﻿ECniNODERMATA. 
  165 
  

  

  Arm 
  of 
  the 
  larger 
  specimen 
  about 
  120, 
  of 
  the 
  smaller 
  about 
  

   85 
  millim. 
  long 
  ; 
  in 
  the 
  former 
  the 
  first 
  pinnule 
  is 
  about 
  20 
  and 
  the 
  

   cirri 
  10 
  millim. 
  long. 
  

  

  Both 
  of 
  the 
  specimens 
  are 
  white 
  and 
  without 
  any 
  dorsal 
  median 
  

   line 
  ; 
  dark 
  spots 
  or 
  marks 
  prominently 
  developed 
  on 
  the 
  pinnules. 
  

  

  For 
  the 
  present, 
  at 
  least, 
  I 
  associate 
  with 
  A. 
  solans 
  a 
  specimen 
  

   from 
  Warrior 
  Reef, 
  in 
  which 
  the 
  characteristic 
  keel 
  to 
  the 
  pinnule 
  

   is 
  developed 
  and 
  iu 
  which 
  the 
  cirri 
  do 
  not 
  seem 
  to 
  have 
  been 
  moro 
  

   than 
  twelve 
  in 
  number, 
  but 
  in 
  which 
  the 
  number 
  of 
  cirrus-joints 
  

   would 
  appear 
  to 
  be 
  less 
  than 
  fifteen. 
  

  

  There 
  are 
  also 
  specimens 
  from 
  Port 
  Curtis 
  and 
  Torres 
  Straits 
  

   which, 
  though 
  still 
  small, 
  hardly 
  promise 
  to 
  ever 
  have 
  the 
  stout 
  arms 
  

   which 
  are 
  so 
  characteristic 
  of 
  the 
  adult 
  ; 
  further 
  experience 
  will, 
  

   I 
  think, 
  show 
  them 
  to 
  be 
  " 
  dwarfs." 
  

  

  Prom 
  the 
  Arafura 
  Sea 
  we 
  have 
  received 
  a 
  comparatively 
  small 
  

   specimen, 
  which 
  is 
  chiefly 
  remarkable 
  for 
  the 
  smaller 
  number 
  of 
  its 
  

   cirrus-joints. 
  

  

  In 
  Dundas 
  Strait 
  there 
  were 
  dredged 
  some 
  small 
  specimens 
  which 
  

   approach 
  iu 
  character 
  A. 
  pectinata 
  and 
  A. 
  purpurea, 
  but 
  give 
  us, 
  

   with 
  our 
  present 
  scanty 
  information, 
  but 
  little 
  aid 
  in 
  determining 
  

   the 
  character 
  or 
  limits 
  of 
  these 
  species. 
  

  

  From 
  Thursday 
  Island 
  we 
  obtained 
  a 
  somewhat 
  injured 
  and 
  large 
  

   specimen 
  belonging 
  to 
  the 
  " 
  type 
  " 
  of 
  A. 
  Solaris, 
  but 
  which 
  com- 
  

   pletely 
  eludes 
  my 
  attempts 
  to 
  understand 
  it. 
  

  

  Under 
  the 
  name 
  of 
  A. 
  alhonbtuta 
  I 
  was 
  inclined 
  to 
  separate 
  a 
  spe- 
  

   cimen 
  from 
  Albany 
  Island, 
  which 
  is 
  to 
  be 
  distinguished 
  from 
  the 
  form 
  

   to 
  which 
  the 
  name 
  A. 
  Solaris 
  is 
  ordinarily 
  restricted 
  by 
  the 
  larger 
  

   number 
  (20-25) 
  of 
  cirri, 
  and 
  the 
  less 
  prominent 
  keels 
  on 
  the 
  basal 
  

   joints 
  of 
  the 
  second 
  pinnules. 
  The 
  general 
  facies, 
  however, 
  of 
  the 
  

   specimen 
  is 
  distinctly 
  that 
  of 
  A. 
  Solaris, 
  with 
  the 
  exception 
  of 
  the 
  

   rather 
  remarkable 
  coloration, 
  which 
  has 
  led 
  to 
  the 
  proposal 
  of 
  a 
  

   distinctive 
  name. 
  When, 
  however, 
  we 
  make 
  a 
  careful 
  comparison 
  

   between 
  the 
  pattern 
  of 
  this 
  coloration 
  and 
  that 
  of 
  the 
  two 
  speci- 
  

   mens 
  first 
  described 
  and 
  unhesitatingly 
  referred 
  to 
  A. 
  Solaris, 
  we 
  

   see 
  that 
  there 
  is 
  really 
  a 
  striking 
  resemblance 
  between 
  the 
  two, 
  and 
  

   we 
  are 
  again 
  led 
  to 
  the 
  reflection 
  that 
  great 
  circumspection 
  is 
  to 
  be 
  

   exercised 
  whensoever 
  we 
  are 
  tempted 
  to 
  make 
  use 
  of 
  difference 
  in 
  

   colour 
  as 
  a 
  distinguishing 
  mark. 
  I 
  have 
  already 
  stated 
  that 
  there 
  

   are 
  black 
  patches 
  or 
  spots 
  on 
  the 
  pinnules 
  of 
  the 
  first-described 
  pair 
  of 
  

   specitueus 
  ; 
  what 
  we 
  find 
  in 
  the 
  one 
  now 
  under 
  consideration 
  is 
  that 
  

   these 
  spots 
  having 
  greatly 
  increased 
  in 
  number, 
  and 
  become 
  more 
  ex- 
  

   tensive 
  than 
  the 
  white, 
  have 
  caused 
  the 
  white 
  ground 
  to 
  assume 
  the 
  

   appearance 
  of 
  spots 
  on 
  a 
  dark 
  ground. 
  The 
  extreme 
  limit 
  of 
  the 
  

   species 
  seems, 
  however, 
  to 
  be 
  reached 
  by 
  this 
  form 
  ; 
  and 
  as 
  the 
  cirri 
  

   are 
  more 
  numerous 
  than 
  usual, 
  and 
  the 
  basal 
  joints 
  of 
  the 
  second 
  

   pinnule 
  less 
  strongly 
  keeled, 
  I 
  propose 
  to 
  speak 
  of 
  it 
  as 
  A. 
  Solaris^ 
  

   var. 
  alhonotata. 
  

  

  We 
  must 
  not 
  be 
  tempted 
  by 
  the 
  diflSculties 
  of 
  specific 
  discrimina- 
  

   tion 
  to 
  make 
  use 
  of 
  mere 
  coloration 
  : 
  there 
  are 
  in 
  the 
  collection 
  two 
  

   specimens 
  of 
  A. 
  Solaris 
  from 
  Thursday 
  Island, 
  one 
  of 
  which 
  is 
  uni- 
  

  

  