﻿AND 
  AYES 
  OF 
  NORTH 
  AMERICA. 
  

  

  73 
  

  

  Measurements. 
  

  

  Length 
  (median 
  above, 
  ) 
  to 
  apex 
  prefrontal, 
  

  

  " 
  (axial) 
  to 
  front 
  of 
  orbit, 
  

  

  " 
  " 
  " 
  crotaphite 
  foramen, 
  

  

  Width 
  between 
  extremities 
  qnadrata, 
  

  

  " 
  " 
  postfrontal 
  angles, 
  

  

  " 
  muzzle 
  at 
  point 
  frontal, 
  

   Length 
  dermal 
  scutum, 
  

  

  ' 
  ' 
  cervical 
  vertebra 
  (to 
  ball), 
  

   Width 
  crotaphite 
  foramen, 
  

  

  In. 
  

  

  5.5 
  

  

  4.15 
  

  

  2.2 
  

  

  6.2 
  

  

  2. 
  

  

  3.32 
  

  

  2.3 
  

  

  1.7 
  

  

  1.7 
  

  

  This 
  species 
  furnishes 
  the 
  generic 
  characters. 
  I 
  have 
  not 
  been 
  able 
  to 
  ascertain 
  the 
  non-existence 
  of 
  the 
  pre- 
  

   frontal 
  foramen 
  in 
  the 
  following 
  species, 
  but 
  as 
  they 
  bear 
  more 
  resemblance 
  in 
  the 
  cranial 
  sculpture 
  and 
  in 
  size 
  to 
  

   this 
  species, 
  than 
  to 
  Thoracosaurus 
  neocaesariensis, 
  I 
  refer 
  them 
  at 
  present 
  to 
  Holops. 
  

  

  HOLOFS 
  CORDATUS, 
  Cope. 
  

  

  Of 
  this 
  species 
  I 
  have 
  only 
  two 
  cervical, 
  two 
  dorsal, 
  and 
  three 
  lumbar 
  vertebrae 
  of 
  one 
  individual, 
  all 
  in 
  a 
  good 
  

   state 
  of 
  preservation. 
  They 
  present 
  characters 
  similar 
  to 
  those 
  of 
  H. 
  obscurus 
  in 
  the 
  cervical 
  vertebrae, 
  and 
  inter- 
  

   mediate 
  between 
  those 
  of 
  that 
  species 
  and 
  the 
  H. 
  tenebrosus 
  in 
  the 
  dorsals. 
  While 
  the 
  fifth 
  dorsal 
  in 
  the 
  former 
  is 
  

   deeper 
  than 
  wide 
  in 
  its 
  articular 
  cup 
  and 
  slightly 
  quadrate, 
  the 
  present 
  species 
  presents 
  a 
  broadly 
  cordate 
  cup 
  to 
  the 
  

   fifth, 
  narrowed 
  below, 
  yet 
  considerably 
  wider 
  than 
  deep 
  ; 
  the 
  H. 
  tenebrosus 
  presents 
  a 
  regularly 
  round 
  or 
  transversely 
  

   oval 
  cup 
  in 
  the 
  same 
  position, 
  much 
  as 
  in 
  IT. 
  brevispinis. 
  The 
  accompanying 
  cut 
  exhibits 
  the 
  difference 
  between 
  

   this 
  species 
  and 
  the 
  H. 
  tenebrosus. 
  The 
  cordate 
  form 
  is 
  distinct 
  on 
  the 
  fourth 
  dorsal, 
  where 
  in 
  H. 
  obscurus 
  the 
  cup 
  

   is 
  regularly 
  oval. 
  The 
  cervicals 
  are 
  not 
  different 
  from 
  those 
  of 
  H. 
  obscurus, 
  except 
  that 
  the 
  cup 
  is 
  rather 
  more 
  pro- 
  

   longed 
  below, 
  or 
  subquadrate. 
  

  

  The 
  cervical 
  vertebrae 
  referred 
  to 
  this 
  species 
  may 
  be 
  known 
  by 
  the 
  outlines 
  of 
  the 
  anterior 
  extremity 
  outside 
  the 
  

   cup, 
  of 
  which 
  the 
  latter 
  partakes, 
  which 
  is 
  between 
  quadrate 
  and 
  cor- 
  

   date 
  ; 
  by 
  the 
  distinct 
  inferior 
  concavity 
  between 
  the 
  parapophyses, 
  and 
  Fig. 
  18. 
  

   by 
  the 
  gradual 
  but 
  complete 
  lateral 
  eversion 
  of 
  the 
  latter. 
  In 
  the 
  

   types 
  the 
  posterior 
  shoulder 
  is 
  remarkably 
  prominent. 
  The 
  inferior 
  

   carina 
  is 
  little 
  marked 
  on 
  the 
  fourth, 
  while 
  the 
  hypapophyses 
  are 
  

   small 
  and 
  united. 
  In 
  a 
  fifth, 
  judging 
  from 
  the 
  more 
  posterior 
  position 
  

   of 
  the 
  parapophysis, 
  it 
  is 
  formed 
  of 
  two 
  partly 
  confluent 
  subacute 
  

   elevations. 
  

  

  The 
  dorsal 
  vertebrae, 
  from 
  their 
  mineralization, 
  condition, 
  and 
  

   time 
  and 
  place, 
  of 
  discovery 
  probably 
  belong 
  to 
  the 
  same 
  animal 
  as 
  the 
  

   cervicals 
  above 
  described. 
  The 
  breadth 
  of 
  the 
  cup 
  of 
  the 
  fifth 
  is 
  a 
  

   little 
  greater 
  than 
  the 
  length 
  to 
  the 
  posterior 
  shoulder, 
  it 
  differs 
  from 
  

   Leidy's 
  figure 
  of 
  the 
  sixth 
  of 
  tenebrosus, 
  T. 
  III., 
  f. 
  13, 
  in 
  its 
  large 
  

   hypapophysis, 
  which 
  stands 
  on 
  nearly 
  the 
  entire 
  centrum, 
  and 
  is 
  very 
  

   prominent, 
  and 
  concave 
  in 
  front 
  ; 
  the 
  sides 
  of 
  the 
  centrum 
  are 
  concave 
  

  

  from 
  cup 
  to 
  shoulder. 
  In 
  the 
  third 
  dorsal 
  but 
  a 
  narrow 
  space 
  exists 
  behind 
  and 
  before 
  the 
  hypapophysis, 
  and 
  the 
  

   vertical 
  diameter 
  of 
  the 
  cup 
  is 
  less 
  than 
  the 
  transverse, 
  and 
  exhibits 
  the 
  same 
  cordate 
  outline. 
  As 
  usual 
  some 
  (the 
  

   anterior) 
  lumbars, 
  are 
  deeper 
  than 
  wide, 
  and 
  in 
  others 
  the 
  bodies 
  are 
  subquadrate 
  in 
  section, 
  and 
  the 
  transverse 
  

   diameter 
  of 
  the 
  cup 
  greater. 
  Measurements 
  are 
  as 
  follows 
  : 
  

  

  AMERI. 
  PH1L0S0. 
  SOC. 
  — 
  VOL. 
  XIV. 
  19 
  

  

  