PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
561 
apex is 6 inches : this production is more conspicuous at the fore (Plate XLVIII. fig. 1, b) 
than at the back part (Plate XLIX. fig. 1). The margin of the articular surface is 
slightly prominent, through the sudden contraction of the rough surface of the neck ; 
but this is chiefly at the fore part (Plate XLVIII. fig. 1, d), towards which aspect the 
head slightly inclines. At the back part of the neck, just beyond the head, there is a 
low ridge 1| inch long (Plate XLIX. fig. 1, e) parallel to the margin of the articular 
surface. 
The rugged surface of the great trochanter commences at the middle of the upper 
part of the neck, with a moderate elevation and a border convex towards the head (Plate 
XLVIII. fig. 2, f) ; its fore-and-aft breadth here is 3| inches, but the process expands 
as it recedes from the head, sloping downward to a breadth of 4 inches 10 lines ; its 
outer expanded termination is subbilobed, the posterior lobe (ib. li) being most pro- 
duced outward ; the anterior one (ib. g) is continued furthest down the shaft. 
Anteriorly the great trochanter is defined by the abrupt rising of the rugged surface 
from the smooth surface of the neck along a curved line (ib. fig. 1, i, i), which bends 
round the lower part of the anterior lobe (ib. fig. 1, g), : this is continued upon the 
fore part of the shaft near its outer margin for an extent of 5 inches from the upper 
surface of the lobe ; the posterior lobe (Plate XLIX. fig. 1, h ) extends a shorter 
way down the outer surface of the femur, and is defined, or rises, very abruptly from the 
smooth tract of that part of the shaft. The posterior part of the trochanter projects as 
a thick oblong tuberosity (ib. fig. 1, Tc) above the trochanterian depression (ib. 1 ) : the 
mouth of this depression is 3 inches 8 lines in length, 1 inch in breadth, opening parallel 
with the lower margin of the neck, and is 3 inches in depth. Beyond the depression 
the posterior margin of the trochanter is less defined from the femoral shaft than is the 
anterior one. The neck of the femur (Plates XLVIII. & XLIX. m) begins by hardly a 
less diameter than the head from above downward, and augments in that direction as it 
extends outward ; it is rapidly compressed from before backward, as it recedes, especially 
where it is continued into the trochanterian fossa ( l ) ; its upper margin is slightly concave 
from within outward, convex from before backward, 2 inches broad in that direction ; 
the lower margin is 2 inches 6 lines. This margin is not uniformly convex across, 
but is remarkable for the production of its hinder half into a long narrow elliptical rough 
ridge, representing the small trochanter, which is 6 inches in length and H inch across 
the middle (Plate XLVIII. fig. 1, n). 
The lower ends of this and of the anterior tuberosity of the great trochanter are on 
the same transverse parallel, at which the proper shaft of the femur may be said to 
commence. This is defined by a gentle concave curve in both outer and inner sides, the 
least transverse diameter being 4 inches 5 lines. At the upper half of the shaft the 
fore-and-aft thickness decreases from the outer to the inner border, which is reduced to 
2 inches before rounding off. This border gains in thickness as it approaches the lower 
end. 
The outer side of the compressed shaft preserves a thickness of about 2-| inches along 
4 G 2 
