218 
PEOFESSOE OWEN ON THE FOSSIL MAMMALS OF AUSTBALIA. 
In the first group was the upper two thirds of a left fourth metatarsal (Plate 30. 
figs. 7, 8, & 9) with a proximal articular surface of the same breadth as in Macropus 
rufus and Macropus major, but with a markedly thicker shaft, being broader from side 
to side in proportion to the depth from before backward. The smooth tendinal groove 
answering to that marked n in figure 4, Plate 29, on the fore part of the shaft in Macro- 
pus rufus, was bounded in the fossil (which I have noted, for convenience, as from a 
Macropus affinis) by stronger ridge-like risings, and the groove does not reach so far 
down the fibular half of the anterior surface of the bone. On the tibial side of the 
tibial ridge of this groove the fore part of the shaft shows a slight concavity in Macropus 
affinis, whereas in both cited species of the large existing Kangaroos the answering part 
of the metatarsal is transversely convex. At the back part of the proximal third of the 
shaft the rough surface or ridge for muscular attachment is more prominent, better 
defined, yet less extended longitudinally, in the fossil. This specimen is from King’s 
Creek, Darling Downs, Queensland. 
§ 13. Phascolagus altus (Metatarsus). — A right fourth metatarsal (Plate 30. figs. 1-5) 
from the same formation and locality has come from a larger kind of Kangaroo than 
Macropus affinis. It is an inch longer than the subject of figure 4, Plate 29 ( Macropus 
rufus), is relatively thicker, and, like the previous fossil, differs in presenting a stronger 
ridge bounding the fibular side of the anterior surface of the shaft. This part of the 
bone is also more prominent, giving a convexity to the outline of a side view (ib. fig. 3) 
not present in the fourth metatarsal of Macropus major or Macr. rufus*. The present 
fossil likewise shows a relatively broader distal end (ib. fig. 6), which is barely 1 line 
less in transverse diameter than is the proximal end (ib. fig. 5). On this surface, as in 
Macr. rufus and Macr. affinis , the hinder prominence shows the oblique tendinal groove 
(ib. fig. 4, g) and the flat inferior facet ( h ) for the articulation of the large tarsal sesamoidf. 
The fibular or outer side of the proximal end, in both fossils, shows, as in the recent 
Kangaroos, the antero-posteriorly prolonged, bilobed, articular surface (ib. fig. 2, m, n) 
for the side of the head of the fifth metatarsal. Below this surface is the depressed 
rough tract (ib. Jc), continued down nearly three fourths of the back third of the fibular 
side of the shaft, for the ligamentous attachment of the smaller compressed shaft of the 
fifth metatarsal. The posterior ridge in the present metatarsal, which I refer to a 
Phascolagus altus, answering to that marked o' in Plate 29. fig. 6 ( Macropus affinis), is 
continued lower down, nearly to the end of the shaft. The hinder half of the distal 
articular surface (Plate 30. fig. 6) is fashioned by a mid rising into a double trochlea, 
as in existing Kangaroos. 
§ 14. Palorchestes (Metatarsus). — The breadth of the middle of the shaft of the 
fourth metatarsal of Macropus rufus is two thirds that of the same part of the femur. 
The breadth of both fourth and fifth metatarsals, naturally united one third down, is 
nearly equal to three fourths of the breadth of that part of the femur. 
The breadth of the middle of the shaft of the fourth metatarsal, the subject of 
* See figs. 1 & 2 of plate lxxxiii. Zool. Trans, tom. cit. f See Cut, fig. 2, p. 441, Zool. Trans, tom. cit. 
