PROFESSOR OWEN ON THE FOSSIL MAMMALS OF AUSTRALIA. 
261 
§ 4. Ospliranter Cooperi, Ow. — The subject of figs. 17 & 18, Plate XXIV., is the fore 
part of the left mandibular ramus of an aged individual of a W allaroo, of the size of 
Ospliranter robustus. It retains the first three molars (p 3 , d 4 , in i), the second of which, 
as having been longest in place, has the crown worn down to its base, from within 
obliquely outwards, and in a rather greater degree than in the corresponding tooth of 
the recent species compared, the mandible of which is the subject of fig. 13, Plate XX. 
The premolar (p 3) shows three small tubercles on its working-surface, arranged from before 
backward ; the crown is subcompressed, and very slightly thickened behind ; the inner 
surface of the fore part of the crown is gibbous, as in Ospliranter , and its proportions 
are as in Ospliranter robustus. The degree of wear of the next tooth is such as would 
be incompatible with the retention of the foremost if it were the deciduous tooth, d 2 ; 
but, for decisive evidence, I removed the inner wall of the ramus where the germ of p 3 
would have been, and there was no trace of such successional tooth. The present 
fossil, therefore, has come from a fully mature individual. A species of true Macropus 
would not have retained the premolar or the following tooth at this age, or have kept 
d 4 with a crown so far worn down. Thus the fossil accords with Ospliranter in the 
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 Ospliranter robustus. 
The outer side of the diastemal and symphysial part of the mandible is less convex 
vertically than in Ospliranter 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. Ospliranter Gouldii, Ow. — The subject of figs. 15 & 16, Plate XXIII., is a corre- 
sponding part of the lower jaw of a young specimen of the same sub genus, 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 XXIV. To this smaller kind of fossil Wallaroo ( Ospliranter Gouldii ) I have 
attached the name of the discoverer and founder of the genus. 
§ 6. Phascolagus altus , Ow. — Of this species a portion of the upper jaw and teeth 
was figured in the Palseontological 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 Ospliranter 
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 XXI. fig. 6) has shown that, in 
size and simplicity of form, the upper premolar much more closely accords with the 
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