413 



proportions of p 3 and d 4 and their long continuance in line with the following molars. 

 The third tooth (m 1) in the fossil is relatively broader than in Osphranter robustus. 

 The outer side of the diastemal and symphysial part of the mandible is less convex 

 vertically than in Osphranter robustus. The symphysis begins behind in the same 

 relative position to the premolar. I indicate the present fossil Kangaroo by the name 

 of the donor, Sir Daniel Cooper, Bart. ; it was discovered in the freshwater beds of 

 Darling Downs, Queensland. 



§ 5. Osphranter Gouldii, Ow. — The subject of figs. 15 & 16, Plate LXXXIIL, is a cor- 

 responding part of the lower jaw of a young specimen of the same subgenus, but of 

 smaller size. The fossil shows a remnant of the socket of d 2, and the much-worn crown 

 of d 3 ; that of d 4, is also much worn, but not reduced to the degree shown in fig. 18, 

 Plate LXXXIV. To this smaller kind of fossil Wallaroo (Osphranter Gouldii) I have 

 attached the name of the discoverer and founder of the genus. 



§ G. Phascolagus alius, Ow. — Of this species a portion of the upper jaw and teeth 

 was figured in the Palaeontological Appendix to Mitchell's ' Three Expeditions into 

 the Interior of Eastern Australia,' &c, vol. ii. plate xxix. (plate xlvii. of 2nd edition) 

 figs. 4 & 5, with the following remark : — " This specimen I believe to belong to 

 Macropus Titan. The permanent false molar, which is concealed in the upper jaw, is 

 larger than that of the lower jaw of Macropus Titan ; but I have observed a similar 

 discrepancy of size in the same teeth of an existing species of Macropus " (ib. p. 360). 

 Subsequent and closer comparisons have, however, shown that the pattern of the 

 grinding-surface of the upper molars is more like that in Halmaturus and Osphranter 

 than in Macropus major or Macropus Titan ; and the discovery of the upper jaw of the 

 latter species at a corresponding phase of dentition (Plate LXXXI. fig. 6) has shown that, 

 in size and simplicity of form, the upper premolar much more closely accords with the 

 lower one in the type mandible of Macropus Titan (Plate LXXXII. fig. 18) than does 

 the premolar exposed in the specimen under examination (ib. fig. 1). 



These phases of dentition, illustrative of the characters and affinities of the fossil 

 under review, are shown in the specimens Nos. 1741, 1742, and 1743, in the Osteo- 

 logical Series of the Museum of the Royal College of Surgeons of England*, and are 

 illustrated in Plate LXXX. figs. 1-12 of the present Paper. In the recent species 

 (Macropus (Phascolagus) erubescens) the upper premolar (ib. fig. Q,p 3), in its form and 

 proportions, still more closely resembles that (Plate LXXXII. fig. l,p*) of the larger 

 extinct Kangaroo (Phascolagus altus) of the Wellington Valley Bone-cave. 



This species combines with the proportion of the premolar, affording one of the cha- 

 racters of the subgenus Halmaturus, the entire or imperforate bony palate, which is 

 found in all the species of Macropus in its restricted or subgeneric sense (ib. fig. 2). In 

 this combination of characters the fossil agrees with the existing Phascolagus erubescens. 



The degree of development of the concealed premolar, the crown being completed 

 with the basal portions of both roots, coincides, as in Phascolagus erubescens, with the 



* Osteological Catalogue, 4to, 1853, p. 324. 



42 



