﻿668 
  EXPLANATION 
  OP 
  THE 
  PIATES. 
  

  

  [D' 
  shows 
  the 
  naked 
  calcareous 
  axis 
  of 
  one 
  of 
  its 
  branches.] 
  

   D". 
  Portion 
  of 
  J)', 
  x 
  6. 
  From 
  Port 
  MoUe. 
  

  

  Pig. 
  E. 
  Acabaria 
  serrata. 
  Portion 
  of 
  larger 
  specimen 
  in 
  spirit, 
  nat. 
  

   size. 
  E'. 
  Portion 
  of 
  second 
  joint 
  above 
  first 
  bifurcation, 
  

   of 
  same 
  specimen, 
  from 
  Port 
  Darwin, 
  7-12 
  fms., 
  x 
  6. 
  

  

  E. 
  Iciligorr/ia 
  orientalis. 
  Type 
  specimen,, 
  in 
  spirit, 
  reduced 
  to 
  

   one 
  half 
  nat, 
  size. 
  F'. 
  Portion 
  of 
  left-baud 
  branch, 
  the 
  

   margin 
  as 
  seen 
  from 
  the 
  side, 
  showing 
  the 
  depressions 
  for 
  

   the 
  zooids 
  and 
  the 
  common 
  groove 
  which 
  contains 
  them, 
  

   x2. 
  F". 
  Portion 
  of 
  main 
  stem 
  just 
  below 
  bifurcation, 
  

   from 
  front, 
  showing 
  four 
  exsert 
  zooids. 
  From 
  Torres 
  Straits, 
  

   10 
  fms. 
  

  

  Plate 
  XXXVIII. 
  

  

  Fig. 
  a. 
  Mopsella 
  clavigera, 
  cortical 
  clavate, 
  a', 
  cortical 
  bifurcate, 
  

   and 
  a" 
  & 
  «'", 
  Blattkeule 
  spicules, 
  x 
  100. 
  

  

  i. 
  Melitodes 
  albitincta, 
  fusiform, 
  and 
  h' 
  , 
  small 
  nodular 
  cortical 
  

   spicules, 
  X 
  100. 
  

  

  c. 
  Acaharia 
  serrata, 
  long, 
  and 
  c', 
  short 
  verruca-spicules 
  ; 
  c", 
  

  

  short, 
  and 
  c'", 
  long 
  cortical 
  fusiform 
  spicules. 
  All 
  x 
  150. 
  

  

  d. 
  Echinomuricea 
  indo-malaccensis. 
  d 
  & 
  d', 
  chief 
  forms 
  of 
  the 
  

  

  toothed 
  spicule 
  of 
  the 
  verruca, 
  d" 
  & 
  d'", 
  cortical 
  spicules. 
  

   All 
  x70. 
  

  

  e. 
  Iciligorgia 
  orientalis. 
  Chief 
  forms 
  of 
  spicules, 
  X 
  TO. 
  

  

  /. 
  Psilacaharia 
  gracillima, 
  cortical, 
  /' 
  & 
  /", 
  verruca-spicules, 
  

   X 
  70. 
  [The 
  ridged 
  cortical 
  spicule 
  has 
  been 
  omitted.] 
  

  

  g. 
  Pleccaura 
  prcelonga, 
  var. 
  tijpica, 
  radiate, 
  and 
  g' 
  , 
  Blatt- 
  

   keule 
  cortical 
  spicules, 
  x 
  70. 
  

  

  Ji. 
  Plecvatira 
  prcelonga, 
  var. 
  cinerea, 
  Blattkeule 
  cortical 
  spicule, 
  

   x70. 
  

  

  SPONGES. 
  

  

  Plate 
  XXXIX. 
  

  

  Fig. 
  A. 
  Stelispongus 
  excavatus. 
  Type 
  specimen 
  (dry) 
  from 
  Arafura 
  

   Sea. 
  Eeduced 
  to 
  one 
  half 
  nat. 
  size. 
  

  

  