12 ON REMAINS OF AN EXTINCT MARSUPIAL, 



larger one, is shallowly excavated for the reception of the neck of 

 the tooth preceding it — the upper part of the hinder surface of 

 this fang is deeply channelled, as though premonitory of its 

 complete division in the true molars. These characters selectively 

 show marks of affinity with Macropus and Palorchestes on the one 

 hand — with Nototherium and Diprotodon on the other — 

 collectively, they point to some bilophodont form differing from 

 both the genera named. The suggestion is strengthened by an 

 examination of the accompanying incisors. Of these, five out 

 of six are serially represented, the three of the right side more or 

 less in perfection. The front tooth (i) assumes the form of a 

 tusk, but instead of the long, strongly-arched, laterally compressed 

 and deeply channelled fang of a tusk before me, which unmistake- 

 ably belongs to the Nototherium (Mitchelli), the present fossil 

 has its fang short, slightly curved, and moderately compressed fore 

 and aft. It is, moreover, conspicuously striated on the upper part 

 of its fore and hind surfaces, and presents at its fracture, an 

 angularly oval, not the bilobed section of the nototherian tooth. 

 JSTototherian tusks again are widest in the middle of the fang 

 whence they contract slightly in both directions, the fang before 

 us thickens rapidly from the pulp cavity upwards to its junction 

 with the crown, where it attains a diameter of 13 lines. Of the 

 projecting blade nothing can be said. The outer tooth (i 2) is as 

 to its fang similar in proportions and not much less in size, being 

 12 lines in breadth and 9 lines in thickness. In section it is sub- 

 triangular. On the inner surface of the neck is an elongate 

 concave facet adapted to the convex surface of the intermediate 

 incisor. The blade is produced to an extent of 15 J lines in the 

 axis of the tooth, forming a long oval strongly concave near the 

 base and thinning suddenly off towards the apex, which appears to 

 have been trenchant. The second or intermediate tooth is 

 comparatively small, its diameter being but 7 lines ; it has a sub- 

 triangular and slightly convex working surface, and when in place 

 seems little more than an extension of the base of the outer tooth. 

 On the whole the incisor group may be regarded as nototheroid 

 in character ; the incisors and molar together as mi generis. 



