﻿106 
  On 
  a 
  new 
  British 
  Species 
  of 
  Microciona, 
  Bk. 
  

  

  Monaxonida, 
  p. 
  154, 
  pi. 
  xxix. 
  figs. 
  4, 
  4 
  a, 
  4 
  b, 
  and 
  4 
  c), 
  and 
  

   its 
  echinating 
  spicule 
  is 
  almost 
  identical 
  with 
  that 
  of 
  M. 
  

   armata. 
  I 
  do 
  not 
  know 
  whether 
  Messrs. 
  Ridley 
  and 
  

   Dendy's 
  dictum 
  under 
  this 
  species, 
  that 
  " 
  there 
  can 
  be 
  

   little 
  doubt 
  that 
  these 
  spined 
  spicules 
  are 
  really 
  homologous 
  

   with 
  the 
  echinating 
  spicules 
  of 
  allied 
  species 
  " 
  (ib. 
  p. 
  154), 
  

   can 
  be 
  fairly 
  and 
  without 
  straining 
  applied 
  to 
  this 
  "Micro- 
  

   ciona 
  group 
  ; 
  " 
  if 
  it 
  can 
  it 
  may 
  perhaps 
  be 
  inferred 
  that 
  these 
  

   gentlemen 
  would 
  have 
  included 
  the 
  group 
  in 
  the 
  Ectyoninas 
  

   had 
  the 
  point 
  arisen 
  for 
  their 
  discussion. 
  But 
  the 
  ' 
  Chal- 
  

   lenger 
  ' 
  had 
  none 
  of 
  the 
  species 
  of 
  it, 
  and 
  all 
  the 
  species 
  of 
  

   Anyjhilectus 
  described 
  by 
  them 
  in 
  their 
  Report 
  are 
  without 
  

   spined 
  styles. 
  

  

  The 
  skeletal 
  arrangement 
  also 
  of 
  this 
  division 
  of 
  Micro- 
  

   ciona 
  appears 
  to 
  me 
  to 
  have 
  considerably 
  greater 
  affinity 
  with 
  

   that 
  of 
  Clathria 
  than 
  with 
  that 
  of 
  an 
  Esperelline 
  sponge. 
  

  

  I 
  desire 
  to 
  express 
  my 
  great 
  indebtedness 
  to 
  Mr. 
  Carter 
  

   for 
  his 
  most 
  kind 
  and 
  courteous 
  assistance 
  and 
  advice, 
  in- 
  

   cluding 
  the 
  loan 
  of 
  rare 
  specimens 
  and 
  microscopic 
  prepara- 
  

   tions 
  from 
  his 
  own 
  collection, 
  also 
  to 
  tender 
  my 
  thanks 
  to 
  

   Dr. 
  A. 
  Giinther, 
  F.R.S., 
  Keeper 
  of 
  Zoology 
  at 
  the 
  Natural- 
  

   History 
  Museum, 
  for 
  kind 
  advice 
  and 
  permission 
  to 
  make 
  use 
  

   of 
  the 
  National 
  Collection 
  freely 
  accorded, 
  as 
  well 
  as 
  to 
  Mr. 
  

   R. 
  Kirkpatrick, 
  in 
  temporary 
  charge 
  of 
  the 
  sponges 
  in 
  the 
  

   Museum, 
  for 
  much 
  trouble 
  taken 
  on 
  my 
  behalf. 
  

  

  It 
  is 
  proposed 
  to 
  deposit 
  the 
  specimen 
  which 
  ha3 
  given 
  

   occasion 
  for 
  these 
  remarks, 
  with 
  microscopic 
  preparations 
  of 
  

   the 
  skeleton 
  and 
  spicules, 
  in 
  the 
  Natural-History 
  Museum. 
  

  

  EXPLANATION 
  OF 
  PLATE 
  VI. 
  

  

  A. 
  Microciona 
  spinarcus. 
  

  

  B. 
  Microciona 
  armata. 
  

  

  C. 
  Microciona 
  atrosanguinea. 
  

  

  Fig. 
  1 
  . 
  A 
  scopulif 
  orm 
  bundle 
  of 
  the 
  skeleton. 
  

  

  Fig. 
  2. 
  Main-skeletal 
  spicules. 
  

  

  Fig. 
  3. 
  Entirely 
  spined 
  styles. 
  

  

  Fig. 
  4. 
  Long 
  slender 
  style. 
  

  

  Fig. 
  5. 
  Toxites. 
  

  

  Fig. 
  6. 
  Isochelae. 
  

  

  Fig. 
  1 
  magnified 
  50 
  diams. 
  ; 
  figs. 
  2-5, 
  250 
  diams. 
  ; 
  fig. 
  6, 
  850 
  diams. 
  

  

  Note. 
  — 
  Spicules 
  of 
  the 
  form 
  no. 
  4 
  in 
  M. 
  armata 
  and 
  M. 
  atrosanguinea 
  

   are 
  not 
  figured, 
  as 
  they 
  differ 
  but 
  slightly 
  from 
  those 
  of 
  M. 
  spinarcus 
  except 
  

   in 
  size. 
  Those 
  of 
  M. 
  armata 
  are 
  sometimes 
  spined 
  at 
  the 
  base 
  in 
  the 
  

   axial 
  line. 
  

  

  