﻿208 
  H. 
  G. 
  SEELEY 
  ON 
  MUK^NOSAURITS 
  LEEDSII. 
  

  

  is 
  10 
  inches 
  long, 
  and 
  but 
  slightly 
  expanded 
  at 
  the 
  proximal 
  end 
  of 
  

   the 
  cylindrical 
  shaft 
  ; 
  and 
  this 
  expansion 
  appears 
  to 
  be 
  due 
  to 
  the 
  

   development 
  of 
  the 
  great 
  trochanter 
  in 
  a 
  transverse 
  direction 
  to 
  the 
  

   distal 
  expansion, 
  which 
  is 
  5| 
  inches 
  from 
  side 
  to 
  side. 
  The 
  bone 
  is 
  

   compressed 
  slightly 
  from 
  the 
  proximal 
  to 
  the 
  distal 
  end, 
  being 
  about 
  

   2| 
  inch 
  deep 
  proximally 
  and 
  1| 
  inch 
  distally. 
  The 
  anterior 
  border 
  

   is 
  slightly 
  concave 
  ; 
  the 
  posterior 
  border 
  is 
  much 
  more 
  concave, 
  

   especially 
  towards 
  the 
  distal 
  end. 
  In 
  the 
  middle 
  the 
  shaft 
  is 
  about 
  

   2 
  inches 
  in 
  diameter. 
  There 
  are 
  strong 
  roughnesses 
  towards 
  the 
  

   proximal 
  end, 
  indicating 
  the 
  attachment 
  of 
  muscles 
  ; 
  and 
  a 
  slightly 
  

   elevated 
  longitudinal 
  ridge 
  marks 
  the 
  middle 
  of 
  the 
  posterior 
  border 
  

   of 
  the 
  bone. 
  The 
  distal 
  articular 
  surface 
  is 
  divided 
  into 
  two 
  flat- 
  

   tened 
  areas, 
  apparently 
  with 
  cartilaginous 
  margins 
  back 
  and 
  front, 
  to 
  

   which 
  bones 
  may 
  not 
  have 
  been 
  articulated. 
  

  

  The 
  ulna 
  and 
  radius 
  are 
  short 
  from 
  above 
  downward, 
  as 
  in 
  Plesio- 
  

   saurus, 
  and 
  quite 
  distinct 
  in 
  form 
  from 
  those 
  bones 
  in 
  that 
  genus. 
  

   The 
  radius 
  is 
  compressed 
  from 
  side 
  to 
  side 
  towards 
  the 
  external 
  border, 
  

   and 
  thickened 
  towards 
  the 
  ulnar 
  border 
  ; 
  it 
  is 
  more 
  than 
  2| 
  inches 
  

   from 
  side 
  to 
  side, 
  and 
  is 
  nearly 
  2 
  inches 
  from 
  above 
  downward 
  

   where 
  deepest, 
  near 
  the 
  external 
  border. 
  The 
  humeral 
  surface 
  is 
  

   slightly 
  convex 
  ; 
  the 
  distal 
  surface 
  is 
  slightly 
  concave 
  from 
  side 
  to 
  

   side 
  ; 
  it 
  shows 
  a 
  short 
  second 
  facet 
  for 
  the 
  middle 
  carpal. 
  The 
  

   ulnar 
  surface 
  is 
  deeply 
  concave 
  from 
  above 
  downward. 
  

  

  The 
  ulna 
  is 
  shorter 
  from 
  above 
  downward 
  on 
  its 
  radial 
  margin, 
  

   where 
  it 
  measures 
  about 
  1 
  inch, 
  than 
  on 
  its 
  external 
  border, 
  which 
  

   is 
  convex, 
  and 
  in 
  extreme 
  depth 
  from 
  above 
  downward 
  measures 
  

   nearly 
  2 
  inches. 
  The 
  bone 
  is 
  about 
  1^ 
  inch 
  through 
  from 
  side 
  to 
  

   side, 
  and 
  1| 
  inch 
  along 
  its 
  proximal 
  articular 
  surface. 
  The 
  distal 
  

   end 
  includes 
  two 
  articular 
  surfaces, 
  of 
  which 
  the 
  posterior 
  is 
  

   rather 
  the 
  smaller. 
  The 
  surface 
  facing 
  the 
  radius 
  is 
  concave 
  from 
  

   above 
  downward, 
  and 
  appears 
  to 
  have 
  been 
  occupied 
  by 
  muscle 
  

   while 
  the 
  external 
  margin, 
  like 
  the 
  external 
  margin 
  of 
  the 
  radius, 
  

   was 
  cartilaginous. 
  There 
  are 
  six 
  thick 
  polygonal 
  carpal 
  bones 
  pre- 
  

   served. 
  They 
  appear 
  to 
  have 
  formed 
  two 
  rows 
  of 
  three 
  each. 
  The 
  

   longest 
  is 
  about 
  1| 
  to 
  1| 
  inch 
  long 
  by 
  1| 
  inch 
  deep. 
  The 
  phalanges 
  

   are 
  strong 
  and 
  thick, 
  like 
  those 
  of 
  Pliosaurus, 
  and 
  not 
  compressed 
  

   from 
  side 
  to 
  side, 
  as 
  in 
  typical 
  Plesiosaurs. 
  Towards 
  the 
  distal 
  

   end 
  of 
  the 
  limb 
  they 
  become 
  short, 
  and 
  have 
  the 
  proximal 
  and 
  

   distal 
  ends 
  of 
  the 
  bone 
  greatly 
  expanded 
  relatively 
  to 
  its 
  length. 
  

   There 
  appear 
  to 
  have 
  been 
  five 
  digits 
  ; 
  but 
  the 
  number 
  of 
  phalanges 
  

   in 
  each 
  is 
  not 
  known. 
  

  

  EXPLANATION 
  OF 
  PLATE 
  XXL 
  

  

  Fig. 
  1. 
  Right 
  side 
  of 
  seventh 
  cervical 
  vertebra 
  of 
  Murcsnosaurus 
  Leedsii. 
  

  

  2. 
  Front 
  view 
  of 
  thirty-third 
  cervical 
  vertebra. 
  

  

  3. 
  Left 
  side 
  of 
  the 
  thirty-ninth 
  and 
  neural 
  arcli 
  of 
  the 
  thirty-eighth 
  cer- 
  

  

  vical 
  vertebrae. 
  

  

  4. 
  Front 
  view 
  of 
  centrum 
  of 
  third 
  caudal 
  vertebra. 
  

  

  5. 
  Under 
  surface 
  of 
  centrum 
  of 
  fifth 
  caudal 
  vertebra. 
  

  

  