202 
PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
mining the hind extension of the great trochanter, and the ridge (p) at the back part 
of the upper half of the shaft, bespeak the macropodal characters of the present fossil 
in the upper portion of the hone, as the partial division of the outer condyle (fig. 2, v) 
by the channel ( w ), and the deep rough oblong fossa (y) above that condyle, do in the 
lower portion *. 
Guided by the proportions of the femur in Macropus major and Macropus rufus, 1 
estimate the subject of fig. 1, Plate 23, to include the proximal third of that bone in 
Palorchestes Azael ; and suspect, as the upper portion of the great trochanter is still 
epiphysial, or but partially united to the shaft, that this thigh-bone may have come 
from a not fully mature individual. 
As in Macropits rufus the extreme breadth of the proximal end of the femur exceeds 
that of the distal end by 3 lines, I estimate the difference in those admeasurements of 
the ends of the fossil femur in Plate 23 to be within the limits of individual character 
in Palorchestes , the breadth of the shaft, where broken across, in both upper and 
lower portions being the same ; and the circumference in both is 5 inches. The some- 
what larger proportional proximal end, due to the development of the great trochanter, 
may be taken as one of the differential characters of the present huge femur as com- 
pared with that bone in the largest living Kangaroos. 
The great trochanter is continued as a strong ridge (ib. fig. 1, g) 5^ inches along the 
outer border of the bone ; but the trochanter itself (/') is, relatively, less raised above 
the head ( a ) than in Macropus major. The articular surface of the head is less convex 
than in Macropus rufus, and the anterior concavity between it and the trochanter is 
less marked. The demarcation of the summit of the trochanter by the antero-internal 
channel is more feebly given in Palorchestes. The upper surface of the neck of the 
femur (c) is relatively broader in Palorchestes than in Macropus. 
The lesser trochanterian ridge (n) is more posterior in position than in Macropus 
rufus , in which its free margin just comes into view when the femur is seen from the 
front f ; this is not the case in Palorchestes, in which the ridge descends to the parallel 
of the beginning of the posterior ridge, which resembles at its most prominent part (p) 
a third trochanter J. The trochanterian fossa (fig. 1, l) has the extreme generic or 
family depth in Palorchestes ; it forms a long narrow cavity, undermining the hinder 
basal part of the great trochanter. 
From the summit of this trochanter (f) to the third trochanter (p) being 6-| inches, 
the total length of the femur of Palorchestes may be reckoned, from the analogy of 
Macropus rufus, to have been not less than 18 inches; in that recent species it is 
10^ inches. The epiphysial line of the great trochanter is distinct, but confluence of 
the central part has kept the process in place in the present fossil. 
The upper end of the linea aspera is preserved, expanding to form the process^?. 
* See the characters of the femur of Macropus described and figured in the Mem. cit. in Trans. Zool. Soc. 
vol. ix. p. 437, plate lxxxi. 
t Mem. cit. tom. cit. plate lxxxi. fig. 1, n. 
X See ibid. fig. 2, p, in OspTiranter rufus. 
