﻿AND 
  AYES 
  OF 
  NORTH 
  AMERICA. 
  

  

  103 
  

  

  Fig. 
  30. 
  

  

  In 
  comparing 
  this 
  series 
  with 
  those 
  of 
  Poecilopleurum, 
  

   so 
  well 
  illustrated 
  by 
  Deslongehamps, 
  it 
  is 
  observable 
  that 
  

   vertebrae 
  of 
  similar 
  proportions 
  in 
  the 
  two 
  are 
  without 
  cliapo- 
  

   physes 
  in 
  the 
  former, 
  while 
  they 
  possess 
  them 
  in 
  the 
  latter. 
  

   Thus 
  the 
  diapophyses 
  probably 
  cease 
  at 
  a 
  point 
  in 
  Laelaps 
  

   anterior 
  to 
  the 
  same 
  in 
  Poecilopleurum 
  . 
  It 
  is 
  also 
  noticeable 
  

   that 
  while 
  they 
  are 
  obliquely 
  directed 
  backwards 
  in 
  the 
  latter, 
  

   those 
  having 
  them 
  as 
  well 
  developed 
  in 
  the 
  former 
  exhibit 
  

   them 
  transverse. 
  

  

  Humerus. 
  — 
  Both 
  are 
  preserved, 
  but 
  lack 
  the 
  distal 
  con- 
  

   dyle; 
  about 
  half 
  the 
  coronoid 
  fossa 
  of 
  one 
  remains, 
  furnish- 
  

   ing 
  an 
  indication 
  of 
  the 
  breadth 
  of 
  that 
  extremity. 
  They 
  

   are 
  proximally 
  much 
  dilated, 
  having 
  a 
  very 
  strong 
  postero- 
  

   external 
  ala 
  and 
  a 
  shorter 
  antero-internal 
  dilatation. 
  They 
  

   are 
  not 
  half 
  the 
  length 
  of 
  the 
  femur; 
  the 
  shaft 
  is 
  flattened 
  

   antero- 
  internally. 
  Of 
  the 
  proximal 
  articulating 
  surface 
  a 
  

   portion 
  is 
  lost, 
  but 
  a 
  narrow 
  surface 
  continuous 
  with 
  it 
  exter- 
  

   nally 
  does 
  not 
  extend 
  further 
  out 
  on 
  the 
  dilatation 
  than 
  oppo- 
  

   site 
  to 
  the 
  middle 
  of 
  the 
  shaft. 
  I 
  find 
  no 
  trace 
  of 
  a 
  globular 
  

   condyle, 
  as 
  is 
  seen 
  in 
  Hadrosaurus. 
  Coronoid 
  fossa 
  large 
  and 
  

   well 
  marked, 
  not 
  near 
  to 
  penetrating; 
  medullary 
  cavity 
  of 
  shaft 
  

   relatively 
  smaller 
  than 
  in 
  the 
  bones 
  of 
  the 
  leg. 
  

  

  Length 
  of 
  humerus 
  (restored), 
  

   Greatest 
  proximal 
  breadth, 
  

   Distal 
  breadth 
  across 
  coronoid 
  fossa, 
  

   Circumference 
  of 
  shaft, 
  

  

  In. 
  

  

  12. 
  

   3.75 
  

   3. 
  

   5.1 
  

  

  These 
  humeri 
  are 
  relatively 
  shorter 
  than 
  in 
  Hadrosaurus 
  

   and 
  Iguanodon, 
  and 
  the 
  external 
  aire 
  do 
  not 
  pass 
  so 
  abruptly 
  

   into 
  the 
  shaft 
  as 
  in 
  them. 
  They 
  resemble 
  most 
  those 
  of 
  Poeci- 
  

   lopleurum. 
  They 
  differ 
  from 
  these 
  in 
  being 
  much 
  dilated 
  dis- 
  

   tally, 
  especially 
  internally, 
  and 
  in 
  having 
  the 
  coronoid 
  fossa 
  

   much 
  more 
  pronounced. 
  

  

  Fore-limb. 
  — 
  In 
  the 
  lack 
  of 
  the 
  necessary 
  pieces, 
  one 
  can- 
  

   not 
  go 
  far 
  wrong 
  in 
  estimating 
  the 
  length 
  after 
  that 
  of 
  Poe- 
  

   cilopleurum. 
  In 
  it 
  the 
  lower 
  arm 
  is 
  three-fifths 
  the 
  humerus, 
  

   which 
  gives 
  for 
  Laelaps 
  a 
  length 
  of 
  19.2 
  in. 
  to 
  the 
  wrist. 
  If 
  

   we 
  accept 
  the 
  Crocodile 
  as 
  the 
  next 
  nearest 
  ally 
  in 
  the 
  fore- 
  

   limbs, 
  we 
  find 
  the 
  carpus 
  and 
  hand 
  to 
  be 
  .75 
  of 
  the 
  humerus. 
  

   The 
  ungueal 
  phalange 
  preserved 
  in 
  Poecilopleurum 
  is 
  shorter 
  

   than 
  in 
  the 
  Crocodile; 
  if 
  however 
  we 
  add 
  9 
  inches 
  to 
  the 
  

   length 
  already 
  estimated, 
  we 
  have 
  for 
  the 
  whole 
  2 
  ft. 
  4 
  - 
  2 
  

   inches. 
  

  

  This 
  is, 
  as 
  will 
  be 
  hereafter 
  shown, 
  a 
  little 
  more 
  than 
  one 
  

   fourth 
  (1-3.71) 
  the 
  length 
  of 
  the 
  hind 
  limb. 
  

  

  