﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  

  

  141 
  

  

  In. 
  

  

  Lin. 
  

  

  3 
  

  

  1.4 
  

  

  

  11.5 
  

  

  2 
  

  

  2.5 
  

  

  3 
  

  

  6 
  

  

  3 
  

  

  3 
  

  

  Length 
  of 
  seventh 
  marginal, 
  

  

  Thickness 
  of 
  " 
  " 
  posteriorly 
  

  

  Width 
  of 
  " 
  " 
  helow 
  

  

  "Width 
  of 
  eleventh 
  " 
  above 
  

  

  Length 
  of 
  " 
  " 
  (median) 
  

  

  Large 
  portions 
  of 
  many 
  costal 
  bones 
  are 
  preserved. 
  These 
  show 
  the 
  ossification 
  to 
  have 
  been 
  more 
  extensive 
  than 
  

   in 
  the 
  species 
  of 
  Chelone. 
  Their 
  thickness 
  is 
  more 
  uniform 
  than 
  in 
  some 
  species. 
  The 
  capitula 
  of 
  the 
  ribs 
  are 
  round, 
  

   and 
  are 
  on 
  subcylindric 
  bases. 
  The 
  anterior 
  is 
  peculiar 
  for 
  its 
  flattened 
  form 
  ; 
  on 
  its 
  anterior 
  margin 
  is 
  a 
  broad 
  rugose 
  

   band, 
  which 
  contracts 
  into 
  a 
  groove 
  on 
  the 
  side 
  of 
  the 
  capitular 
  process. 
  The 
  dermal 
  sutures 
  are 
  quite 
  distinct. 
  The 
  

   vertebral 
  scuta 
  are 
  longer 
  than 
  wide, 
  with 
  bracket-shaped 
  lateral 
  sutures, 
  little 
  prolonged 
  at 
  the 
  angles. 
  One 
  of 
  the 
  

   transverse 
  intervertebral 
  sutures 
  is 
  strongly 
  concave, 
  probably 
  backward. 
  Where 
  the 
  capitulum 
  springs 
  from 
  the 
  

   inferior 
  surface 
  of 
  the 
  costal 
  bone, 
  there 
  are 
  usually 
  six, 
  or 
  more 
  or 
  less, 
  radiating 
  short 
  grooves, 
  pointing 
  towards 
  it 
  

   as 
  a 
  centre. 
  

  

  In. 
  Lin. 
  

  

  Width 
  of 
  costal 
  bone, 
  1 
  7.2 
  

  

  Thickness 
  " 
  -'on 
  margin, 
  3 
  

  

  Length 
  poster 
  half 
  lateral 
  suture 
  vertebral 
  scute, 
  2 
  2 
  

  

  Width 
  vertebral 
  scute 
  on 
  costal 
  bone 
  (greatest) 
  2 
  4 
  

  

  Large 
  portions 
  of 
  both 
  liyosternals 
  and 
  both 
  hyposternals 
  are 
  preserved, 
  with 
  fragments 
  of 
  an 
  epi- 
  and 
  xiphisternal. 
  

   The 
  inguinal 
  margin 
  is 
  strongly 
  curved 
  and 
  thickened 
  ; 
  its 
  median 
  portion 
  is 
  concave, 
  with 
  a 
  sharp 
  margin 
  below. 
  

   The 
  axillary 
  thinned 
  medially 
  and 
  inwardly, 
  and 
  thickened 
  outwardly. 
  The 
  hyposternals 
  are 
  also 
  thinned 
  towards 
  

   the 
  hyosternals. 
  The 
  episternal 
  is 
  acuminate 
  posteriorly, 
  and 
  steeply 
  bevelled 
  on 
  the 
  outer 
  margin. 
  The 
  xiphis- 
  

   ternal 
  is 
  attached 
  as 
  in 
  osteopygis, 
  by 
  a 
  groove 
  on 
  its 
  inner 
  face, 
  embracing 
  the 
  margin 
  of 
  the 
  hyosternal. 
  This 
  

   groove 
  is, 
  relatively, 
  considerably 
  shorter 
  than 
  in 
  the 
  two 
  species 
  of 
  that 
  genus 
  known. 
  The 
  proportions 
  of 
  the 
  bone 
  

   are 
  narrower 
  than 
  in 
  them 
  ; 
  the 
  edge 
  is 
  thin, 
  and 
  the 
  surface 
  rises 
  abruptly 
  from 
  it 
  over 
  a 
  thickening 
  which 
  does 
  

   not 
  appear 
  in 
  either 
  of 
  the 
  before 
  mentioned 
  species. 
  The 
  external 
  sutural 
  process 
  is 
  also 
  more 
  posterior. 
  The 
  

   margin 
  of 
  the 
  hyosternals 
  is 
  thinner 
  than 
  in 
  0. 
  emarginatus, 
  and 
  they 
  thicken 
  inwardly 
  as 
  well 
  as 
  outwardly 
  ; 
  they 
  

   only 
  thicken 
  outwardly 
  in 
  0. 
  platylomus. 
  

  

  Lin. 
  

   Width 
  hyosternal, 
  24.5 
  

  

  Thickness 
  inguinal 
  margin 
  hyposternal, 
  5.8 
  

  

  Width 
  xiphisternal 
  (cross 
  axis) 
  at 
  end 
  inner 
  hyposternal 
  groove, 
  19 
  

  

  Width 
  episternal 
  two 
  inches 
  from 
  proximal 
  end, 
  14.5 
  

  

  A 
  perfect 
  femur, 
  and 
  a 
  humerus 
  with 
  the 
  head 
  injured, 
  were 
  procured 
  with 
  the 
  other 
  bones. 
  The 
  former 
  is 
  

   characterized 
  by 
  its 
  slender 
  shaft, 
  the 
  great 
  antero-posterior 
  extent 
  of 
  its 
  united 
  head 
  and 
  great 
  trochanter, 
  and 
  the 
  

   large 
  transverse 
  extent 
  of 
  the 
  condyles. 
  In 
  general 
  form 
  it 
  is 
  much 
  more 
  like 
  Chelys 
  than 
  Chelone, 
  though 
  in 
  the 
  

   points 
  mentioned 
  it 
  exceeds 
  the 
  former. 
  The 
  articular 
  surface 
  of 
  the 
  head 
  is 
  very 
  convex, 
  and 
  is 
  prolonged 
  in 
  a 
  

   narrow 
  band 
  along 
  the 
  summit 
  of 
  the 
  great 
  trochanter. 
  The 
  little 
  trochanter 
  stands 
  nearly 
  at 
  right 
  angles 
  to 
  the 
  

   first. 
  The 
  shaft 
  is 
  sub-round 
  medially. 
  Compared 
  with 
  the 
  femur 
  described 
  under 
  Taphrosphys 
  molops, 
  but 
  which 
  

   may 
  belong 
  to 
  Propleura 
  augusta, 
  the 
  inner 
  tubercle 
  is 
  not 
  so 
  prominent 
  and 
  acute, 
  and 
  the 
  posterior 
  projections 
  of 
  

   the 
  condyles 
  are 
  not 
  so 
  strong. 
  The 
  head 
  of 
  the 
  uncertain 
  femur 
  is 
  not 
  projected 
  so 
  far 
  forwards, 
  and 
  is 
  much 
  more 
  

   convex 
  ; 
  the 
  great 
  trochanter 
  is 
  not 
  continuous 
  with 
  it, 
  hence 
  the 
  articular 
  surface 
  is 
  not 
  prolonged. 
  

  

  In. 
  

  

  Length 
  of 
  femur, 
  

   Width 
  of 
  head 
  and 
  trochanter, 
  

   Width 
  of 
  condyles, 
  

   AMERI. 
  PIIILOSO. 
  SOC 
  VOL 
  XIV. 
  35 
  

  

  Lin. 
  

  

  o 
  

  

  22 
  

   18 
  

  

  