﻿38 
  A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  

  

  communication 
  between 
  the 
  gastral 
  cavities 
  of 
  tlie 
  Ascon-tubes 
  and 
  the 
  pseudogaster. 
  

   Then 
  again 
  we 
  must 
  not 
  forget 
  that 
  in 
  many 
  sponges 
  the 
  oscuhim 
  has 
  the 
  power 
  of 
  

   closing 
  up 
  entirely, 
  and 
  many 
  forms 
  described 
  as 
  lipostomous 
  are 
  probably 
  only 
  forms 
  

   in 
  which 
  the 
  oscnlum 
  is 
  temporarily 
  closed, 
  possibly 
  by 
  the 
  action 
  of 
  the 
  spirit 
  in 
  which 
  

   the 
  specimen 
  has 
  been 
  preserved. 
  I 
  am 
  unwilling 
  to 
  admit 
  without 
  further 
  evidence 
  

   that 
  species 
  exist 
  in 
  which 
  the 
  prosopyles 
  serve 
  both 
  as 
  incurrent 
  and 
  excurrent 
  

   openings, 
  there 
  being 
  no 
  special 
  excurrent 
  opening 
  or 
  openings 
  present 
  in 
  the 
  adult 
  

   sponge. 
  Even, 
  however, 
  if 
  we 
  admit 
  the 
  existence 
  of 
  truly 
  lipostomous 
  Honwccela, 
  

   there 
  is 
  no 
  reason 
  to 
  alter 
  or 
  add 
  to 
  the 
  classification 
  of 
  the 
  canal 
  system 
  proposed 
  

   above, 
  for 
  the 
  lipostomous 
  forms 
  might 
  stand 
  side 
  by 
  side 
  in 
  the 
  various 
  groups 
  with 
  

   the 
  ordinary 
  osculate 
  types. 
  

  

  Of 
  the 
  fifteen 
  "artificial 
  genera" 
  described 
  by 
  Hgeckel 
  and 
  diagnosed 
  in 
  the 
  

   next 
  section 
  of 
  the 
  present 
  memoir, 
  the 
  first 
  seven, 
  Olynthus, 
  Olynthella, 
  Olynthium, 
  

   Clistolynthns, 
  Soleniscus, 
  Solenida 
  and 
  Solenidiiun 
  fall 
  under 
  my 
  section 
  Homocoela 
  

   s'unplicia 
  ; 
  Nardonis, 
  Nardopsis, 
  Nardoiiia, 
  Tarrus, 
  Tarropsis 
  and 
  Tarroina 
  are 
  

   reticulate 
  forms, 
  while 
  the 
  last 
  genus 
  Ascometra 
  is, 
  according 
  toHseckel, 
  a 
  compound 
  

   of 
  several 
  of 
  the 
  preceding 
  genera 
  in 
  a 
  single 
  colony, 
  but 
  I 
  prefer 
  to 
  regard 
  it 
  as 
  a 
  

   colony 
  composed 
  of 
  individuals 
  in 
  various 
  stages 
  of 
  development. 
  

  

  Concerning 
  the 
  types 
  of 
  canal 
  system 
  represented 
  by 
  von 
  Lendenfeld's 
  genera 
  

   Homodenna 
  and 
  Lencopsis* 
  there 
  is 
  little 
  to 
  say 
  ; 
  Homoderma, 
  if 
  it 
  really 
  be 
  a 
  

   Homoccelous 
  sponge, 
  comes 
  under 
  my 
  section 
  Radiata, 
  while 
  Leucopsis 
  is 
  too 
  

   imperfectly 
  described 
  to 
  be 
  taken 
  into 
  serious 
  consideration, 
  though 
  as 
  far 
  as 
  we 
  can 
  

   judge 
  from 
  the 
  description 
  and 
  figure 
  it 
  appears 
  to 
  be 
  simply 
  a 
  reticulate 
  Leucosolenla 
  

   with 
  well 
  developed 
  pseudogaster. 
  

  

  As 
  to 
  HsBckel's 
  Ascaltis 
  canariensis 
  and 
  Ascaltis 
  lamarckii, 
  which 
  von 
  Lendenfeld 
  

   nowf 
  includes 
  in 
  his 
  family 
  HomodermidcB, 
  I 
  cannot 
  see 
  any 
  reason 
  for 
  placing 
  them 
  

   amongst 
  the 
  radiate 
  Homocoela. 
  The 
  endodermal 
  papiUse 
  which 
  project 
  into 
  the 
  

   gastral 
  cavity 
  around 
  the 
  apical 
  rays 
  of 
  the 
  quadriradiates 
  appear, 
  to 
  judge 
  from 
  

   HEeckel's 
  description 
  and 
  figures, 
  +^ 
  to 
  be 
  merely 
  exaggerations 
  of 
  the 
  slight 
  projections 
  

   of 
  the 
  endoderm 
  which 
  frequently 
  surround 
  the 
  bases 
  of 
  projecting 
  spicule-rays 
  

   (c/. 
  Leucosolenia 
  stolonifer, 
  PL 
  VI., 
  Fig. 
  1) 
  and 
  they 
  certainly 
  in 
  no 
  way 
  mdicate 
  

   the 
  formation 
  of 
  radial 
  tubes, 
  which 
  originate 
  as 
  outgrowths 
  and 
  not 
  as 
  ingrowths. 
  

   A 
  moment's 
  reflection 
  will 
  shoAv 
  that 
  such 
  ingrowths 
  of 
  the 
  endoderm 
  as 
  those 
  

   figured 
  by 
  HaBckel 
  could 
  never 
  give 
  rise 
  to 
  the 
  formation 
  of 
  radial 
  tubes. 
  

  

  * 
  Proceedings 
  of 
  the 
  Liunean 
  Society 
  of 
  New 
  South 
  Wales. 
  Vol. 
  IX., 
  Part 
  4, 
  pp. 
  1088, 
  1089. 
  

  

  n 
  11 
  ^J'P^^ 
  ^^'^^^fi''" 
  Spongien." 
  (Separatabdruck 
  aus 
  den 
  Abhandlungen 
  der 
  Senckenbergischen 
  naturforschenden 
  

   Gesellschaft.) 
  Frankfurt 
  a.M. 
  1890. 
  

  

  J 
  " 
  Die 
  Kalkschwamme," 
  Vol. 
  2, 
  pp. 
  52, 
  60. 
  Vol. 
  3, 
  Plate 
  IX, 
  Figs. 
  1, 
  2, 
  3, 
  5. 
  

  

  