﻿A 
  MONOGEAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  9 
  

  

  spongologists 
  seem 
  to 
  have 
  thought 
  themselves 
  justified 
  in 
  figuring 
  them 
  in 
  what 
  was 
  

   considered 
  to 
  be 
  the 
  orthodox 
  manner 
  whether 
  they 
  had 
  been 
  able 
  to 
  make 
  out 
  the 
  

   structure 
  or 
  not. 
  Certainly 
  they 
  were 
  tolerably 
  correct 
  as 
  to 
  what 
  may 
  be 
  

   called 
  the 
  typical 
  form 
  of 
  the 
  collared 
  cell, 
  and 
  before 
  passing 
  on 
  to 
  describe 
  the 
  

   various 
  modifications 
  which 
  have 
  been 
  shown 
  to 
  exist 
  by 
  more 
  independent 
  investi- 
  

   gation 
  we 
  may 
  with 
  advantage 
  describe 
  the 
  structure 
  of 
  this 
  typical 
  form. 
  

  

  Typically, 
  then, 
  the 
  collared 
  cell 
  consists 
  of 
  a 
  rounded 
  or 
  sometimes 
  cylindrical 
  

   body 
  produced 
  above 
  into 
  a 
  neck 
  or 
  collum. 
  The 
  neck 
  is 
  surmounted 
  by 
  a 
  long, 
  

   vibratile, 
  whip-like 
  flagellum, 
  and 
  the 
  flagellum 
  is 
  surrounded 
  by 
  a 
  very 
  delicate, 
  

   transparent, 
  membranous 
  collar 
  which 
  is 
  usually 
  more 
  or 
  less 
  funnel-shaped 
  and 
  is 
  

   inserted 
  on 
  the 
  collum 
  around 
  the 
  base 
  of 
  the 
  flagellum. 
  In 
  the 
  body 
  of 
  the 
  cell 
  is 
  

   a 
  large 
  nucleus, 
  provided 
  sometimes, 
  if 
  not 
  always, 
  with 
  a 
  distinct 
  nucleolus. 
  The 
  

   protoplasm 
  around 
  the 
  nucleus 
  is 
  more 
  or 
  less 
  granular 
  and 
  sometimes 
  contains, 
  

   according 
  to 
  James-Clark, 
  Carter 
  and 
  Hi^ckel, 
  one 
  or 
  more 
  contractile 
  vacuoles. 
  Both 
  

   collar 
  and 
  flagellum 
  appear 
  to 
  be 
  capable 
  of 
  complete 
  retraction 
  and 
  in 
  this 
  retracted 
  

   condition 
  the 
  collared 
  cells 
  are 
  generally 
  met 
  with 
  in 
  sections. 
  According 
  to 
  

   Carter' 
  the 
  collared 
  cell 
  (spongozoon), 
  after 
  removal 
  from 
  the 
  body 
  of 
  the 
  

   sponge, 
  may 
  be 
  seen 
  moving 
  about 
  the 
  field 
  of 
  the 
  microscope 
  in 
  the 
  form 
  

   of 
  an 
  Amoeba, 
  with 
  or 
  without 
  the 
  flagellum. 
  It 
  is 
  not 
  improbable 
  that 
  the 
  amoeboid 
  

   phase 
  may 
  also 
  occur 
  normally 
  within 
  the 
  sponge. 
  For 
  further 
  details 
  and 
  excellent 
  

   figures 
  I 
  may 
  refer 
  the 
  reader 
  to 
  the 
  works 
  of 
  James-Clark, 
  Carter, 
  Hcieckel, 
  and 
  

   Schulze 
  last 
  quoted. 
  

  

  In 
  his 
  article 
  on 
  Sponges 
  ui 
  tlie 
  "Encyclopaedia 
  Britaimica" 
  (Ed. 
  IX.), 
  Sollas 
  first 
  

   showed 
  that 
  in 
  some 
  Tetractinellid 
  forms 
  a 
  peculiar 
  moditication 
  of 
  the 
  collared 
  cells 
  

   occurs, 
  and 
  he 
  gives 
  further 
  details 
  in 
  his 
  Keport 
  on 
  the 
  "Cliallenger" 
  Tetractinelhda. 
  

   This 
  modification 
  consists 
  in 
  the 
  fusion 
  of 
  the 
  margins 
  of 
  the 
  collars 
  of 
  adjacent 
  

   collared 
  cells 
  in 
  such 
  a 
  manner 
  as 
  to 
  form 
  a 
  distinct 
  membrane, 
  stretching 
  from 
  

   collar 
  to 
  collar 
  and 
  perforated 
  by 
  circular 
  apertures 
  through 
  which 
  the 
  llagella 
  

   })roJ0ct. 
  Soon 
  after 
  this 
  I 
  discovered 
  the 
  same 
  membrane 
  very 
  clearly 
  shown 
  in 
  a 
  

   horny 
  sponge 
  (Carter's 
  Slelospoiigus 
  Jlabelli/oniiis), 
  and 
  proposed! 
  for 
  it 
  the 
  name 
  

   " 
  Sollas's 
  membrane.'' 
  Bidder 
  also 
  mentioned]; 
  its 
  existence 
  in 
  Calcareous 
  s[)onges, 
  

   a 
  discovery 
  confirmed 
  l)y 
  myself 
  in 
  the 
  case 
  of 
  Grantia 
  labyrinthica.'^ 
  So 
  far, 
  

   however, 
  no 
  one 
  had 
  been 
  able 
  to 
  see 
  both 
  Sollas's 
  membrane 
  and 
  the 
  llagella 
  of 
  

   the 
  collared 
  cells 
  co-existent, 
  but 
  since 
  then 
  I 
  have 
  very 
  clearly 
  seen 
  both 
  at 
  once 
  in 
  

  

  * 
  IjOC. 
  cit. 
  

  

  t 
  " 
  Studies 
  oil 
  tlie 
  Coinpurative 
  Aualomy 
  of 
  Spougcy, 
  II. 
  — 
  On 
  tlio 
  Anatomy 
  aiul 
  Histology 
  ot 
  Slelonpoiiiiun 
  

   Jlabelliformis, 
  Gaiter 
  ; 
  with 
  Note^ 
  on 
  tlio 
  Development." 
  Quarterly 
  Journal 
  of 
  Microscopical 
  Science, 
  December, 
  1888. 
  

   } 
  Proceedings 
  of 
  tiio 
  Cambridgo 
  I'hilosopliical 
  Society, 
  Vol. 
  VI., 
  Part 
  -1, 
  p. 
  18;j. 
  

   § 
  " 
  Studies 
  on 
  the 
  Couiparativo 
  Anatomy 
  of 
  Sponge;;, 
  III.," 
  loc. 
  cit. 
  

  

  