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worn away by mastication at the period when the animal perished. The 

 smooth and polished exterior of the enamel covering the anterior part of 

 the posterior eminence presents a striking contrast to the reticulo-punc- 

 tate character of the enamel at the corresponding part of the molar in 

 the Diprotodon, which in the general form and proportion of this part 

 of the jaw so closely agrees with the present fossil. The Diprotodon 

 australis exceeded, however, the Nototherium inerme in size, so far as 

 can be judged by the lower jaw and teeth. 



The penultimate and last molar teeth in the present specimen do not 

 exceed in any comparable dimension those in No. 1505, which from the 

 length of the fangs were as completely developed, and belonged there- 

 fore to a mature animal ; but the depth of the jaw below the middle of 

 the penultimate molar in the present fossil is three inches three lines, 

 and in No. 1505 it is only two inches nine lines : the thickest part of 

 the jaw beneath the same molar in No. 1506 is two inches three lines, 

 but in No. 1505 it is one inch eleven lines. In No. 1505, the external 

 wall of the alveolar process immediately swells out to form this thick 

 part of the ramus, but in the present jaw it maintains its thinness for an 

 inch below the margin of the socket ; and the outer part of the jaw is 

 slightly concave here, before it begins to swell into and form the bold 

 convexity which is continued to the thick inferior border of the jaw. 

 This difference in the shape, as well as the size of the jaw, bespeaks at 

 least a specific distinction from No. 1505. But a more marked distinc- 

 tive character in the present fossil is afforded by the relative position of 

 the last molar tooth, which is in advance of the origin or base of the 

 coronoid process, instead of being internal to and hidden by that part 

 when the jaw is viewed from its outer side. The outer surface of the 

 anterior part of the base of the coronoid appears by a fracture there to 

 have projected outwards further in the present specimen than in No. 1505. 



The important marsupial character afforded by the inward bending of 

 the angle of the jaw is well manifested by the present specimen, in which 

 the angle is entire : it is thick, obtuse and inflected, slightly produced in 

 comparison with the Wombat or Kangaroo, but it bounds a well-marked 



