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  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  costals 
  is 
  without 
  gomphosis, 
  and 
  by 
  light 
  squamosal 
  suture, 
  except 
  in 
  front 
  and 
  at 
  the 
  

   bridge, 
  where 
  the 
  suture 
  is 
  closer 
  and 
  the 
  bones 
  thicker. 
  

  

  In 
  three 
  species 
  the 
  iliac 
  pit 
  has 
  been 
  seen 
  in 
  numerous 
  specimens 
  from 
  both 
  sides 
  of 
  

   the 
  carapace. 
  In 
  all 
  cases 
  it 
  is 
  very 
  elongate, 
  opening 
  posteriorly 
  on 
  the 
  plane 
  of 
  the 
  

   costal 
  bone. 
  It 
  extends 
  to 
  near 
  the 
  margins 
  of 
  the 
  last 
  and 
  penultimate 
  costals, 
  commen- 
  

   cing 
  near 
  the 
  proximal 
  or 
  vertebral 
  end. 
  The 
  pit 
  which 
  receives 
  the 
  axillary 
  buttress 
  is 
  

   well 
  defined, 
  near 
  the 
  extremity 
  of 
  the 
  first 
  costal 
  bone 
  ; 
  the 
  end 
  opposite 
  to 
  it 
  is 
  crossed 
  

   by 
  a 
  suture 
  of 
  the 
  first 
  vertebral 
  scutum 
  ; 
  a 
  ridge 
  also 
  extends 
  from 
  the 
  pit 
  to 
  the 
  capitu- 
  

   lum 
  : 
  just 
  anterior 
  to 
  the 
  latter 
  a 
  strong 
  crest 
  probably 
  represents 
  the 
  connate 
  first 
  rib, 
  

   which 
  is 
  free 
  in 
  some 
  Emydidae. 
  

  

  The 
  posterior 
  lobe 
  of 
  the 
  plastron 
  is 
  deeply 
  emarginate. 
  

  

  The 
  materials 
  on 
  which 
  the 
  generic 
  and 
  specific 
  characters 
  of 
  the 
  tortoises 
  included 
  

   under 
  this 
  head 
  have 
  been 
  based 
  are 
  abundant 
  in 
  the 
  middle 
  bed 
  of 
  Cretaceous 
  Green 
  

   Sand 
  in 
  New 
  Jersey, 
  but 
  are 
  usually 
  obtained 
  in 
  such 
  a 
  fragmentary 
  condition 
  as 
  to 
  require 
  

   much 
  labor 
  for 
  their 
  interpretation. 
  The 
  case 
  has 
  been 
  especially 
  difficult 
  in 
  the 
  present 
  

   genus, 
  owing 
  to 
  the 
  difference 
  in 
  the 
  sculpture 
  of 
  different 
  parts 
  of 
  the 
  same 
  carapace. 
  

   These 
  varieties 
  are 
  the 
  longitudinal 
  parallel 
  grooved 
  surface, 
  the 
  coarser 
  and 
  more 
  finely 
  

   reticularly 
  grooved, 
  and 
  the 
  plane 
  ; 
  the 
  last 
  either 
  erose 
  or 
  smooth. 
  The 
  reticulate 
  groove 
  

   is 
  sometimes 
  so 
  deep, 
  and 
  the 
  areolae 
  so 
  raised 
  as 
  to 
  be 
  truly 
  tubercular. 
  

  

  These 
  differences 
  indicate 
  both 
  parts 
  of 
  the 
  same 
  species 
  and 
  different 
  species. 
  The 
  

   longitudinal 
  grooving 
  is 
  characteristic 
  of 
  the 
  costal 
  bones 
  of 
  Taphrosphys 
  strenuus, 
  and 
  

   the 
  costal 
  and 
  some 
  thoracic 
  bones 
  of 
  T. 
  molops. 
  The 
  reticulate 
  sculpture 
  is 
  close 
  on 
  the 
  

   marginal 
  bones 
  of 
  T. 
  molops 
  and 
  T. 
  sulcatus, 
  closest 
  on 
  a 
  portion 
  of 
  the 
  bridge 
  of 
  the 
  for- 
  

   mer. 
  It 
  is 
  coarse 
  and 
  open 
  on 
  the 
  abdominal 
  bones 
  of 
  T. 
  molops 
  and 
  T. 
  sulcatus, 
  but 
  

   often 
  passes 
  into 
  an 
  eroded 
  surface, 
  which 
  gives 
  no 
  distinct 
  pattern, 
  but 
  is 
  generally 
  

   roughened. 
  In 
  P. 
  nodosus 
  the 
  reticulate 
  sculpture 
  is 
  so 
  close 
  and 
  strong, 
  as 
  to 
  leave 
  tu- 
  

   bercle-like 
  interspaces 
  ; 
  while 
  P. 
  enodis 
  is 
  entirely 
  smooth 
  

  

  Six 
  species 
  may 
  be 
  clearly 
  distinguished. 
  They 
  differ 
  considerably 
  in 
  the 
  forms 
  of 
  the 
  

   mesosternal 
  bones, 
  and 
  their 
  relations 
  to 
  the 
  intergular 
  scutum, 
  which 
  covers 
  them 
  in 
  

   part. 
  The 
  forms 
  of 
  the 
  pubic 
  and 
  inguinal 
  sutural 
  articulations 
  are 
  also 
  quite 
  character- 
  

   istic, 
  as 
  well 
  as 
  the 
  relative 
  thickness 
  of 
  the 
  shells. 
  In 
  size 
  the 
  species 
  vary 
  from 
  that 
  of 
  

   an 
  average 
  snapping 
  turtle 
  (T. 
  leslianus) 
  to 
  that 
  of 
  the 
  largest 
  sea 
  turtles 
  (T. 
  strenuus.) 
  

  

  Synopsis 
  of 
  Species, 
  

   a 
  An 
  azygus 
  bone 
  in 
  front 
  of 
  the 
  caudal 
  marginal. 
  Taphrosphys. 
  

   Mesosternum 
  transverse, 
  broader 
  than 
  long; 
  intergular 
  scute, 
  not 
  reaching 
  the 
  poste- 
  

   rior 
  border 
  ; 
  first 
  vertebral 
  scute 
  shorter 
  ; 
  shell 
  heavy 
  ; 
  pubic 
  scar 
  wide, 
  much 
  elevated 
  ; 
  

   xiphisternum 
  thin 
  edged 
  ; 
  large 
  size. 
  t. 
  molops. 
  

  

  