﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  163 
  

  

  penultimate 
  and 
  ultimate 
  costals, 
  covering 
  their 
  sutural 
  union, 
  as 
  indicated 
  by 
  sutural 
  areas 
  remaining. 
  The 
  penul- 
  

   timates 
  are 
  separated 
  anteriorly 
  by 
  the 
  round 
  bone 
  above 
  mentioned; 
  their 
  posterior 
  united 
  halves 
  supported 
  the 
  first 
  

   supernumerary 
  vertebral. 
  The 
  remaining 
  two 
  were 
  beneath 
  the 
  last 
  pair 
  of 
  costals. 
  Pygal 
  bone 
  .sub-triangular 
  with 
  

   two 
  obtuse 
  ridges 
  medio-anteriorly, 
  and 
  a 
  slight 
  projection 
  laterally 
  in 
  front. 
  This 
  whole 
  region 
  is 
  precisely 
  like 
  that 
  

   in 
  T. 
  sulcatus. 
  

  

  The 
  iliac 
  pit 
  is 
  much 
  like 
  that 
  in 
  T. 
  sulcatus, 
  but 
  the 
  anterior 
  bounding 
  ridge 
  is 
  wanting 
  for 
  most 
  of 
  the 
  length; 
  the 
  

   distal 
  extremity 
  of 
  the 
  same, 
  also, 
  is 
  not 
  distinctly 
  outlined. 
  The 
  inner 
  margin 
  is 
  more 
  so, 
  by 
  an 
  elevated 
  ridge 
  or 
  

   ridges. 
  Proximally 
  its 
  margin 
  is 
  partly 
  formed 
  by 
  the 
  rudimental 
  costal, 
  of 
  a 
  subcubic 
  form 
  attached 
  by 
  a 
  suture 
  in 
  

  

  a 
  pit, 
  as 
  in 
  T. 
  sulcatus. 
  

  

  M. 
  M. 
  

  

  Length 
  average 
  vertebral, 
  0.035 
  

  

  Width, 
  greatest, 
  .025 
  

  

  " 
  anterior, 
  .0075 
  

  

  " 
  last 
  vertebral, 
  .019 
  

  

  Length 
  " 
  " 
  .017 
  

  

  pygal, 
  .061 
  

  

  " 
  united 
  extremities 
  two 
  last 
  costals, 
  .036 
  

  

  " 
  penultimate 
  costal, 
  .104 
  

  

  The 
  vertebral 
  regarded 
  as 
  of 
  average 
  form 
  exhibits 
  but 
  a 
  short 
  lamina 
  or 
  neural 
  spine 
  connecting 
  the 
  arch 
  and 
  su- 
  

   perior 
  plate. 
  The 
  neural 
  arch 
  is 
  not 
  coossified 
  with 
  the 
  centrum, 
  and 
  the 
  capitular 
  articular 
  face 
  is 
  well 
  developed. 
  

   The 
  inguinal 
  articular 
  pit 
  is 
  strongly 
  marked 
  and 
  rather 
  wide; 
  distally 
  its 
  fundus 
  is 
  continuous 
  with 
  the 
  plane 
  of 
  

  

  the 
  costal 
  bearing 
  it. 
  

  

  M. 
  M. 
  

  

  Length 
  inguinal 
  pit. 
  .032 
  

  

  Width 
  " 
  " 
  .006 
  

  

  " 
  costal 
  bone 
  bearing 
  it. 
  .0475 
  

  

  " 
  average 
  costal 
  bone, 
  0.33 
  

  

  A 
  marked 
  character 
  of 
  the 
  species 
  is 
  seen 
  in 
  the 
  mesosternal 
  bone, 
  one-half 
  of 
  which 
  is 
  preserved. 
  From 
  the 
  

   acute 
  angle 
  formed 
  by 
  the 
  extremity, 
  it 
  is 
  evidently 
  even 
  more 
  transverse 
  than 
  that 
  of 
  T. 
  molops. 
  The 
  sutures 
  are 
  

   very 
  coarse, 
  as 
  in 
  other 
  species, 
  the 
  anterior 
  directed 
  forwards, 
  the 
  posterior 
  outwards. 
  The 
  intergular 
  scute 
  is 
  larger 
  

   than 
  in 
  the 
  other 
  species, 
  as 
  its 
  right 
  margin 
  extends 
  nearly 
  to 
  the 
  outer 
  and 
  posterior 
  sutures 
  of 
  the 
  bone. 
  All 
  the 
  

   sutures 
  of 
  the 
  plastron 
  are 
  coarse. 
  

  

  The 
  axillary 
  margin 
  of 
  the 
  hyosternal 
  is 
  not 
  thinned; 
  that 
  of 
  the 
  xiphisternal 
  is 
  thinned, 
  and 
  they 
  enclose 
  a 
  wide 
  

  

  median 
  emargination 
  behind. 
  Their 
  extremities 
  are 
  not 
  so 
  acute 
  as 
  in 
  one 
  example 
  of 
  T. 
  molops. 
  The 
  iliac 
  scar 
  is 
  

  

  very 
  prominent 
  and 
  rugose. 
  The 
  pubic 
  scar 
  is 
  longer 
  and 
  much 
  wider 
  in 
  proportion 
  to 
  the 
  general 
  size, 
  than 
  in 
  T. 
  

  

  sulcatus, 
  and 
  is 
  wider 
  behind 
  than 
  before. 
  It 
  is 
  not 
  elevated 
  as 
  in 
  T. 
  molops. 
  Its 
  sutural 
  l-idges 
  are 
  very 
  numerous 
  

  

  and 
  acute. 
  

  

  M. 
  M. 
  

  

  Length 
  from 
  median 
  suture 
  to 
  xiphisternal 
  posterior 
  angle, 
  .059 
  

  

  " 
  xiphisternal 
  scar, 
  .037 
  

  

  Width 
  " 
  " 
  (greatest), 
  .0085 
  

  

  The 
  marginals 
  are 
  like 
  those 
  of 
  T. 
  molops, 
  on 
  a 
  smaller 
  scale. 
  The 
  posteriors 
  are 
  light, 
  the 
  anterior 
  heavier, 
  

   those 
  of 
  the 
  bridge 
  present 
  a 
  small 
  angle, 
  but 
  not 
  thin 
  nor 
  revolute. 
  The 
  reticulation 
  is 
  with 
  their 
  length. 
  Length 
  

   and 
  width 
  of 
  a 
  posterior 
  marginal 
  about 
  equal, 
  viz: 
  m. 
  0.0465. 
  

  

  The 
  scapula 
  is 
  continued 
  into 
  a 
  procoracoid 
  with 
  axis 
  at 
  right 
  angles 
  to 
  it, 
  and 
  length 
  of 
  union 
  not 
  great, 
  but 
  

  

  about 
  as 
  in 
  Emydioid 
  Pleurodira. 
  

  

  M. 
  

  

  Diameter 
  glenoid 
  cavity. 
  .014 
  

  

  Length 
  of 
  scapulo-procoracoid 
  neck, 
  .021 
  

  

  