﻿16 
  " 
  J. 
  W. 
  HtTLKE 
  ON 
  A 
  LARGE 
  SAURIAN 
  LIMB-BONE 
  

  

  3. 
  Note 
  on 
  a 
  very 
  Large 
  Saurian 
  Limb-bone 
  adapted 
  for 
  Progres- 
  

   sion 
  upon 
  Land, 
  from 
  the 
  Kimmeridge 
  Clay 
  of 
  Weymouth, 
  Dorset. 
  

   By 
  J. 
  W. 
  Hulke, 
  Esq., 
  E.G.S., 
  E.R.S. 
  (Read 
  November 
  5, 
  1873.) 
  

  

  [Plate 
  II.] 
  

  

  At 
  rare 
  intervals 
  there 
  have 
  been 
  obtained 
  from 
  the 
  Kimmeridge 
  

   Clay 
  in 
  several 
  localities 
  (inland 
  and 
  also 
  on 
  the 
  Dorset 
  coast) 
  re- 
  

   mains 
  of 
  very 
  large 
  reptiles 
  differing 
  from 
  the 
  contemporary 
  Enalio- 
  

   saurs 
  (the 
  Plio-, 
  Plesio-, 
  and 
  Ichthyosaurs) 
  by 
  the 
  adaptation 
  of 
  

   their 
  limbs 
  to 
  walking 
  upon 
  dry 
  land. 
  On 
  June 
  23, 
  1869, 
  1 
  brought 
  

   before 
  the 
  Society 
  a 
  large 
  humerus 
  of 
  such 
  a 
  reptile, 
  which 
  had 
  been 
  

   obtained 
  in 
  Kimmeridge 
  Bay 
  by 
  J. 
  C. 
  Mansel 
  Pleydell, 
  Esq., 
  a 
  

   Fellow 
  of 
  our 
  Society. 
  It 
  was 
  afterwards 
  presented 
  by 
  him 
  to 
  the 
  

   British 
  Museum 
  * 
  ; 
  and 
  to 
  the 
  Saurian 
  indicated 
  by 
  it 
  I 
  gave 
  the 
  

   name 
  of 
  Ischyrosaurus. 
  

  

  The 
  subject 
  of 
  this 
  note 
  is 
  a 
  much 
  larger 
  limb-bone 
  lately 
  

   found 
  in 
  the 
  Kimmeridge- 
  clay 
  beds, 
  near 
  "Weymouth, 
  by 
  Mr. 
  R. 
  I. 
  

   Smith, 
  and 
  intended 
  to 
  be 
  added 
  to 
  the 
  national 
  collection. 
  It 
  was 
  

   enveloped 
  in 
  large 
  septarian 
  masses, 
  which 
  stuck 
  so 
  closely 
  to 
  it 
  that 
  

   thin 
  laminae 
  of 
  the 
  surface 
  of 
  the 
  bone 
  were 
  unavoidably 
  detached 
  

   in 
  stripping 
  the 
  matrix 
  from 
  it. 
  The 
  natural 
  surface, 
  where 
  unin- 
  

   jured, 
  is 
  smooth 
  ; 
  it 
  has 
  a 
  close, 
  fine 
  grain 
  resembling 
  that 
  of 
  the 
  

   humerus 
  of 
  the 
  Ischyrosaurus, 
  and 
  quite 
  unlike 
  the 
  coarse 
  texture 
  of 
  

   many 
  Enaliosaurian 
  bones. 
  The 
  bone 
  has 
  been 
  much 
  fissured, 
  and 
  

   cemented 
  together 
  by 
  spar 
  ; 
  and 
  some 
  parts 
  have 
  been 
  distorted 
  by 
  

   squeezing 
  ; 
  but 
  the 
  general 
  figure 
  is 
  well 
  preserved 
  f. 
  

  

  It 
  has 
  a 
  closer 
  resemblance 
  to 
  the 
  Crocodilian 
  type 
  of 
  humerus 
  

   than 
  to 
  any 
  other 
  bone 
  ; 
  and 
  I 
  am 
  disposed 
  to 
  regard 
  it 
  as 
  a 
  humerus, 
  

   the 
  left 
  one. 
  Its 
  present 
  length 
  is 
  54 
  inches 
  ; 
  but 
  the 
  articular 
  sur- 
  

   faces 
  of 
  both 
  ends 
  are 
  wanting, 
  and 
  for 
  these 
  scarcely 
  less 
  than 
  9 
  addi- 
  

   tional 
  inches 
  can 
  be 
  allowed 
  ; 
  so 
  that 
  the 
  whole 
  length 
  of 
  the 
  perfect 
  

   bone 
  can 
  hardly 
  have 
  been 
  less 
  than 
  63 
  inches, 
  The 
  middle 
  of 
  the 
  

   shaft 
  is 
  eylindroid; 
  its 
  girth 
  is 
  21 
  inches; 
  and 
  its 
  horizontal 
  transverse 
  

   diameter 
  is 
  7'8. 
  Its 
  transverse 
  section 
  (PI. 
  II. 
  fig. 
  4) 
  is 
  a 
  subtrigonal 
  

   figure 
  ; 
  and 
  it 
  exhibits 
  a 
  large 
  coarsely 
  cancellated 
  core 
  enclosed 
  in 
  a 
  

   stout 
  compact 
  cortical 
  ring. 
  Towards 
  the 
  proximal 
  end 
  the 
  width 
  

   increases, 
  chiefly 
  by 
  the 
  backward 
  sweep 
  of 
  the 
  posterior 
  border, 
  

   to 
  a 
  present 
  maximum 
  of 
  17 
  inches 
  ; 
  but 
  this 
  would 
  be 
  increased 
  

   by 
  the 
  absent 
  posterior 
  moiety 
  of 
  the 
  proximal 
  surface, 
  including 
  the 
  

   articular 
  caput 
  and 
  the 
  adjoining 
  end 
  of 
  the 
  posterior 
  border. 
  The 
  

   outline 
  of 
  the 
  dorsal 
  or 
  upper 
  surface 
  in 
  this 
  situation 
  is 
  transversely 
  

   convex, 
  whilst 
  longitudinally 
  it 
  rises 
  in 
  a 
  gentle 
  curve 
  from 
  the 
  

   eylindroid 
  shaft 
  to 
  the 
  proximal 
  end, 
  owing 
  to 
  the 
  increased 
  thick 
  - 
  

  

  * 
  A 
  description 
  and 
  figures 
  of 
  it 
  will 
  be 
  found 
  in 
  the 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  

   tol. 
  xxv. 
  p. 
  386. 
  

  

  t 
  In 
  the 
  following 
  description 
  the 
  bone 
  is 
  imagined 
  to 
  be 
  placed 
  nearly 
  hori- 
  

   zontally, 
  with 
  its 
  long 
  axis 
  perpendicular 
  to 
  the 
  animal's 
  trunk. 
  

  

  