■192 



"small trochanter" (ib. fig. 2, n), whereby that outstanding ridge-like process does 

 not appear in a direct front view (ib. fig. 1). The same relative position of n in the 

 femur of Palorchestes Azael (Plate CXV. fig. 1) is also due to the inward extension of 

 the support of the neck and head of the bone. 



The femoral shaft in the present fossil is relatively thicker, especially from before back- 

 ward, than in Macro/nis major and Macr. rufus. The rough depression (Plate CXIV. 

 fig. 4, y) above the outer condyle is relatively larger, deeper, more sharply defined. 

 The inner condyle (ib. figs. 1 & 2, t) has its inner (tibial) border better defined and 

 produced so as to give a slight concavity, transversely, to that half of the back part 

 of the condyle. This character is more marked in Palorchestes (Plate CXV. fig. 2, t) ; 

 but there is no trace of it in the inner femoral condyle of the large existing Kangaroos. 

 The intercondylar notch (u, fig. 2, Plate CXIV.) is narrower and deeper than in 

 M'K-ropus rufus, again repeating a femoral character of Palorchestes, but not in so 

 marked a degree. The ectocondylar pit (ib. fig. 4, v) is equally well marked. 



The broad shallow vertical groove at the back part of the outer condyle, which in 

 Macropod'uhe offers so interesting an approach to the characteristic structure of that 

 part of the thigh-bone in Birds, is well shown in the femur of the fossil Macropus (ib. 

 fig. 2, w) as it is in that of Palorchestes (Plate CXV. fig. 2, w). 



The epiphyses are confluent with the shaft at both ends of the femur, but the line of 

 separation is traceable in the fossil as in the figured femur of Macropus rufus above 

 referred to. 



I may here refer to portions of fossil femora which depart from the type of the two 

 already described by deviating further from the characters of the femur in the existing 

 species of Macropus. The chief difference is in the smaller and shallower depression 

 ( Plate CXV. fig. 2, y) above the outer condyle, such depression being filled up, as it 

 were, in fig. 3, z, by a rough and thick ascending process of the distal epiphysis, of which 

 a rudiment only exists in the femur of the fossil Macropus (Plate CXIV. fig. 4, z) and 

 of Palorchestes Azael (Plate CXV. fig. 2, z). The femora with the larger and longer 

 "clamping process" are thicker in proportion to their length than in the above-cited 

 fossils, and still more so than in the recent Kangaroos. This stronger type is manifested 

 by full-sized or mature femora of three dimensions, of which the distal end of the largest 

 is figured in Plate CXV. fig. 3. I shall at the conclusion of the present Chapter adduce 

 evidence which leads me to deem these fossils to belong to the genus Procoptodon ; and 

 I, provisionally, refer the portion of femur figured and the shorter type of calcaneum in 

 the same Plate (fig. 4) to Procoptodon Goliah. 



§ 9. Palorchestes \ (Femur). — The fossil thigh-bone of which the two extremities are 

 figured in Plate CXV. figs. 1 & 2, shows an articular head (a) fitting the acetabulum 

 of the pelvic fossil (§ 2, Plate CXXX.). The height of the trochanter major (/'), the 

 length and backward position of the narrow trochanter minor (n), the depth of the 

 cavity (/) undermining 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 



