﻿178 
  PROF. 
  OWEN 
  ON 
  AN 
  EXTINCT 
  CHELONIAN 
  

  

  17. 
  On 
  an 
  Extinct 
  Chelonian 
  Reptile 
  (Notochelys 
  costata, 
  Owen), 
  

   from 
  Australia. 
  By 
  Prof. 
  Owen, 
  C.B., 
  F.B.S., 
  F.G.S., 
  &c. 
  

   (Bead 
  January 
  25, 
  1882.) 
  

  

  Order 
  CHELONIA. 
  

  

  Genus 
  Notochelys 
  *. 
  

  

  Species 
  Notochelys 
  costata. 
  

  

  Hitherto 
  the 
  fossil 
  reptilian 
  remains 
  transmitted 
  to 
  me 
  for 
  descrip- 
  

   tion 
  from 
  Australia 
  have 
  been 
  limited 
  to 
  parts 
  of 
  the 
  skeleton 
  of 
  

   the 
  great 
  horned 
  Lacertian 
  (Megalania 
  prisca, 
  Ow.t). 
  

  

  The 
  first 
  evidence 
  of 
  a 
  Chelonian 
  from 
  that 
  continent 
  was 
  sent 
  in 
  the 
  

   present 
  year 
  (1881), 
  by 
  our 
  fellow 
  Member 
  Professor 
  Archibald 
  

   Liversidge, 
  of 
  the 
  University 
  of 
  Sydney, 
  New 
  South 
  Wales. 
  He 
  

   kindly 
  permitted 
  a 
  mould 
  to 
  be 
  taken 
  of 
  the 
  specimen, 
  with 
  the 
  

   request 
  that 
  the 
  original 
  should 
  be 
  returned 
  to 
  him 
  after 
  a 
  de- 
  

   scription 
  and 
  figure 
  had 
  appeared. 
  The 
  mould 
  and 
  casts 
  are 
  in 
  the 
  

   British 
  Museum, 
  Cromwell 
  Boad. 
  

  

  The 
  specimen 
  was 
  found 
  in 
  a 
  formation 
  at 
  Minders 
  Biver, 
  Queens- 
  

   land 
  ; 
  but 
  the 
  nature 
  and 
  age 
  of 
  the 
  deposit 
  are 
  not 
  stated. 
  It 
  is 
  

   petrified 
  and, 
  with 
  the 
  imbedding 
  matrix, 
  of 
  great 
  weight. 
  

  

  The 
  fossil 
  consists 
  of 
  an 
  anterior 
  portion 
  of 
  the 
  carapace 
  (fig. 
  1) 
  

   and 
  of 
  the 
  plastron 
  (fig. 
  2) 
  brought 
  into 
  unnaturally 
  close 
  contact 
  by 
  

   posthumous 
  pressure. 
  

  

  The 
  carapace 
  includes 
  the 
  four 
  anterior 
  and 
  part 
  of 
  the 
  fifth 
  

   neural 
  plates 
  (fig. 
  1, 
  s 
  i, 
  2, 
  3, 
  4, 
  s), 
  and 
  the 
  second, 
  third, 
  fourth 
  

   and 
  expanded 
  portion 
  of 
  the 
  first 
  costal 
  plates 
  of 
  the 
  left 
  side 
  (ib. 
  

   pi 
  i', 
  2', 
  3', 
  4') 
  ; 
  of 
  the 
  proximal 
  or 
  expanded 
  portions 
  of 
  the 
  right 
  

   second, 
  third, 
  and 
  fourth 
  costal 
  plates 
  (ib. 
  pi. 
  2, 
  3, 
  4,) 
  with 
  a 
  frag- 
  

   ment 
  of 
  the 
  first 
  (pi. 
  lr) 
  ; 
  a 
  portion 
  of 
  the 
  left 
  half 
  of 
  the 
  nuchal 
  

   plate 
  (cli) 
  ; 
  and 
  portions 
  of 
  the 
  first 
  and 
  second 
  marginal 
  plates 
  of 
  

   the 
  left 
  side 
  (m 
  1, 
  m 
  2). 
  

  

  The 
  preserved 
  part 
  of 
  the 
  plastron 
  includes 
  the 
  right 
  and 
  left 
  

   coalesced 
  hyo- 
  and 
  hyposternals 
  (fig. 
  2, 
  Jvps, 
  r, 
  and 
  hps, 
  I), 
  indications 
  

   of 
  the 
  episternals 
  and 
  the 
  entosternal 
  ; 
  and, 
  anterior 
  to 
  these 
  parts 
  

   of 
  the 
  plastron, 
  both 
  scapulo- 
  acromial 
  bones 
  (51) 
  have 
  been 
  brought 
  

   into 
  view. 
  

  

  The 
  first 
  neural 
  plate 
  (fig. 
  1, 
  s 
  1), 
  1 
  inch 
  10 
  lines 
  long 
  by 
  9 
  lines 
  

   broad, 
  has 
  a 
  small 
  portion 
  of 
  the 
  left 
  antero-lateral 
  angle 
  preserved 
  

   with 
  the 
  rest 
  of 
  the 
  plate 
  : 
  this 
  slightly 
  decreases 
  in 
  breadth 
  toward 
  

   the 
  hinder 
  junction 
  with 
  the 
  second 
  neural 
  (s 
  2). 
  The 
  impression 
  of 
  

   the 
  transverse 
  junction 
  of 
  the 
  first 
  vertebral 
  scute 
  (v 
  1), 
  with 
  the 
  

   second 
  (v 
  2), 
  crosses 
  the 
  plate 
  s 
  1 
  near 
  its 
  mid 
  length. 
  

  

  * 
  votos, 
  south, 
  xeAw?, 
  tortoise. 
  

  

  t 
  Phil. 
  Trans, 
  for 
  the 
  years 
  1858, 
  1880 
  and 
  1881. 
  

  

  