498 



§ 10. Macropus affinis (Metatarsal ir). — Of this extinct Kangaroo I select for 

 description and figuring a fossil referable to the upper two thirds of a left fourth 

 metatarsal (Plate CXVI. fig. 0, and Plate CXVII. figs. 7 & 9) with a proximal articular 

 surface (fig. 9) 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 CXVI., on the fore part of the shaft in Macropus rvfus, is bounded in 

 the fossil 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. 

 \\ In Teas 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 (Plate CXVI. fig. G, o) is more 

 prominent, better defined, yet less extended longitudinally, in the fossil. This speci- 

 men is from King's Creek, Darling Downs, Queensland. 



§ 17. Pliascolagus alius (Metatarsal zr). — A right fourth metatarsal (Plate CXVII. 

 figs. 1-5), from the same formation and locality, has come from a larger kind of Kan- 

 garoo than Macropus affinis. It is an inch longer than the subject of figure 4, Plate 

 CXVII. (Macropus rufus), is relatively thicker, and, like the previous fossil, differs in 

 presenting a stronger ridge (Plate CXVII. fig. 1, r) 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, r) not present in the fourth metatarsal 

 of Macropus major or Osphranter 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. A,g) and the flat inferior 

 facet (h) for the articulation of the large tarsal sesamoid (Cut, fig. 3, p. 391). 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. k), 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 

 Pliascolagus alius, answering to that marked o' in Plate CXVI. fig. 6 (Macropms affinis), 

 is continued lower down, nearly to the end of the shaft. The hinder half of the distal 

 articular surface (Plate CXVII. fig. 6) is fashioned by a mid rising into a double 

 trochlea, as in existing Kangaroos. 



§ 18. Protemnodon Anak (Metatarsal zr). — The metatarsal referred to this species 

 (Plate CXX.) combines equality of length with that of Macropus (Ospliranier) rufus 

 (Plate CXVI. figs. 4 & 5), and a greater antero-posterior thickness of shaft with greater 

 breadth of the distal portion of the bone (compare Plate CXX. fig. 1, with Plate CXVI. 



