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  THE 
  ZOOLOGIST. 
  

  

  be 
  either 
  obtusely 
  or 
  acutely 
  pyriforrn. 
  An 
  egg 
  of 
  Hcsmatopus 
  

   ostralegns, 
  e. 
  g., 
  owing 
  to 
  its 
  shape, 
  has 
  a 
  greater 
  displacement 
  

   than 
  one 
  of 
  Charadrius 
  pluvialis 
  of 
  the 
  same 
  length 
  and 
  breadth. 
  

   Another 
  conspicuous 
  drawback 
  to 
  the 
  method 
  of 
  estimating 
  the 
  

   size 
  of 
  eggs 
  by 
  their 
  measurements 
  alone 
  is 
  at 
  once 
  apparent 
  

   when 
  those 
  of 
  several 
  species 
  have 
  to 
  be 
  compared. 
  It 
  is 
  almost 
  

   impossible 
  to 
  form 
  a 
  just 
  appreciation 
  where 
  two 
  factors, 
  both 
  

   very 
  variable, 
  are 
  all 
  the 
  data 
  in 
  one's 
  possession. 
  Now, 
  it 
  is 
  

   when 
  several 
  sorts 
  of 
  eggs 
  have 
  to 
  be 
  contrasted 
  that 
  the 
  real 
  

   value 
  of 
  a 
  knowledge 
  of 
  their 
  weights 
  is 
  revealed. 
  Apart 
  from 
  

   the 
  advantage 
  of 
  having 
  only 
  one 
  eet 
  of 
  figures 
  to 
  consider, 
  in 
  

   absolutely 
  fresh 
  specimens, 
  under 
  normal 
  conditions, 
  disparity 
  

   in 
  weight 
  indicates 
  a 
  superiority 
  or 
  inferiority 
  in 
  size, 
  and 
  the 
  

   difference 
  in 
  weight 
  represents 
  the 
  true 
  difference 
  in 
  mass. 
  

  

  Much 
  more 
  might 
  be 
  adduced 
  in 
  favour 
  of 
  the 
  hypothesis, 
  

   that 
  a 
  knowledge 
  of 
  the 
  weights 
  of 
  eggs 
  is 
  more 
  useful 
  than 
  a 
  

   knowledge 
  of 
  their 
  measurements 
  ; 
  but 
  no 
  useful 
  purpose 
  would 
  

   be 
  served 
  by 
  prolonging 
  this 
  argument. 
  We 
  cannot, 
  however, 
  

   leave 
  the 
  subject 
  without 
  illustrating 
  the 
  benefit 
  accruing 
  from 
  a 
  

   judicious 
  consideration 
  of 
  measurements 
  and 
  weights 
  when 
  taken 
  

   in 
  conjunction. 
  An 
  oologist, 
  with 
  a 
  precise 
  knowledge 
  of 
  the 
  

   measurements 
  and 
  weights 
  of 
  the 
  eggs 
  of 
  the 
  Limicolm, 
  reading 
  

   a 
  description 
  of 
  those 
  of 
  the 
  Gavice, 
  could 
  readily 
  deduce 
  the 
  

   more 
  obtuse 
  pyriformity 
  of 
  the 
  latter, 
  if 
  their 
  lengths, 
  breadths, 
  

   and 
  weights 
  were 
  given. 
  

  

  In 
  compiling 
  the 
  following 
  statistics 
  we 
  have 
  not 
  included 
  

   particulars 
  of 
  abnormal 
  eggs, 
  for, 
  however 
  interesting 
  they 
  may 
  

   be 
  to 
  the 
  specialist, 
  they 
  supply 
  no 
  material 
  help 
  to 
  the 
  intelli- 
  

   gent 
  study 
  of 
  ornithology. 
  At 
  the 
  same 
  time, 
  mistakes 
  arising 
  

   from 
  purely 
  natural 
  causes 
  are 
  so 
  easily 
  overlooked, 
  that 
  we 
  

   must 
  make 
  special 
  mention 
  of 
  a 
  few 
  of 
  them. 
  The 
  subtle 
  changes 
  

   incident 
  to 
  the 
  development 
  of 
  the 
  embryo 
  exert 
  a 
  profound 
  in- 
  

   fluence 
  on 
  the 
  weight 
  of 
  an 
  egg 
  ; 
  and, 
  as 
  nearly 
  all 
  " 
  errors 
  of 
  

   observation 
  " 
  arise 
  from 
  this 
  cause, 
  we 
  have 
  made 
  it 
  a 
  rule 
  to 
  

   reject 
  any 
  eggs 
  in 
  which 
  incubation 
  has 
  advanced 
  beyond 
  the 
  

   stage 
  of 
  the 
  " 
  primitive 
  streak." 
  Another 
  source 
  of 
  error 
  is 
  the 
  

   keeping 
  of 
  eggs 
  for 
  some 
  time 
  before 
  weighing 
  them, 
  for 
  as 
  soon 
  

   as 
  an 
  egg 
  is 
  laid 
  it 
  begins 
  to 
  lose 
  weight 
  owing 
  to 
  evaporation. 
  

   In 
  small 
  eggs 
  this 
  loss, 
  it 
  is 
  true, 
  is 
  infinitesimal 
  ; 
  but 
  in 
  large 
  

  

  