﻿SPONQIIDA. 
  615 
  

  

  near 
  centre 
  to 
  sharp 
  points 
  ; 
  size 
  -32 
  by 
  -0063 
  millim. 
  (in 
  axis 
  of 
  

   outer 
  extremities 
  of 
  primary 
  fibres, 
  and 
  loose 
  in 
  the 
  meshes 
  of 
  the 
  

   skeleton). 
  (4) 
  Tricurvate 
  acerate, 
  smooth; 
  the 
  curves 
  bold; 
  taper- 
  

   ing 
  to 
  sharp 
  points 
  ; 
  size 
  -076 
  to 
  -12 
  b^ 
  -0032 
  millim. 
  (in 
  sarcode). 
  

   (5) 
  Equianchorate, 
  shuttle-shaped, 
  shaft 
  slender, 
  slightly 
  and 
  gra- 
  

   dually 
  curved, 
  palms 
  each 
  about 
  one 
  third 
  the 
  total 
  length 
  of 
  the 
  

   •spicule 
  ; 
  length 
  -025 
  millim. 
  

  

  Hah. 
  Marie 
  Louise 
  Island, 
  Amirante 
  group, 
  17 
  fms.: 
  bottom 
  coral. 
  

  

  The 
  specimen 
  on 
  which 
  this 
  species 
  is 
  based 
  coats 
  continuously 
  

   for 
  a 
  distance 
  of 
  100 
  millim. 
  (4 
  inches) 
  most 
  of 
  the 
  circumference 
  

   of 
  a 
  stem 
  (probably 
  algal) 
  3 
  millim. 
  in 
  thickness. 
  The 
  surface 
  

   of 
  S^iongia 
  vulpina, 
  Lamarck, 
  in 
  the 
  Museum 
  at 
  the 
  Jardin 
  des 
  

   Plantes, 
  Paris, 
  decidedly 
  recalls 
  this 
  sponge 
  ; 
  but 
  that 
  species 
  is 
  

   tall, 
  stipitate, 
  and 
  arborescent, 
  with 
  a 
  superficial 
  spicular 
  incrustation, 
  

   and 
  hence 
  is 
  rather 
  referable 
  to 
  RhapJiidopJilus 
  than 
  Clathria 
  ; 
  it 
  

   seems 
  to 
  want 
  the 
  tricurvate 
  acerate 
  spicule 
  of 
  the 
  present 
  species. 
  

  

  One 
  remarkable 
  point 
  about 
  the 
  species 
  is 
  the 
  unusually 
  great 
  

   proportion 
  of 
  horny 
  matter 
  to 
  spicules 
  in 
  the 
  fibres. 
  This 
  is 
  also 
  

   shown 
  in 
  Tenacia 
  dathrata, 
  Schmidt, 
  of 
  the 
  W. 
  Indies, 
  which, 
  besides 
  

   its 
  clathrous 
  habit, 
  differs 
  from 
  this 
  species 
  mainly 
  in 
  the 
  very 
  coarse 
  

   horny 
  fibre, 
  the 
  considerably 
  superior 
  dimensions 
  of 
  the 
  smooth 
  

   acuates, 
  and 
  the 
  rather 
  clumsy 
  form 
  of 
  the 
  spined 
  echinating 
  

   spicules. 
  

  

  37. 
  Acarnus 
  tematus. 
  

  

  See 
  Part 
  I., 
  p. 
  453, 
  of 
  this 
  Report. 
  

  

  A 
  young 
  specimen. 
  The 
  tricurvates 
  are 
  somewhat 
  shorter, 
  

   thicker, 
  and 
  more 
  strongly 
  curved 
  than 
  in 
  the 
  Australian 
  specimens. 
  

   Hab. 
  He 
  des 
  Neufs, 
  Amirante 
  Islands, 
  15 
  fms. 
  

  

  ECHINONEMA, 
  Carter. 
  

  

  This 
  genus 
  was 
  nominally 
  established 
  in 
  1875 
  (Ann. 
  & 
  Mag. 
  N. 
  H. 
  

   1875, 
  xvi. 
  p. 
  185), 
  in 
  Mr. 
  Carter's 
  " 
  Notes 
  Introductory 
  to 
  the 
  Study 
  

   and 
  Classification 
  of 
  the 
  Spongida," 
  by 
  the 
  insertion 
  of 
  the 
  words 
  

   " 
  Ediinonema 
  typicum, 
  C, 
  MS.," 
  under 
  the 
  Group 
  Pluriformia, 
  

   Family 
  Ectyonida, 
  of 
  the 
  Order 
  Echinonemata; 
  but 
  its 
  characters 
  were 
  

   not 
  made 
  known 
  until 
  1881 
  {op. 
  cit. 
  1881, 
  vii. 
  pp. 
  378-380), 
  when 
  

   Mr. 
  Carter 
  somewhat 
  briefly 
  described 
  two 
  species 
  under 
  this 
  name, 
  

   viz. 
  E. 
  typkmn 
  and 
  E. 
  anchor 
  atum, 
  without, 
  however, 
  giving 
  any 
  

   definition 
  of 
  the 
  genus. 
  I 
  have 
  been 
  able 
  to 
  examine 
  a 
  consider- 
  

   able 
  number 
  of 
  the 
  specimens 
  thus 
  identified 
  by 
  Mr. 
  Carter, 
  and 
  find 
  

   them 
  to 
  be 
  nearly 
  allied 
  to 
  IthaplMoplilus 
  of 
  Ehlers 
  (Espersch. 
  

   Spong. 
  pp. 
  19,31) 
  and 
  to 
  Clathria, 
  Schmidt, 
  having 
  the 
  same 
  general 
  

   character 
  of 
  spiculation 
  and 
  arrangement 
  of 
  the 
  skeleton 
  as 
  these 
  

   genera, 
  but 
  differing 
  from 
  Clathria 
  in 
  having 
  a 
  non-fibrous 
  and 
  

   purely 
  spicular 
  cortical 
  layer, 
  composed 
  of 
  acuates 
  or 
  spinulates 
  

   with 
  their 
  points 
  directed 
  outwards, 
  and 
  while 
  agreeing 
  with 
  

   EhapUdophlus 
  in 
  this 
  point, 
  differing 
  from 
  it 
  in 
  the 
  possession 
  (not 
  

  

  