﻿British 
  Species 
  of 
  Microciona, 
  Bk. 
  105 
  

  

  spiculation 
  generally 
  is 
  finer 
  than 
  in 
  either 
  M. 
  armata 
  or 
  M. 
  

   atrosanguinea, 
  and 
  the 
  even 
  flat 
  habit 
  in 
  the 
  growth 
  of 
  the 
  

   sponge 
  is 
  also 
  a 
  point 
  of 
  difference 
  from 
  both 
  species. 
  The 
  

   spicules 
  of 
  M. 
  atrosanguinea 
  figured 
  (viz. 
  C, 
  2, 
  3, 
  5, 
  and 
  6) 
  

   are 
  from 
  a 
  Hastings 
  specimen 
  taken 
  at 
  the 
  locality 
  given 
  by 
  

   Dr. 
  Bowerbank 
  (Mon. 
  Brit. 
  Spong. 
  vol. 
  ii. 
  p. 
  140). 
  

  

  As 
  the 
  sponge 
  (M. 
  spinarcus) 
  coats 
  a 
  shell, 
  it 
  has 
  been 
  

   possible 
  by 
  decalcifying 
  the 
  latter 
  to 
  get 
  a 
  very 
  small 
  portion 
  

   fairly 
  undisturbed 
  and 
  mounted 
  for 
  microscopical 
  examina- 
  

   tion. 
  In 
  the 
  part 
  thus 
  treated 
  I 
  have 
  been 
  able 
  to 
  detect 
  only 
  

   one 
  form 
  of 
  spicule 
  in 
  the 
  " 
  scopuliform 
  bundles 
  " 
  and 
  radia- 
  

   ting 
  tufts 
  of 
  the 
  main 
  skeleton, 
  viz. 
  the 
  large 
  basally 
  tuber- 
  

   culated 
  styles 
  (fig. 
  A, 
  2). 
  The 
  long, 
  slender, 
  smooth 
  styles 
  

   (fig. 
  A, 
  4) 
  lie 
  in 
  wisps 
  in 
  both 
  the 
  basal 
  and 
  dermal 
  mem- 
  

   branes 
  ; 
  the 
  toxa 
  (fig. 
  A, 
  5) 
  have 
  been 
  seen 
  in 
  the 
  basal 
  film 
  

   only, 
  where 
  they 
  seem 
  to 
  be 
  roughly 
  arranged 
  in 
  lines 
  with 
  

   the 
  ends 
  of 
  the 
  component 
  spicules 
  overlapping 
  ; 
  their 
  abun- 
  

   dance, 
  however, 
  makes 
  it 
  probable 
  that 
  they 
  are 
  to 
  be 
  found 
  

   in 
  other 
  parts 
  of 
  the 
  sponge 
  also. 
  The 
  spined 
  styles 
  stand 
  

   upright 
  from 
  the 
  base 
  in 
  the 
  intervals 
  of 
  the 
  bundles 
  and 
  

   tufts, 
  sometimes 
  echinating 
  the 
  wisps 
  of 
  spicules. 
  No 
  

   chela? 
  were 
  detected 
  in 
  situ 
  (fig. 
  A, 
  6). 
  The 
  piece 
  suitable 
  

   for 
  examination 
  is, 
  however, 
  so 
  comparatively 
  minute 
  and 
  

   the 
  dry 
  condition 
  of 
  the 
  sponge 
  so 
  unfavourable 
  that 
  these 
  

   observations 
  are 
  probably 
  of 
  no 
  value 
  ; 
  they 
  are 
  given 
  only 
  

   for 
  what 
  they 
  are 
  worth. 
  

  

  The 
  generic 
  name 
  u 
  Microciona 
  " 
  has 
  been 
  provisionally 
  

   retained 
  for 
  the 
  purposes 
  of 
  this 
  paper 
  for 
  what 
  may 
  perhaps 
  

   be 
  denominated 
  the 
  typical 
  division 
  or 
  group 
  of 
  Dr. 
  Bower- 
  

   bank's 
  genus 
  of 
  that 
  name 
  (comprising 
  M. 
  armata, 
  M. 
  atro- 
  

   sanguinea, 
  and, 
  if 
  the 
  above 
  views 
  be 
  allowed, 
  M. 
  spinarcus), 
  

   mainly 
  on 
  account 
  of 
  the 
  close 
  resemblance 
  of 
  the 
  spiculation 
  

   of 
  the 
  group 
  to 
  that 
  of 
  some 
  species 
  of 
  the 
  genera 
  Clathria 
  

   and 
  Rhaphidophlus. 
  This 
  seems 
  to 
  be 
  a 
  strong 
  argument 
  in 
  

   favour 
  of 
  the 
  course 
  pursued 
  by 
  Mr. 
  Carter 
  in 
  placing 
  Micro- 
  

   ciona 
  in 
  his 
  family 
  " 
  Ectyonida," 
  which 
  is 
  given 
  by 
  Messrs. 
  

   Ridley 
  and 
  Dendy 
  as 
  a 
  synonym 
  of 
  their 
  subfamily 
  " 
  Ectyo- 
  

   ninas 
  " 
  ('Challenger' 
  Reports, 
  " 
  Monaxonida," 
  p. 
  128). 
  

   This 
  would 
  imply 
  the 
  exclusion 
  of 
  the 
  group 
  from 
  the 
  genus 
  

   Amphilectus, 
  Vosmaer, 
  which 
  is 
  a 
  member 
  of 
  the 
  subfamily 
  

   " 
  Esperellinae," 
  Ridley 
  and 
  Dendy 
  (see 
  'Challenger' 
  Mon- 
  

   axonida, 
  p. 
  123). 
  The 
  occurrence 
  of 
  the 
  spined 
  toxa 
  in 
  M. 
  

   spinarcus 
  somewhat 
  strengthens 
  the 
  case 
  ; 
  in 
  Rhaphidophlus 
  

   Lobatus, 
  for 
  instance, 
  each 
  of 
  the 
  five 
  different 
  forms 
  of 
  

   spicule 
  possessed 
  by 
  that 
  sponge 
  is 
  represented 
  in 
  the 
  "Micro- 
  

   ciona 
  group 
  " 
  by 
  a 
  closely 
  similar 
  form 
  (' 
  Challenger 
  ' 
  

  

  Ann. 
  c£- 
  Mag. 
  N. 
  Hist. 
  Ser. 
  6. 
  Vol. 
  iii. 
  8 
  

  

  