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individual, probably female. Photographs of both these specimens, now in the Museum 

 of Natural History, Sydney, New South Wales, have been transmitted to me by direction 

 of the Trustees of the Museum. 



Of Nototherium inerme I have the entire molar series of both sides of the upper jaw ; 

 with sufficient of that part of the skull to demonstrate its generic concordance with the 

 more complete specimen of the skull of the type-species in the Museum at Sydney. 



From these materials the characters of the upper molars of the present genus can be 

 satisfactorily given. 



The series of five molars in the entire skull [Plate XXXVI. fig. 1, Plate XXXVII. 

 fig. 3 (reduced), Plate XLIII. figs. 3 & 4, nat. size] occupies an alveolar extent of 7 

 inches 2 lines ; it describes a slight convexity downward and also outward, the right 

 and left series converging anteriorly (Plate XXXVII. fig. 3) in a rather greater degree 

 than in Liprotodon. The interval between the anterior lobes of the right and left last 

 molars (ma) is 2 inches 3 lines; that between the first small molars (da) is 2 inches. 

 As in Diprotodon, the inner end of the front lobe of each two-ridged molar projects 

 inward beyond the inner surface or contour of the antecedent tooth ; but the hind lobe 

 does not project so far beyond the level of the front lobe of the succeeding tooth as in 

 Diprotodon. 



The first upper molar (d 3 ) may be said to be two-lobed, but is divided in an opposite 

 direction to that in the rest of the series ; viz. into an outer and an inner, rather than a 

 front and a back, lobe. The working-surface is sub triangular in form, the angles 

 obtusely rounded, measuring in fore-and-aft extent 1 inch 1 line in the male Nototherium 

 Mitehelli (Plate XLIII. figs. 3 & 4, d a) ; the transverse diameter, posteriorly, is 11 lines. 

 The outer lobe or division is the chief one, and constitutes the outer two thirds and the 

 whole fore-and-aft extent of the tooth ; the outer side of its base swells out like part 

 of a cingulum or ridge ; the summit is subcompressed, and seems to have been trituber- 

 culate ; the inner and lower division consists of a larger hind tubercle and a smaller front 

 one. On the whole, therefore, the tooth approaches the subsectorial type of its homologue 

 in the Koala (Phascolarctos, p. 153, fig. 6, p *) l it is implanted by two roots, one behind 

 the other, the posterior being the largest and grooved anteriorly, as if preparatory to 

 further transverse subdivision. 



The second molar (Plate XLIII. figs. 3 & 4, d i) has a subquadrate working-surface, 

 divided into two transverse wedge-shaped lobes (a, b), with an anterior (f) and a posterior 

 (g) basal ridge ; the latter is the thickest, and developes a small tuberosity at its outer end. 

 This ridge is continued upon the outer and inner borders of the hind surface of the hind 

 lobe, and further upon the outer than the inner one. A short ridge closes the outer and 

 inner ends of the transverse valley. The antero-posterior diameter of the crown is 1 inch 

 1 line, as is likewise the transverse diameter of the broadest part of the tooth. The 

 direction of the summits of the two lobes is downward and a little forward ; they run 

 across the tooth rather more obliquely than in Diprotodon (Plate XXI. fig. 2, d 4), but 

 with a similar curve of the apical ridge slightly concave backward. The less exposed 



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