﻿166-B 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  TAPHROSPHTS 
  STRENUUS, 
  Cope. 
  

  

  This, 
  the 
  largest 
  of 
  our 
  extinct 
  Pleurodira, 
  is 
  represented 
  by 
  portions 
  of 
  three 
  individuals. 
  

  

  The 
  largest 
  has 
  been 
  much 
  broken 
  up 
  by 
  the 
  workmen, 
  and 
  many 
  parts 
  of 
  the 
  carapace 
  and 
  plastron 
  are 
  recogni- 
  

   zable 
  in 
  the 
  larger 
  and 
  smaller 
  fragments. 
  

  

  The 
  various 
  elements 
  are 
  of 
  great 
  thickness, 
  proportionately 
  as 
  well 
  as 
  absolutely, 
  so 
  that 
  this 
  is 
  the 
  most 
  mas- 
  

   sive 
  as 
  well 
  as 
  largest 
  species 
  of 
  the 
  genus 
  ; 
  in 
  two 
  of 
  the 
  specimens 
  the 
  episternals 
  are 
  considerably 
  thickened 
  at 
  the 
  

   anterior 
  suture, 
  a 
  feature 
  not 
  seen 
  in 
  the 
  next 
  stoutest 
  species, 
  T. 
  molops. 
  In 
  the 
  first 
  specimen, 
  the 
  costals 
  have 
  the 
  

   longitudinal 
  reticulate 
  sculpture; 
  the 
  marginals 
  close 
  reticulate, 
  and 
  the 
  sternal 
  bones 
  are 
  openly 
  reticulate. 
  The 
  in- 
  

   guinal 
  costal 
  articular 
  groove 
  is 
  characteristic. 
  Instead 
  of 
  lying 
  in 
  one 
  plane 
  as 
  in 
  other 
  species, 
  it 
  occupies 
  the 
  crest 
  

   of 
  a 
  ridge 
  which 
  ascends 
  proximally 
  to 
  a 
  considerable 
  elevation, 
  resembling 
  in 
  this, 
  the 
  pubic 
  scar 
  of 
  T. 
  molops. 
  It 
  

   is, 
  however, 
  nearly 
  smooth 
  within 
  and 
  has 
  no 
  distal 
  boundary; 
  the 
  fact 
  of 
  its 
  being 
  on 
  the 
  middle 
  line 
  of 
  a 
  costal 
  bone, 
  

   tixes 
  its 
  character. 
  

  

  One 
  of 
  the 
  elements 
  of 
  the 
  plastron 
  at 
  one 
  of 
  the 
  sutural 
  angles, 
  exhibits 
  an 
  extensive 
  overlapping, 
  or 
  squamosal 
  

   suture, 
  to 
  the 
  extent 
  of 
  half 
  the 
  thickness 
  of 
  the 
  bone, 
  and 
  distance 
  of 
  M. 
  .028. 
  The 
  articular 
  extremities 
  of 
  the 
  two 
  

   scapulae 
  are 
  remarkable 
  for 
  their 
  size. 
  The 
  forms 
  of 
  the 
  mesosternum, 
  and 
  marginal 
  bones 
  of 
  the 
  bridge 
  are 
  unknown. 
  

   The 
  anterior 
  marginals 
  are 
  thick 
  and 
  of 
  coarse 
  cellular 
  structure. 
  The 
  posterior 
  are 
  thinned 
  out 
  ±o 
  an 
  edge. 
  

  

  M. 
  

   Width 
  of 
  ordinary 
  costal, 
  0.061 
  

  

  Thickness 
  '• 
  " 
  .015 
  

  

  "Width 
  costal 
  bearing 
  inguinal 
  groove, 
  .084 
  

  

  Thickness 
  " 
  '" 
  - 
  " 
  .013 
  

  

  " 
  " 
  at 
  proximal 
  part 
  of 
  groove, 
  .037 
  

  

  Diameter 
  articular 
  and 
  scapula, 
  .065 
  

  

  " 
  glenoid 
  cavity 
  (transverse), 
  .044- 
  

  

  Thickness 
  episternal 
  at 
  median 
  suture, 
  .023 
  

  

  General 
  uniform 
  thickness 
  of 
  hyposternal, 
  .018 
  

  

  Of 
  the 
  second 
  specimen 
  numerous 
  portions 
  of 
  carapace 
  and 
  plastron, 
  with 
  head 
  of 
  femur 
  and 
  coracoid, 
  furnish 
  

   various 
  characters. 
  

  

  The 
  costal 
  bones 
  are 
  marked 
  with 
  shallow 
  grooves, 
  more 
  closely 
  placed 
  than 
  in 
  Taphr. 
  molops, 
  and 
  with 
  less 
  

   transverse 
  inosculation. 
  The 
  marginals 
  are 
  rough 
  from 
  the 
  reticulate 
  sculpture. 
  The 
  abdominal 
  surface 
  presents 
  a 
  

   coarser 
  and 
  less 
  distinct 
  sculpture 
  of 
  the 
  same 
  kind; 
  its 
  dermal 
  sutures 
  are 
  also 
  distinct. 
  

  

  The 
  pubic 
  scar 
  is 
  lost, 
  but 
  the 
  ischiadic 
  remains. 
  It 
  is 
  obliquely 
  oval, 
  and 
  very 
  near 
  the 
  margin 
  of 
  the 
  deep 
  pos- 
  

   terior 
  notch 
  of 
  the 
  plastron. 
  Anterior 
  and 
  exterior 
  to 
  it 
  is 
  the 
  shallow 
  fossa 
  seen 
  in 
  the 
  same 
  position 
  in 
  T. 
  strenuus. 
  

   The 
  anterior 
  lobe 
  of 
  the 
  sternum 
  has 
  convergent 
  margins, 
  but 
  is 
  broadly 
  truncate 
  in 
  front, 
  each 
  half 
  of 
  the 
  margin 
  

   being 
  slightly 
  concave. 
  

  

  The 
  point 
  of 
  union 
  of 
  the 
  episternals 
  is 
  prominent, 
  upwards 
  and 
  forwards. 
  The 
  margin 
  of 
  the 
  posterior 
  part 
  of 
  

   the 
  episternal, 
  and 
  anterior 
  part 
  of 
  the 
  hyosternal, 
  is 
  rather 
  thinned 
  out, 
  without 
  intermarginal 
  ridge. 
  The 
  suture 
  

   between 
  the 
  two 
  is 
  at 
  right 
  angles 
  to 
  it, 
  and 
  at 
  a 
  little 
  distance 
  from 
  it, 
  it 
  turns 
  forward. 
  

  

  All 
  the 
  bones 
  are 
  thick 
  except 
  the 
  costals, 
  and 
  the 
  spongy 
  layer 
  is 
  vesicular. 
  The 
  sutures 
  of 
  the 
  costals 
  are 
  smooth 
  

   and 
  dense, 
  except 
  opposite 
  the 
  spongy 
  layer. 
  

  

  The 
  femur 
  is 
  characterized 
  by 
  the 
  wide 
  expanse 
  of 
  its 
  trochanters 
  and 
  slenderness 
  of 
  its 
  shaft. 
  The 
  planes 
  of 
  the 
  

   former 
  make 
  an 
  angle 
  together 
  of 
  over 
  90°. 
  The 
  greater 
  is 
  nearly 
  continuous 
  with 
  the 
  head. 
  The 
  coracoid 
  has 
  two 
  

   short 
  sutural, 
  and 
  one 
  cotyloid 
  articular 
  faces; 
  its 
  shaft 
  is 
  contracted 
  and 
  slightly 
  curved. 
  

  

  In. 
  Lin. 
  

  

  Width 
  plastron 
  in 
  front, 
  6 
  1.5 
  

  

  " 
  " 
  at 
  hyo- 
  episternal 
  suture, 
  12 
  1.5 
  

  

  " 
  from 
  mesosternal 
  to 
  front 
  margir, 
  20. 
  

  

  " 
  costal, 
  2 
  3.5 
  

  

  