447 



system and in the skull. If the unworn crown of i 1, in Sthenurns Brehus, should show 

 other proportions to the two following incisors than in Sthenurus Atlas, it might tempt 

 a labourer in the ' gattungs-macherei ' to impose a new generic term upon the larger 

 Wallaby. 



§ 17. Protemnodon Mimas (mandibular dentition, continued). — Of this genus and 

 species a portion of a right mandibular ramus, recently received, shows the molar series 

 entire, and from an older animal than that yielding the type-specimen (Plate LXXXV1. 

 figs. 1, 2, 3). The last molar (m 3) is in place with the hinder slope of the ridge of each 

 lobe worn, but not so as to expose the dentine. The narrow postbasal ridge is present 

 as in the type ; m 2 is worn to about the same degree as mi in that specimen (ib. fig. 3) ; 

 m 1 in the present jaw shows a broad field of dentine on each lobe, on a level with the 

 low link. In d 4 the fields are connected by a linear strip of dentine traversing the mid 

 link. A small spot of dentine is exposed on the inner part of the hind swelling of the 

 premolar. 



The dimensions of this molar series, as of the individual teeth, are almost precisely 

 those of the type. The anterior part of the alveolar border of the four anterior teeth 

 swells into a narrow ridge or bead below their bases. A corresponding longitudinal 

 narrow groove is below the ridge, and a little lower down is a second shorter but wider 

 groove. 



This specimen affords satisfactory confirmation of the mandibular dental characters of 

 the species Protemnodon Mimas. 



Another example of the species is afforded by a larger portion of a left mandibular 

 ramus with the base or root of the incisor and the molar series, save the fore end of the 

 premolar. This is from an old, and by the size I believe, male individual, with the 

 dentine exposed on both lobes of the last molar (m 3). The next molar (m 2) has the 

 dentinal lozenges of both lobes united by a linear strip across the low link; a broader 

 bit of dentine is exposed upon the fore link. In m 1, as in d 4, a uniform field of dentine 

 is bounded by a peripheral line of enamel, and no lobes or other characters of the crown 

 are left, the crown being worn down to the stumps. A narrow triangular strip of dentine 

 is exposed on the hinder two thirds of the premolar. The oblique wear of the enamel 

 of the back part of the last molar has destroyed the inner half of the postbasal ridge, 

 but the outer half remains. The bead and groove along the outer alveolar plate are 

 feebly shown ; the lower wider subparallel longitudinal groove is also there. The upper 

 and lower borders of the horizontal ramus are nearly parallel; the depth of the jaw 

 beneath the last molar and beneath the premolar is the same, viz. 1 inch 8 lines. The 

 lower contour of the ramus is straighter, less undulate than in Macropus Titan or 

 Macropus major ; more resembles that in Stlienurus. The upper sharp border of the 

 diastema descends with a less abrupt curve than in Protemnodon Og. The outlet of the 

 dental canal is nearer the vertical line from the fore part of the premolar in the present 

 specimen of Protemnodon Mimas. The symphysis begins, behind, in the same relative 

 position as in Protemnodon Anak ; but it occupies only the lower half of the inner 



