﻿A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  3 
  

  

  Society, 
  It 
  is 
  hoped 
  that 
  this 
  plan 
  of 
  pubHcation 
  will 
  render 
  the 
  work 
  much 
  more 
  

   easy 
  of 
  reference 
  to 
  students. 
  It 
  will 
  probably 
  be 
  a 
  long 
  time 
  before 
  the 
  volume 
  is 
  

   completed, 
  as 
  the 
  work 
  can 
  only 
  be 
  undertaken 
  in 
  the 
  intervals 
  between 
  other 
  duties. 
  

  

  It 
  is 
  proposed 
  to 
  complete 
  the 
  examination 
  of 
  the 
  collection 
  systematically, 
  

   group 
  by 
  group, 
  and 
  to 
  publish 
  the 
  account 
  of 
  each 
  larger 
  or 
  smaller 
  group 
  as 
  soon 
  as 
  

   it 
  is 
  completed. 
  

  

  The 
  present 
  contribution 
  contains 
  the 
  account 
  of 
  the 
  simplest 
  and 
  most 
  lowly 
  

   organised 
  group 
  of 
  sponges, 
  the 
  Calcarea 
  Homocoela. 
  Considerable 
  difficulty 
  was 
  

   experienced 
  in 
  working 
  out 
  this 
  group 
  owing 
  to 
  the 
  very 
  serious 
  imperfection 
  of 
  our 
  

   knowledge 
  of 
  the 
  anatomy 
  of 
  these 
  sponges. 
  There 
  appears 
  to 
  be 
  a 
  general 
  idea 
  that 
  

   the 
  Calcarea 
  Homoccela 
  are 
  all 
  very 
  much 
  alike 
  one 
  another 
  in 
  organisation, 
  and 
  that 
  

   such 
  small 
  differences 
  as 
  may 
  exist 
  are 
  scarcely 
  worthy 
  of 
  investigation. 
  Hasckel, 
  

   indeed, 
  in 
  his 
  famous 
  Monograph 
  of 
  the 
  Calcareous 
  Sponges, 
  recognises 
  several 
  distinct 
  

   types 
  of 
  canal 
  system, 
  but 
  he 
  seems 
  to 
  regard 
  them 
  more 
  as 
  " 
  sports 
  " 
  than 
  anything 
  

   else, 
  and 
  illustrates 
  them 
  all 
  from 
  what 
  he 
  considers 
  to 
  be 
  a 
  single 
  species 
  [Ascandra 
  

   reticiilwn) 
  .* 
  I 
  do 
  not 
  consider 
  that 
  there 
  is 
  any 
  sufficient 
  evidence 
  in 
  favour 
  of 
  such 
  

   an 
  extraordinary 
  variation 
  in 
  canal 
  system 
  within 
  the 
  species 
  as 
  Hasckel 
  imagines. 
  

   Of 
  course 
  the 
  whole 
  difficulty 
  turns 
  upon 
  the 
  question, 
  "What 
  is 
  a 
  species 
  ?" 
  and 
  

   this 
  is 
  a 
  question 
  which 
  no 
  man 
  can 
  presume 
  to 
  settle 
  oft'-hand. 
  Whatever 
  else 
  a 
  

   species 
  may 
  be, 
  however, 
  there 
  can 
  be 
  no 
  doubt 
  that 
  such 
  a 
  thing 
  has 
  no 
  existence 
  in 
  

   Nature, 
  the 
  term 
  being 
  used 
  by 
  zoologists 
  and 
  botanists 
  merely 
  as 
  a 
  matter 
  of 
  

   convenience 
  to 
  indicate 
  a 
  group 
  of 
  individuals 
  which 
  resemble 
  one 
  another 
  to 
  a 
  certain 
  

   extent.! 
  If, 
  however, 
  we 
  are 
  going 
  to 
  place 
  in 
  one 
  and 
  the 
  same 
  species 
  forms 
  so 
  

   widely 
  divergent 
  in 
  anatomical 
  characters 
  (canal 
  system) 
  as 
  those 
  which 
  Ha}ckel 
  places 
  

   in 
  his 
  Ascandra 
  reticnltim 
  we 
  might 
  as 
  well 
  do 
  away 
  with 
  the 
  term 
  altogetlier. 
  

  

  Von 
  Lendenfeld 
  has 
  added 
  two 
  types 
  of 
  canal 
  system 
  to 
  the 
  Calcarea 
  Ilomoea'la, 
  

   for 
  which, 
  while 
  accepting 
  Ha3ckers 
  views 
  as 
  to 
  the 
  intra-specific 
  variation 
  of 
  the 
  

   canal 
  system 
  in 
  other 
  forms, 
  ho 
  creates 
  two 
  new 
  families, 
  Hoinodcnnidw 
  and 
  Leiicop- 
  

   sidcc. 
  The 
  former 
  are 
  supposed 
  to 
  be 
  a 
  transition 
  form 
  between 
  tlic 
  Asconid.ii 
  and 
  

   Syconidio, 
  and 
  the 
  latter 
  between 
  the 
  Asconidje 
  and 
  licuconida'. 
  The 
  mania 
  for 
  dis- 
  

   covering 
  (or 
  inventing) 
  "connecting 
  links 
  " 
  has 
  probably 
  done 
  an 
  immense 
  amount 
  

   of 
  harm 
  to 
  the 
  progress 
  of 
  biological 
  science. 
  If 
  zoologists 
  would 
  be 
  content 
  to 
  

   describe 
  what 
  they 
  see 
  in 
  a 
  straightforward 
  manner, 
  instead 
  of 
  going 
  out 
  of 
  their 
  way 
  

   to 
  discover 
  connecting 
  Hnks, 
  \\\o, 
  study 
  of 
  zoology 
  in 
  general 
  and 
  of 
  spongology 
  in 
  

   particular 
  would 
  bo 
  greatly 
  facilitated. 
  

  

  • 
  " 
  Dio 
  Kalksohwiimme." 
  Vol. 
  3, 
  Plato 
  '10. 
  

  

  t 
  This 
  question 
  ia 
  fiutlicr 
  discussed 
  Inter 
  on, 
  in 
  tlio 
  section 
  dealing 
  with 
  the 
  olassilication 
  or 
  tlio 
  Ciilcnren 
  

   HomoccL'la. 
  

  

  