﻿Systematic 
  Position 
  of 
  Meiolania, 
  Owen. 
  57 
  

  

  We 
  see 
  itiere 
  is 
  not 
  a 
  single 
  definite 
  character 
  in 
  the 
  skull 
  of 
  

   Meiolania 
  which 
  could 
  prove 
  its 
  Pleurodiran 
  nature. 
  

  

  The 
  cervical 
  vertebras 
  form 
  another 
  evidence 
  for 
  the 
  syste- 
  

   matic 
  position 
  of 
  Meiolania 
  among 
  the 
  Pleurodira, 
  according 
  

   to 
  Mr. 
  Boulenger. 
  

  

  Only 
  the 
  first 
  two 
  vertebras 
  being 
  present 
  in 
  Meiolania, 
  we 
  

   may 
  at 
  first 
  examine 
  what 
  are 
  the 
  principal 
  characters 
  of 
  the 
  

   first 
  two 
  cervical 
  vertebras 
  in 
  the 
  Pleurodira. 
  

  

  1. 
  The 
  centrum 
  of 
  the 
  first 
  vertebra 
  (the 
  so-called 
  odontoid 
  

   process) 
  is 
  absolutely 
  free 
  from 
  the 
  second, 
  with 
  which 
  it 
  

   articulates 
  freely. 
  

  

  2. 
  It 
  is 
  the 
  centrum 
  which 
  supports 
  the 
  neuroids 
  of 
  the 
  

   atlas 
  5 
  the 
  first 
  intercentrum 
  (hypapophysis) 
  is 
  very 
  small, 
  

   free 
  or 
  coossified 
  with 
  the 
  atlas-centrum. 
  The 
  atlas 
  therefore 
  

   looks 
  very 
  much 
  like 
  the 
  other 
  cervical 
  vertebras, 
  especially 
  in 
  

   the 
  Sternothasridas 
  and 
  Chelydridas. 
  The 
  Podocnemididse 
  

   show 
  the 
  same 
  character 
  ; 
  but 
  the 
  atlas-centrum 
  is 
  not 
  so 
  

   elongate 
  and 
  the 
  neuroids 
  are 
  not 
  ossified 
  as 
  in 
  the 
  other 
  

   Pleurodira. 
  The 
  first 
  intercentrum 
  is 
  very 
  small, 
  free, 
  and 
  

   slightly 
  connected 
  with 
  the 
  neuroids; 
  but 
  there 
  is 
  never 
  an 
  

   " 
  atlas-ring." 
  

  

  3. 
  In 
  all 
  the 
  Pleurodira 
  well-developed 
  diapophyses 
  are 
  

   present, 
  in 
  the 
  second 
  and 
  all 
  the 
  following 
  cervicals 
  they 
  are 
  

   placed 
  in 
  the 
  middle 
  of 
  the 
  vertebras. 
  

  

  4. 
  In 
  none 
  of 
  the 
  Pleurodira 
  does 
  the 
  diapophysis 
  of 
  the 
  

   first 
  vertebra 
  form 
  a 
  foramen 
  with 
  the 
  first 
  intercentrum. 
  

  

  Now 
  what 
  do 
  we 
  find 
  in 
  Meiolania'} 
  

  

  1. 
  The 
  centrum 
  of 
  the 
  first 
  vertebra 
  is 
  not 
  absolutely 
  free 
  

   from 
  the 
  second, 
  but 
  more 
  or 
  less 
  connected, 
  as 
  in 
  the 
  Cryp- 
  

   todira. 
  

  

  2. 
  The 
  first 
  intercentrum 
  is 
  very 
  large 
  and 
  supports 
  the 
  

   neuroids 
  of 
  the 
  atlas, 
  forming 
  an 
  atlas-ring, 
  exactly 
  as 
  in 
  the 
  

   Cryptodira. 
  

  

  3. 
  There 
  is 
  a 
  very 
  well-developed 
  diapophysis 
  on 
  the 
  second 
  

   vertebra, 
  not 
  placed 
  in 
  the 
  middle, 
  but 
  on 
  the 
  anterior 
  part 
  of 
  

   the 
  vertebra, 
  exactly 
  as 
  in 
  Staurotypus 
  and 
  especially 
  in 
  

  

  Testudo 
  polyphemus 
  and 
  other 
  Cryptodira. 
  

  

  4. 
  The 
  diapophysis 
  of 
  the 
  neuroids 
  of 
  the 
  atlas 
  forms 
  a 
  

   foramen 
  with 
  the 
  first 
  intercentrum 
  exactly 
  as 
  in 
  Staurotypus, 
  

   Testudo 
  polyphemus, 
  and 
  other 
  Cryptodira. 
  

  

  We 
  see 
  that 
  the 
  cervical 
  vertebras 
  are 
  not 
  at 
  all 
  Pleuro- 
  

   diran, 
  but 
  truly 
  Cryptodiran. 
  

  

  How 
  Mr. 
  Boulenger 
  could 
  compare 
  the 
  cervicals 
  of 
  Meio- 
  

   lania 
  with 
  those 
  of 
  Chelys 
  I 
  do 
  not 
  understand. 
  There 
  could 
  

   not 
  be 
  a 
  greater 
  fundamental 
  difference. 
  

  

  The 
  so-called 
  Pleurodiran 
  characters 
  of 
  Mr. 
  Boulenger 
  do 
  

  

  