﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  173 
  

  

  In 
  the 
  last 
  the 
  vertebra 
  is 
  broken 
  obliquely 
  away, 
  leaving 
  the 
  condyle 
  at 
  one 
  extremity 
  and 
  the 
  bifid 
  surspectant 
  

   zygapophyses 
  at 
  the 
  other, 
  thus 
  demonstrating 
  their 
  character. 
  In 
  No. 
  31 
  one 
  face 
  of 
  the 
  diapophysis 
  is 
  straight, 
  the 
  

   distal 
  dilatation 
  being 
  occasioned 
  by 
  the 
  expansion 
  of 
  the 
  opposite 
  margin. 
  

  

  Linen. 
  

   Length 
  of 
  diapophysis, 
  fi 
  

  

  Width 
  distally, 
  2 
  

  

  At 
  No. 
  20 
  there 
  are 
  four 
  vertebrae 
  in 
  their 
  natural 
  succession, 
  but 
  separated 
  and 
  disarranged. 
  There 
  are 
  no 
  ribs 
  

   near 
  them. 
  

  

  Lines. 
  

   Length 
  body 
  a 
  (anterior), 
  4.5 
  

  

  " 
  diapophysis 
  b 
  (from 
  body), 
  3. 
  

  

  " 
  " 
  c 
  " 
  5. 
  

  

  None 
  of 
  the 
  vertebrae 
  exhibit 
  from 
  the 
  vertical 
  view 
  the 
  breadth 
  dependent 
  on 
  longitudinal 
  alae 
  from 
  the 
  zygapo. 
  

   physes 
  so 
  common 
  among 
  the 
  Lacertilia. 
  

  

  Of 
  sections 
  and 
  views 
  of 
  the 
  extremities 
  of 
  the 
  vertebrae 
  there 
  are 
  many. 
  They 
  show 
  the 
  form 
  of 
  the 
  neural 
  

   canal 
  to 
  have 
  varied 
  from 
  vertically 
  to 
  transversely 
  oval, 
  and 
  the 
  neural 
  arch 
  to 
  have 
  been 
  tectiform 
  with 
  plane 
  

   sides, 
  when 
  the 
  canal 
  is 
  large, 
  as 
  in 
  cervical 
  and 
  dorsal 
  regions; 
  but 
  to 
  have 
  been 
  fiat 
  where 
  the 
  neural 
  canal 
  is 
  

   transverse, 
  as 
  in 
  the 
  lumbar 
  region. 
  Of 
  the 
  former 
  kind 
  we 
  have 
  those 
  with 
  no, 
  low, 
  or 
  elevated 
  neural 
  spines, 
  and 
  

   the 
  centra 
  depressed; 
  of 
  the 
  latter 
  kind 
  the 
  neural 
  spine 
  elevated, 
  and 
  the 
  centrum 
  compressed. 
  This 
  form, 
  which 
  

   Owen 
  points 
  out 
  among 
  the 
  birds 
  in 
  the 
  same 
  region 
  of 
  Apetenodytes, 
  occurs 
  also, 
  according 
  to 
  H. 
  von 
  Meyer, 
  in 
  the 
  

   lumbar 
  region 
  of 
  Pterodactylus 
  longipelvis 
  Myr. 
  Three 
  exhibit 
  a 
  nearly 
  cylindric 
  form. 
  Measurements 
  of 
  one 
  of 
  the 
  

   most 
  compressed, 
  from 
  which 
  no 
  diapophyses 
  proceed 
  (perhaps 
  lost): 
  

  

  Lines. 
  

   Depth 
  of 
  centrum, 
  2. 
  

  

  Width 
  " 
  1.5 
  

  

  Depth 
  neural 
  canal, 
  1. 
  

  

  A 
  transversely 
  fractured 
  vertebra, 
  without 
  centrum 
  and 
  with 
  short 
  neural 
  spine 
  and 
  long 
  diapophysis, 
  is 
  perhaps 
  

  

  a 
  rib-bearing 
  dorsal. 
  

  

  Lines. 
  

  

  Depth 
  centrum, 
  1.7 
  

  

  Heigh 
  th 
  spine 
  above 
  canal, 
  3. 
  

  

  Of 
  neural 
  canal, 
  1 
  . 
  

  

  Length 
  diapophysis 
  from 
  axis 
  vertebra, 
  5.8 
  

  

  There 
  are 
  remains 
  of 
  numerous 
  long 
  bones, 
  but 
  generally 
  broken 
  or 
  uncharacteristic. 
  The 
  extremities 
  when 
  pre- 
  

   served 
  are 
  generally 
  oval, 
  without 
  angles 
  or 
  processes. 
  Some 
  are 
  so 
  slender 
  and 
  straight, 
  as 
  to 
  be 
  probably 
  referable 
  

   to 
  wing 
  phalanges. 
  Three 
  others 
  are 
  characteristic; 
  one 
  of 
  these 
  is 
  quite 
  of 
  the 
  form 
  of 
  Pterodactyle 
  humerus, 
  

   having 
  an 
  extensive 
  proximal 
  ala, 
  with 
  the 
  transverse 
  extent 
  greater 
  than 
  the 
  longitudinal; 
  a 
  slender 
  shank 
  and 
  two 
  

   distal 
  articular 
  surfaces. 
  This 
  has 
  belonged 
  to 
  a 
  small 
  individual; 
  length 
  only 
  7.6 
  lines. 
  An 
  equally 
  characteristic 
  

   element 
  is 
  the 
  ulno-radius, 
  most 
  probably. 
  This 
  is 
  a 
  moderately 
  slender 
  bone, 
  with 
  two 
  nearly 
  equal 
  concave 
  articu- 
  

   lar 
  surfaces 
  at 
  an 
  extremity, 
  which 
  is 
  slightly 
  dilated. 
  The 
  other 
  extremity 
  has 
  been 
  more 
  dilated, 
  and 
  of 
  an 
  elongate 
  

   oval 
  form, 
  without 
  irregularities, 
  as 
  far 
  as 
  the 
  specimen 
  shows. 
  

  

  Lines. 
  

   Length, 
  14. 
  

  

  Width 
  simple 
  extremity, 
  2.5 
  

  

  " 
  shank, 
  1.1 
  

  

  " 
  cotyloid 
  extremity, 
  2. 
  

  

  AMERICA. 
  PHILO. 
  SOC. 
  — 
  VOL. 
  XIV. 
  44 
  

  

  