﻿353 
  

  

  Tyansactions.-~— 
  Zoology 
  i 
  

  

  On 
  a 
  compavlson 
  of 
  these 
  

   specimens 
  it 
  is 
  perfectly 
  

   clear 
  that 
  the 
  one 
  originally 
  

   described 
  by 
  me 
  in 
  the 
  

   ' 
  Birds 
  of 
  New 
  Zealand 
  ' 
  is 
  

   an 
  adult 
  bird, 
  and 
  not 
  

   " 
  immature" 
  as 
  Dr. 
  Finsch 
  

   supposed. 
  It 
  is 
  in 
  the 
  con- 
  

   dition 
  of 
  those 
  described 
  

   Eeclucecl 
  to 
  half 
  the 
  natural 
  sizo. 
  by 
  Mr. 
  Saunders 
  from 
  

  

  Layard's 
  collection, 
  " 
  all 
  of 
  which 
  were 
  in 
  the 
  act 
  of 
  losing 
  and 
  renewing 
  

   the 
  central 
  tail-feathers 
  and 
  the 
  outer 
  primaries, 
  which 
  are 
  the 
  last 
  to 
  be 
  

   moulted." 
  The 
  remarkable 
  filamentous 
  appearance 
  of 
  the 
  central 
  rectrices 
  

   in 
  my 
  first 
  bird 
  is 
  shown 
  in 
  the 
  second 
  sketch 
  (fig. 
  2) 
  : 
  — 
  ■ 
  

  

  There 
  is 
  an 
  ob- 
  

   vious 
  difference 
  in 
  

   the 
  colouration 
  of 
  

   the 
  two 
  quasi- 
  adult 
  

   specimens 
  exhibited, 
  

   the 
  one 
  having 
  (as 
  

   described 
  in 
  my 
  

   work) 
  the 
  breast 
  

   greyish 
  - 
  white 
  and 
  

   the 
  abdomen 
  ashy- 
  

   Eeducecl 
  to 
  half 
  the 
  natural 
  size. 
  g^'^J, 
  tinged 
  with 
  

  

  brown, 
  while 
  the 
  other 
  has 
  the 
  entire 
  under 
  surface 
  white, 
  marked 
  on 
  

   the 
  breast 
  and 
  sides 
  with 
  interrupted 
  bars 
  of 
  sooty 
  brown. 
  In 
  both, 
  

   however, 
  the 
  under 
  surface 
  of 
  the 
  wings 
  and 
  the 
  axillary 
  plumes 
  are 
  of 
  a 
  

   uniform 
  dark 
  ashy-grey. 
  These 
  individual 
  differences 
  are 
  thus 
  accounted 
  

   for 
  by 
  Mr. 
  Saunders 
  in 
  treating 
  of 
  S. 
  crepuhitus 
  : 
  — 
  " 
  It 
  is 
  now 
  well 
  known 
  

   that 
  there 
  are 
  two 
  very 
  distinct 
  plumages 
  to 
  be 
  found 
  in 
  birds 
  of 
  this 
  

   species, 
  even 
  in 
  the 
  same 
  breeding-places 
  — 
  an 
  entirely 
  sooty 
  form, 
  and 
  one 
  

   with 
  light 
  underparts 
  — 
  and 
  that 
  white-breasted 
  pair 
  with 
  whole-coloured 
  

   birds 
  as 
  well 
  as 
  with 
  those 
  of 
  their 
  respective 
  varieties. 
  If 
  this 
  sjDecies 
  is 
  

   ' 
  dimorphic,' 
  the 
  offspring 
  of 
  one 
  parti-coloured 
  and 
  one 
  white-coloured 
  bird 
  

   ought 
  to 
  resemble 
  one 
  or 
  other 
  of 
  their 
  i)arent3 
  without 
  reference 
  to 
  sex. 
  

   My 
  examination 
  of 
  upwards 
  of 
  a 
  hundred 
  specimens 
  from 
  widely 
  different 
  

   localities, 
  and 
  in 
  all 
  stages, 
  inclines 
  me 
  to 
  the 
  belief 
  that 
  this 
  is 
  not 
  the 
  case, 
  

   and 
  that 
  the 
  young 
  of 
  such 
  Union 
  will 
  be 
  intermediate, 
  whilst 
  the 
  offspring 
  

   of 
  two 
  similar 
  parents 
  will 
  ' 
  breed 
  true,' 
  This 
  point 
  can 
  only 
  be 
  solved 
  by 
  

  

  