﻿614 
  rnocKEinxcrS 
  of 
  the 
  xatioxjl 
  museum. 
  

  

  It 
  is 
  not 
  too 
  mueh 
  to 
  say, 
  then, 
  that 
  as 
  there 
  is 
  probably 
  not 
  a 
  single 
  

   island 
  all 
  of 
  the 
  resident 
  land 
  birds 
  of 
  which 
  are 
  known 
  the 
  broken 
  line 
  

   in 
  our 
  curves 
  is 
  everywhere 
  too 
  low; 
  that 
  the 
  error 
  is 
  smallest 
  for 
  those 
  

   islands 
  that 
  are 
  best 
  known 
  and 
  greatest 
  for 
  those 
  that 
  are 
  least 
  

   known. 
  

  

  Unfortunately 
  the 
  number 
  of 
  genera 
  recorded 
  from 
  an 
  island 
  is 
  not 
  

   exactly 
  indicative 
  of 
  the 
  completeness 
  of 
  our 
  knowledge 
  of 
  it, 
  since 
  

   some 
  islands 
  doubtless 
  have 
  more 
  genera 
  tlian 
  others. 
  It 
  seems, 
  how- 
  

   ever, 
  to 
  be 
  the 
  most 
  satisfactory 
  index 
  available, 
  and 
  in 
  Curve 
  III 
  the 
  

   islands 
  are 
  arranged 
  not 
  according 
  to 
  size, 
  but 
  on 
  the 
  number 
  of 
  genera 
  

   having 
  two 
  or 
  more 
  species 
  in 
  the 
  Philippines 
  known 
  from 
  each. 
  The 
  

   number 
  t)f 
  genera 
  is 
  indicated 
  by 
  units 
  arranged 
  in 
  horizontal 
  series, 
  

   4 
  units 
  being 
  allowed 
  for 
  each 
  genus. 
  On 
  this 
  basis 
  I 
  have 
  compared 
  

   the 
  percentages 
  of 
  genera 
  distributed 
  in 
  the 
  two 
  ways 
  for 
  each 
  island, 
  

   reckoning 
  percentages 
  as 
  before. 
  

  

  Irregularities 
  in 
  our 
  curve 
  are 
  not 
  lacking, 
  but 
  the 
  more 
  imi)(>rtant 
  

   of 
  them 
  have 
  already 
  been 
  discussed, 
  and 
  the 
  curve 
  establishes 
  beyond 
  

   a 
  doubt 
  the 
  fact 
  that 
  Steere's 
  law 
  receives 
  its 
  strongest 
  confirmation 
  in 
  

   the 
  islands 
  from 
  which 
  the 
  smallest 
  number 
  of 
  genera 
  is 
  at 
  present 
  

   known, 
  and 
  that 
  as 
  our 
  knowledge 
  increases 
  the 
  percentage 
  of 
  genera 
  

   represented 
  by 
  a 
  single 
  species 
  steadily 
  falls. 
  

  

  It 
  may 
  be 
  objected 
  that 
  my 
  treatment 
  of 
  this 
  subject 
  has 
  been 
  unfair, 
  

   in 
  that 
  I 
  have 
  omitted 
  from 
  consideration, 
  in 
  reckoning 
  percentages 
  for 
  

   Curves 
  II 
  and 
  III, 
  the 
  genera 
  of 
  Table 
  I> 
  wherever 
  they 
  happened 
  to 
  

   be 
  represented 
  by 
  but 
  a 
  single 
  species. 
  It 
  may 
  be 
  said 
  that 
  I 
  ought 
  to 
  

   consider 
  each 
  instance 
  where 
  a 
  single 
  species 
  of 
  one 
  of 
  these 
  genera 
  is 
  

   recorded 
  from 
  an 
  island 
  as 
  a 
  contirmation 
  of 
  Steere's 
  law, 
  rather 
  than 
  

   as 
  a 
  bit 
  of 
  evidence 
  incomplete, 
  and 
  therefore 
  to 
  be 
  ignored. 
  

  

  I 
  might 
  well 
  reply 
  that 
  in 
  view 
  of 
  the 
  heavj' 
  chances 
  against 
  the 
  dis- 
  

   covery 
  of 
  exceptions 
  to 
  the 
  law, 
  it 
  is 
  no 
  more 
  than 
  fair 
  to 
  leave 
  the 
  gen- 
  

   era 
  of 
  Table 
  B 
  out 
  of 
  account 
  in 
  islands 
  where 
  but 
  one 
  species 
  happens 
  

   to 
  have 
  been 
  recorded, 
  and 
  as 
  a 
  further 
  offset 
  might 
  add 
  that 
  in 
  plot- 
  

   ting 
  the 
  curves 
  no 
  more 
  importance 
  has 
  been 
  given 
  to 
  an 
  exception 
  

   where 
  six 
  species 
  of 
  a 
  genus 
  occur 
  in 
  an 
  island 
  than 
  to 
  one 
  based 
  upon 
  

   the 
  occurrence 
  of 
  but 
  two. 
  On 
  the 
  whole, 
  then, 
  I 
  believe 
  my 
  treatment 
  

   has 
  been 
  fair; 
  but 
  in 
  order 
  to 
  test 
  further 
  the 
  general 
  correctness 
  of 
  my 
  

   results 
  I 
  have 
  constructed 
  two 
  more 
  curves, 
  in 
  which 
  I 
  have 
  given 
  

   Steere's 
  law 
  the 
  benefit 
  of 
  every 
  doubt, 
  and 
  have 
  counted 
  every 
  case 
  

   where 
  a 
  genus 
  of 
  Table 
  B 
  is 
  recorded 
  with 
  but 
  one 
  species 
  as 
  a 
  con 
  

   firmation 
  of 
  it. 
  In 
  Curves 
  IV 
  and 
  V 
  the 
  percentages 
  of 
  .v^^ecie^- 
  distributed 
  

   in 
  the 
  two 
  ways 
  are 
  shown. 
  

  

  Arranging 
  the 
  islands 
  in 
  order 
  of 
  their 
  size 
  we 
  get 
  Curve 
  lY, 
  which 
  

   does 
  not 
  differ 
  in 
  any 
  essential 
  particular 
  from 
  those 
  already 
  obtained, 
  

   and 
  enforces 
  the 
  same 
  conclusiou 
  stated 
  in 
  terms 
  of 
  species 
  that 
  Curve 
  

   II 
  enforces 
  stated 
  in 
  terms 
  of 
  genera. 
  We 
  see 
  that 
  in 
  the 
  smaller 
  

   islands 
  nearly 
  or 
  quite 
  all 
  the 
  recorded 
  species 
  belong 
  to 
  different 
  gen- 
  

  

  