﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  15 
  

  

  Measurements. 
  Lines. 
  

  

  Preserved 
  length 
  of 
  ramus 
  (imperfect), 
  11 
  

  

  Depth 
  at 
  last 
  tooth, 
  2 
  

  

  Length 
  of 
  exposed 
  tooth, 
  1.7 
  

  

  Length 
  dentary, 
  7.5 
  

  

  Depth 
  at 
  coronoid, 
  3.5 
  

  

  Do. 
  at 
  first 
  tooth, 
  1.3 
  

   In 
  the 
  mandibular 
  ramus 
  of 
  the 
  Hylerpeton 
  dawsoni, 
  there 
  are 
  according 
  to 
  Owen 
  at 
  least 
  nine 
  teeth 
  ; 
  in 
  the 
  

   present 
  species 
  there 
  are 
  but 
  seven. 
  

  

  SAITROPLEURA, 
  Cope. 
  

   Proceed. 
  Acad. 
  Nat. 
  Sci. 
  Phil. 
  18C8, 
  p. 
  215. 
  

  

  This 
  genus 
  embraces 
  a 
  single 
  species 
  only, 
  as 
  I 
  at 
  present 
  understand 
  it. 
  The 
  

   extremities 
  are 
  well 
  developed, 
  and 
  the 
  body 
  is 
  stout 
  and 
  lizard-like. 
  It 
  is 
  represented 
  by 
  

   but 
  one 
  individual 
  which 
  has 
  been 
  spread 
  over 
  a 
  surface 
  of 
  the 
  coal 
  slate, 
  exhibiting 
  ventral 
  

   armature, 
  dorsal 
  region 
  with 
  ribs, 
  and 
  anterior 
  and 
  posterior 
  limbs. 
  Of 
  skull 
  and 
  caudal 
  

   vertebra? 
  nothing 
  remains. 
  

  

  The 
  dermal 
  riblets 
  are 
  arranged 
  as 
  in 
  Urocordylus, 
  i. 
  e. 
  in 
  parallel 
  lines 
  directed 
  

   obliquely 
  forwards 
  and 
  continuous 
  on 
  the 
  median 
  line, 
  forming 
  there 
  a 
  chevron 
  directed 
  

   forwards. 
  The 
  striae 
  are 
  not 
  so 
  closely 
  placed 
  as 
  in 
  O. 
  pectinata, 
  but 
  are 
  separated 
  by 
  

   grooves 
  wider 
  than 
  themselves. 
  

  

  The 
  humerus, 
  ulna 
  and 
  radius, 
  are 
  rather 
  stout, 
  and 
  of 
  a 
  size 
  relative 
  to 
  the 
  body, 
  as 
  

   in 
  common 
  types 
  of 
  existing 
  sauria; 
  the 
  ulna 
  and 
  radius 
  separate. 
  There 
  is 
  no 
  carpus, 
  

   but 
  five 
  well 
  developed 
  digits 
  have 
  phalanges 
  in 
  the 
  following 
  numbers, 
  commencing 
  on 
  

   the 
  inside, 
  3, 
  4, 
  5, 
  6, 
  5. 
  The 
  last 
  phalange 
  of 
  the 
  second 
  is 
  obscured, 
  and 
  it 
  is 
  not 
  

   positive 
  that 
  the 
  number 
  is 
  as 
  given 
  ; 
  it 
  is 
  more 
  probable 
  than 
  that 
  it 
  should 
  have 
  been 
  3. 
  

   The 
  outer 
  toe 
  has 
  been 
  more 
  slender 
  than 
  the 
  others 
  ; 
  the 
  distal 
  phalanges 
  of 
  all 
  the 
  toes 
  

   are 
  short 
  conic, 
  as 
  in 
  Salamanders. 
  Thus 
  this 
  form 
  differs 
  much 
  from 
  Amphibamus, 
  

   where 
  the 
  numbers 
  are 
  3, 
  3, 
  4, 
  5, 
  4, 
  showing 
  a 
  lower 
  development 
  of 
  limbs. 
  

  

  The 
  ribs 
  are 
  long 
  and 
  curved 
  as 
  in 
  Reptiles, 
  and 
  judging 
  by 
  their 
  distances 
  the 
  

   vertebra? 
  are 
  short; 
  the 
  latter 
  are 
  not 
  well 
  denned 
  but 
  there 
  is 
  no 
  indication 
  of 
  prominent 
  

   spines 
  of 
  any 
  kind. 
  

  

  The 
  pelvic 
  bones 
  and 
  portions 
  of 
  those 
  of 
  the 
  hind 
  limbs 
  are 
  present, 
  but 
  so 
  obscured 
  

   and 
  confused 
  as 
  not 
  to 
  be 
  made 
  out. 
  Enough 
  remains 
  to 
  show 
  that 
  the 
  hind 
  limbs 
  are 
  

   considerably 
  longer 
  than 
  the 
  anterior. 
  

  

  