﻿A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  59 
  

  

  (c.) 
  The 
  spicules 
  (PL 
  XI,, 
  Fig. 
  1). 
  — 
  Triradiates 
  only, 
  of 
  slightly 
  different 
  size 
  and 
  

   shape 
  according 
  to 
  whether 
  they 
  lie 
  in 
  the 
  psendoderm 
  or 
  in 
  the 
  deeper 
  parts 
  of 
  the 
  

   colony. 
  Dermal. 
  These 
  are 
  eqiiiradiate 
  and 
  equiangular 
  (regular), 
  fairly 
  sharj^ly 
  

   pointed 
  ; 
  the 
  rays 
  are 
  almost 
  cylindrical 
  till 
  pretty 
  near 
  the 
  apex 
  Avhen 
  they 
  begin 
  to 
  

   taper 
  off 
  gradually, 
  they 
  meavSnre 
  about 
  0*14 
  by 
  0"0136 
  mm. 
  Deep. 
  Like 
  the 
  

   preceding 
  but 
  with 
  slenderer 
  rays 
  measuring 
  about 
  0*14 
  by 
  0.009 
  mm. 
  Numerous 
  very 
  

   small 
  triradiates 
  occur 
  amongst 
  these 
  as 
  in 
  other 
  species 
  and 
  as 
  figured 
  by 
  Haeckel 
  

   for 
  Ascetta 
  priniordialis 
  ; 
  these 
  are 
  doubtless 
  young 
  forms. 
  The 
  spicules 
  of 
  the 
  

   pseudoscular 
  fringe 
  and 
  of 
  the 
  membrane 
  which 
  lines 
  the 
  pseudogaster 
  resemble 
  

   the 
  ordinary 
  deep-seated 
  triradiates. 
  

  

  {d.) 
  Affinities. 
  — 
  The 
  identification 
  of 
  the 
  four 
  large 
  specimens 
  of 
  this 
  species 
  in 
  

   the 
  collection 
  with 
  Carter's 
  Clathrina 
  priniordialis 
  is 
  a 
  safe 
  one, 
  because 
  not 
  only 
  

   have 
  I 
  his 
  long, 
  published 
  description 
  and 
  manuscript 
  figures 
  to 
  go 
  by, 
  but 
  also 
  a 
  

   l^iece 
  of 
  one 
  of 
  his 
  own 
  types 
  from 
  the 
  British 
  Museum. 
  Mr. 
  Carter's 
  identification 
  of 
  

   his 
  specimens 
  with 
  Haeckel's 
  Ascetta 
  priniordialis 
  is 
  more 
  open 
  to 
  doubt 
  but 
  appears 
  

   to 
  me 
  to 
  hold 
  good 
  if 
  restricted 
  to 
  Haeckel's 
  variety 
  Ascetta 
  priniordialis 
  var. 
  

   protogenes, 
  although 
  in 
  our 
  specimens 
  the 
  dermal 
  spicules 
  are 
  slightly 
  thicker 
  than 
  

   the 
  deep 
  ones. 
  I 
  do 
  not 
  however 
  place 
  any 
  great 
  importance 
  on 
  so 
  slight 
  a 
  

   distinction, 
  although 
  the 
  specimens 
  thereby 
  make 
  an 
  approach 
  to 
  HiBckel's 
  Ascetta 
  

   priniordialis 
  var. 
  poteriiini 
  with 
  its 
  stout 
  dermal 
  spicules. 
  

  

  Polejaeff 
  records 
  in 
  the 
  case 
  of 
  the 
  specimens 
  in 
  the 
  " 
  Challenger 
  " 
  collection 
  

   identified 
  by 
  him 
  as 
  Leucosolenia 
  poteriiini 
  (?) 
  the 
  presence 
  of 
  sagittal 
  spicules 
  in 
  

   the 
  pseudoscular 
  membrane. 
  I 
  have 
  found 
  none 
  such 
  in 
  my 
  specimens 
  of 
  

   Leucosolenia 
  protogenes. 
  

  

  HndckeW 
  Ascetta 
  priinordialis 
  vav. 
  protogenes 
  includes 
  of 
  course 
  specimens 
  with 
  

   various 
  types 
  of 
  canal 
  system, 
  but 
  I 
  [)ropose 
  to 
  admit 
  the 
  specific, 
  or 
  at 
  any 
  rate 
  

   varietal, 
  identity 
  only 
  of 
  forms 
  with 
  the 
  same 
  type 
  of 
  canal 
  system, 
  and 
  hence 
  the 
  

   nomenclature 
  l)econies 
  a 
  matter 
  of 
  considerable 
  difficulty. 
  In 
  the 
  absence 
  of 
  definite 
  

   information 
  as 
  to 
  the 
  canal 
  system 
  of 
  the 
  original 
  typ(> 
  o( 
  protogenes 
  I 
  pro})ose 
  at 
  

   present 
  to 
  restrict 
  the 
  name 
  to 
  specimens 
  which 
  conform 
  to 
  my 
  type 
  D 
  of 
  the 
  

   Reticulata. 
  

  

  My 
  reason 
  for 
  considering 
  that 
  von 
  Lendenfeld's 
  A 
  seel 
  t 
  a 
  /^roemnlhiis 
  is 
  

   synonymous 
  with 
  Leucosolenia 
  protogenes 
  is 
  that 
  I 
  have 
  examined 
  a 
  IVagineiit 
  of 
  oik^ 
  of 
  

   his 
  type 
  specimens 
  from 
  Port 
  Jackson, 
  sent 
  to 
  nu> 
  from 
  the 
  British 
  Museum, 
  and 
  can 
  

   find 
  no 
  points 
  of 
  distinction. 
  Von 
  Lendenfi-ld 
  says, 
  loe. 
  eit. 
  — 
  " 
  Our 
  species 
  is 
  

   distinguislied 
  from 
  the 
  allied 
  species 
  by 
  thc^ 
  rays 
  of 
  tlu* 
  s[)icul(>s 
  l)(>ing 
  n(Mther 
  

   cylindi'ical 
  as 
  in 
  Ascetta 
  coriacea 
  nor 
  pointed 
  as 
  in 
  the 
  numerous 
  varii^ties 
  of 
  Ascc^tta 
  

   primordialis. 
  Besides 
  that, 
  the 
  spicules 
  are 
  shorter 
  than 
  in 
  the 
  latter 
  anil 
  thicker 
  

  

  