﻿British 
  Species 
  o/" 
  Microciona, 
  Bk. 
  101 
  

  

  at 
  the 
  commencement 
  of 
  this 
  paper 
  (' 
  Annals,' 
  vol. 
  xi\ 
  r 
  . 
  

   p. 
  456 
  &c. 
  ; 
  for 
  an 
  illustration 
  of 
  the 
  spined 
  extremity 
  &c. 
  

   see 
  ib. 
  pi. 
  xxi. 
  fig. 
  27, 
  d). 
  

  

  And 
  in 
  1880-81 
  Vosmaer 
  instituted 
  a 
  new 
  genus, 
  under 
  

   the 
  name 
  of 
  Artemisina, 
  for 
  a 
  sponge 
  that 
  was 
  brought 
  

   from 
  the 
  seas 
  about 
  Spitzbergen 
  by 
  the 
  ' 
  Willem 
  Barents 
  ' 
  2nd 
  

   Expedition, 
  which 
  he 
  named 
  A. 
  suberitoides 
  (Bronn's 
  Klass. 
  

   u. 
  Ordn. 
  " 
  Porifera," 
  p. 
  351, 
  Taf. 
  xxvii. 
  fig. 
  10), 
  and 
  which 
  

   possessed 
  a 
  tricurvate 
  with 
  spined 
  extremities. 
  Also 
  another 
  

   under 
  the 
  generic 
  name 
  of 
  Amphilectus, 
  in 
  the 
  Leyden 
  

   Museum, 
  which, 
  possessing 
  the 
  tricurvate, 
  but 
  not 
  with 
  spined 
  

   extremities, 
  he 
  identified 
  with 
  Microciona 
  armata, 
  Bk. 
  = 
  

   Scopalina 
  toxotes, 
  O. 
  S. 
  (ib. 
  p. 
  353, 
  Taf. 
  xvi. 
  fig. 
  41). 
  

   Thus 
  Amp 
  hi 
  led 
  us, 
  Vosmaer, 
  is 
  identified 
  with 
  Bowerbank's 
  

   Microciona. 
  

  

  Finally, 
  in 
  1887 
  Messrs. 
  S. 
  Bidley 
  and 
  Dendy's 
  Report 
  on 
  

   the 
  Monaxonida 
  dredged 
  by 
  H.M.S. 
  ' 
  Challenger 
  ' 
  was 
  pub- 
  

   lished, 
  and 
  in 
  this 
  three 
  sponges 
  have 
  been 
  described, 
  viz. 
  

   Amphilectus 
  apollinis, 
  Rhaphidophlus 
  lobatus, 
  var. 
  horrida, 
  

   and 
  Plocamia 
  coriacea, 
  var. 
  elegans, 
  each 
  of 
  which 
  possesses 
  

   a 
  tricurvate 
  (toxite, 
  11. 
  & 
  D.) 
  with 
  spined 
  extremities, 
  as 
  

   illustrated 
  in 
  their 
  plate 
  xix. 
  fig. 
  3 
  b 
  and 
  pi. 
  xxix. 
  fig. 
  4 
  b, 
  

   respectively, 
  for 
  the 
  first 
  two, 
  the 
  last 
  having 
  only 
  been 
  

   described 
  in 
  the 
  text 
  (op. 
  cit. 
  p. 
  158). 
  The 
  only 
  difference 
  

   of 
  any 
  consequence 
  between 
  Isodictya 
  coriacea, 
  Bk. 
  (1874), 
  

   and 
  the 
  var. 
  elegans 
  of 
  Ridley 
  and 
  Dendy 
  appears 
  to 
  me 
  

   to 
  be 
  in 
  the 
  adult 
  form, 
  that 
  is 
  in 
  the 
  manner 
  of 
  growth, 
  

   Bowerbank's 
  specimen 
  and 
  my 
  own 
  being 
  massive, 
  while 
  

   the 
  ' 
  Challenger 
  ' 
  variety 
  is 
  dendriform 
  and 
  branched 
  

   (pi. 
  xxxi. 
  fig. 
  1). 
  

  

  Thus 
  the 
  tricurvate 
  with 
  spined 
  extremities 
  alone 
  in 
  Micro- 
  

   ciona 
  is 
  of 
  no 
  specific 
  value 
  ; 
  but 
  when 
  combined 
  with 
  other 
  

   characters 
  will 
  be 
  found 
  to 
  constitute 
  a 
  distinct 
  species, 
  as 
  

   will 
  be 
  seen 
  from 
  the 
  following 
  description 
  by 
  Mr. 
  Hope. 
  

  

  §2. 
  By 
  Mr. 
  Hope. 
  

   Microciona 
  spinarcus, 
  n. 
  sp. 
  Crtr. 
  (PI. 
  VI. 
  figs. 
  1-6.) 
  

  

  The 
  sponge 
  alluded 
  to 
  by 
  Mr. 
  Carter 
  in 
  the 
  preceding 
  

   remarks 
  on 
  the 
  prevalence 
  of 
  the 
  tricurvate 
  (toxite, 
  R. 
  & 
  D.) 
  

   with 
  spined 
  extremities 
  was 
  obtained 
  by 
  me 
  in 
  the 
  month 
  of 
  

   February 
  of 
  the 
  present 
  year 
  (1888) 
  on 
  the 
  " 
  Stade 
  " 
  at 
  

   Hastings 
  among 
  the 
  heaps 
  of 
  scallops 
  piled 
  up 
  there 
  as 
  they 
  

   are 
  landed 
  from 
  the 
  fishing-boats 
  of 
  the 
  town. 
  

  

  It 
  coats 
  very 
  nearly 
  the 
  whole 
  fragment, 
  about 
  25 
  milliin. 
  

  

  