﻿98 
  PROCEEDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIETT. 
  

  

  Tasmanian 
  specimens 
  of 
  glmcca, 
  Q,. 
  & 
  G., 
  differed 
  slightly, 
  and 
  these 
  

   he 
  christens 
  Tasmmiica 
  on 
  account 
  of 
  the 
  prior 
  glaucus, 
  Gray. 
  

  

  Dissecting 
  shells 
  received 
  from 
  Mr. 
  Bednall 
  under 
  the 
  name 
  glauca, 
  

   Q,. 
  & 
  G., 
  he 
  makes 
  them 
  differ 
  and 
  calls 
  them 
  Bednalli. 
  His 
  figures 
  

   did 
  not 
  appear 
  to 
  show 
  sufficient 
  characters 
  to 
  enable 
  me 
  to 
  judge 
  of 
  

   their 
  specific 
  value, 
  so 
  I 
  dissected 
  a 
  further 
  number 
  of 
  Tasmanian 
  and 
  

   South 
  Australian 
  shells. 
  

  

  South 
  Australian 
  glauca 
  were 
  easily 
  costata, 
  but 
  South 
  Australian 
  

   petholata 
  varied, 
  some 
  being 
  costata, 
  others 
  albida, 
  and 
  others 
  midway 
  

   between 
  albida 
  and 
  Tasmanica. 
  

  

  A 
  number 
  of 
  Tasmanian 
  shells 
  furnished 
  still 
  more 
  interesting 
  

   results. 
  One 
  was 
  a 
  beautiful 
  typical 
  Bednalli, 
  a 
  second 
  was 
  nearer 
  

   Tasmanica, 
  whilst 
  a 
  bigger 
  specimen, 
  though 
  undoubtedly 
  the 
  same 
  

   species, 
  had 
  much 
  longer 
  insertion 
  plates, 
  and 
  of 
  course 
  the 
  shape 
  of 
  

   the 
  valves 
  differed. 
  Some 
  were 
  corrugated, 
  others 
  smoothish, 
  one 
  

   South 
  Australian 
  example, 
  though 
  almost 
  typicallj' 
  alhidus, 
  being 
  

   very 
  smooth, 
  yet 
  young. 
  Young 
  shells, 
  wherever 
  collected, 
  differed 
  

   among 
  themselves, 
  but 
  not 
  constantly, 
  and 
  it 
  seemed 
  useless 
  to 
  attempt 
  

   to 
  allocate 
  them. 
  

  

  I 
  am 
  therefore 
  compelled 
  to 
  advise 
  the 
  rejection 
  of 
  Tasmanica 
  

   { 
  = 
  Bednalli), 
  and 
  cannot 
  even 
  advise 
  its 
  use 
  as 
  a 
  varietal 
  designation. 
  

   Further 
  study 
  must 
  be 
  carried 
  out 
  in 
  the 
  field, 
  and 
  it 
  is 
  just 
  possible 
  

   that 
  the 
  habits 
  of 
  the 
  animals 
  may 
  give 
  clues 
  which 
  will 
  enable 
  the 
  

   fixation 
  of 
  differential 
  characters. 
  From 
  my 
  studies 
  I 
  feel 
  sure 
  that 
  

   no 
  such 
  features 
  have 
  yet 
  been 
  grasped. 
  

  

  Thiele's 
  fifth 
  species 
  is 
  the 
  second 
  Port 
  Jackson 
  species 
  I 
  have 
  above 
  

   indicated. 
  He 
  has 
  named 
  it 
  Pceteliana, 
  and 
  by 
  means 
  of 
  the 
  sculpture 
  

   and 
  form 
  it 
  seems 
  well 
  characterized. 
  From 
  the 
  depressed 
  form 
  and 
  

   long 
  insertion 
  plates 
  it 
  lives 
  on 
  more 
  exposed 
  situations 
  than 
  its 
  

   companion. 
  As 
  the 
  shells 
  from 
  Australia 
  labelled 
  ^^;!/w/a^ffi 
  and 
  glauca 
  

   have 
  resulted 
  in 
  such 
  mixed 
  results, 
  no 
  correct 
  synonymy 
  of 
  the 
  new 
  

   names 
  can 
  be 
  drawn 
  up. 
  Suter 
  (Journ. 
  Malac, 
  1905, 
  vol. 
  xii, 
  p. 
  66) 
  

   has 
  recorded 
  glauca, 
  Q,. 
  & 
  G., 
  from 
  the 
  Chatham 
  Islands. 
  It 
  will 
  be 
  

   interesting 
  to 
  know 
  to 
  which 
  species, 
  if 
  either, 
  the 
  Chatham 
  Island 
  

   shell 
  has 
  to 
  be 
  referred. 
  Thiele 
  has 
  introduced 
  a 
  new 
  species 
  

   Schauinslandi 
  from 
  that 
  locality, 
  but 
  that 
  is 
  clearly 
  only 
  a 
  fine 
  

   ccdata, 
  Reeve. 
  

  

  Plaxiphora 
  costata 
  (Blainville). 
  

  

  Chiton 
  costatus, 
  Plain., 
  Diet. 
  Sci. 
  Nat., 
  1825, 
  vol. 
  xxxvi, 
  p. 
  548; 
  

  

  Pilsbry, 
  Man. 
  Conch., 
  1893, 
  vol. 
  xv, 
  p. 
  105. 
  

   Plaxiphora 
  costata, 
  Plain. 
  : 
  Thiele, 
  Zool. 
  Chun, 
  1909, 
  Heft 
  Ivi, 
  p. 
  24, 
  

   pi. 
  iii, 
  figs. 
  20, 
  21. 
  

   I 
  have 
  seen 
  this 
  shell 
  from 
  Queensland, 
  Tasmania, 
  and 
  South 
  

   Australia. 
  

  

  Plaxiphora 
  albida 
  (Blainville). 
  

  

  Chiton 
  albidus. 
  Plain., 
  Diet. 
  Sci. 
  JSTat., 
  1825, 
  vol. 
  xxxvi, 
  p. 
  547; 
  

  

  Pilsbry, 
  Man. 
  Conch., 
  1893, 
  vol. 
  xv, 
  p. 
  105. 
  

   C. 
  glaucus, 
  Q. 
  & 
  G., 
  Voy. 
  Astrolabe, 
  Zool., 
  1834, 
  vol. 
  iii, 
  p. 
  376, 
  

  

  pi. 
  Ixxiv, 
  figs. 
  7-11. 
  

  

  