﻿516 
  J. 
  W. 
  HTJLKE 
  ON 
  A 
  REPTILIAN 
  TIBIA 
  AND 
  HUMERUS 
  

  

  39. 
  Note 
  on 
  a 
  Reptilian 
  Tibia 
  and 
  Humerus 
  (probably 
  of 
  Hylaeo- 
  

   saurus) 
  from 
  the 
  Wealden 
  Formation 
  in 
  the 
  Isle 
  op 
  Wight. 
  By 
  

   J. 
  W. 
  Hulke, 
  Esq., 
  F.R.S., 
  F.G.S. 
  (Read 
  June 
  10, 
  1874.) 
  

   [Plate 
  XXXI.] 
  

  

  I 
  am 
  indebted 
  to 
  Dr. 
  Wilkins, 
  of 
  Newport, 
  who 
  has 
  already 
  so 
  fre- 
  

   quently 
  afforded 
  me 
  valuable 
  materials 
  for 
  the 
  study 
  of 
  the 
  fossil 
  

   Reptilian 
  fauna 
  of 
  the 
  Isle 
  of 
  Wight, 
  for 
  the 
  opportunity 
  of 
  bringing 
  

   two 
  very 
  remarkable 
  limb-bones 
  before 
  this 
  Society. 
  They 
  were 
  

   obtained 
  several 
  years 
  ago, 
  in 
  Brixton 
  Bay, 
  by 
  a 
  fisherman 
  since 
  dead. 
  

   The 
  soft 
  and 
  brittle 
  state 
  of 
  their 
  tissues, 
  the 
  complete 
  substitution 
  

   throughout 
  them 
  of 
  the 
  red 
  oxide 
  of 
  iron 
  for 
  the 
  pyrites 
  with 
  which 
  

   bones 
  in 
  this 
  locality 
  are 
  usually 
  impregnated, 
  their 
  envelopment 
  

   in 
  a 
  concretionary 
  matrix 
  of 
  this 
  oxide 
  and 
  clay, 
  and 
  their 
  incrus- 
  

   tation 
  with 
  recent 
  zoophytes 
  and 
  algae 
  concur 
  in 
  making 
  it 
  very 
  

   probable 
  that 
  they 
  had 
  been 
  long 
  exposed 
  to 
  the 
  waves 
  and 
  winds 
  

   upon 
  the 
  shore 
  between 
  high- 
  and 
  low-water 
  marks 
  before 
  they 
  were 
  

   discovered. 
  The 
  horizon 
  of 
  their 
  gisement 
  cannot 
  be 
  fixed 
  more 
  

   nearly 
  than 
  somewhere 
  in 
  the 
  mottled 
  purple 
  and 
  grey 
  clays, 
  there- 
  

   fore 
  in 
  the 
  beds 
  west 
  of 
  Cowleaze 
  Chine, 
  below 
  the 
  Hypsilophodon- 
  

   bed. 
  It 
  is 
  not 
  even 
  known 
  that 
  they 
  were 
  found 
  lying 
  so 
  close 
  

   together 
  as 
  to 
  justify 
  the 
  inference 
  from 
  juxtaposition 
  that 
  they 
  

   originally 
  formed 
  part 
  of 
  one 
  skeleton. 
  Dr. 
  Wilkins 
  informed 
  me, 
  

   when 
  I 
  first 
  saw 
  them 
  in 
  1870, 
  that 
  he 
  believed 
  they 
  were 
  so 
  asso- 
  

   ciated 
  when 
  discovered 
  ; 
  and 
  the 
  close 
  agreement 
  of 
  their 
  general 
  

   facies, 
  of 
  their 
  texture, 
  of 
  their 
  mineralization, 
  of 
  the 
  matrix 
  about 
  

   .them, 
  and 
  of 
  their 
  algal 
  and 
  zoophytic 
  crusts 
  concur 
  in 
  rendering 
  

   this 
  extremely 
  probable, 
  and 
  dispose 
  me 
  to 
  regard 
  them 
  as 
  members 
  

   of 
  one 
  individual. 
  

  

  Remarkable 
  shortness 
  relatively 
  to 
  their 
  bulk, 
  singularly 
  dwarfed 
  

   shafts, 
  and 
  as 
  notably 
  expanded 
  articular 
  extremities 
  characterize 
  

   both 
  bones. 
  

  

  Tibia 
  (PI. 
  XXXI. 
  figs. 
  1 
  & 
  2). 
  — 
  The 
  general 
  resemblance 
  of 
  this 
  

   bone 
  to 
  the 
  tibiae 
  of 
  such 
  typical 
  Dinosaurs 
  as 
  Iguanodon 
  Mantelli 
  

   and 
  Megalosaurus 
  Bucklandi 
  leaves 
  no 
  doubt 
  of 
  its 
  place 
  in 
  the 
  

   skeleton 
  ; 
  but 
  its 
  proportions 
  make 
  it 
  impossible 
  to 
  mistake 
  it 
  for 
  the 
  

   tibia 
  of 
  either 
  of 
  these 
  Sauria. 
  

   Its 
  total 
  length 
  is 
  16 
  inches. 
  

  

  The 
  proximal 
  end 
  is 
  so 
  very 
  massive 
  that 
  it 
  greatly 
  overhangs 
  the 
  

   slender 
  shaft. 
  An 
  inner 
  and 
  an 
  outer 
  condyle, 
  the 
  latter 
  separated 
  

   behind 
  by 
  a 
  wide, 
  deep, 
  roundish 
  notch 
  from 
  a 
  stout 
  praecnemial 
  

   process, 
  are 
  obscurely 
  mapped 
  on 
  the 
  upper 
  or 
  articular 
  surface. 
  Its 
  

   antero-internal 
  surface, 
  and 
  the 
  praecnemial 
  process 
  into 
  which 
  the 
  

   former 
  is 
  prolonged 
  outwards, 
  are 
  rough 
  as 
  if 
  for 
  the 
  attachment 
  of 
  

   muscles 
  and 
  ligaments 
  ; 
  and 
  a 
  rather 
  strong 
  tuberosity 
  marks 
  the 
  

   junction 
  of 
  the 
  internal 
  and 
  anterior 
  portions. 
  The 
  long 
  diameter 
  

   of 
  this 
  end, 
  passing 
  through 
  the 
  inner 
  condyle 
  and 
  the 
  base 
  of 
  the 
  

   praecnemial 
  process, 
  measures 
  about 
  7 
  inches 
  ; 
  and 
  when 
  the 
  back 
  

   of 
  the 
  condyles 
  rests 
  upon 
  a 
  fiat 
  surface 
  it 
  includes 
  with 
  this 
  surface 
  

  

  