﻿160 
  PKOCEEDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIETr. 
  

  

  Australia, 
  and, 
  though 
  scanty, 
  there 
  appears 
  distinct 
  evidence 
  of 
  an 
  

   Antarctic 
  element 
  which 
  has 
  not 
  arrived 
  there 
  via 
  Tasmania. 
  I 
  suggest 
  

   an 
  Autochthonian 
  element 
  showing 
  forms 
  more 
  closely 
  allied 
  to 
  

   Neozelanic 
  species 
  than 
  to 
  Euronotian, 
  and 
  that 
  this 
  will 
  be 
  clearly 
  

   shown 
  by 
  the 
  study 
  of 
  the 
  Chiton 
  fauna. 
  

  

  Kermadec 
  Islands 
  Chiton 
  Fauna. 
  

  

  In 
  the 
  preceding 
  note 
  I 
  have 
  discussed 
  the 
  complex 
  nature 
  of 
  the 
  

   Australian 
  Polyplacophora 
  and 
  how 
  the 
  forms 
  resolve 
  themselves 
  into 
  

   four 
  groups, 
  agreeing 
  with 
  the 
  divisions 
  of 
  the 
  Australian 
  marine 
  

   fauna 
  proposed 
  by 
  Hedley. 
  

  

  " 
  It 
  is 
  to 
  be 
  noted 
  that 
  the 
  Antarctic 
  fauna 
  which 
  passed 
  over 
  New 
  

   Zealand 
  is 
  quite 
  distinct 
  from, 
  and 
  probably 
  far 
  older 
  than, 
  that 
  other 
  

   Antarctic 
  element, 
  the 
  Euronotian, 
  which 
  reached 
  Australia 
  through 
  

   Tasmania" 
  (Hedley, 
  P.L.S. 
  N.S.W., 
  1899, 
  p. 
  399). 
  

  

  In 
  support 
  of 
  this 
  may 
  be 
  cited 
  the 
  Neozelanic 
  Chiton 
  fauna, 
  which 
  

   differs 
  essentially 
  from 
  the 
  Euronotian 
  Chiton 
  fauna. 
  The 
  noticeable 
  

   features 
  are 
  the 
  poverty 
  of 
  species 
  of 
  Ischnochiton, 
  the 
  large 
  size 
  of 
  the 
  

   AcanthocMtes, 
  the 
  distinct 
  nature 
  of 
  the 
  Plaxiphora 
  and 
  O^iithochiton, 
  

   and 
  the 
  presence 
  of 
  the 
  genus 
  Eudoxochiton. 
  

  

  The 
  Chitons 
  collected 
  at 
  Sunday 
  Island 
  agree 
  in 
  the 
  majority 
  of 
  

   these 
  items, 
  yet 
  possess 
  so 
  many 
  peculiarities 
  that 
  they 
  deserve 
  some 
  

   little 
  notice. 
  Eudoxochiton 
  is 
  endemic 
  in 
  Neozelanic 
  waters 
  with 
  two 
  

   distinct 
  species. 
  E. 
  7iobilis, 
  Gray, 
  lives 
  on 
  the 
  surf-swept 
  boulders, 
  

   and 
  its 
  form 
  and 
  internal 
  characters 
  are 
  well 
  suited 
  to 
  withstand 
  the 
  

   force 
  of 
  the 
  waves. 
  E. 
  Huttoni, 
  Pilsbry, 
  is 
  easily 
  separated 
  by 
  its 
  

   much 
  more 
  depressed 
  form 
  and 
  longer 
  teeth, 
  it 
  is 
  only 
  found 
  on 
  the 
  

   most 
  exposed 
  situations, 
  and 
  would 
  appear 
  to 
  be 
  much 
  rarer. 
  Which 
  

   is 
  the 
  parent 
  or 
  to 
  which 
  would 
  the 
  parent 
  form 
  be 
  more 
  like 
  would 
  

   be 
  difficult 
  to 
  suggest. 
  The 
  question 
  is 
  more 
  complicated 
  by 
  the 
  

   finding 
  on 
  Sunday 
  Island 
  of 
  two 
  forms 
  of 
  Eudoxochiton. 
  The 
  

   occurrence 
  of 
  this 
  genus 
  so 
  far 
  north 
  was 
  entirely 
  unexpected, 
  

   Acanthopleura 
  being 
  anticipated 
  instead. 
  The 
  existence 
  of 
  that 
  genus 
  

   in 
  New 
  Zealand 
  now 
  depends 
  on 
  the 
  record 
  of 
  two 
  specimens 
  of 
  

   a 
  West 
  Indian 
  species 
  supposed 
  to 
  have 
  been 
  collected 
  there. 
  As 
  no 
  

   locality 
  or 
  collector 
  is 
  known, 
  surely 
  no 
  acceptance 
  can 
  be 
  given 
  to 
  

   such 
  records 
  in 
  the 
  face 
  of 
  the 
  examination 
  of 
  the 
  Australian 
  

   Polyplacophora. 
  Acantliopleura 
  has 
  a 
  wide 
  range, 
  but 
  in 
  Australia 
  it 
  

   does 
  not 
  extend 
  much 
  outside 
  the 
  tropics. 
  The 
  occurrence 
  of 
  an 
  

   Australian 
  species 
  of 
  that 
  genus 
  in 
  New 
  Zealand 
  would 
  be 
  doubted 
  ; 
  

   how 
  much 
  more 
  doubt 
  must 
  be 
  received 
  by 
  the 
  report 
  of 
  a 
  West 
  

   Indian 
  species 
  ? 
  The 
  Eudoxochitons 
  of 
  Sunday 
  Island 
  are 
  very 
  

   puzzling, 
  as 
  the 
  existence 
  of 
  two 
  forms 
  on 
  such 
  a 
  small 
  island 
  

   I 
  could 
  scarcely 
  credit 
  myself. 
  Yet 
  the 
  shells 
  seem 
  easily 
  separable 
  

   into 
  two 
  lots, 
  which 
  might 
  be 
  classed 
  as 
  varieties 
  of 
  noUlis, 
  Gray 
  : 
  

   they 
  differ 
  in 
  general 
  form 
  as 
  much 
  from 
  each 
  other 
  as 
  from 
  that 
  

   species, 
  and 
  are 
  both 
  less 
  elevated. 
  One 
  form 
  is 
  even 
  lower 
  than 
  

   Huttoni, 
  Pils., 
  though 
  in 
  the 
  characters 
  and 
  number 
  of 
  the 
  teeth 
  it 
  

   absolutely 
  agrees 
  with 
  the 
  other. 
  I 
  have 
  so 
  far 
  been 
  unable 
  to 
  

   provide 
  a 
  satisfactory 
  explanation 
  for 
  the 
  differentiation 
  of 
  these 
  from 
  

  

  