﻿138 
  , 
  THE 
  EXTINCT 
  BATRACHIA, 
  HEPTIEIA 
  

  

  The 
  femur 
  presents 
  the 
  usual 
  constricted 
  cylindrie 
  shaft, 
  with 
  trochanters 
  whose 
  planes 
  include 
  an 
  angle 
  a 
  little 
  

   less 
  than 
  90°. 
  

  

  In. 
  Lin. 
  

  

  Length 
  of 
  eleventh 
  marginal, 
  3 
  6.3 
  

  

  Width 
  " 
  " 
  4 
  .3 
  

  

  Width 
  of 
  a 
  costal, 
  3 
  2. 
  

  

  " 
  " 
  first 
  marginal, 
  22.5 
  

  

  Length 
  " 
  " 
  2 
  7. 
  

  

  " 
  nuchal 
  hone, 
  5 
  

  

  " 
  vertebral, 
  2 
  3. 
  

  

  Width 
  " 
  15.5 
  

  

  Diameter 
  shaft 
  of 
  femur, 
  7.3 
  

  

  OSTEOPYGIS 
  CHELYDRINTIS, 
  Cope, 
  Sp. 
  nov. 
  

  

  This 
  large 
  and 
  most 
  distinct 
  species 
  was 
  found 
  in 
  the 
  same 
  locality 
  as 
  the 
  preceding. 
  It 
  is 
  unfortunately 
  only 
  

   represented 
  by 
  ten 
  marginal 
  plates 
  more 
  or 
  less 
  perfect, 
  and 
  portions 
  of 
  some 
  costals, 
  hut 
  these 
  are 
  sufficient 
  to 
  indicate 
  

   some 
  of 
  its 
  peculiarities. 
  It 
  combines 
  more 
  of 
  the 
  peculiarities 
  of 
  Chelydra 
  in 
  these 
  pieces, 
  as 
  Euclastes 
  does 
  in 
  the 
  

   physiognomy 
  of 
  its 
  cranium. 
  

  

  The 
  marginal 
  bones 
  are 
  relatively 
  much 
  shorter 
  than 
  in 
  any 
  of 
  the 
  other 
  species. 
  It 
  is 
  however 
  referred 
  to 
  this 
  

   genus 
  with 
  certainty 
  since 
  the 
  anterior 
  rib-bearing 
  marginal 
  bone 
  has 
  been 
  united 
  with 
  the 
  middle 
  disc 
  by 
  suture, 
  

   and 
  some 
  of 
  those 
  posterior 
  are 
  ossified 
  within 
  the 
  common 
  margin 
  of 
  the 
  costal 
  and 
  marginal 
  scuta. 
  The 
  outer 
  

   margin 
  of 
  these 
  and 
  of 
  the 
  median 
  bones 
  of 
  the 
  series, 
  is 
  very 
  heavy, 
  but 
  little 
  produced, 
  but 
  projecting 
  from 
  a 
  

   concave 
  upper 
  face. 
  The 
  inferior 
  faces 
  of 
  the 
  posterior 
  median 
  are 
  convex 
  and 
  produced 
  inwards 
  further 
  than 
  usual, 
  

   and 
  joins 
  the 
  inner 
  face 
  by 
  an 
  obtuse 
  angle. 
  The 
  rib-pits 
  extend 
  deeply, 
  or 
  to 
  within 
  a 
  short 
  distance 
  of 
  the 
  surface. 
  

   One 
  posterior 
  marginal 
  is 
  thicker 
  than 
  in 
  0. 
  e 
  m 
  a 
  r 
  g 
  i 
  n 
  a 
  t 
  u 
  s 
  and 
  has 
  a 
  convex 
  inferior 
  face. 
  The 
  upper 
  margin 
  

   of 
  the 
  inner 
  face 
  is 
  prolonged 
  above 
  the 
  lower. 
  The 
  rib-pit 
  is 
  round; 
  the 
  dermal 
  suture 
  well 
  marked. 
  On 
  this 
  bone 
  

   the 
  character 
  of 
  the 
  posterior 
  outline 
  is 
  marked. 
  The 
  anterior 
  half 
  of 
  the 
  margin 
  is 
  quite 
  concave, 
  leaving 
  a 
  strong 
  

   and 
  prominent 
  angle 
  at 
  the 
  extremity 
  of 
  the 
  dermal 
  suture. 
  This 
  is 
  much 
  stronger 
  than 
  those 
  seen 
  in 
  Catapleura 
  

   repanda, 
  though 
  the 
  bone 
  described 
  is 
  more 
  posterior 
  than 
  those 
  of 
  the 
  latter. 
  

  

  The 
  surface 
  of 
  the 
  posterior 
  bone 
  has 
  some 
  faint 
  vascular 
  grooves; 
  the 
  others 
  are 
  without 
  them, 
  but 
  are 
  of 
  a 
  

   coarse 
  texture. 
  

  

  Measurements. 
  

  

  Length 
  posterior 
  marginal, 
  

  

  Width 
  " 
  " 
  

  

  Depth 
  " 
  " 
  within, 
  

  

  Width 
  lower 
  face 
  middle 
  marginal, 
  

  

  Length 
  anterior 
  united 
  marginal, 
  

  

  Width 
  " 
  " 
  " 
  

  

  Width 
  dermal 
  scute 
  on 
  same, 
  

  

  Thickness 
  costal 
  bone, 
  

  

  PROPLEURA, 
  Cope. 
  

  

  This 
  genus 
  of 
  Chelydrinae 
  is 
  intermediate 
  between 
  Ostcopygis 
  and 
  Lytoloma, 
  present- 
  

   ing 
  more 
  characters 
  of 
  the 
  former 
  than 
  of 
  the 
  latter, 
  so 
  for 
  as 
  regards 
  the 
  carapace. 
  The 
  

   marginal 
  hones 
  are 
  free 
  behind, 
  except 
  probably 
  that 
  the 
  median 
  is 
  attached 
  to 
  the 
  

   posterior 
  supernumerary 
  vertebral 
  (this 
  piece 
  is 
  lost 
  in 
  my 
  specimens) 
  ; 
  and 
  the 
  series 
  of 
  

   marginal 
  dermal 
  scuta 
  are 
  connected 
  by 
  a 
  median 
  marginal 
  cut 
  off 
  from 
  the 
  anterior 
  

  

  In 
  

  

  Lin. 
  

  

  2 
  

  

  9.3 
  

  

  3 
  

  

  2. 
  

  

  

  9.o 
  

  

  1 
  

  

  7.7 
  

  

  2 
  

  

  G. 
  

  

  1 
  

  

  9. 
  

  

  1 
  

  

  ?.S 
  

  

  

  4. 
  

  

  