﻿Wliite's 
  Thrush 
  hi 
  European 
  Russia. 
  371 
  

  

  appreciate 
  the 
  amount 
  of 
  information 
  that 
  he 
  is 
  rendering 
  

   available. 
  What 
  I 
  do 
  object 
  to 
  in 
  the 
  present 
  connection 
  is 
  

   the 
  utterance 
  of 
  sweeping 
  generalizations 
  based 
  on 
  the 
  

   examination 
  and 
  comparison 
  of 
  a 
  limited 
  number 
  of 
  local 
  

   forms, 
  and 
  the 
  assumption 
  that 
  certain 
  questions 
  have 
  been 
  

   definitely 
  answered 
  when 
  we 
  are 
  really 
  just 
  beginning 
  to 
  gather 
  

   in 
  the 
  facts 
  that 
  shall 
  make 
  such 
  answer 
  possible. 
  

  

  Festhia 
  lente 
  is 
  a 
  good 
  motto. 
  When 
  we 
  know 
  the 
  

   anatomy 
  (using 
  the 
  term 
  in 
  its 
  broadest 
  sense) 
  of 
  every 
  well- 
  

   marked 
  form 
  among 
  the 
  Swifts 
  and 
  Humming-birds, 
  when 
  

   the 
  embryology 
  of 
  the 
  two 
  groups 
  has 
  been 
  thoroughly 
  

   worked 
  out, 
  when 
  Ave 
  are 
  agreed 
  as 
  to 
  what 
  are 
  morphological 
  

   and 
  what 
  purely 
  adaptive 
  characters, 
  then, 
  and 
  only 
  then, 
  

   can 
  we 
  with 
  some 
  degree 
  of 
  certainty 
  say 
  what 
  are 
  the 
  exact 
  

   relations 
  between 
  these 
  two 
  highly 
  specialized 
  forms, 
  

  

  XXXV. 
  — 
  On 
  the 
  Occurrence 
  of 
  White's 
  Thrush 
  in 
  European 
  

   Russia. 
  By 
  Dr. 
  M. 
  Menzbier, 
  Professor 
  in 
  the 
  Uni- 
  

   versity 
  of 
  Moscow. 
  

  

  The 
  life 
  -history 
  and 
  geographical 
  distribution 
  of 
  White's 
  

   Ground-Thrush 
  {Tardus 
  varius) 
  being 
  so 
  insufficiently 
  known, 
  

   I 
  have 
  endeavoured 
  to 
  procure 
  some 
  facts 
  for 
  the 
  elucidation 
  

   of 
  this 
  question. 
  Contrary 
  to 
  the 
  opinion 
  of 
  Mr. 
  Seebohm 
  

   that 
  the 
  western 
  range 
  of 
  this 
  species 
  in 
  summer 
  is 
  probably 
  

   limited 
  to 
  the 
  watershed 
  of 
  the 
  Yenisei 
  and 
  the 
  Lena, 
  I 
  

   have 
  always 
  been 
  of 
  opinion 
  that 
  White's 
  Ground-Thrush 
  

   is 
  distributed 
  in 
  the 
  summer 
  throughout 
  the 
  whole 
  wooded 
  

   districts 
  of 
  Siberia. 
  My 
  conviction 
  was 
  based 
  on 
  the 
  fact 
  

   that 
  this 
  species 
  is 
  much 
  too 
  common 
  in 
  Western 
  Europe 
  

   to 
  be 
  only 
  an 
  accidental 
  straggler 
  from 
  Eastern 
  Siberia. 
  

   Moreover, 
  it 
  is 
  very 
  remarkable 
  that 
  not 
  a 
  single 
  occur- 
  

   rence 
  of 
  White's 
  Ground-Thrush 
  from 
  any 
  part 
  of 
  Russia 
  

   has 
  been 
  recorded, 
  though 
  it 
  without 
  doubt 
  migrates 
  to 
  

   Western 
  Europe 
  through 
  our 
  country. 
  For 
  many 
  years 
  I 
  

   have 
  sought 
  for 
  White's 
  Ground-Thrush 
  among 
  skins 
  of 
  

   the 
  Missel-Thrush 
  {Turdus 
  viscivorus) 
  from 
  various 
  parts 
  

   of 
  Russia, 
  but 
  in 
  vain. 
  At 
  last, 
  during 
  my 
  visit 
  to 
  Siberia 
  

  

  2d 
  2 
  

  

  