﻿FROM 
  THE 
  KIMMERIDGE 
  CLAY 
  OF 
  "WEYMOUTH. 
  17 
  

  

  ness 
  required 
  here 
  for 
  the 
  support 
  of 
  the 
  termiual 
  articular 
  caput. 
  

   The 
  distal 
  moiety 
  of 
  the 
  dorsal 
  surface 
  beyond 
  the 
  shaft 
  expands 
  

   gradually 
  to 
  a 
  maximum, 
  width 
  of 
  16 
  inches 
  at 
  the 
  distal 
  articular 
  

   surface. 
  A 
  very 
  long, 
  wide, 
  and 
  rather 
  deep 
  intercondyloid 
  groove 
  

   traverses 
  it 
  longitudinally. 
  The 
  ventral 
  surface 
  of 
  the 
  expanded 
  

   proximal 
  moiety 
  is 
  very 
  hollow 
  transversely 
  ; 
  and 
  beyond 
  the 
  shaft 
  

   its 
  distal 
  moiety 
  in 
  the 
  same 
  direction 
  is 
  gently 
  convex. 
  The 
  distal 
  

   articular 
  surface 
  (fig. 
  3) 
  is 
  an 
  oblong, 
  the 
  long 
  diameter 
  of 
  which 
  

   measures 
  16 
  inches, 
  and 
  the 
  short 
  one 
  averages 
  6 
  inches. 
  It 
  is 
  

   divided 
  into 
  a 
  pair 
  of 
  condyles 
  by 
  a 
  very 
  shallow 
  vertical 
  groove, 
  

   which 
  above 
  joins 
  the 
  dorsal 
  intercondylar 
  groove 
  and 
  below 
  ends 
  

   between 
  two 
  low 
  eminences 
  at 
  the 
  ventral 
  surface. 
  The 
  posterior 
  

   border, 
  gradually 
  contracting 
  from 
  the 
  shaft 
  towards 
  the 
  proximal 
  

   end, 
  becomes 
  here 
  a 
  relatively 
  thin 
  rounded 
  edge. 
  In 
  the 
  distal 
  

   moiety 
  this 
  border 
  is 
  stouter. 
  The 
  anterior 
  border 
  in 
  its 
  proximal 
  half 
  

   is 
  much 
  wider 
  than 
  the 
  corresponding 
  part 
  of 
  the 
  posterior 
  border 
  ; 
  

   it 
  is 
  flattened 
  and 
  produced 
  downwards 
  as 
  a 
  ventrally 
  projecting 
  crest 
  

   (fig. 
  2, 
  d 
  c.) 
  which 
  greatly 
  increases 
  the 
  hollowness 
  of 
  the 
  ventral 
  

   surface 
  in 
  this 
  part. 
  The 
  distal 
  moiety 
  of 
  this 
  border, 
  in 
  its 
  whole 
  

   length, 
  has 
  the 
  form 
  of 
  a 
  thin, 
  rough, 
  very 
  prominent 
  crest 
  project- 
  

   ing 
  forwards. 
  These 
  crests 
  form 
  one 
  of 
  the 
  most 
  striking 
  features 
  

   of 
  the 
  humerus, 
  which 
  distinguish 
  it 
  immediately 
  from 
  the 
  almost 
  

   equally 
  large 
  Mantellian 
  Pelorosaurian 
  humerus 
  preserved 
  in 
  the 
  

   British 
  Museum*, 
  and 
  from 
  the 
  almost 
  equally 
  huge, 
  but 
  rather 
  

   stouter, 
  humeri 
  of 
  the 
  Ceteosaurus 
  oxoniensis 
  in 
  the 
  Oxford 
  Univer- 
  

   sity 
  Museum, 
  so 
  admirably 
  restored 
  by 
  Prof. 
  Phillips 
  f, 
  as 
  also 
  from 
  

   the 
  much 
  smaller 
  humerus 
  of 
  Iscliyrosaurus 
  to 
  which 
  I 
  have 
  already 
  

   referred. 
  

  

  A 
  general 
  correspondence 
  with 
  the 
  humerus 
  of 
  Ceteosaurus 
  oxoni- 
  

   ensis 
  inclines 
  me 
  to 
  provisionally 
  refer 
  this 
  new 
  Kimmeridge 
  Saurian 
  

   to 
  the 
  genus 
  Ceteosaurus 
  as 
  typified 
  in 
  C. 
  oxoniensis. 
  Its 
  rough 
  strong 
  

   crests 
  suggest 
  the 
  specific 
  designation 
  humero-cristatus 
  (Ceteosaurus 
  

   humero-cristatus). 
  

  

  EXPLANATION 
  OF 
  PLATE 
  II. 
  

  

  Fig. 
  1. 
  Dorsal 
  or 
  posterior 
  surface 
  of 
  humerus: 
  d. 
  distal 
  end; 
  px. 
  proximal 
  

   end 
  ; 
  ant. 
  anterior 
  border 
  ; 
  post, 
  posterior 
  border 
  ; 
  cr. 
  crest. 
  

  

  2. 
  Ventral 
  or 
  anterior 
  surface 
  of 
  humerus 
  : 
  px. 
  proximal 
  end 
  ; 
  d. 
  distal 
  

  

  end 
  ; 
  ant. 
  anterior 
  or 
  outer 
  border 
  ; 
  post, 
  posterior 
  or 
  inner 
  border 
  ; 
  

   d 
  c. 
  deltoid 
  crest. 
  

  

  3. 
  View 
  of 
  distal 
  articular 
  end. 
  

  

  4. 
  Transverse 
  section 
  near 
  middle 
  of 
  shaft. 
  

  

  Discussion-. 
  

  

  Mr. 
  Seeley 
  remarked 
  that 
  the 
  internal 
  structure 
  of 
  the 
  bone 
  re- 
  

   sembled 
  that 
  found 
  in 
  Gigantosaurus, 
  and 
  the 
  general 
  form 
  of 
  the 
  

   humerus 
  was 
  such 
  as 
  might 
  be 
  expected 
  did 
  it 
  belong 
  to 
  an 
  animal 
  

   of 
  that 
  genus. 
  

  

  * 
  British 
  Fossil 
  Eeptilia 
  of 
  the 
  Wealden 
  Formation, 
  Supplement 
  ii. 
  vol. 
  xii. 
  

   p. 
  39. 
  

  

  f 
  Geology 
  of 
  Oxford, 
  p. 
  272. 
  

   Q.J. 
  G. 
  S. 
  No. 
  117. 
  c 
  

  

  