500 



side of the proximal end of the fourth metatarsal by a surface which is extended by the 

 backwardly directed process (ib. fig. 2, c). Below the articular head (ib. a—c) the shaft 

 narrows and becomes compressed in its upper third, below which it assumes a subtri- 

 hedral figure, with a trenchant margin both before and behind along its upper fourth. 



The shaft does not exceed 2 lines in breadth at the point of fracture (d). The bone 

 closely adheres, either by anchylosis or matrix, to the shaft of the great fourth meta- 

 tarsal, inclining from the inner (tibial) side to the plantar aspect of the shaft, as does 

 the corresponding metatarsal in Macropus rufus (Plate LXXV. fig. 1, in). The 

 proximal articular surface of the fourth metatarsal (Plate CXVI. fig. 3, iv) presents 

 an undulating tract adapted to the distal surface of the cuboid ; its broadest rotular 

 (anterior) half is gently convex transversely at the fibular half, concave at the tibial 

 half; the narrower plantar or posterior subquadrate tract is feebly concave rotulo- 

 plantad, almost level transversely ; this tract extends plantad, or backward, so as to 

 overhang the shaft; it is grooved at e, fig. 3, by the "peroneus" tendon, which runs 

 across the back or under (plantar) aspect of the tarsus to be inserted into the ento- 

 cuneiform bone ; also, as in existing Kangaroos and in Macropus affinis, it has a flat 

 articular surface at the underside of the overhanging part for the large tarsal sesamoid. 

 The inner or tibial side of the proximal end of the fourth metatarsal shows the two 

 small vertical facets for the ectocuneiform, and a well-marked rough depression for the 

 proximal ends of the third and second slender metatarsals. 



The shaft of the great metatarsal of Palorchestes is subtrihedral ; the rotular surface 

 (ib. fig. 1, iv) is slightly concave transversely along its middle third as in Macropus 

 Titan, not prominent as in Macropus rufus (ib. fig. 4). The plantar side (ib. fig. 2) is 

 produced into a ridge, broad along the upper third (o), becoming sharper (h, h) as it 

 descends, and subsiding about one half of the length of the bone (o') from the distal 

 end. The corresponding portion of the metatarsal of Macropus rufus (ib: fig. 6) is 

 widely channelled where in the fossil it is angularly convex. The greatest rotulo- 

 plantar thickness of the shaft in Palorchestes is 1 inch 4 lines, the greatest transverse 

 thickness is 1 inch; that of the proximal end is 1 inch 6 lines, its rotulo-plantar thick- 

 ness is 1 inch 5 lines. 



The fifth metatarsal of Palorchestes Azael (Plate CXVI. figs. 1, 2, 3, r) is relatively 

 much stronger than in Macropus major or Macr. rufus (ib. fig. 4, r). The plantar part 

 of the proximal end, broken away in the fossil figured, is entire in a later acquired 

 homologous bone of Palorchestes. This presents a small, oval, flat, vertical surface for 

 the fourth metatarsal, a broader subtriangular one for the backwardly extended process 

 of the cuboid (Plate LXXV. fig. 11, k), and a larger horizontal facet for the surface, 

 marked I, of the same tarsal bone. The proximal articular surface of the fifth meta- 

 tarsal is very small in proportion to the bone in Palorchestes. External (fibulad) to that 

 surface the bone rises above the proximal end of the fourth metatarsal in the form of an 

 antero-posteriorly extended thick round edge. 



The shaft of the fifth metatarsal is subcompressed along the proximal three fourths; 



