126 FEMUR PROBABLY OF THYLACOLEO; 
contracted by the convexity of the side of the outer 
condyle, its lesser and more uniform width is repeated in 
Sarcophilus, but is here rendered somewhat sinuous by a 
slight convexity of the outside of the inner and concavity 
of that of the outer condyle. There is no trace of the deep 
pit in the intercondylar groove present in Phascolomys. 
COMPARATIVE MEASUREMENTS. 
Fossil. Sarcophilus. Phascolomys. 
mm. mm. mm. 
Total length 296'0 1090 160°0 
Least width of shaft 24°0 8:0 14°5 
Breadth of proximal end = _71°5 28°0 46°0 
Breadth of distal end 61'0 20°5 37°0 
Length of fossa 57'0 19'5 370 
The fossil bone is relatively stouter than the femur of Sar- 
cophilus, and slenderer than that of Phascolomys ; its proximal end 
is narrower than in either of these; its distal end (imperfect) may 
be narrower than in Phascolomys, and is broader than in Sar- 
cophilus ; its fossa is shorter than in Phascolomys, but longer than 
in Sarcophilus. . 
Recapitulating the more salient points of comparison, 
we find that the fossil resembles the femur of the carnivore 
in the shortness and direction of the lesser trochanterian- 
ridge, in the obliquity of the post-trochanterian fossa, in the 
shape of the head, in that of the shaft anteriorly, and 
generally of the whole distal extremity. To this we may 
add that the backward curvature of the shaft is found in 
the allied genus Dasyurus. On the other hand, it resembles 
the corresponding bone in Phascolomys in the shape of the 
great trochanter exteriorly, in the prominence of the lesser 
trochanter, in the insertion of the ligamentum teres in the 
depth of the neck between the great trochanter and the 
head, and in the turgidity of the space between the fossa 
and the head. In brief, its proximal extremity, with pre- 
vailing characters of its own, has more of Phascolomys than 
of Sarcophilus in its composition, while its shaft and distal 
end show relation almost exclusively (as between these 
two) to Sarcophilus. But, withal, there are features of 
Macropus not to be overlooked ; the angle of articulation, 
the shape anteriorly and length of the outer condyle, the 
tumid quadratus insertion, and the extracondylar groove. 
