﻿J. 
  W. 
  HtTLKE 
  ON 
  A 
  MODIFIED 
  FORM 
  OF 
  DINOSAURIAN 
  ILIUM. 
  525 
  

  

  W. 
  Fox, 
  the 
  large, 
  smooth 
  articular 
  arc 
  (a) 
  at 
  the 
  lower 
  end 
  of 
  the 
  

   body 
  must 
  be, 
  in 
  its 
  entirety, 
  the 
  scapular 
  share 
  of 
  the 
  glenoid 
  fossa, 
  

   because 
  it 
  alone, 
  as 
  Dr. 
  Wilkins's 
  smaller 
  specimen 
  demonstrates, 
  

   affords 
  evidence 
  of 
  having 
  formed 
  part 
  of 
  a 
  freely 
  movable 
  joint, 
  

   and 
  it 
  bears 
  no 
  mark 
  of 
  a 
  subdivision 
  into 
  a 
  glenoid 
  and 
  a 
  coracoid 
  

   portion. 
  The 
  " 
  appearance 
  of 
  a 
  subdivision 
  of 
  the 
  thickened 
  arti- 
  

   cular 
  end 
  into 
  two 
  surfaces, 
  one 
  for 
  the 
  humerus, 
  the 
  other 
  for 
  the 
  

   coracoid," 
  which 
  Prof. 
  Owen 
  observed 
  in 
  Mr. 
  Holmes's 
  specimen*, 
  

   if 
  descriptive 
  of 
  this 
  articular 
  arc, 
  was 
  perhaps 
  due 
  to 
  a 
  post-mortem 
  

   distortion 
  ; 
  but 
  there 
  is 
  the 
  possibility 
  that 
  Prof. 
  Owen 
  considered 
  

   the 
  whole 
  of 
  this 
  arc 
  as 
  the 
  coracoid 
  division, 
  and 
  the 
  stout 
  buttress 
  

   which 
  posteriorly 
  limits 
  it, 
  as 
  that 
  against 
  which 
  the 
  humerus 
  

   rested. 
  

  

  Assuming, 
  then, 
  as 
  proved, 
  that 
  the 
  large, 
  arched 
  articular 
  sur- 
  

   face 
  in 
  its 
  entirety 
  represents 
  (on 
  the 
  scapular 
  hypothesis) 
  the 
  sca- 
  

   pular 
  part 
  of 
  the 
  glenoid 
  fossa 
  for 
  the 
  humerus, 
  its 
  entirety 
  and 
  

   diarthrodial 
  nature 
  being 
  placed 
  beyond 
  doubt 
  by 
  Dr. 
  Wilkins's 
  spe- 
  

   cimens, 
  the 
  coracoid 
  attachment 
  must 
  be 
  sought 
  in 
  front 
  of 
  it. 
  Dr. 
  

   Mantell 
  (unless 
  I 
  misunderstand 
  him) 
  supposed 
  that 
  one 
  or 
  both 
  of 
  

   the 
  small 
  projections 
  from 
  the 
  under 
  surface 
  of 
  the 
  long 
  slender 
  

   process 
  gave 
  attachment 
  to 
  the 
  coracoid 
  bone; 
  but 
  these, 
  even 
  if 
  

   complemented 
  by 
  the 
  long 
  slender 
  process, 
  appear 
  very 
  inadequate 
  

   for 
  the 
  firm 
  attachment 
  of 
  a 
  bone 
  which 
  contributes 
  about 
  an 
  equal 
  

   share 
  with 
  the 
  scapula 
  to 
  the 
  shoulder-joint, 
  and 
  has 
  with 
  it 
  to 
  bear 
  

   very 
  considerable 
  pressures 
  ; 
  besides, 
  in 
  Iguanodon 
  Mantelli, 
  Hyp- 
  

   sdophodon 
  Foxii, 
  Megcdosaurus 
  Bucklandi, 
  JJylceosaurus 
  Conybeari, 
  

   and 
  Scelidosaurus 
  Harrisoni 
  (the 
  only 
  British 
  Dinosaurs 
  of 
  which 
  

   scapulae 
  in 
  union 
  with 
  coracoids 
  have, 
  so 
  far 
  as 
  my 
  knowledge 
  

   reaches, 
  as 
  yet 
  been 
  found) 
  the 
  coracoid 
  border 
  of 
  the 
  scapula 
  is 
  

   so 
  much 
  longer, 
  relatively 
  to 
  the 
  humeral 
  border, 
  than 
  these 
  two 
  

   little 
  projections 
  are 
  to 
  the 
  arch 
  behind 
  them, 
  that 
  it 
  is 
  hardly 
  pos- 
  

   sible 
  to 
  conceive 
  that 
  they 
  can 
  be 
  the 
  functional 
  equivalents 
  of 
  the 
  

   coracoid 
  border 
  of 
  the 
  scapula 
  as 
  we 
  know 
  it 
  in 
  the 
  Dinosaurs 
  just 
  

   mentioned. 
  But 
  conceding 
  that 
  they 
  are 
  corresponding 
  parts, 
  what 
  

   explanation 
  can 
  be 
  given 
  of 
  the 
  stout 
  posterior 
  inferior 
  angle 
  of 
  the 
  

   body 
  which 
  limits 
  the 
  smooth 
  articular 
  arc 
  behind 
  ? 
  Its 
  truncated 
  

   terminal 
  surface, 
  directed 
  downwards 
  and 
  backwards, 
  bears, 
  in 
  Dr. 
  

   "Wilkins's 
  smaller 
  specimen, 
  the 
  stamp 
  of 
  a 
  firm 
  cartilaginous 
  union 
  

   with 
  some 
  other 
  bone. 
  But 
  what 
  bone 
  is 
  there 
  united 
  with 
  the 
  

   scapula 
  behind 
  the 
  glenoid 
  fossa 
  ? 
  

  

  There 
  remains 
  only 
  the 
  suggested 
  resemblance 
  of 
  the 
  long, 
  slender, 
  

   anterior 
  process 
  detached 
  from 
  the 
  anterior 
  margin 
  of 
  the 
  body 
  

   near 
  its 
  lower 
  end, 
  to 
  certain 
  processes 
  found 
  in 
  Bylceosaurus, 
  and 
  

   in 
  some 
  existing 
  Lacertians, 
  notably 
  in 
  Scincus. 
  

  

  The 
  part 
  of 
  the 
  Hyloeosaurian 
  scapula 
  to 
  which 
  Prof. 
  Owen 
  com- 
  

   pares 
  this 
  long 
  slender 
  process 
  is 
  described 
  by 
  him 
  in 
  these 
  terms 
  : 
  — 
  

   " 
  On 
  the 
  outer 
  side 
  of 
  the 
  scapula 
  two 
  broad 
  convex 
  ridges 
  descend 
  

   and 
  converge 
  to 
  form 
  the 
  beginning 
  of 
  a 
  thick 
  and 
  strong 
  spine 
  at 
  

   fourteen 
  inches 
  distance 
  from 
  the 
  base 
  ; 
  this 
  then 
  expands 
  into 
  a 
  

   * 
  Brit.. 
  Foss. 
  Eept., 
  Mcgalo^aurus, 
  p. 
  14. 
  

  

  