part 
  of 
  a 
  section 
  of 
  a 
  single 
  Ascon-tube 
  more 
  highly 
  magnified 
  

   (Zeiss 
  C, 
  Oc. 
  2, 
  Camera); 
  showing 
  the 
  subdivision 
  of 
  the 
  gastral 
  cavity 
  by 
  endogastric 
  

   septa. 
  The 
  collared 
  cells 
  appear 
  to 
  form 
  several 
  layers 
  in 
  some 
  places, 
  but 
  this 
  is 
  

   probably 
  due 
  chiefly, 
  if 
  not 
  entirely, 
  to 
  the 
  irregularity 
  of 
  the 
  surface 
  which 
  the 
  

   endoderm 
  covers 
  causing 
  the 
  latter 
  to 
  be 
  often 
  cut 
  tangentially. 
  

  

  ect. 
  Ectoderm. 
  

  

  e. 
  s. 
  Endogastric 
  septum. 
  

  

  g. 
  c. 
  Gastral 
  cavity. 
  

  

  St. 
  c. 
  Stellate 
  cells 
  in 
  mesoderm. 
  

  

  Figure 
  3. 
  — 
  Section 
  similar 
  to 
  that 
  represented 
  in 
  Figure 
  2, 
  but 
  with 
  the 
  endo- 
  

   gastric 
  septa 
  more 
  developed 
  and 
  containing 
  embryos 
  lying 
  in 
  special 
  cavities 
  lined 
  

   by 
  large 
  endothelial 
  cells. 
  (Zeiss 
  C, 
  Oc. 
  2, 
  Camera.) 
  

  

  em. 
  Embryo. 
  

  

  11. 
  c. 
  Nutriant 
  endothelial 
  colls 
  forming 
  the 
  embryo-capsule. 
  

  

  n'.c'. 
  An 
  embryo 
  capsule 
  cut 
  tangentially 
  so 
  as 
  to 
  show 
  the 
  

   polygonal 
  form 
  of 
  the 
  endothelial 
  cells. 
  

  

  Other 
  lettering 
  as 
  in 
  Figure 
  2. 
  

  

  Figure 
  4. 
  J^jctodermal 
  (>i)ithelium 
  seen 
  in 
  ;i 
  tang(Miti;il 
  S(>c'tion 
  of 
  an 
  Ascon-tube. 
  

   (Zeiss 
  F, 
  Oc. 
  2, 
  Camera.) 
  

  

  