﻿BPONGIIDA. 
  431 
  

  

  straight, 
  sharp, 
  slender, 
  about 
  -002 
  millim. 
  long 
  at 
  head, 
  where 
  

   they 
  are 
  closely 
  aggregated, 
  gradually 
  decreasing 
  in 
  size 
  and 
  

   numbers 
  towards 
  point, 
  where 
  they 
  cease 
  entirely 
  ; 
  size 
  of 
  spicule 
  

   •1 
  to 
  -17 
  by 
  -0063 
  to 
  -0079 
  millim. 
  (2) 
  Hastate 
  cylindrical 
  or 
  

   subacerate, 
  smooth, 
  of 
  almost 
  uniform 
  diameter 
  from 
  centre 
  to 
  

   within 
  two 
  diameters 
  of 
  ends, 
  whence 
  it 
  tapers 
  to 
  a 
  sharp 
  point 
  ; 
  

   size 
  "2 
  by 
  -0042 
  millim. 
  Flesh-spicule, 
  (3) 
  Equianchorate 
  ; 
  tri- 
  

   dentate, 
  with 
  stout, 
  strongly 
  backwardly 
  curved 
  shaft 
  -0026 
  millim. 
  

   in 
  diameter 
  ; 
  lateral 
  arms 
  of 
  heads 
  subtriangular, 
  about 
  '0063 
  

   millim. 
  long, 
  the 
  middle 
  of 
  the 
  margin 
  of 
  the 
  arm 
  conspicuously 
  

   folded 
  inwards 
  ; 
  the 
  middle 
  arm 
  narrow, 
  oblong, 
  about 
  '0032 
  millim. 
  

   long 
  ; 
  length 
  of 
  spicule 
  -025 
  milHm. 
  

  

  Hah. 
  Port 
  Jackson, 
  to 
  5 
  fms. 
  

  

  The 
  entire 
  " 
  stock 
  " 
  or 
  head, 
  of 
  which 
  the 
  single 
  well-preserved 
  

   spirit-specimen 
  consists, 
  is 
  42 
  milhm. 
  (1| 
  inch) 
  in 
  height 
  by 
  40 
  

   in 
  greatest 
  diameter 
  ; 
  the 
  individual 
  branches 
  may 
  be 
  as 
  much 
  as 
  

   9 
  millim. 
  in 
  diameter 
  at 
  their 
  broadest 
  palmate 
  part. 
  I 
  am 
  under 
  

   the 
  impression 
  that 
  this 
  is 
  the 
  species 
  alluded 
  to 
  by 
  Mr. 
  Carter 
  

   (Z. 
  c.) 
  as 
  Halklinndria 
  j'ltimosa, 
  from 
  Kerguelen 
  Island. 
  It 
  differs, 
  

   however, 
  in 
  spiculation 
  from 
  the 
  typical 
  form 
  of 
  that 
  British 
  spe- 
  

   cies 
  in 
  having 
  the 
  shaft 
  of 
  the 
  anehorate 
  about 
  twice 
  as 
  thick 
  and 
  

   in 
  the 
  longer 
  and 
  slenderer 
  hastate 
  spicule 
  ; 
  the 
  difference 
  between 
  

   the 
  anchorates 
  is 
  perceptible 
  even 
  under 
  a 
  low 
  magnifying-power. 
  

   It 
  is, 
  however, 
  nearly 
  allied 
  to 
  both 
  it 
  and 
  Myxilla 
  fictitia 
  of 
  

   Bowerbank, 
  and 
  to 
  some 
  Mediterranean 
  Myxillce 
  of 
  Schmidt. 
  

  

  I 
  add 
  the 
  measurements 
  of 
  the 
  spicules 
  of 
  what 
  is 
  probably 
  the 
  

   type 
  specimen 
  oi 
  UaJichondria 
  (Microciona, 
  Hk.) 
  2^iumosa, 
  Mont,, 
  for 
  

   comparison 
  : 
  — 
  

  

  1. 
  Spined 
  acuate, 
  '16 
  by 
  -0063 
  millim. 
  

  

  2. 
  Hastate 
  acerate 
  (hastate 
  only 
  at 
  one 
  end), 
  -17 
  by 
  -0063 
  

   millim. 
  

  

  3. 
  Equianchorate, 
  -016 
  millim. 
  long, 
  shaft 
  "0013 
  millim. 
  in 
  

   diameter. 
  

  

  Mr. 
  Carter 
  places 
  species 
  of 
  this 
  nature 
  in 
  a 
  new 
  Group, 
  called 
  

   Plumohalichondvhvi 
  (Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  1875, 
  xvi. 
  p. 
  144, 
  and 
  

   1880, 
  vi. 
  p. 
  39), 
  as 
  being 
  distinguished 
  by 
  their 
  habit 
  and 
  their 
  an- 
  

   gulated, 
  not 
  " 
  naviculiform 
  " 
  anehorate 
  ; 
  but 
  his 
  genus 
  Pluniohali- 
  

   chondria{op.cit. 
  1876, 
  xviii. 
  p. 
  236) 
  must 
  be 
  carefully 
  distinguished 
  

   fr(»m 
  this 
  similarly 
  named 
  Group, 
  for 
  it 
  is 
  described 
  as 
  possessing 
  a 
  

   naviculiform 
  anehorate. 
  

  

  CRELLA. 
  

  

  Crella, 
  Gray, 
  P. 
  Z. 
  S. 
  18G7, 
  p. 
  521. 
  

   Cribrella, 
  ISchmidt, 
  Adr. 
  Meer. 
  p. 
  69. 
  

  

  Schmidt's 
  generic 
  name 
  was 
  already 
  in 
  use 
  for 
  a 
  genus 
  of 
  

   Asteridean 
  Echinodermata 
  (L. 
  Agassiz, 
  1835, 
  Mem. 
  Soc. 
  iSci. 
  Neuf- 
  

   chatel, 
  i. 
  p. 
  191). 
  Dr. 
  Gray 
  therefore 
  very 
  properly 
  altered 
  it. 
  

  

  The 
  present 
  species, 
  although 
  the 
  first 
  assigned 
  to 
  the 
  genua 
  from 
  

  

  