﻿82 
  Mr. 
  A. 
  Dendy 
  on 
  Sponges 
  from 
  

  

  tinge. 
  The 
  texture 
  in 
  the 
  dry 
  state 
  is 
  stiff 
  and 
  resilient, 
  but 
  

   very 
  brittle. 
  

  

  The 
  dermal 
  skeleton 
  is 
  a 
  delicate 
  close-meshed 
  network 
  of 
  

   relatively 
  stout 
  horny 
  fibre 
  cored 
  by 
  uniserially 
  arranged 
  

   slender 
  spicules. 
  

  

  The 
  main 
  skeleton 
  is 
  composed 
  of 
  stout 
  primary 
  and 
  secon- 
  

   dary 
  fibres 
  arranged 
  rectangularly 
  and 
  fairly 
  regularly, 
  cored 
  

   by 
  slender 
  spicules 
  arranged 
  uniserially 
  in 
  the 
  secondary 
  fibres 
  

   and 
  either 
  uni- 
  or 
  multiserially 
  in 
  the 
  primaries. 
  Spicules 
  

   also 
  occur 
  plentifully 
  scattered 
  outside 
  the 
  fibres. 
  

  

  The 
  spicules 
  are 
  slender, 
  very 
  slightly 
  curved 
  oxea, 
  gradu- 
  

   ally 
  sharp-pointed 
  at 
  the 
  ends, 
  measuring 
  when 
  full-grown 
  

   about 
  0-126 
  by 
  0*0047 
  millim. 
  

  

  Mr. 
  Carter 
  gives 
  no 
  generic 
  diagnosis 
  of 
  Tubulodigitus, 
  

   and 
  the 
  species 
  falls 
  very 
  well 
  under 
  Siphonochalina 
  as 
  at 
  

   present 
  understood. 
  His 
  specimens 
  also 
  came 
  from 
  the 
  Gulf 
  

   of 
  Manaar. 
  

  

  Sij)honochiUna 
  crassifibra, 
  n. 
  sp. 
  

  

  The 
  single 
  specimen 
  in 
  the 
  collection 
  consists 
  of 
  four 
  tubes 
  

   arising 
  from 
  a 
  common 
  base. 
  Three 
  of 
  them 
  grow 
  up 
  side 
  

   by 
  side 
  in 
  the 
  same 
  plane, 
  while 
  the 
  fourth, 
  which 
  is 
  smaller, 
  

   lies 
  in 
  a 
  different 
  plane, 
  either 
  in 
  front 
  of 
  or 
  behind 
  the 
  other 
  

   three, 
  according 
  to 
  the 
  point 
  of 
  view. 
  There 
  are 
  evident 
  

   traces 
  of 
  the 
  existence, 
  in 
  the 
  living 
  sponge, 
  of 
  a 
  fifth 
  tube, 
  

   which 
  has 
  been 
  taken 
  off 
  and 
  preserved 
  in 
  spirit. 
  The 
  tubes 
  

   are 
  subcylindrical, 
  but 
  slightly 
  compressed 
  in 
  one 
  plane, 
  and 
  

   they 
  are 
  constricted 
  occasionally 
  at 
  irregular 
  intervals. 
  Each 
  

   tube 
  has 
  a 
  large 
  oscular 
  opening 
  at 
  the 
  top. 
  The 
  total 
  

   height 
  of 
  the 
  specimen 
  is 
  150 
  millim., 
  the 
  diameter 
  of 
  the 
  

   tubes 
  about 
  25 
  millim., 
  and 
  the 
  thickness 
  of 
  the 
  tube-wall 
  

   about 
  7 
  or 
  8 
  millim., 
  but 
  variable. 
  The 
  surface 
  of 
  the 
  tubes, 
  

   owing 
  to 
  the 
  projection 
  of 
  the 
  ends 
  of 
  the 
  stout 
  primary 
  fibres, 
  

   is 
  coarsely 
  granular. 
  It 
  has 
  also 
  a 
  reticulate 
  appearance, 
  due 
  

   to 
  the 
  arrangement 
  of 
  the 
  dermal 
  skeleton. 
  The 
  colour 
  of 
  

   the 
  living 
  sponge 
  was 
  deep 
  blue, 
  in 
  spirit 
  and 
  in 
  the 
  dry 
  state 
  

   it 
  is 
  brown, 
  in 
  the 
  dry 
  state 
  with 
  a 
  decided 
  tinge 
  of 
  purple. 
  

   The 
  texture 
  is 
  coarsely 
  fibrous, 
  resilient. 
  

  

  The 
  dermal 
  skeleton 
  is 
  an 
  irregular 
  network 
  of 
  coarse 
  fibre, 
  

   whose 
  meshes 
  are 
  broken 
  up 
  by 
  an 
  equally 
  irregular 
  network 
  

   of 
  fine 
  fibre. 
  Both 
  sets 
  of 
  fibres 
  contain 
  numerous 
  spicules 
  

   and 
  an 
  abundance 
  of 
  spongin 
  ; 
  the 
  spicules 
  are 
  rather 
  loosely 
  

   scattered 
  through 
  the 
  fibre, 
  but 
  usually 
  more 
  numerous 
  in 
  

   the 
  axis 
  than 
  towards 
  the 
  periphery 
  ; 
  sometimes 
  also 
  they 
  are 
  

  

  