﻿AND 
  AYES 
  OF 
  NORTH 
  AMERICA. 
  " 
  125 
  

  

  timate 
  marginal, 
  joins 
  a 
  superior 
  angle 
  of 
  the 
  antepenult. 
  The 
  superior 
  margin 
  of 
  the 
  penultimate 
  is 
  straight, 
  and 
  

   but 
  little 
  elevated 
  above 
  the 
  caudal 
  pair. 
  From 
  this 
  increased 
  width 
  of 
  the 
  last 
  vertebral, 
  its 
  lateral 
  suture 
  is 
  

   more 
  oblique, 
  and 
  what 
  remains 
  of 
  the 
  lateral 
  suture 
  of 
  the 
  penultimate 
  vertebral 
  is 
  still 
  more 
  oblique, 
  indicating 
  

   a 
  still 
  wider 
  scutum. 
  The 
  posterior 
  vertebral 
  bone 
  is 
  a 
  little 
  more 
  elongate 
  than 
  in 
  several 
  individuals 
  of 
  0. 
  clausa. 
  

  

  The 
  posterior 
  margin 
  is 
  not 
  recurved, 
  but 
  is 
  vertical, 
  and 
  therefore 
  from 
  a 
  female 
  animal. 
  There 
  are 
  no 
  em; 
  r- 
  

   ginations 
  or 
  processes. 
  On 
  the 
  inferior 
  aspect, 
  the 
  concavity 
  which 
  receives 
  the 
  crest 
  of 
  the 
  ilium 
  is 
  deeper 
  and 
  

   nearer 
  the 
  margin 
  than 
  in 
  C. 
  clausa. 
  

  

  This 
  species 
  was 
  found 
  by 
  Samuel 
  E. 
  Harrison, 
  M. 
  D., 
  of 
  Easton, 
  Md., 
  on 
  Oxford 
  Neck 
  in 
  Talbot 
  Co., 
  Mary- 
  

   land, 
  in 
  connection 
  with 
  postpliocene 
  fossils, 
  as 
  follows: 
  Elephas 
  americanus, 
  Cervus 
  canadensis, 
  Cariacus 
  virginianus, 
  

   Chelydra 
  serpentina. 
  

  

  Remains 
  of 
  a 
  Cistudo 
  occur 
  in 
  the 
  postpliocene 
  bone 
  breccia 
  of 
  caves 
  in 
  S. 
  W. 
  Virginia, 
  but 
  whether 
  they 
  belong 
  

   . 
  to 
  C. 
  cl 
  a 
  usa 
  or 
  some 
  other 
  species 
  is 
  not 
  as 
  yet 
  determined. 
  

  

  EMYS, 
  Brongniart. 
  

  

  The 
  only 
  species 
  of 
  this 
  genus 
  which 
  I 
  have 
  had 
  the 
  opportunity 
  of 
  studying 
  are 
  the 
  

   three 
  following 
  from 
  the 
  cretaceous 
  green-sand 
  of 
  New 
  Jersey. 
  They 
  agree 
  in 
  the 
  mas- 
  

   sive 
  thickness 
  and 
  dense 
  structure 
  of 
  plastron 
  and 
  carapace, 
  which 
  peculiarity 
  suggests 
  

   doubt 
  as 
  to 
  their 
  aquatic 
  habitat, 
  and 
  enquiry 
  as 
  to 
  whether 
  they 
  may 
  not 
  have 
  been 
  

   more 
  or 
  less 
  terrestrial. 
  Their 
  reference 
  to 
  Emys 
  is 
  provisional, 
  as 
  the 
  limbs, 
  cranium 
  

   and 
  caudal 
  marginal 
  scute 
  are 
  unknown. 
  In 
  E. 
  petrosus 
  the 
  heads 
  of 
  the 
  posterior 
  ribs 
  

   are 
  rudimental 
  as 
  in 
  Adocus. 
  

  

  The 
  species 
  may 
  be 
  distinguished 
  as 
  follows: 
  

  

  Sutures 
  of 
  hyo-and 
  hyposternal 
  bones, 
  coarse 
  and 
  ragged; 
  hyosternal 
  nearly 
  twice 
  as 
  

   thick 
  anteriorly 
  as 
  posteriorly; 
  eighth 
  marginal 
  acute 
  edged, 
  its 
  width 
  11-12 
  length 
  hyos- 
  

   ternal, 
  its 
  depth 
  5—4 
  the 
  same. 
  

  

  E. 
  FIRMUS. 
  

  

  Sutures 
  minutely 
  rugulose, 
  hyosternal 
  thicker 
  anteriorly; 
  eighth 
  marginal 
  with 
  thick 
  

   obtuse 
  edge, 
  depth 
  3-4 
  length 
  hyosternal, 
  its 
  width 
  .55 
  same 
  ; 
  superior 
  plane 
  of 
  hyoster- 
  

   nal 
  transversely 
  as 
  wide 
  as 
  a 
  costal, 
  inferior 
  plane 
  very 
  convex 
  ; 
  mesosternum 
  width 
  .66 
  

   length 
  of 
  do.; 
  size 
  medium. 
  

  

  E. 
  PETROSUS. 
  

  

  Sutures 
  minutely 
  rugulose; 
  hyosternal 
  thickest 
  posteriorly, 
  its 
  inferior 
  face 
  plane, 
  

   superior 
  plane 
  twice 
  as 
  wide 
  as 
  a 
  costal 
  ; 
  width 
  of 
  mesosternum 
  6—7 
  length, 
  and 
  width 
  of 
  

   eighth 
  marginal 
  .05 
  length 
  of 
  same; 
  size 
  smaller; 
  

  

  E. 
  TURGIDUS. 
  

  

  AMERI. 
  nilLOSO. 
  SOC. 
  — 
  VOL. 
  XIV. 
  32 
  

  

  