﻿A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  39 
  

  

  UL— 
  THE 
  CLASSIFICATION 
  OF 
  THE 
  CALCAREA 
  HOMOCCELA. 
  

  

  In 
  classifying 
  the 
  Calcarea 
  we 
  have 
  two 
  primary 
  sets 
  of 
  characters 
  to 
  guide 
  us 
  ; 
  

   these 
  are 
  (1) 
  the 
  structure 
  of 
  the 
  individual 
  (person) 
  and 
  (2) 
  the 
  structure 
  of 
  the 
  

   sponge-colony 
  as 
  a 
  whole. 
  

  

  Haeckel 
  apparently 
  considers 
  the 
  structure 
  of 
  the 
  individual 
  to 
  be 
  the 
  most 
  

   important. 
  In 
  his 
  great 
  monograph 
  of 
  the 
  group, 
  he 
  distinguishes 
  three 
  "families" 
  

   of 
  calcareous 
  sponges 
  : 
  — 
  

  

  1. 
  Ascones," 
  = 
  Calcisponges 
  " 
  mit 
  Loch-Canalen." 
  

  

  2. 
  Leucones, 
  = 
  Calcisponges 
  " 
  mit 
  Ast-Oaiialen." 
  

  

  3. 
  Sy 
  cones, 
  = 
  Calcisponges 
  "mit 
  Strahl-Canalen." 
  

  

  But 
  here 
  already 
  we 
  are 
  landed 
  in 
  confusion, 
  for 
  the 
  "Loch-Canalen," 
  " 
  Ast- 
  

   Canalen," 
  and 
  " 
  Strahl-Canalen 
  " 
  are 
  not 
  homologous 
  or 
  even 
  comparable 
  structures. 
  

   The 
  Loch-Canalen 
  of 
  the 
  Ascones 
  (Homocoela) 
  are 
  simply 
  the 
  inhalant 
  pores 
  (prosopyles) 
  

   in 
  the 
  thin 
  wall 
  of 
  the 
  Ascon-person, 
  while 
  the 
  " 
  Strahl-Canalen" 
  of 
  the 
  Sycones 
  are 
  

   totally 
  distinct 
  structures, 
  being 
  really, 
  according 
  to 
  Hseckel, 
  the 
  homologues 
  of 
  entire 
  

   Ascon-persons, 
  and 
  the 
  Sycon-person 
  as 
  a 
  whole 
  equivalent 
  to 
  a 
  colony 
  of 
  Ascon- 
  

   persons 
  formed 
  by 
  gemmation. 
  Each 
  " 
  Strahl-Canal 
  " 
  is, 
  according 
  to 
  this 
  view,t 
  

   nothing 
  but 
  an 
  Ascon-person, 
  and 
  each 
  certainly 
  has 
  its 
  own 
  "Loch-Canalen" 
  

   exactly 
  as 
  in 
  a 
  typical 
  Homocoelous 
  (Ascon) 
  form. 
  

  

  If 
  Haeckel's 
  opinion 
  that 
  the 
  Sycon-person 
  is 
  equivalent 
  to 
  a 
  colony 
  of 
  Ascon- 
  

   persons 
  is 
  correct, 
  he 
  really 
  makes 
  use 
  of 
  the 
  form 
  of 
  the 
  colony 
  and 
  not 
  of 
  the 
  

   structure 
  of 
  the 
  individual 
  as 
  the 
  family 
  characteristic 
  of 
  the 
  Sycones. 
  When, 
  

   however, 
  he 
  comes 
  to 
  subdivide 
  the 
  Ascones 
  {^^ 
  Homocoela) 
  into 
  genera 
  he 
  denies 
  

   the 
  value 
  of 
  the 
  form 
  of 
  the 
  colony 
  as 
  a 
  Avhole 
  as 
  a 
  natural 
  character, 
  replying 
  

   entirely 
  for 
  the 
  distinction 
  of 
  what 
  he 
  terms 
  his 
  " 
  natural 
  " 
  gen(U-a 
  upon 
  the 
  

   structure 
  of 
  the 
  skeleton, 
  and 
  using 
  the 
  form 
  of 
  the 
  colony 
  only 
  in 
  what 
  he 
  terms 
  his 
  

   " 
  artificial 
  " 
  system. 
  

  

  Accordingly 
  we 
  find 
  two 
  schemes 
  of 
  classitication 
  in 
  HaHd<('rs 
  nioiu>gr;i|)li 
  itlaced 
  

   side 
  by 
  side, 
  the 
  artilicial 
  and 
  natural, 
  as 
  he 
  calls 
  tlu^iii. 
  We 
  will 
  consider 
  at 
  i)resiuit 
  

  

  * 
  Hirckol's 
  Ascoiicn 
  are 
  cciiiivolcnt 
  to 
  our 
  IlomocaUi, 
  his 
  Leucones 
  ami 
  N(/co)i« 
  to 
  tho 
  Ucteroexla. 
  

   I 
  I 
  do 
  not 
  wish 
  to 
  commit 
  myself 
  at 
  present 
  to 
  any 
  detiuite 
  view 
  on 
  this 
  (luestion, 
  which 
  will 
  be 
  discussed 
  in 
  n 
  later 
  

   portion 
  of 
  the 
  present 
  work. 
  

  

  \ 
  

  

  