﻿138 
  J. 
  W. 
  HTTLKE 
  ON 
  SOME 
  IGUANODON-EEMAINS. 
  

  

  dered. 
  Those 
  of 
  the 
  right 
  metatarsus 
  had 
  fallen 
  apart, 
  but 
  were 
  

   lying 
  by 
  one 
  another. 
  Both 
  metatarsi 
  demonstrate 
  conclusively 
  that 
  

   the 
  hind 
  foot 
  in 
  Iguanodon 
  has 
  three, 
  and 
  only 
  three, 
  functional 
  

   toes, 
  the 
  number 
  actually 
  present 
  in 
  the 
  hind 
  foot 
  of 
  an 
  immature 
  

   Iguanodon 
  in 
  Mr. 
  S. 
  H. 
  Beckles's 
  collection, 
  several 
  years 
  since 
  de- 
  

   scribed 
  and 
  figured 
  by 
  Prof. 
  Owen, 
  in 
  his 
  ' 
  Fossil 
  Reptilia 
  of 
  the 
  

   Wealden 
  Formations.' 
  

  

  Of 
  the 
  three 
  metatarsals 
  the 
  inner 
  is 
  shortest, 
  being 
  26centim. 
  (10| 
  

   in.) 
  long. 
  Its 
  proximal 
  end 
  is 
  much 
  extended 
  in 
  the 
  dorso-plantar 
  

   direction, 
  this 
  diameter 
  measuring 
  21*3 
  centim. 
  (8-f 
  in.), 
  whilst 
  the 
  

   transverse 
  or 
  horizontal 
  diameter 
  is 
  but 
  10*2 
  centim. 
  (4 
  in.). 
  The 
  

   distal 
  end, 
  condylarly 
  divided, 
  is 
  asymmetrical, 
  the 
  outer 
  condyle 
  

   being 
  narrower 
  and 
  slightly 
  deeper 
  than 
  the 
  inner, 
  than 
  which 
  it 
  also 
  

   diverges 
  more 
  from 
  the 
  axis 
  of 
  the 
  bone. 
  The 
  intercondylar 
  groove 
  

   scarcely 
  rises 
  above 
  the 
  middle 
  of 
  the 
  articular 
  surface. 
  The 
  inner 
  

   surface 
  of 
  the 
  metatarsal 
  (that 
  which 
  looks 
  towards 
  the 
  middle 
  

   metatarsal 
  bone) 
  is 
  flattened 
  ; 
  and 
  its 
  junction 
  with 
  the 
  dorsal 
  or 
  

   upper 
  surface 
  in 
  the 
  distal 
  half 
  of 
  the 
  bone 
  projects 
  in 
  the 
  form 
  of 
  

   a 
  thin 
  overhanging 
  lip, 
  by 
  which 
  it 
  may 
  be 
  distinguished 
  from 
  the 
  

   outer 
  metatarsal. 
  This 
  process 
  is 
  not 
  peculiar 
  to 
  Iguanodon 
  ; 
  for 
  

   it 
  is 
  distinctly 
  represented 
  in 
  a 
  metatarsal 
  of 
  Poikilopleuron 
  Buclc- 
  

   landi, 
  figured 
  by 
  E.Deslongchamps, 
  pere, 
  also 
  in 
  Prof. 
  Cope's 
  figures 
  

   of 
  a 
  metatarsal 
  of 
  Hadrosaurus 
  Foulkii, 
  and 
  it 
  is 
  present 
  in 
  the 
  inner- 
  

   most 
  metatarsal 
  of 
  Hypsilophodon 
  Foxii. 
  

  

  The 
  middle 
  metatarsal 
  bone 
  is 
  35*5 
  centim. 
  (14 
  in.) 
  long. 
  The 
  

   shape 
  and 
  proportions 
  of 
  its 
  proximal 
  end, 
  now 
  distorted, 
  do 
  not 
  

   appear 
  to 
  have 
  differed 
  much 
  from 
  those 
  of 
  the 
  inner 
  metatarsal. 
  

   The 
  dorsal 
  border 
  of 
  this 
  end 
  is 
  produced 
  upwards 
  in 
  the 
  form 
  of 
  a 
  

   lip 
  adapted 
  to 
  the 
  pulley-groove 
  of 
  the 
  conjoined 
  astragalo-calca- 
  

   neum. 
  The 
  distal 
  condyles 
  are 
  nearly 
  symmetrical. 
  The 
  inter- 
  

   condylar 
  groove 
  rises 
  higher 
  than 
  in 
  the 
  other 
  metatarsals. 
  The 
  

   breadth 
  across 
  the 
  condyles 
  is 
  14 
  centim. 
  (5| 
  in.) 
  ; 
  that 
  of 
  the 
  middle 
  

   of 
  the 
  shaft 
  is 
  10*5 
  centim. 
  (4 
  J 
  in.),the 
  vertical 
  diameter 
  at 
  this 
  part 
  

   being 
  6*4 
  centim. 
  (2J 
  in.). 
  

  

  The 
  outer 
  metatarsal 
  is 
  29 
  centim. 
  (11 
  J- 
  in.) 
  long 
  ; 
  its 
  length 
  is 
  

   therefore 
  intermediate 
  between 
  those 
  of 
  the 
  other 
  two 
  metatarsals. 
  

   The 
  proximal 
  end 
  is 
  concave 
  vertically 
  and 
  slightly 
  so 
  horizontally, 
  

   its 
  figure 
  being 
  the 
  counterpart 
  of 
  the 
  corresponding 
  articular 
  surface 
  

   of 
  the 
  calcaneum. 
  The 
  distal 
  condyles 
  are 
  asymmetrical 
  ; 
  the 
  outer, 
  

   that 
  furthest 
  from 
  the 
  middle 
  line 
  of 
  the 
  foot, 
  is 
  narrower, 
  deeper, 
  

   and 
  more 
  divergent 
  from 
  the 
  axis 
  of 
  the 
  bone 
  than 
  is 
  the 
  inner 
  

   condyle. 
  The 
  breadth 
  across 
  the 
  condjles 
  is 
  12*6 
  centim. 
  (5 
  in.) 
  ; 
  

   and 
  that 
  of 
  the 
  proximal 
  end 
  is 
  15 
  centim. 
  (5-^- 
  in.). 
  

  

  It 
  has 
  been 
  already 
  stated 
  that 
  neither 
  of 
  these 
  metatarsi 
  lends 
  

   any 
  support 
  to 
  the 
  idea 
  that 
  the 
  hind 
  foot 
  in 
  Iguanodon 
  had 
  more 
  

   than 
  three 
  functional 
  toes. 
  A 
  fragment 
  cemented 
  by 
  rock 
  to 
  the 
  basal 
  

   end 
  of 
  the 
  inner 
  metatarsal 
  in 
  the 
  left 
  metatarsus 
  perhaps 
  represents 
  

   the 
  rudiment 
  of 
  a 
  fourth 
  metatarsal 
  preserved 
  in 
  Mr. 
  Beckles's 
  fossil, 
  

   to 
  which 
  reference 
  was 
  lately 
  made. 
  The 
  alternative 
  of 
  its 
  being 
  a 
  

   piece 
  of 
  a 
  chevron 
  is 
  suggested 
  by 
  the 
  agglutination 
  of 
  two 
  chevrons 
  

   to 
  the 
  plantar 
  surface 
  of 
  the 
  metatarsus. 
  

  

  Phalanges. 
  — 
  With 
  the 
  exception 
  of 
  one 
  proximal 
  phalanx 
  referable 
  

  

  