431 



§ 12. Protemnodon Mimas, 0\v. — In this species a greater depth and thickness of 

 mandible and a concomitant larger size of molars are associated with a relatively smaller 

 size of the trenchant premolar, which does not exceed that in Protemnodon Anak. Such 

 character of the variable tooth might be expected, having regard to those which it 

 exhibits in different species of existing Wallabies [Halmaturus, Cuv.). 



In the present large extinct species of Protemnodon a marked modification of the 

 molar teeth accompanies their relative proportions to the premolar, and confirms the 

 taxonomic deductions as to specific status, but does not give ground for assigning thereto 

 subgeneric value. 



The postbasal ridge (Plate LXXXVI. fig 3, g) though narrow is definite ; the pre- 

 basal ridge (ib. f) is proportionately as well developed as in Protemnodon Anak; its 

 " link " (ib. s) also, and that (ib. r) of the two chief lobes, are more distinct than in the 

 type of that species. 



The smaller mandible and teeth (Plate LXXXV. figs. 7 & 8) cannot have come from 

 a younger specimen of the present species; both molars and premolars are more worn, 

 and prove that fossil to have been derived from an older Kangaroo than the animal 

 which owned the subject of the present description. 



The premolar of Protemnodon Mimas ( Plate LXXXVI. fig. 1, p z) shows on the outer 

 side of the intermediate part of its crown five vertical grooves and four ridges, more 

 strongly developed than in Protemnodon Anak ; these are, in part, worn smooth on that 

 side of the tooth of the subject of fig. 7, Plate LXXXV. For the rest, the characters 

 of the premolar of the larger species are those of Protemnodon Anak. 



The crown of d 4, figs. 1-3, has suffered more from fracture than abrasion. A linear 

 tract of dentine is exposed in each transverse lobe of m i, slightly expanding at the 

 origin of the i4 link *' from near the outer end of their anterior surface. Only the 

 enamel shows abrasion in m 2. The crown of m 3 is entire, has but recently risen into 

 place, and, contrasted with that tooth in the subjects of fig. 6 & fig. 13, Plate LXXXV., 

 exemplifies the coronal character of the molars of the present well-marked species. It 

 is partially concealed in a direct outer side view by the coronoid process, q, fig. 1. Plato 

 LXXXVI. 



For this fine evidence of Protemnodon Mimas I am indebted to mv friend Dr. George 

 BENNETT, F.L.S., of Sydney, New South Wales, who obtained it from the freshwater 

 deposits forming the bed of " Gowrie Creek," Darling Downs. 



From the same fertile district, but in another locality (Eton Vale), Sir Daniel Cooper. 

 Bart., received and presented to the British Museum the portions of mandible (Plate 

 LXXXIV. figs. 13 & 14, and Plate LXXXVI. figs. 4 & 5), little, if at all, exceeding in size 

 the corresponding part of that of Macropus major or Macropus rufus. The best-preserved 

 molar in each of these fossils indicated, however, a larger species. This molar, more- 

 over, presented good differential characters in the presence of the well-defined, though 

 small, postbasal ridge (ib. fig. 7, g), the large prebasal ridge (ib. f), and the well- 

 developed and almost equal-sized fore-link (s) and mid-link (r) ; the proportions of the 



44* 



