﻿56 
  Dr. 
  G. 
  Baur 
  on 
  the 
  

  

  7. 
  The 
  condyle 
  of 
  the 
  lower 
  jaw 
  is 
  more 
  or 
  less 
  convex 
  

   and 
  fits 
  into 
  a 
  concavity 
  of 
  the 
  quadrate*. 
  

  

  If 
  Meiolania 
  belongs 
  to 
  the 
  Pleurodira 
  we 
  ought 
  to 
  find 
  

   the 
  above 
  characters. 
  

  

  1. 
  The 
  sutures 
  between 
  the 
  pterygoids 
  and 
  the 
  adjacent 
  

   elements 
  cannot 
  be 
  distinguished 
  in 
  Meiolania 
  ; 
  a 
  comparison, 
  

   however, 
  of 
  the 
  skull 
  of 
  Meiolania 
  with 
  the 
  skulls 
  of 
  repre- 
  

   sentatives 
  of 
  the 
  different 
  families 
  of 
  the 
  Pleurodira 
  proves 
  

   that 
  the 
  pterygoids 
  extend 
  between 
  the 
  quadrate 
  and 
  basi- 
  

   sphenoid. 
  This 
  view 
  is 
  also 
  suggested 
  by 
  the 
  position 
  of 
  the 
  

   foramen 
  pterygoideurn. 
  

  

  In 
  the 
  Pleurodira 
  this 
  foramen 
  is 
  situated 
  free 
  on 
  the 
  base 
  

   of 
  the 
  skull 
  between 
  the 
  pterygoids 
  and 
  the 
  basisphenoid 
  ; 
  in 
  

   Meiolania 
  it 
  is 
  placed 
  far 
  back 
  as 
  in 
  the 
  Cryptodira. 
  

  

  2. 
  Meiolania 
  has 
  very 
  strong 
  descending 
  processes 
  to 
  join 
  

   the 
  well- 
  developed 
  vomer, 
  a 
  character 
  of 
  the 
  Cryptodira. 
  

  

  3. 
  The 
  pterygoids 
  in 
  Meiolania 
  are 
  not 
  turned 
  up 
  at 
  the 
  

   anterior 
  end, 
  as 
  in 
  all 
  Pleurodira. 
  Mr. 
  Boulenger 
  states 
  

   that 
  their 
  outer 
  palatal 
  borders, 
  instead 
  of 
  " 
  being 
  emarginate, 
  

   form 
  wing-like 
  expansions." 
  

  

  The 
  same 
  character 
  we 
  find 
  in 
  the 
  Trionychidse 
  and 
  very 
  

   often 
  in 
  the 
  Testudinidas 
  among 
  the 
  Cryptodira. 
  The 
  want 
  

   of 
  this 
  emargination 
  therefore 
  is 
  not 
  unique 
  for 
  the 
  Pleuro- 
  

   dira. 
  

  

  4. 
  The 
  front 
  of 
  the 
  brain- 
  case, 
  between 
  quadrate 
  and 
  pet- 
  

   rosal, 
  is 
  produced 
  as 
  in 
  the 
  Cryptodira. 
  

  

  5. 
  In 
  regard 
  to 
  the 
  epipterygoid 
  I 
  cannot 
  give 
  a 
  definite 
  

   opinion, 
  but 
  I 
  suppose 
  that 
  it 
  was 
  present. 
  

  

  6. 
  There 
  is 
  a 
  thin 
  bony 
  layer 
  extending 
  behind 
  over 
  the 
  

   tympanic 
  cavity 
  ; 
  but 
  this 
  layer 
  is 
  not 
  a 
  part 
  of 
  the 
  quadrate 
  

   as 
  in 
  all 
  the 
  Pleurodira, 
  but 
  it 
  represents 
  only 
  an 
  extension 
  

   of 
  the 
  dermal 
  ossifications 
  so 
  highly 
  developed 
  in 
  the 
  skull 
  of 
  

   Meiolania. 
  This 
  dermal 
  ossification 
  reaches 
  beliind 
  the 
  

   quadrate, 
  and 
  just 
  this 
  condition 
  proves 
  its 
  dermal 
  origin 
  ; 
  in 
  

   no 
  other 
  Chelonian 
  do 
  we 
  find 
  a 
  posterior 
  process 
  of 
  the 
  

   quadrate. 
  

  

  7. 
  The 
  condyle 
  of 
  the 
  lower 
  jaw 
  is 
  not 
  visible, 
  the 
  latter 
  

   being 
  not 
  separate 
  from 
  the 
  skull. 
  The 
  articular 
  face 
  of 
  the 
  

   quadrate, 
  however, 
  is 
  very 
  distinctly 
  shown 
  in 
  some 
  of 
  the 
  

   remains. 
  I 
  cannot 
  find 
  any 
  essential 
  difference 
  between 
  this 
  

   face 
  and 
  that 
  in 
  some 
  of 
  the 
  Testudinidse 
  ; 
  besides, 
  I 
  do 
  not 
  

   give 
  much 
  value 
  to 
  this 
  character, 
  only 
  well 
  developed 
  in 
  the 
  

   Podocnemididte 
  among 
  the 
  Pleurodira. 
  

  

  * 
  The 
  condyle 
  is 
  well 
  developed 
  in 
  the 
  Podocnemididye 
  and 
  Steruo- 
  

   thferida?, 
  but 
  not 
  distinct 
  in 
  the 
  Uhelvdridae. 
  

  

  