﻿IREDALE 
  : 
  NOTES 
  O'S 
  POLYPLACOPHOEA. 
  101 
  

  

  I 
  intended 
  to 
  make 
  drawings 
  of 
  productus 
  when 
  I 
  recognized 
  that 
  

   Carpenteri 
  was 
  founded 
  on 
  such 
  drawings. 
  Of 
  this 
  there 
  is 
  not 
  the 
  

   slightest 
  doubt. 
  

  

  As 
  Thiele 
  lias 
  just 
  published 
  a 
  species 
  of 
  Craspedochiton 
  from 
  

   Mauritius, 
  which 
  is 
  very 
  closely 
  allied 
  to 
  productus, 
  it 
  would 
  seem 
  

   the 
  South 
  African 
  locality 
  is 
  more 
  likely 
  to 
  be 
  correct. 
  

  

  It 
  will 
  be 
  noted 
  that 
  Pilsbry 
  included 
  the 
  drawings 
  under 
  Notoplax. 
  

  

  My 
  examination 
  of 
  the 
  type 
  lias 
  induced 
  me 
  to 
  propose 
  that 
  it 
  

   be 
  relegated 
  to 
  Craspedochiton, 
  using 
  that 
  name 
  as 
  a 
  section 
  of 
  

   Acanthochites. 
  My 
  reasons 
  are 
  : 
  the 
  tail- 
  valve 
  of 
  productus 
  is 
  

   essentially 
  the 
  same 
  as 
  that 
  of 
  violaceus, 
  Q. 
  & 
  G., 
  the 
  tj'pe 
  of 
  

   Loloplax} 
  Rubiginosus, 
  Hutton,^ 
  has 
  been 
  shown 
  by 
  Thiele^ 
  to 
  be 
  

   typically 
  a 
  Lohoplax, 
  where 
  Suter 
  * 
  had 
  previously 
  referred 
  it. 
  But 
  

   from 
  laqueatiis, 
  Sow.,* 
  the 
  type 
  of 
  Craspedochiton,^ 
  that 
  species 
  

   can 
  scarcely 
  be 
  separated. 
  Indeed, 
  I 
  anticipate 
  the 
  reduction 
  of 
  

   ruhiginosiis, 
  Hutton, 
  to 
  a 
  synonym 
  of 
  laqueatus, 
  Sow., 
  when 
  a 
  longer 
  

   series 
  of 
  the 
  latter 
  is 
  examined. 
  The 
  ribbing 
  of 
  the 
  head-valve 
  of 
  

   Loloplax 
  is 
  the 
  chief 
  character 
  separating 
  it 
  from 
  Notoplax 
  ; 
  but, 
  

   in 
  a 
  series 
  of 
  any 
  species 
  of 
  Loloplax 
  or 
  Craspedochiton, 
  that 
  becomes 
  

   faint, 
  and 
  in 
  some 
  cases 
  obsolete. 
  There 
  seems 
  no 
  reason 
  for 
  the 
  

   retention 
  of 
  Notoplax, 
  when 
  Craspedochiton 
  is 
  used 
  as 
  sectional 
  under 
  

   Acanthochites, 
  which 
  course 
  has 
  already 
  been 
  indicated 
  by 
  Smith.' 
  

  

  The 
  difficult}' 
  of 
  separating 
  these 
  Acanthochites 
  into 
  sections 
  is 
  

   well 
  shown 
  in 
  Thiele's 
  work. 
  In 
  the 
  first 
  part 
  he 
  generically 
  uses 
  

   Spo7igiochiton, 
  Lohoplax, 
  Notoplax, 
  and 
  Craspedochiton. 
  In 
  the 
  second 
  

   he 
  still 
  retains 
  Craspedochiton, 
  but 
  has 
  eliminated 
  Lohoplax 
  in 
  favour 
  

   of 
  Spongiochiton, 
  which 
  he 
  reduces 
  to 
  a 
  sub-genus, 
  whilst 
  Notoplax 
  

   becomes 
  only 
  a 
  section 
  of 
  the 
  latter. 
  He 
  had, 
  however, 
  introduced 
  

   a 
  new 
  sub-genus 
  and 
  genus 
  upon 
  very 
  slight 
  characters, 
  and 
  these 
  he 
  

   retains. 
  Our 
  knowledge 
  of 
  the 
  species 
  of 
  Acanthochites 
  is 
  too 
  slight 
  

   to 
  form 
  correct 
  conclusions 
  as 
  to 
  the 
  variation 
  in 
  form 
  in 
  closely 
  allied 
  

   species, 
  and 
  at 
  present 
  the 
  only 
  safe 
  way 
  is 
  to 
  treat 
  them 
  broadly. 
  

   A 
  multiplicity 
  of 
  sections 
  should 
  not 
  be 
  founded 
  on 
  the 
  variation 
  of 
  

   inconstant 
  features. 
  So 
  few 
  specimens 
  of 
  any 
  Australasian 
  Acantho- 
  

   chites 
  have 
  been 
  handled, 
  that 
  it 
  cannot 
  be 
  said 
  that 
  we 
  know 
  the 
  

   limits 
  of 
  variation 
  of 
  any 
  species. 
  

  

  Acanthochites 
  carinatus. 
  Ad. 
  & 
  Ang. 
  

  

  Acanthochites 
  carinatus. 
  Ad. 
  & 
  Aug., 
  P.Z.S., 
  1864, 
  p. 
  194; 
  1867, 
  

  

  p. 
  224 
  ; 
  Pilsbry, 
  Man. 
  Conch., 
  vol. 
  xv, 
  p. 
  17. 
  

  

  This 
  species, 
  very 
  definitely 
  stated 
  to 
  have 
  been 
  found 
  at 
  Port 
  

  

  Jackson, 
  I^.S.W., 
  was 
  never 
  figured. 
  Though 
  a 
  large 
  and 
  striking 
  

  

  shell, 
  it 
  has 
  never 
  been 
  refound. 
  E. 
  A. 
  Smith 
  (P.Z.S., 
  1891, 
  p. 
  392) 
  

  

  1 
  Pilsbry, 
  Nautilus, 
  1893, 
  vol. 
  vii, 
  p. 
  32. 
  

  

  2 
  T.N.Z.I., 
  1871 
  (1872), 
  vol. 
  iv, 
  p. 
  180. 
  

  

  3 
  Zool. 
  Chuu, 
  1909, 
  Heft 
  Ivi, 
  p. 
  38, 
  pi. 
  v, 
  figs. 
  16, 
  17. 
  

  

  * 
  Journ. 
  Malac, 
  1906, 
  vol. 
  xii, 
  p. 
  68, 
  pi. 
  ix, 
  figs. 
  12-17. 
  

  

  5 
  P.Z.S., 
  1841, 
  p. 
  104. 
  

  

  « 
  Bern. 
  Mittheil., 
  1853, 
  p. 
  67. 
  

  

  '' 
  Fauna 
  and 
  Geog. 
  Maldive 
  and 
  Laccadive 
  Arcliipel., 
  vol. 
  ii, 
  p. 
  620. 
  

  

  VOL. 
  IX. 
  — 
  JUNE, 
  1910. 
  8 
  

  

  