﻿128 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILlA 
  

  

  nals, 
  and 
  thinner 
  edged 
  more 
  recurved 
  marginals. 
  The 
  size 
  of 
  the 
  marginals 
  is 
  similar 
  

   to 
  those 
  of 
  the 
  last, 
  while 
  the 
  mesosternal 
  element 
  is 
  larger. 
  The 
  scutal 
  sutures 
  are 
  

   better 
  preserved 
  than 
  in 
  the 
  type 
  of 
  E. 
  petrosus, 
  nevertheless 
  none 
  are 
  preserved 
  on 
  the 
  

   lower 
  surfaces 
  except 
  that 
  which 
  divides 
  the 
  mesosternum 
  longitudinally 
  throughout. 
  

   The 
  vertebral 
  scuta 
  are 
  § 
  as 
  wide 
  as 
  long, 
  and 
  have 
  longitudinal 
  borders, 
  which 
  are 
  

   scarcely 
  produced 
  at 
  the 
  junction 
  with 
  the 
  intercostal 
  suture, 
  and 
  are 
  otherwise 
  somewhat 
  

   irregular. 
  The 
  carapace 
  is 
  swollen 
  in 
  an 
  interrupted 
  line 
  bordering 
  the 
  vertebral 
  scuta 
  

   externally, 
  leaving 
  the 
  median 
  parts 
  of 
  these 
  smooth. 
  The 
  marginals 
  are 
  also 
  slightly 
  

   swollen 
  just 
  within 
  the 
  costal-marginal 
  sutures. 
  The 
  marginal 
  bones 
  are 
  concave 
  exter- 
  

   nally, 
  and 
  thickened 
  inferiorly 
  at 
  some 
  distance 
  within 
  the 
  margin. 
  That 
  from 
  the 
  bridge 
  

   is 
  angulated 
  at 
  one 
  extremity 
  at 
  45°, 
  at 
  the 
  other 
  less. 
  The 
  union 
  of 
  the 
  hyosternals 
  

   behind 
  and 
  with 
  the 
  mesosternal 
  behind, 
  is 
  by 
  a 
  groove 
  and 
  keel 
  suture. 
  The 
  mesosternal 
  

   is 
  much 
  thinner 
  anteriorly 
  than 
  posteriorly. 
  

  

  In. 
  

  

  Length 
  heads 
  of 
  four 
  costals, 
  4.375 
  

  

  vertebral, 
  1.06 
  

  

  Width 
  " 
  1. 
  

  

  Length 
  hyosternal, 
  2.4 
  

  

  " 
  " 
  from 
  mesosternal, 
  1.8 
  

  

  Thickness 
  " 
  at 
  " 
  .65 
  

  

  " 
  . 
  " 
  posteriorly, 
  .7 
  

  

  Length 
  vertebral 
  scutum, 
  2.3 
  

   Width 
  " 
  " 
  .75 
  

  

  From 
  the 
  upper 
  Green 
  Sand 
  Bed, 
  Cretaceous 
  N. 
  J., 
  at 
  Hornerstown, 
  N. 
  J. 
  

  

  EMYS 
  PETROLEI, 
  Leidy. 
  

  

  Proceed. 
  Academy, 
  1858, 
  Postpliocene, 
  Harden 
  Co., 
  Texas. 
  

  

  A 
  very 
  distinct 
  species, 
  probably 
  of 
  the 
  more 
  terrestrial 
  type 
  of 
  the 
  genus, 
  as 
  Chc- 
  

   lopus, 
  etc. 
  

  

  ADOCUS, 
  Cope. 
  

  

  Emydoid 
  tortoises 
  in 
  which 
  the 
  rib 
  heads 
  of 
  the 
  posterior 
  costal 
  bones 
  are 
  represented 
  

   by 
  a 
  rudimental 
  lamina, 
  and 
  the 
  anterior 
  by 
  a 
  crest 
  or 
  truncate 
  ridge 
  in 
  addition. 
  Verte- 
  

   bral 
  scuta 
  narrow; 
  external 
  surfaces 
  smooth 
  or 
  nearly 
  so. 
  

  

  Name 
  from 
  A 
  privative 
  and 
  Awyms 
  rafter 
  {%. 
  e., 
  rib 
  head). 
  - 
  

  

  This 
  genus, 
  formerly 
  characterized, 
  differs 
  from 
  Emys 
  in 
  the 
  absence 
  of 
  costal 
  capitula 
  

   of 
  the 
  costal 
  plates 
  of 
  the 
  carapace, 
  a 
  feature 
  pointed 
  out 
  by 
  Leidy 
  in 
  the 
  type 
  species. 
  

  

  