﻿46 
  On 
  the 
  Extinct 
  Giant 
  Birds 
  of 
  Argentina. 
  

  

  over 
  the 
  extensor 
  groove 
  of 
  the 
  tibia^ 
  the 
  South 
  American 
  

   forms 
  resemble 
  the 
  Dinoi'mthid(e 
  , 
  and 
  thereby 
  differ 
  from 
  

   all 
  existing 
  representatives 
  of 
  the 
  RatitaB. 
  They 
  likewise 
  

   approximate 
  to 
  Dinornis 
  (as 
  distinct 
  from 
  the 
  other 
  Moas) 
  and 
  

   Gastoi'nis 
  in 
  the 
  general 
  proportions 
  of 
  the 
  tibia 
  and 
  tarso- 
  

   metatarsus 
  ; 
  the 
  trochlese 
  of 
  the 
  latter 
  bone 
  having, 
  indeed, 
  

   j)recisely 
  the 
  same 
  relative 
  lengths 
  as 
  in 
  the 
  European 
  genus. 
  

   It 
  is 
  true 
  that 
  the 
  lower 
  end 
  of 
  the 
  tibia 
  has 
  not 
  the 
  inflection 
  

   characteristic 
  of 
  Gastornis, 
  but 
  the 
  Moas 
  show 
  that 
  this 
  

   feature 
  is 
  not 
  of 
  more 
  than 
  generic 
  importance. 
  So 
  far, 
  

   therefore, 
  as 
  the 
  limb-bones 
  go, 
  Phororhacos 
  and 
  Brontornis 
  

   might 
  apparently 
  be 
  distantly 
  related 
  to 
  Gastornis 
  and 
  the 
  

   Moas, 
  The 
  skulls 
  of 
  the 
  latter 
  show, 
  however, 
  that 
  the 
  giant 
  

   New 
  Zealand 
  birds 
  are 
  of 
  a 
  type 
  widely 
  different 
  from 
  those 
  

   of 
  South 
  America 
  ; 
  although, 
  if 
  we 
  believe 
  in 
  an 
  affinity 
  

   between 
  the 
  Moas 
  and 
  the 
  Kiwis, 
  we 
  must 
  not 
  attach 
  an 
  undue 
  

   weight 
  to 
  this 
  point 
  of 
  difference. 
  

  

  With 
  regard 
  to 
  Gastornis, 
  the 
  case 
  is 
  more 
  difficult. 
  

   According, 
  however, 
  to 
  Lemoine's 
  restoration, 
  the 
  mandibular 
  

   symphysis 
  was 
  short, 
  and 
  the 
  upper 
  jaw 
  wider 
  than 
  in 
  PAoro- 
  

   rhacos. 
  Still, 
  however, 
  we 
  have 
  a 
  declination 
  of 
  the 
  tip 
  o£ 
  

   the 
  premaxilla 
  comparable 
  to 
  the 
  description 
  of 
  the 
  latter 
  ; 
  

   and, 
  for 
  what 
  it 
  is 
  worth, 
  the 
  presence 
  in 
  both 
  of 
  alveolar- 
  

   like 
  structures. 
  

  

  That 
  both 
  Gastornis 
  on 
  the 
  one 
  hand, 
  and 
  Brontornis 
  and 
  

   Phororhacos 
  on 
  the 
  other, 
  cannot 
  be 
  excluded 
  from 
  the 
  

   Ratitse 
  as 
  at 
  present 
  defined, 
  appears, 
  as 
  I 
  have 
  already 
  said, 
  

   certain. 
  If, 
  however, 
  they 
  be 
  rightly 
  included 
  in 
  that 
  group, 
  

   and 
  the 
  presumed 
  affinity 
  of 
  Gastornis 
  to 
  the 
  Anseres 
  be 
  

   sustained, 
  while 
  the 
  apparent 
  resemblance 
  of 
  the 
  jaw 
  of 
  

   Phororhacos 
  to 
  Psophia 
  indicates 
  a 
  relationship, 
  then 
  we 
  shall 
  

   have 
  confirmatory 
  evidence 
  in 
  favour 
  of 
  the 
  modern 
  German 
  

   view 
  that 
  the 
  Ratitse 
  form 
  a 
  compound 
  group, 
  of 
  which 
  the 
  

   various 
  sections 
  have 
  been 
  independently 
  derived 
  from 
  several 
  

   perfectly 
  distinct 
  Carinate 
  ancestors, 
  and 
  that 
  their 
  mutual 
  

   resemblances 
  to 
  one 
  another 
  are 
  solely 
  owing 
  to 
  the 
  effects 
  of 
  

   adaptation. 
  I 
  confess, 
  however, 
  that 
  the 
  supposed 
  Anserine 
  

   affinities 
  of 
  Gastornis 
  appear 
  far 
  from 
  clear 
  to 
  me, 
  while 
  I 
  

  

  