﻿54 
  A 
  MONOGKAPH 
  OF 
  THE 
  VICTOEIAN 
  SPONGES-. 
  

  

  7. 
  Lencosolcnia 
  pclliciilata, 
  n. 
  sp. 
  

  

  (PL 
  III., 
  Fig, 
  2; 
  PL 
  VIIL, 
  Fig. 
  7; 
  PL 
  X., 
  Figs. 
  1, 
  2.) 
  

  

  [a.) 
  General 
  Appearance 
  and 
  Canal 
  System. 
  — 
  The 
  sponge 
  forms 
  rather 
  small, 
  

   low-growing, 
  lobular 
  masses 
  of 
  irregnlar 
  shape 
  (PL 
  III., 
  Fig. 
  2,) 
  and 
  with 
  a 
  very 
  

   well 
  marked 
  outer 
  skin 
  or 
  pseudoderm. 
  The 
  largest 
  specimen 
  in 
  the 
  collection 
  is 
  

   scarcely 
  37 
  mm. 
  in 
  greatest 
  diameter. 
  The 
  skin 
  is 
  smooth 
  and 
  somewhat 
  glabrous. 
  

   Here 
  and 
  there 
  over 
  the 
  surface 
  of 
  the 
  lobes 
  are 
  scattered 
  small, 
  true 
  oscula, 
  

   generally 
  surrounded 
  by 
  a 
  very 
  slightly 
  developed 
  oscular 
  fringe. 
  The 
  general 
  

   external 
  appearance 
  of 
  the 
  sponge 
  varies 
  a 
  good 
  deal 
  on 
  account 
  of 
  the 
  variation 
  in 
  

   the 
  size 
  of 
  the 
  pseudopores. 
  In 
  some 
  specimens 
  these 
  are 
  very 
  minute 
  and 
  very 
  

   closely 
  arranged, 
  so 
  small 
  that 
  to 
  the 
  naked 
  eye 
  the 
  surface 
  has 
  merely 
  a 
  minutely 
  

   punctate 
  appearance, 
  while 
  in 
  others 
  they 
  are 
  a 
  little 
  over 
  0*5 
  mm. 
  in 
  diameter. 
  

   Even 
  in 
  different 
  parts 
  of 
  the 
  same 
  specimen 
  they 
  vary 
  much 
  in 
  size. 
  The 
  small 
  

   size 
  of 
  the 
  pseudopores 
  causes 
  the 
  skin 
  to 
  appear 
  unusually 
  Avell 
  developed, 
  whence 
  

   the 
  specific 
  name 
  pelliculata. 
  

  

  The 
  colour 
  of 
  the 
  sponge 
  in 
  spirit 
  may 
  be 
  pure 
  white, 
  pale 
  brown 
  or 
  even 
  

   pinkish.* 
  The 
  canal 
  system 
  belongs 
  to 
  type 
  B 
  and 
  agrees 
  precisely 
  with 
  that 
  of 
  

   Leucosolenia 
  pulcherrinia, 
  figured 
  on 
  Plate 
  IV., 
  Figure 
  3. 
  The 
  walls 
  of 
  the 
  Ascon-tubes 
  

   are 
  characteristically 
  thin 
  and 
  delicate, 
  and, 
  as 
  is 
  usual 
  in 
  such 
  cases, 
  the 
  prosop3des 
  

   are 
  very 
  clearly 
  shown. 
  Even 
  the 
  outermost 
  Ascon-tubes 
  generally 
  retain 
  their 
  wide 
  

   gastral 
  cavity, 
  so 
  that 
  the 
  skin 
  (pseudoderm) 
  is 
  formed 
  out 
  of 
  the 
  outer 
  walls 
  only 
  of 
  

   the 
  outer 
  tubes, 
  strengthened 
  by 
  specially 
  large 
  spicules. 
  

  

  {b.) 
  Arrangement 
  of 
  the 
  Skeleton. 
  — 
  The 
  skeleton 
  consists 
  of 
  quadriradiate 
  and 
  

   triradiate 
  spicules, 
  arranged 
  in 
  a 
  perfectly 
  normal 
  manner 
  ; 
  the 
  spicules 
  in 
  the 
  pseudo- 
  

   derm 
  are 
  markedly 
  larger 
  thap 
  those 
  inside 
  the 
  colony 
  and 
  the 
  spicules 
  in 
  the 
  oscular 
  

   membrane 
  have 
  a 
  strong 
  tendency 
  to 
  become 
  sagittal. 
  The 
  apical 
  rays 
  of 
  the 
  

   quadriradiates, 
  of 
  course, 
  project 
  freely 
  into 
  the 
  gastral 
  cavities 
  of 
  the 
  Ascon-tubes. 
  

  

  [€.) 
  The 
  Spicules. 
  — 
  As 
  these 
  vary 
  somewhat 
  in 
  different 
  specimens, 
  especially 
  in 
  

   size, 
  I 
  propose 
  to 
  give 
  separate 
  accounts 
  of 
  the 
  spiculation 
  of 
  four 
  specimens, 
  which 
  

   we 
  may 
  call 
  A, 
  B, 
  and 
  D, 
  and 
  in 
  this 
  way 
  to 
  give 
  a 
  fair 
  idea 
  of 
  the 
  extent 
  of 
  

   variation. 
  The 
  spicules 
  of 
  the 
  two 
  extreme 
  forms 
  (A 
  and 
  D) 
  are 
  figured 
  (PL 
  X., 
  

   Figs. 
  1, 
  2.) 
  

  

  Specimen 
  A. 
  (PL 
  X., 
  Fig. 
  1.) 
  

  

  (1.) 
  Triradiates. 
  — 
  Dermal. 
  Regular; 
  rays 
  conical, 
  fairly 
  gradually 
  sharp- 
  

   pointed, 
  measuring 
  about 
  0-15 
  by 
  0-014 
  mm. 
  Deep. 
  Of 
  the 
  same 
  

   form 
  as 
  the 
  dermal 
  spicules 
  but 
  with 
  smaller 
  and 
  slenderer 
  rays, 
  

   measuring 
  O'll 
  by 
  0-0085 
  mm. 
  

  

  * 
  Possibly 
  stained 
  by 
  other 
  specimens 
  in 
  the 
  same 
  jar 
  with 
  the 
  sponge. 
  

  

  