640 
PROFESSOR OWEN ON THE PELVIC 
tuberosity, s'. In the Marsupial it contributes four-fifths of the outer border of 
the relatively large obturator vacuity, o. In Felts the shorter, broader, and thicker 
body of the ischium, as it descends or retrogrades to the tuberosity, s', contributes 
but half of the outer border of the relatively smaller obturator foramen, o, the 
anterior third of each border running parallel with the acetabulum. 
The portion of pelvis from the Wellington cave (Plate 46, fig. 1) corresponds in 
size, and includes the parts to which the above-defined characters of the carnivorous 
and herbivorous Mammals can be respectively compared. The ilium, i, is lamellar 
in form, not a triedral bar. The acetabulum, a, has a wide and shallow sub-circular 
synovial cavity, p, the entry to which is not encroached upon by the mesial and 
distal acetabular border, but is partially overarched thereby posteriorly or laterally. 
The tuberosity, fig. 1, t, for the origin of the superacetabular tendon of the rectus 
femoris muscle is rather more prominent than in Felts, fig. 3, t ; in Macropus, fig. 2, t, 
it is almost flat, and is indicated by a roughened surface.* The distance of this 
surface from the acetabulum is the same in the Kangaroo as is that of the process, t, 
in the cave-fossil; in the Lion it is nearer to the acetabular border. 
In Macropus major a subquadrate process, i, with a basal breadth of one inch, 
extends for seven lines forward from the ilio-pubic commencement of the brim of the 
pelvis. This process does not relate to the attachment of a marsupial bone, it answers 
rather to the “ anterior inferior spine ” of the human ilium, and gives attachment to the 
main origin of the “ rectus femoris; ” it may relate, in both, to the action of that 
muscle in maintaining the erect, bipedal posture. 
The “anterior inferior spine” is represented by a narrow rough slightly produced 
ridge from the same position in the leonine pelvis, and is not more developed in the 
cave-fossil. In this the facets, fig. 1, m, at the fore-end of the ischio-pubic symphysis 
for the attachment of marsupial bones, are present: but such surface is not upon an 
outwardly produced epiphysial bone, as in the full-grown Macropus major. 
But now it may be asked—“ Why is the comparison confined to the largest of the 
existing herbivorous Marsupials ? ” To which I reply that size seems to relate to the 
sphere of activity in which Marsupials obtain their vegetable food. Those that seek 
it in trees, like the arboreal Phalangers and Koalas, do not exceed a Cat or Rabbit 
in size, while the grazers attain a bulk which equals that of Thylacoleo carnifex, 
and the vegetarian contemporaries of that extinct species much exceeded in size the 
Boomer Kangaroo ( Macropus major). Among the cave remains of the prey of 
Thylacoleo is part of a gnawed pelvis twice the size of that of the Boomer, but 
closely repeating the Macropodal characters of that part of the skeleton in the 
existing Kangaroos.! 
* In man it is a groove, and gives attachment to the so-called “ reflected tendon ’ of the rectus 
femoris. 
f ‘ Fossil Mammals of Australia,’ 4to., vol. ii., pi. cxxx. ( Palorchestes). 
