491 



plates with figures of fragments of bone which cannot with certainty be referred to 

 their species. 



It appears to me to be probable, however, that the relatively shorter bones would 

 belong to animals which had more of the general form of the existing Kangaroos; 

 while the relatively larger humeri, associated with correspondingly proportioned fore 

 limbs, and with a nearer approach to equality with the hind limbs, might have 

 belonged to extinct species which, like the Procoptodonts, made a nearer approach to 

 the equipedal giants of the Diprotodont family. 



The way and degree in which this indication may be pursued will be exemplified in 

 the bones of the hind limb. 



§ 8. Macropus (Femur). — I have received many fossils of thigh-bones, for the most 

 part fragmentary, and here proceed to notice those showing characters of the Macropodal 

 type of femur. These characters have been defined and illustrated (Plate LXXIII.) in 

 that bone of a large male Osphranter rufus. 



Several of the fossils exhibit the large rough depression (ib. y) at the back of the 

 shaft, a little way above the outer condyle (Plate CXIV. figs. 2 & 4, y, Plate CXV. 

 fig. 2, y) ; but some with a shallower pit here (Plate CXV. fig. 3, z) have a smaller 

 depression, and this is in great part filled up, as it were, by a rough thickening of an 

 ascending process of the distal epiphysis, of which a rudiment exists in the first defined 

 series, and is shown in Plate LXXIII. fig. 3, z. 



I commence the special description of the more instructive and better preserved of 

 these femoral fossils by specimens which, retaining the character above referred to in 

 Osphranter rufus, may be inferred to have departed least from the type of such existing 

 large Kangaroos. 



Of these femora an almost entire one, in the same petrified condition as the skull 

 described at p. 436, is from the same freshwater drift in King's Creek. It is of the right 

 side, in length 11 inches 6 lines; but would equal, if not exceed, a foot in length were 

 the summit of the great trochanter entire. The bone is figured, of the natural size, in 

 Plate CXIV., 1\ inches of the middle of the shaft being omitted in figs. 1 and 2 to 

 bring them into the quarto form. The macropodal characters of this fine fossil femur, 

 and the deviations, besides size, from the femur of the largest existing Kangaroos, will 

 be readily appreciated if the above Plate be compared with Plate LXXIII. of the femur 

 of Macropus {Osphranter) rufus. 



A trace of the antero-internal groove, defining in that recent species the super- 

 trochanterian tuberosity, is plain in the fossil at e, figs. 1 & 2, Plate CXIV., where 

 that tuberosity has been broken away. Compared with the femur of Macropus ruf us 

 that of the present fossil shows a relatively wider and shallower concavity (ib. fig. 1, d) 

 between the fore part of the great trochanter and the head (a) of the bone. The 

 " cervix femoris " (b) is relatively thicker. The transverse diameter below the head is 

 relatively greater, mainly through the greater extent of the bone internal to the 



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