﻿126 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  EMYS 
  FIRML 
  T 
  S, 
  Leidy. 
  

  

  Cretac. 
  Rept. 
  IOC, 
  Smithsonian 
  C 
  out 
  rib., 
  No. 
  192, 
  Adocus 
  firmus 
  Cope, 
  Proceed. 
  Acad. 
  Nat. 
  Sci., 
  Phil., 
  1868, 
  235, 
  

   Geolog. 
  Surv. 
  N. 
  Jersey, 
  App. 
  C. 
  

  

  An 
  individual 
  of 
  this 
  species 
  is 
  represented 
  by 
  same 
  characteristic 
  fragments 
  in 
  the 
  Museum 
  of 
  Rutger's 
  College, 
  

   N. 
  J. 
  As 
  remarked, 
  they 
  have 
  many 
  characters 
  like 
  the 
  following 
  species 
  ; 
  while 
  in 
  the 
  surface 
  markings, 
  dermal 
  

   scutes, 
  etc., 
  they 
  resemble 
  as 
  much 
  the 
  Adocus 
  beatus. 
  I 
  have 
  not 
  seen 
  the 
  costal 
  bones. 
  

  

  This 
  is 
  a 
  large 
  species 
  and 
  of 
  extraordinarily 
  massive 
  construction. 
  This 
  was 
  no 
  

  

  doubt 
  an 
  adaptation 
  in 
  defense 
  of 
  enemies, 
  perhaps 
  as 
  protection 
  from 
  blows 
  or 
  snaps 
  of 
  

  

  the 
  more 
  gigantic 
  reptiles 
  of 
  that 
  time. 
  I 
  give 
  the 
  measurement 
  of 
  this 
  species 
  from 
  

  

  Leidy. 
  

  

  In. 
  

  

  Length 
  margin 
  7th 
  and 
  eighth 
  marginals, 
  5.75 
  

  

  Width 
  seventh 
  plate, 
  2.5 
  

  

  eighth 
  " 
  2.75 
  

  

  Depth 
  " 
  3.75 
  

  

  Left 
  hyosternal, 
  length 
  from 
  exterior 
  angle 
  mesosternum 
  , 
  3. 
  

  

  Thickness 
  at 
  latter 
  suture, 
  1.+ 
  

  

  " 
  postero-medially, 
  .625 
  

  

  This 
  species 
  is 
  distinguished 
  from 
  both 
  the 
  following 
  by 
  the 
  relatively 
  much 
  larger 
  

   size 
  of 
  the 
  postero-median, 
  and 
  probably 
  the 
  other 
  marginal 
  bones. 
  Its 
  points 
  of 
  resem- 
  

   blance 
  to 
  the 
  E. 
  turgidus 
  are 
  more 
  numerous 
  than 
  to 
  the 
  E. 
  petrosus. 
  Like 
  both 
  of 
  

   these 
  the 
  mesosternum 
  is 
  truncate 
  behind. 
  

  

  Position. 
  The 
  upper 
  bed 
  of 
  Cretaceous 
  Green 
  Sand, 
  New 
  Jersey. 
  

  

  EMYS 
  PETROSTJS, 
  Cope. 
  

   Adocus 
  petrosus, 
  Cope, 
  Proc. 
  Acad. 
  Nat. 
  Sci., 
  Phila., 
  1868, 
  -36, 
  Geol. 
  Surv. 
  N. 
  Jersey, 
  App. 
  C. 
  

  

  This 
  species 
  is 
  represented 
  by 
  portions 
  of 
  four 
  costal 
  bones, 
  parts 
  or 
  wholes 
  of 
  six 
  marginal 
  bones, 
  most 
  of 
  the 
  

   right 
  hyosternal, 
  and 
  a 
  posterior 
  portion 
  of 
  the 
  right 
  hyposternal, 
  with 
  the 
  head 
  of 
  the 
  os 
  coracoVdeum. 
  They 
  were 
  

   found 
  in 
  the 
  West 
  Jersey 
  Marl 
  Company's 
  pits, 
  Gloucester 
  Co., 
  N. 
  J., 
  in 
  the 
  same 
  locality 
  whence 
  the 
  Laelaps 
  was 
  

   procured. 
  It 
  is 
  characterized 
  by 
  the 
  very 
  massive 
  structure 
  of 
  its 
  carapace 
  and 
  plastron, 
  and 
  for 
  the 
  posteriorly 
  

   truncate 
  form 
  of 
  its 
  mesosternum. 
  Another 
  species 
  (E. 
  firmus) 
  which 
  unites 
  the 
  same 
  peculiarities, 
  is 
  included 
  in 
  

   this 
  genus, 
  though 
  I 
  have 
  not 
  seen 
  its 
  costal 
  bones. 
  

  

  The 
  hyosternal 
  bone 
  is 
  preserved 
  in 
  its 
  axillary 
  margin, 
  and 
  is 
  continuous 
  with 
  two 
  marginals 
  of 
  the 
  carapace 
  

   of 
  the 
  same 
  side. 
  Two 
  of 
  the 
  costals 
  are 
  adjacent 
  and 
  give 
  the 
  outlines 
  of 
  the 
  vertebral 
  bones 
  and 
  scutes. 
  These 
  

   show 
  the 
  inferior 
  outline 
  to 
  be 
  very 
  convex, 
  the 
  whole, 
  from 
  angle 
  to 
  angle 
  of 
  the 
  marginal 
  bones 
  of 
  opposite 
  

   sides 
  amounting 
  to 
  an 
  arc 
  of 
  about 
  124 
  degrees. 
  Each 
  hyosternal 
  is 
  slightly 
  concave 
  below 
  the 
  plane 
  of 
  

   their 
  common 
  suture. 
  Each 
  thins 
  out 
  laterally, 
  though 
  the 
  one 
  preserved 
  is 
  very 
  thick 
  on 
  the 
  axillary 
  margin. 
  

   There 
  is 
  little 
  difference 
  between 
  the 
  thickness 
  at 
  the 
  mesosternal 
  and 
  the 
  hyposternal 
  sutures. 
  All 
  the 
  sutures 
  

   have 
  minute 
  rugosities, 
  differing 
  much 
  from 
  sternals 
  in 
  Adocus 
  and 
  Taphrosphys, 
  which 
  are 
  very 
  ragged, 
  and 
  

   resembling 
  those 
  of 
  Pleurosternum 
  pectorale 
  m. 
  The 
  piece 
  of 
  hyposternal 
  is 
  even 
  thicker 
  than 
  the 
  hyosternal. 
  The 
  

  

  