﻿A 
  MONOGKAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  55 
  

  

  (2.) 
  Qiindriradiatcs. 
  — 
  Abundant. 
  Of 
  the 
  same 
  size 
  and 
  shape 
  as 
  the 
  deep 
  

   tiiradiates 
  except 
  for 
  the 
  nsnally 
  perfectly 
  straight 
  apical 
  ray 
  projecting 
  

   from 
  the 
  centre 
  at 
  right 
  angles 
  to 
  the 
  facial 
  rays. 
  The 
  apical 
  ray 
  is 
  

   well 
  developed 
  and 
  gradually 
  and 
  very 
  sharply 
  pointed, 
  but 
  not 
  quite 
  

   so 
  long 
  as 
  the 
  facial 
  rays 
  and 
  a 
  trifle 
  slenderer. 
  

  

  In 
  the 
  oscular 
  membrane 
  many 
  of 
  the 
  spicules 
  are 
  markedly 
  sagittal. 
  

  

  Specimen 
  B. 
  

  

  (1.) 
  Triradiates. 
  — 
  Dermal. 
  Eegular; 
  rays 
  conical 
  or 
  slightly 
  fusiform, 
  

   gradually 
  sharp-pointed, 
  measuring 
  about 
  0"24 
  by 
  0*03 
  mm. 
  Deep. 
  

   Regular 
  ; 
  rays 
  slender, 
  conical, 
  fairly 
  sharp-pointed, 
  measuring 
  about 
  

   0-14 
  by 
  0-01 
  mm. 
  

  

  (2.) 
  Qiiadriradiates. 
  — 
  Of 
  about 
  the 
  same 
  size 
  and 
  shape 
  as 
  the 
  deep 
  

   triradiates, 
  but 
  with 
  an 
  apical 
  ray 
  projecting 
  at 
  right 
  angles 
  from 
  the 
  

   centre. 
  The 
  apical 
  ray 
  is 
  usually 
  straight, 
  slightly 
  fusiform, 
  not 
  quite 
  

   so 
  long 
  as 
  the 
  facials, 
  very 
  slender 
  and 
  linely 
  pointed. 
  

  

  In 
  the 
  oscular 
  membrane 
  the 
  spicules 
  often 
  become 
  beautifully 
  sagittal, 
  l)oth 
  

   quadriradiates 
  and 
  triradiates 
  having 
  the 
  oral 
  rays 
  curved 
  backwards 
  towards 
  the 
  

   basal 
  ray, 
  which 
  is 
  rather 
  longer 
  than 
  the 
  orals. 
  (Here, 
  and 
  in 
  the 
  other 
  specimens 
  

   also, 
  the 
  spicules 
  of 
  the 
  oscular 
  fringe 
  are 
  of 
  about 
  the 
  same 
  size 
  as 
  the 
  deep 
  

   triradiates.) 
  

  

  Specimen 
  C. 
  

  

  (1.) 
  Triradiates. 
  — 
  Dermal, 
  [a) 
  Regular, 
  large 
  and 
  stout; 
  rays 
  conical 
  or 
  

   subfusiform, 
  gradually 
  sharp-pointed, 
  measuring 
  about 
  0*25 
  by 
  0-085 
  

   mm. 
  (/;) 
  Sagittal, 
  occurring 
  in 
  small 
  numbers 
  around 
  some 
  of 
  the 
  

   })scudopores 
  and 
  probably 
  also 
  in 
  the 
  oscular 
  membrane. 
  These 
  are 
  

   ap})roximately 
  equiangular 
  and 
  the 
  rays 
  are 
  about 
  equal 
  in 
  length, 
  

   but 
  the 
  oral 
  rays 
  are 
  curved 
  symmetrically, 
  while 
  the 
  basal 
  ray 
  is 
  

   straight, 
  Rays 
  conical, 
  sharp-pointed, 
  measuring 
  about 
  O'l 
  ])y 
  

   O'Ol 
  nnn. 
  Deep. 
  Regular 
  ; 
  rays 
  slender, 
  conical 
  or 
  slightly 
  fusiform, 
  

   sharp-pointed, 
  measuring 
  about 
  0*15 
  by 
  0'014 
  mm. 
  

  

  (2.) 
  Oitadriradiales. 
  — 
  These 
  are 
  scarce 
  and 
  also 
  of 
  two 
  forms, 
  (a) 
  Regular, 
  

   like 
  the 
  deep 
  triradiates 
  in 
  shape 
  and 
  size 
  but 
  with 
  a 
  straiglit, 
  slender 
  

   apical 
  ray 
  i)roj(!cting 
  from 
  the 
  centre, 
  (b) 
  Sagittal, 
  round 
  in 
  the 
  

   oscular 
  membrane 
  and 
  (?)around 
  some 
  of 
  th(^ 
  iiscndoiJores 
  ; 
  much 
  

   like 
  the 
  sagittal 
  triradiates 
  in 
  size 
  and 
  shape 
  but 
  willi 
  ;i 
  long 
  and 
  wcll- 
  

   develojjed, 
  though 
  slender 
  a])ical 
  ray, 
  curving 
  gnidunlly 
  upwards, 
  

   sickle-like, 
  from 
  the 
  centre 
  of 
  the 
  spicule 
  and 
  gradually 
  and 
  finely 
  

   pointed. 
  

  

  