﻿394 
  PROF. 
  OWEN 
  DESCRIPTION 
  OP 
  Pi.RT 
  OF 
  THE 
  

  

  40. 
  Description 
  of 
  Part 
  of 
  the 
  Femur 
  of 
  Nototherifm 
  Mitchelli. 
  

   By 
  Prof. 
  Owen! 
  C.B., 
  F.B.S., 
  F.G.S., 
  &c. 
  (Read 
  June 
  7, 
  1882.) 
  

  

  [Plate 
  XVI.] 
  

  

  In 
  my 
  work 
  on 
  the 
  Extinct 
  Mammals 
  of 
  Australia 
  * 
  the 
  osteology 
  

   of 
  the 
  existing 
  species 
  is 
  described 
  and 
  figured 
  in 
  the 
  degree 
  requi- 
  

   site 
  for 
  the 
  comparisons 
  with 
  the 
  fossil 
  bones. 
  

  

  In 
  the 
  Kangaroos 
  the 
  femur, 
  amongst 
  other 
  characteristics, 
  shows 
  

   " 
  the 
  rough 
  depression 
  (plate 
  lxxiii. 
  figs. 
  2, 
  3, 
  y, 
  op. 
  cit.) 
  above 
  the 
  

   outer 
  condyle 
  (ib 
  i/)' 
  and 
  " 
  the 
  great 
  transverse 
  extent 
  of 
  the 
  arti- 
  

   cular 
  surface 
  of 
  that 
  condyle 
  by 
  the 
  production 
  of 
  its 
  outer 
  part, 
  

   changing, 
  there, 
  the 
  convexity 
  into 
  a 
  concavity 
  transversely 
  (ib. 
  

   fig. 
  2, 
  w) 
  " 
  f 
  . 
  With 
  these 
  may 
  be 
  noted 
  the 
  narrowness 
  and 
  depth 
  

   of 
  the 
  postcondylar 
  or 
  popliteal 
  fossa 
  (fig. 
  2, 
  u). 
  

  

  The 
  corresponding 
  part 
  of 
  the 
  femur 
  in 
  the 
  Wombats 
  (ib. 
  pi. 
  ciii. 
  

   figs. 
  1-4) 
  differs 
  in 
  the 
  absence 
  of 
  " 
  the 
  rough 
  depression, 
  y 
  ; 
  " 
  in 
  

   the 
  relatively 
  less 
  transverse 
  extent 
  of 
  the 
  articular 
  surface 
  of 
  the 
  

   outer 
  condyle, 
  especially 
  at 
  its 
  back 
  part 
  ; 
  in 
  the 
  continuous 
  trans- 
  

   verse 
  convexity 
  of 
  that 
  part 
  of 
  the 
  condyle, 
  and 
  in 
  the 
  minor 
  rela- 
  

   tive 
  depth 
  and 
  greater 
  relative 
  width 
  of 
  the 
  postcondylar 
  fossa. 
  

  

  In 
  the 
  comparison 
  of 
  the 
  fossil 
  femur 
  of 
  the 
  Diprotodon 
  (op. 
  cit. 
  

   pp. 
  231-234) 
  the 
  rough 
  longitudinal 
  depression 
  above 
  the 
  outer 
  

   condyle 
  (pi. 
  xxxiv. 
  fig. 
  1, 
  o)£, 
  the 
  concavo-convex 
  hinder 
  part 
  of 
  the 
  

   articular 
  surface 
  of 
  the 
  outer 
  condyle 
  (ib. 
  v), 
  the 
  length, 
  depth, 
  and 
  

   relativo 
  narrowness 
  of 
  the 
  postcondylar 
  fossa 
  (ib. 
  it), 
  with 
  other 
  

   characters 
  of 
  the 
  bone, 
  showed 
  its 
  closer 
  resemblance 
  to 
  the 
  femur 
  

   of 
  the 
  Kangaroo 
  than 
  to 
  that 
  of 
  the 
  Wombat 
  or 
  other 
  of 
  the 
  larger 
  

   existing 
  kinds 
  of 
  Marsupialia. 
  

  

  In 
  the 
  lower 
  or 
  distal 
  portion 
  (probably 
  one 
  half) 
  of 
  a 
  large 
  fossil 
  

   femur 
  (PI. 
  XVI.) 
  transmitted 
  from 
  Australia 
  by 
  my 
  friend 
  Dr. 
  

   George 
  Bennett, 
  F.L.S., 
  the 
  following 
  differences 
  present 
  them- 
  

   selves 
  : 
  — 
  There 
  [is 
  no 
  depression 
  above 
  the 
  outer 
  condyle 
  ; 
  but 
  there 
  

   is 
  a 
  rough 
  longitudinal 
  rising 
  (ib. 
  fig. 
  1, 
  o) 
  in 
  the 
  corresponding 
  

   Xnace, 
  for 
  the 
  attachment 
  of 
  the 
  same 
  or 
  homologous 
  muscle. 
  The 
  

   hind 
  surface 
  of 
  the 
  outer 
  condyle 
  (ib. 
  fig. 
  4) 
  is 
  transversely 
  convex 
  : 
  

   in 
  Diprotodon 
  the 
  transversely 
  concave 
  tract 
  of 
  that 
  condyle 
  is 
  rela- 
  

   tively 
  greater 
  than 
  in 
  the 
  largest 
  existing 
  Kangaroo 
  ; 
  but 
  I 
  may 
  

   remark 
  that 
  in 
  some 
  of 
  the 
  still 
  larger 
  extinct 
  Macropodidae 
  that 
  

   concavity 
  comes 
  nearer 
  in 
  relative 
  extent 
  to 
  the 
  proportions 
  shown 
  

   in 
  Diprotodon 
  §. 
  The 
  same 
  remark 
  applies 
  to 
  the 
  proportional 
  

   breadth 
  of 
  the 
  postcondylar 
  fossa, 
  which, 
  though 
  small 
  in 
  Maeropus 
  

   rufus, 
  is 
  still 
  less 
  in 
  Maeropus 
  titan, 
  where 
  it 
  repeats 
  the 
  character 
  

   of 
  this 
  part 
  in 
  Diprotodon. 
  

  

  * 
  4to, 
  1877. 
  I 
  Ib. 
  p. 
  390, 
  $ 
  Ib. 
  p. 
  231. 
  

  

  § 
  Op. 
  cit. 
  pi. 
  xxxiv. 
  fig. 
  1, 
  i\ 
  

  

  

  