﻿SPONGIIDA. 
  453 
  

  

  strongly 
  recurvate 
  ; 
  size 
  of 
  spicule 
  '07 
  by 
  -0095 
  millim. 
  : 
  very 
  

   abundant 
  on 
  the 
  fibre. 
  (4) 
  Navicular 
  equianchorate 
  of 
  sarcode, 
  

   shaft 
  slender, 
  almost 
  straight 
  ; 
  length 
  of 
  spicule 
  'OlS 
  millim. 
  

   Hah. 
  Prince 
  of 
  Wales 
  Channel, 
  Torres 
  Straits, 
  5-7 
  fms. 
  

  

  Gray, 
  P. 
  Z. 
  S. 
  1867, 
  p. 
  544. 
  

  

  ACARNUS. 
  

  

  Acarnia 
  is 
  used 
  as 
  a 
  generic 
  name 
  in 
  an 
  earlier 
  part 
  (torn. 
  

   cit. 
  p. 
  515) 
  of 
  the 
  same 
  paper 
  as 
  that 
  in 
  which 
  Dr. 
  Gray 
  described 
  

   Acarnus; 
  but 
  it 
  has 
  not 
  come 
  into 
  general 
  use, 
  otherwise 
  the 
  

   essential 
  agreement 
  in 
  form 
  between 
  the 
  two 
  words 
  would 
  neces- 
  

   sitate 
  the 
  suppression, 
  on 
  that 
  ground, 
  of 
  the 
  later 
  one. 
  A 
  careful 
  

   comparison 
  of 
  the 
  grapucl-spicule, 
  which 
  characterizes 
  the 
  genus, 
  

   with 
  the 
  spined 
  cyliudricals 
  of 
  Clathria 
  and 
  EcliinoclicUjum 
  shows 
  

   that 
  the 
  affinity 
  of 
  the 
  sponge 
  is 
  with 
  these 
  genera 
  rather 
  than 
  with 
  

   the 
  "Tethyadaj" 
  of 
  Dr. 
  Gray, 
  as 
  held 
  by 
  him, 
  or 
  with 
  the 
  " 
  Espcriadse," 
  

   as 
  supposed 
  by 
  Mr. 
  Carter 
  (Ann. 
  & 
  Mag. 
  Xat. 
  Hist. 
  1871, 
  vii. 
  p. 
  274). 
  

  

  A. 
  innominatus. 
  Gray* 
  (I. 
  c), 
  besides 
  the 
  remarkable 
  4-hooked 
  

   grapnel-like 
  spicule 
  and 
  the 
  acuato 
  (not 
  cylindrical, 
  as 
  stated 
  by 
  

   Gray, 
  I.e.) 
  form 
  wbich 
  characterize 
  the 
  main 
  skeleton, 
  possesses 
  — 
  as 
  I 
  

   have 
  been 
  able 
  to 
  ascertain 
  by 
  an 
  examination 
  of 
  a 
  mounting 
  made 
  

   by 
  Dr. 
  Bowerbank, 
  who 
  was 
  the 
  first 
  to 
  figure 
  and 
  describe 
  these 
  

   spicules 
  (Mon. 
  Brit. 
  Spong. 
  i. 
  figs. 
  73-76, 
  292), 
  which 
  Dr. 
  Gray 
  after- 
  

   wards 
  embodied 
  in 
  his 
  description 
  of 
  the 
  species 
  — 
  also 
  a 
  tricurvate 
  

   (figured 
  by 
  Bowerbank) 
  and 
  an 
  equianchorate 
  flesh-spicule 
  ; 
  the 
  

   former 
  about 
  "13 
  by 
  '0042 
  millim. 
  in 
  dimensions, 
  the 
  latter 
  •OK) 
  to 
  

   •024 
  millim. 
  long 
  ; 
  also 
  a 
  tibiella, 
  measuring 
  about 
  '28 
  by 
  -0045 
  

   (shaft) 
  or 
  -0063 
  (head) 
  millim. 
  

  

  82. 
  Acarnus 
  ternatus. 
  (Plate 
  XLII. 
  figs. 
  6, 
  b'.) 
  

  

  From 
  a 
  mounting 
  which 
  the 
  Museum 
  owes 
  to 
  the 
  liberality 
  of 
  Dr. 
  

   John 
  Millar, 
  and 
  from 
  the 
  spirit-specimen 
  in 
  the 
  present 
  collection, 
  

   we 
  learn 
  that 
  in 
  this 
  new 
  species 
  the 
  acuate 
  spicules 
  are 
  imbedded 
  

   in 
  a 
  reticulate 
  horny 
  skeleton 
  of 
  a 
  pale 
  salmon-red 
  colour, 
  and 
  not, 
  

   as 
  usual, 
  yellow. 
  The 
  grapnel 
  has 
  but 
  three 
  hooks, 
  and 
  the 
  tibiella 
  

   has 
  the 
  shaft 
  only 
  -003 
  millim. 
  thick. 
  The 
  other 
  spicules 
  agree 
  with 
  

   those 
  of 
  A. 
  innominatus. 
  The 
  largest 
  of 
  the 
  present 
  specimens 
  is 
  

   about 
  65 
  by 
  25 
  millim. 
  (2| 
  inches 
  by 
  1 
  inch), 
  and 
  forms 
  a 
  clathrous 
  

   structure 
  of 
  round 
  soft 
  anastomosing 
  trabeculoe 
  which 
  are 
  about 
  

   3 
  millim. 
  in 
  diameter. 
  Colour 
  in 
  spirit 
  reddish 
  brown. 
  Several 
  

   specimens 
  occur 
  in 
  the 
  present 
  collection. 
  

  

  Hab. 
  West 
  Island 
  and 
  Prince 
  of 
  Wales 
  Channel, 
  Torres 
  Straits, 
  

   7 
  fms. 
  ; 
  bottom 
  sand 
  and 
  coral. 
  

  

  Distribution. 
  Bombay? 
  (coll. 
  Brit. 
  Mus.). 
  

  

  * 
  Mr. 
  Carter 
  gives 
  reasons 
  (l. 
  c.) 
  for 
  bis 
  supposition 
  that 
  the 
  West 
  Indies 
  

   are 
  the 
  home 
  of 
  this 
  species; 
  the 
  specimen, 
  however, 
  to 
  which 
  he 
  appeals 
  in 
  

   support 
  of 
  this 
  view, 
  viz. 
  that 
  attached 
  to 
  the 
  base 
  of 
  a 
  specimen 
  of 
  the 
  West- 
  

  

  